Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-30 (of 52 Records) |
Query Trace: Flanders WD [original query] |
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Medicaid expansion and health care use among adults with asthma and low incomes: The Adult Asthma Call-Back Survey
Qin X , Mirabelli MC , Flanders WD , Hsu J . Public Health Rep 2024 333549241228501 OBJECTIVES: Asthma disproportionately affects Black people and people with low incomes, but Medicaid expansion (hereinafter, expansion) data on these populations are limited. We investigated health care use among adults with asthma, before and after expansion, and examined whether asthma-related health care use after expansion varied by demographic characteristics. METHODS: We analyzed data from the 2011-2013 and 2015-2019 Behavioral Risk Factor Surveillance System Adult Asthma Call-Back Survey on participants aged 18-64 years with current asthma and low incomes in 23 US states. We assessed 5 asthma-related outcomes, including medical visits (routine and emergency) and medication use, for expansion and nonexpansion groups. We used t tests to compare weighted percentages and 95% CIs, then performed adjusted difference-in-differences analyses. Secondary analyses stratified data by race, ethnicity, and sex. RESULTS: Primary analyses (N = 10 796) found no significant associations between expansion and any outcome. Analyses stratified by race and ethnicity found no significant changes (eg, asthma controller medication use among non-Hispanic Black participants in the expansion group was 24.1% [95% CI, 14.4%-37.5%] in 2011-2013 and 35.5% [95% CI, 27.0%-45.1%] in 2015-2019; P = .13). Use of asthma controller medication increased significantly among non-Hispanic Other participants in the nonexpansion group (2011-2013: 16.0% [95% CI, 9.5%-25.5%]; 2015-2019: 40.2% [95% CI, 25.5%-56.8%]; P = .01). Asthma-related hospitalizations decreased significantly among women in the expansion group: 2011-2013 (7.8%; 95% CI, 5.3%-11.3%) and 2015-2019 (3.5%; 95% CI, 2.5%-4.9%) (P = .009). CONCLUSIONS: Investigating factors other than health insurance (eg, social determinants of health) that influence the use of asthma-related health care could advance knowledge of potential strategies to advance health equity for adults with asthma and lower incomes. |
Ambient air quality and fatal asthma exacerbations among children in North Carolina
Mirabelli MC , Flanders WD , Vaidyanathan A , Beavers DP , Gower WA . Epidemiology 2023 34 (6) 888-891 BACKGROUND: Little is known about the role of air quality in fatal asthma exacerbations among children. METHODS: We collected information about 80 deaths that occurred in North Carolina from 2001 through 2016, among children aged 5-17 years, with asthma identified as the primary cause of death. We linked information about each death with county-level estimates of particulate matter ≤2.5 µm (PM2.5) and ozone (O3). Using the linked data, we conducted a case-crossover analysis of associations between PM2.5 and O3 lagged by 3-5 days with the odds of fatal asthma exacerbations. RESULTS: In the highest tertile of PM2.5 lag(3-5), the odds of a fatal exacerbation of asthma were more than twice the odds in the lowest tertile (odds ratio = 2.2; 95% confidence interval = 1.1, 4.6). CONCLUSION: These findings from North Carolina provide evidence to support the hypothesis that ambient air pollution increases the risk of fatal exacerbations of asthma among children. |
Using randomized controlled trials to estimate the effect of community interventions for childhood asthma
Flanders WD , Nurmagambetov TA , Cornwell CR , Kosinski AS , Sircar K . Prev Chronic Dis 2023 20 E44 INTRODUCTION: The Centers for Disease Control and Prevention's Controlling Childhood Asthma and Reducing Emergencies initiative aims to prevent 500,000 emergency department (ED) visits and hospitalizations within 5 years among children with asthma through implementation of evidence-based interventions and policies. Methods are needed for calculating the anticipated effects of planned asthma programs and the estimated effects of existing asthma programs. We describe and illustrate a method of using results from randomized control trials (RCTs) to estimate changes in rates of adverse asthma events (AAEs) that result from expanding access to asthma interventions. METHODS: We use counterfactual arguments to justify a formula for the expected number of AAEs prevented by a given intervention. This formula employs a current rate of AAEs, a measure of the increase in access to the intervention, and the rate ratio estimated in an RCT. RESULTS: We justified a formula for estimating the effect of expanding access to asthma interventions. For example, if 20% of patients with asthma in a community with 20,540 annual asthma-related ED visits were offered asthma self-management education, ED visits would decrease by an estimated 1,643; and annual hospitalizations would decrease from 2,639 to 617. CONCLUSION: Our method draws on the best available evidence from RCTs to estimate effects on rates of AAEs in the community of interest that result from expanding access to asthma interventions. |
Large-scale agricultural burning and cardiorespiratory emergency department visits in the U.S. state of Kansas
Pennington AF , Vaidyanathan A , Ahmed FS , Manangan A , Mirabelli MC , Sircar KD , Yip F , Flanders WD . J Expo Sci Environ Epidemiol 2023 33 (4) 663-669 BACKGROUND: Prescribed agricultural burning is a common land management practice, but little is known about the health effects from the resulting smoke exposure. OBJECTIVE: To examine the association between smoke from prescribed burning and cardiorespiratory outcomes in the U.S. state of Kansas. METHODS: We analyzed a zip code-level, daily time series of primary cardiorespiratory emergency department (ED) visits for February-May (months when prescribed burning is common in Kansas) in the years 2009-2011 (n = 109,220). Given limited monitoring data, we formulated a measure of smoke exposure using non-traditional datasets, including fire radiative power and locational attributes from remote sensing data sources. We then assigned a population-weighted potential smoke impact factor (PSIF) to each zip code, based on fire intensity, smoke transport, and fire proximity. We used Poisson generalized linear models to estimate the association between PSIF on the same day and in the past 3 days and asthma, respiratory including asthma, and cardiovascular ED visits. RESULTS: During the study period, prescribed burning took place on approximately 8 million acres in Kansas. Same-day PSIF was associated with a 7% increase in the rate of asthma ED visits when adjusting for month, year, zip code, meteorology, day of week, holidays, and correlation within zip codes (rate ratio [RR]: 1.07; 95% confidence interval [CI]: 1.01, 1.13). Same-day PSIF was not associated with a combined outcome of respiratory ED visits (RR [95% CI]: 0.99 [0.97, 1.02]), or cardiovascular ED visits (RR [95% CI]: 1.01 [0.98, 1.04]). There was no consistent association between PSIF during the past 3 days and any of the outcomes. SIGNIFICANCE: These results suggest an association between smoke exposure and asthma ED visits on the same day. Elucidating these associations will help guide public health programs that address population-level exposure to smoke from prescribed burning. |
Changes in asthma emergency department visits in the United States during the COVID-19 pandemic
Ye D , Gates A , Radhakrishnan L , Mirabelli MC , Flanders WD , Sircar K . J Asthma 2023 60 (8) 1-8 OBJECTIVE: A better understanding of the impacts of the Coronavirus disease 2019 (COVID-19) pandemic on emergency department (ED) visits for asthma is needed to improve asthma control. METHODS: Using data from the National Syndromic Surveillance Program (NSSP), we assessed changes in average weekly asthma ED visits in the United States in 3 surveillance periods: (1) March 15, 2020-January 2, 2021; (2) January 3, 2021-January 1, 2022; and (3) January 2-March 5, 2022, relative to pre-pandemic comparison periods between December 30, 2018 and December 28, 2019. For each surveillance period, we assessed changes in asthma ED visits by age group and sex. RESULTS: For the surveillance period beginning March 15, 2020, average weekly asthma ED visits declined 31% relative to what was observed during the comparison period - that is, from 45,276 visits/week in 2019 to 31,374 visits/week in 2020. Declines of over 19% and 26% were observed for 2021 and 2022, respectively, relative to the comparison periods. In all surveillance periods, the largest declines occurred among children, especially those ages 0-4 (74%) and 5-11 (66%) years. CONCLUSIONS: The COVID-19 pandemic impacted asthma ED visits in the United States. The impact was greater among children than adults, as ED visits among children were notably lower during all three pandemic surveillance periods than during the corresponding pre-pandemic periods. Additional information about the roles of behaviors of patients with asthma and changes in asthma care might improve our understanding of the reasons underlying these observed changes. |
Maternal dietary patterns during pregnancy and exposure to persistent endocrine disrupting chemicals in two European birth cohorts
Marks KJ , Northstone K , Papadopoulou E , Brantsæter AL , Haug LS , Howards PP , Smarr MM , Flanders WD , Hartman TJ . Environ Adv 2021 6 Food consumption, particularly of animal-based products, is considered the most important contributor to persistent endocrine disrupting chemical (EDC) exposure. This study aims to describe the association between maternal diet during pregnancy and exposure to persistent EDCs using dietary pattern analysis. This study is based on subsamples of the Avon Longitudinal Study of Parents and Children (ALSPAC) (N=422) and the Norwegian Mother, Father, and Child Cohort Study (MoBa) (N=276) which uses data from the Medical Birth Registry of Norway (MBRN). Women in both studies completed food frequency questionnaires (FFQs) during pregnancy, from which consumption data were categorized into 38 aggregated food groups. Maternal blood samples were collected during pregnancy and concentrations of perfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in serum/plasma were measured. Dietary patterns were identified using reduced rank regression, with blood EDC concentrations as response variables. Within ALSPAC, all patterns (PFAS, PCB, and OCP) were characterized by high consumption of meat, poultry, white fish, and biscuits. In MoBa, high consumption of sausages and burgers (representing processed meats), pasta, and chocolate bars characterized PCB and OCP dietary patterns, while high consumption of cheese characterized the PFAS pattern. Across both cohorts, PFAS patterns were characterized by high consumption of cheese, PCB patterns by high consumption of rice, and OCP patterns by poultry. Dietary patterns explained between 8 and 20% of the variation in serum EDC concentrations, with explained variance being the highest for PCBs in both cohorts. In conclusion, dietary patterns high in animal-based products appear to be associated with persistent EDC concentrations among pregnant women. Diet explains more variation in PCB concentrations than for other persistent EDC classes. © 2021 |
Clinical outcomes among hospitalized US adults with asthma or chronic obstructive pulmonary disease, with or without COVID-19.
Cornwell CR , Hsu J , Tompkins LK , Pennington AF , Flanders WD , Sircar K . J Asthma 2021 59 (12) 1-16 Objective: This study assesses the risk of severe clinical outcomes during hospitalizations of adults with asthma and/or COPD plus COVID-19 and compares those risks with those during hospitalizations of adults with asthma and/or COPD without COVID-19.Methods: We used data from 877 U.S. hospitals from the Premier Healthcare Database during March 2020-March 2021. Hospitalizations (n = 311,215) among patients aged ≥18 years with an ICD-10-CM diagnosis involving asthma or COPD were classified into three groups: adults with asthma (but not COPD), adults with COPD (but not asthma), and adults with both asthma and COPD. We used multivariable Poisson regression to assess associations of severe clinical outcomes [intensive care unit (ICU) admission, use of invasive mechanical ventilation (IMV), and death] and COVID-19 status.Results: The percentage of hospitalizations among patients with asthma and COVID-19 resulting in ICU admission, IMV, and death were 46.9%, 14.0%, and 8.0%, respectively. These risks were higher than those among patients with asthma without COVID-19 (adjusted risk ratio [aRR], 1.17 [95% confidence interval (CI), 1.14-1.21], 1.61 [95% CI, 1.50-1.73], and 5.56 [95% CI, 4.89-6.32]), respectively. Risks of ICU admission, IMV, and death were also high among patients with COPD and COVID-19 and exceeded the corresponding risks among patients with COPD without COVID-19.Conclusion: Hospitalizations among patients with asthma and/or COPD with COVID-19 had a more severe clinical course than hospitalizations for asthma and/or COPD exacerbations without COVID-19. |
Prenatal exposure to mixtures of persistent endocrine disrupting chemicals and postnatal body size in British girls
Marks KJ , Howards PP , Smarr MM , Flanders WD , Northstone K , Daniel JH , Sjödin A , Calafat AM , Hartman TJ . Early Hum Dev 2021 161 105450 BACKGROUND: Endocrine disrupting chemical (EDC) exposure is ubiquitous. EDC exposure during critical windows of development may interfere with the body's endocrine system, affecting growth. Previous human studies have examined one EDC at a time in relation to infant growth. By studying mixtures, the human experience can be better approximated. AIMS: We investigated the association of prenatal exposure to persistent EDCs (per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs)) as mixtures with postnatal body size among female offspring. SUBJECTS: We used a sub-sample of the Avon Longitudinal Study of Parents and Children (N = 425), based in the United Kingdom. STUDY DESIGN: We quantified 52 EDCs in maternal serum collected during pregnancy. We used Bayesian kernel machine regression with a random intercept to examine the association of prenatal concentrations of EDC mixtures with longitudinal postnatal body size measures for each EDC class separately (PFAS, PCBs, and OCPs) and for all three classes combined. OUTCOME MEASURES: Weight and height measures at 0, 2, 9, and 19 months were obtained by health professionals as part of routine child health surveillance. RESULTS: The mixture representing all three classes combined (31 chemicals) (n = 301) was inversely associated with postnatal body size. Holding all EDCs in the 31-chemical mixture at the 75th percentile compared to the 50th percentile was associated with 0.15 lower weight-for-age z-score (95% credible interval -0.26, -0.03). Weak inverse associations were also seen for height-for-age and body mass index-for-age scores. CONCLUSIONS: These results suggest that prenatal exposure to mixtures of persistent EDCs may affect postnatal body size. |
Asthma-Related Emergency Department Visits in North Carolina Following Hurricane Irene
Cowan KN , Pennington AF , Sircar K , Flanders WD . Disaster Med Public Health Prep 2021 17 1-4 OBJECTIVE: Previous research suggests that people with asthma may experience a worsening of symptoms following hurricanes due to changes in environmental exposures, discontinuity in chronic disease management, and stress. The objective of this study was to estimate changes in asthma-related emergency department (ED) visits in North Carolina following Hurricane Irene, which made landfall in August 2011. METHODS: Changes in asthma-related ED visits in September to December of 2010 and 2011 were examined using data from the Healthcare Cost and Utilization Project State Emergency Department and Inpatient Databases. A Poisson generalized linear model was used to estimate the association between Federal Emergency Management Agency disaster declarations following Hurricane Irene and county-level asthma-related ED visits controlling for month, year, and county. RESULTS: Following Hurricane Irene, disaster declarations were made for 38 of 100 counties in North Carolina. In September 2010, the rate of asthma-related ED visits for North Carolina was 6 per 10,000 person-months. In September 2011, rates of asthma-related ED visits were similar in counties with and without disaster declarations (7 and 5 per 10,000 person-months, respectively). When adjusting for covariates, there was little or no difference in the rate of asthma ED visits before and after the hurricane between counties with and without a disaster declaration (rate ratio {RR} [95% confidence interval {CI}] = 1.02[0.97, 1.08]). CONCLUSIONS: Although risk factors for asthma exacerbations increase following hurricanes, these results found little evidence of an increase in asthma-related ED visits in North Carolina following Hurricane Irene. |
Prenatal exposure to mixtures of persistent endocrine-disrupting chemicals and birth size in a population-based cohort of British girls
Marks KJ , Howards PP , Smarr MM , Flanders WD , Northstone K , Daniel JH , Sjödin A , Calafat AM , Hartman TJ . Epidemiology 2021 32 (4) 573-582 BACKGROUND: Previous studies of endocrine-disrupting chemicals have examined one of these chemicals at a time in association with an outcome; studying mixtures better approximates human experience. We investigated the association of prenatal exposure to mixtures of persistent endocrine disruptors [per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), and organochlorine pesticides] with birth size among female offspring in the Avon Longitudinal Study of Parents and Children (ALSPAC), based in the United Kingdom in 1991-1992. METHODS: We quantified concentrations of 52 endocrine-disrupting chemicals in maternal serum collected during pregnancy at median 15 weeks' gestation. Birth weight, crown-to-heel length, and head circumference were measured at birth; ponderal index and small for gestational age were calculated from these. We used repeated holdout weighted quantile sum regression and Bayesian kernel machine regression to examine mixtures in 313 mothers. RESULTS: Using weighted quantile sum regression, all mixtures (each chemical class separately and all three together) were inversely associated with birth weight. A one-unit increase in WQS index (a one-decile increase in chemical concentrations) for all three classes combined was associated with 55 g (β: -55 g, 95% CI: -89, -22 g) lower birth weight. Associations were weaker but still inverse using Bayesian kernel machine regression. Under both methods, PFAS were the most important contributors to the association with birth weight. We also observed inverse associations for crown-to-heel length. CONCLUSIONS: These results are consistent with the hypothesis that prenatal exposure to mixtures of persistent endocrine-disrupting chemicals affects birth size. |
Prepregnancy body mass index and spina bifida: Potential contributions of bias
Johnson CY , Honein MA , Rasmussen SA , Howards PP , Strickland MJ , Flanders WD . Birth Defects Res 2021 113 (8) 633-643 BACKGROUND: Epidemiologists have consistently observed associations between prepregnancy obesity and spina bifida in offspring. Most studies, however, used self-reported body mass index (potential for exposure misclassification) and incompletely ascertained cases of spina bifida among terminations of pregnancy (potential for selection bias). We conducted a quantitative bias analysis to explore the potential effects of these biases on study results. METHODS: We included 808 mothers of fetuses or infants with spina bifida (case mothers) and 7,685 mothers of infants without birth defects (control mothers) from a population-based case-control study, the National Birth Defects Prevention Study (1997-2011). First, we performed a conventional epidemiologic analysis, adjusting for potential confounders using logistic regression. Then, we used 5,000 iterations of probabilistic bias analysis to adjust for the combination of confounding, exposure misclassification, and selection bias. RESULTS: In the conventional confounding-adjusted analysis, prepregnancy obesity was associated with spina bifida (odds ratio 1.4, 95% confidence interval: 1.2, 1.7). In the probabilistic bias analysis, we tested nine different models for the combined effects of confounding, exposure misclassification, and selection bias. Results were consistent with a weak to moderate association between prepregnancy obesity and spina bifida, with the median odds ratios across the nine models ranging from 1.1 to 1.4. CONCLUSIONS: Given our assumptions about the occurrence of bias in the study, our results suggest that exposure misclassification, selection bias, and confounding do not completely explain the association between prepregnancy obesity and spina bifida. |
Prenatal exposure to mixtures of persistent endocrine disrupting chemicals and early menarche in a population-based cohort of British girls
Marks KJ , Howards PP , Smarr MM , Flanders WD , Northstone K , Daniel JH , Calafat AM , Sjödin A , Marcus M , Hartman TJ . Environ Pollut 2021 276 116705 Exposure to endocrine disrupting chemicals (EDCs) is ubiquitous. EDC exposure, especially during critical periods of development like the prenatal window, may interfere with the body's endocrine system, which can affect growth and developmental outcomes such as puberty. Most studies have examined one EDC at a time in relation to disease; however, humans are exposed to many EDCs. By studying mixtures, the human experience can be more closely replicated. We investigated the association of prenatal exposure to persistent EDCs (poly- and perfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs)) as mixtures with early menarche among female offspring in a nested case-control study within the Avon Longitudinal Study of Parents and Children (ALSPAC) recruited in the United Kingdom in 1991-1992. Concentrations of 52 EDCs were quantified in maternal serum samples collected during pregnancy. Daughter's age at menarche was ascertained through mailed questionnaires sent annually. We used repeated holdout weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) to examine the association between prenatal exposure to multiple EDCs and early menarche (<11.5 (n = 218) vs. ≥11.5 years (n = 230)) for each chemical class separately (PFAS, PCBs, and OCPs) and for all three classes combined. Models adjusted for maternal age at menarche, maternal education, parity, pre-pregnancy body mass index, maternal age, prenatal smoking, and gestational week at sample collection. Mixture models showed null associations between prenatal exposure to EDC mixtures and early menarche. Using WQS regression, the odds ratio for early menarche for a one-decile increase in chemical concentrations for all three classes combined was 0.89 (95% CI: 0.76, 1.05); using BKMR, the odds ratio when all exposures were at the 60th percentile compared to the median was 0.98 (95% CI: 0.91, 1.05). Results suggest the overall effect of prenatal exposure to persistent EDC mixtures is not associated with early menarche. |
Medicaid expansion, health insurance coverage, and cost barriers to care among low-income adults with asthma: The Adult Asthma Call-Back Survey
Hsu J , Qin X , Mirabelli MC , Flanders WD . J Asthma 2020 58 (11) 1-15 Objective: To examine Medicaid expansion (ME) effects on health insurance coverage (HIC) and cost barriers to medical care among people with asthma.Method: We analyzed 2012-2013 and 2015-2016 data from low-income adults with current asthma aged 18-64 years in the Behavioral Risk Factor Surveillance System Asthma Call-Back Survey (state-level telephone survey). We calculated weighted percentages and 95% confidence intervals from ME and non-ME jurisdictions (according to 2014 ME status). Outcomes were HIC and cost barriers to buying asthma medication (MED), seeing a health care provider for asthma (HCP), or any asthma care (AAC). Using SUDAAN, we performed survey-weighted difference-in-differences analyses, adjusting for demographics. Subgroup analyses were stratified by demographics.Results: Our study population included 6445 participants from 25 states plus Puerto Rico. In 2015-2016 compared to 2012-2013, HIC was more common in ME jurisdictions (P < 0.001) but unchanged in non-ME jurisdictions. Adjusted difference-in-differences analyses showed ME was associated with a statistically significant 13.36 percentage-point increase in HIC (standard error =0.053). Cost barriers to MED, HCP, and AAC did not change significantly for either group in descriptive and difference-in-differences analyses. In subgroup analyses, we noted variation in outcomes by demographics and 2014 ME status.Conclusions: We found ME significantly affected HIC among low-income adults with asthma, but not cost barriers to asthma-related health care. Strategies to reduce cost barriers to asthma care could further improve health care access among low-income adults with asthma in ME jurisdictions. |
Use of the CUSUM and Shewhart control chart methods to identify changes of public health significance using childhood blood lead surveillance data
Dignam T , Hodge J , Chuke S , Mercado C , Ettinger AS , Flanders WD . Environ Epidemiol 2020 4 (2) Background: Local, state, and national childhood blood lead surveillance is based on healthcare providers and clinical laboratories reporting test results to public health departments. Increased interest in detecting blood lead level (BLL) patterns and changes of potential public health significance in a timely manner has highlighted the need for surveillance systems to rapidly detect and investigate these events. Objective(s): Decrease the time to detect changes in surveillance patterns by using an alerting algorithm developed and assessed through historical child blood lead surveillance data analysis. Method(s): We applied geographic and temporal data-aggregation strategies on childhood blood lead surveillance data and developed a novel alerting algorithm. The alerting algorithm employed a modified cumulative summary/Shewhart algorithm, initially applied on 113 months of data from two jurisdictions with a known increase in the proportion of children <6 years of age with BLLs >=5 micro g/dl. Result(s): Alert signals retrospectively identified time periods in two jurisdictions where a known change in the proportion of children <6 years of age with BLLs >=5 micro g/dl occurred. Additionally, we identified alert signals among six of the 18 (33%) randomly selected counties assessed where no previously known or suspected pattern changes existed. Conclusion(s): The modified cumulative summary/Shewhart algorithm provides a framework for enhanced blood lead surveillance by identifying changes in the proportion of children with BLLs >=5 micro g/dl. The algorithm has the potential to alert public health officials to changes requiring further important public health investigation. |
Prevalence of cigarette smoking among patients with different histological types of kidney cancer
Gansler T , Fedewa SA , Flanders WD , Pollack LA , Siegel DA , Jemal A . Cancer Epidemiol Biomarkers Prev 2020 29 (7) 1406-1412 BACKGROUND: Cigarette smoking is causally linked to renal cell carcinoma (RCC). However, associations for individual RCC histologies are not well-described. Newly-available data on tobacco use from population-based cancer registries allow characterization of associations with individual RCC types. METHODS: We analyzed data for 30,282 RCC cases from 8 states that collected tobacco use information for a National Program of Cancer Registry project. We compared the prevalence and adjusted prevalence ratios (aPR) of cigarette smoking (current vs never, former vs never) among individuals diagnosed between 2011 and 2016 with clear cell RCC, papillary RCC, chromophobe RCC, renal collecting duct/medullary carcinoma, cyst-associated RCC, and unclassified RCC. RESULTS: Of 30,282 RCC patients, 50.2% were current or former cigarette smokers. By histology, proportions of current or formers smokers ranged from 38% in patients with chromophobe carcinoma to 61.9% in those with collecting duct/medullary carcinoma. The aPRs (with the most common histology, clear cell RCC, as referent group) for current and former cigarette smoking among chromophobe RCC cases (4.9% of our analytic sample) were 0.58 (95% CI, 0.50-0.67) and 0.88 (95% CI, 0.81-0.95), respectively. Other aPRs were slightly increased (papillary RCC and unclassified RCC, current smoking only), slightly decreased (unclassified RCC, former smoking only) or not significantly different from 1.0 (collecting duct/medullary carcinoma and cyst-associated RCC). CONCLUSIONS: Compared with other RCC histological types, chromophobe RCC has a weaker (if any) association with smoking. IMPACT: This study shows the value of population-based cancer registries' collection of smoking data, especially for epidemiological investigation of rare cancers. |
Differences in heat-related mortality by citizenship status: United States, 2005-2014
Taylor EV , Vaidyanathan A , Flanders WD , Murphy M , Spencer M , Noe RS . Am J Public Health 2018 108 S131-s136 OBJECTIVES: To determine whether non-US citizens have a higher mortality risk of heat-related deaths than do US citizens. METHODS: We used place of residence reported in mortality data from the National Vital Statistics System from 2005 to 2014 as a proxy for citizenship to examine differences in heat-related deaths between non-US and US citizens. Estimates from the US Census Bureau American Community Survey of self-reported citizenship status and place of birth provided the numbers for the study population. We calculated the standardized mortality ratio and relative risk for heat-related deaths between non-US and US citizens nationally. RESULTS: Heat-related deaths accounted for 2.23% (n = 999) of deaths among non-US citizens and 0.02% (n = 4196) of deaths among US citizens. The age-adjusted standardized mortality ratio for non-US citizens compared with US citizens was 3.4 (95% confidence ratio [CI] = 3.2, 3.6). This risk was higher for Hispanic non-US citizens (risk ratio [RR] = 3.6; 95% CI = 3.2, 3.9) and non-US citizens aged 18 to 24 years (RR = 20.6; 95% CI = 16.5, 25.7). CONCLUSIONS: We found an increased mortality risk among non-US citizens compared with US citizens for heat-related deaths, especially those younger and of Hispanic ethnicity. |
Maternal serum concentrations of perfluoroalkyl substances during pregnancy and gestational weight gain: The Avon Longitudinal Study of Parents and Children
Marks KJ , Jeddy Z , Flanders WD , Northstone K , Fraser A , Calafat AM , Kato K , Hartman TJ . Reprod Toxicol 2019 90 8-14 Perfluoroalkyl substances (PFAS) are chemicals used in the manufacture of consumer products. PFAS may act as endocrine disruptors, influencing metabolic pathways and weight-related outcomes. We analyzed associations of maternal serum pregnancy concentrations of PFAS with gestational weight gain (GWG). We used data from 905 women in a subsample of the Avon Longitudinal Study of Parents and Children. Women were routinely weighed in antenatal check-ups; absolute GWG was determined by subtracting the first weight measurement from the last. Linear regression was used to explore associations of maternal PFAS concentrations with absolute GWG, stratified by pre-pregnancy body mass index. Associations of maternal PFAS concentrations with absolute GWG were null. Ten percent higher perfluorooctane sulfonic acid (PFOS) was associated with GWG of -0.03kg (95% CI: -0.11, 0.06) and -0.12kg (95% CI: -0.30, 0.06) among under-/normal weight and overweight/obese mothers, respectively. Overall, findings suggest no association between maternal PFAS concentrations and GWG. |
Characterizing environmental asthma triggers and healthcare use patterns in Puerto Rico
Lewis LM , Mirabelli MC , Beavers SF , Kennedy CM , Shriber J , Stearns D , Morales Gonzalez JJ , Santiago MS , Felix IM , Ruiz-Serrano K , Dirlikov E , Lozier MJ , Sircar K , Flanders WD , Rivera-Garcia B , Irizarry-Ramos J , Bolanos-Rosero B . J Asthma 2019 57 (8) 1-12 Objective: Asthma carries a high burden of disease for residents of Puerto Rico. We conducted this study to better understand asthma-related healthcare use and to examine potential asthma triggers. Methods: We characterized asthma-related healthcare use in 2013 by demographics, region, and date using outpatient, hospital, and emergency department (ED) insurance claims with a primary diagnostic ICD-9-CM code of 493.XX. We examined environmental asthma triggers, including outdoor allergens (i.e., mold and pollen), particulate pollution, and influenza-like illness. Analyses included descriptive statistics and Poisson time-series regression. Results: During 2013, there were 550,655 medical asthma claims reported to the Puerto Rico Healthcare Utilization database, representing 148 asthma claims/1,000 persons; 71% of asthma claims were outpatient visits, 19% were hospitalizations, and 10% were ED visits. Females (63%), children aged </=9 years (77% among children), and adults aged >/=45 years (80% among adults) had the majority of asthma claims. Among health regions, Caguas had the highest asthma claim-rate at 142/1,000 persons (overall health region claim-rate = 108). Environmental exposures varied across the year and demonstrated seasonal patterns. Metro health region regression models showed positive associations between increases in mold and particulate matter <10 microns in diameter (PM10) and outpatient asthma claims. Conclusions: This study provides information about patterns of asthma-related healthcare use across Puerto Rico. Increases in mold and PM10 were associated with increases in asthma claims. Targeting educational interventions on exposure awareness and reduction techniques, especially to persons with higher asthma-related healthcare use, can support asthma control activities in public health and clinical settings. |
Prenatal concentrations of perfluoroalkyl substances and bone health in British girls at age 17
Jeddy Z , Tobias JH , Taylor EV , Northstone K , Flanders WD , Hartman TJ . Arch Osteoporos 2018 13 (1) 84 Prenatal exposures to perfluoroalkyl substances (PFAS) have been associated with developmental outcomes in offspring. We found that prenatal concentrations of some PFAS may be associated with reduced bone mass and size in 17-year-old British girls, although it is not clear whether these associations are driven by body size. PURPOSE: PFAS are used to make protective coatings on common household products. Prenatal exposures have been associated with developmental outcomes in offspring. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we investigated the association between prenatal concentrations of PFAS and bone health in girls at 17 years of age and whether body composition can explain any associations. METHODS: We measured concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorononanoic acid (PFNA) in maternal serum samples collected during pregnancy. We obtained bone health outcomes in the girls, such as bone mineral density, bone mineral content, bone area, and area-adjusted bone mineral content from whole-body dual-energy X-ray absorptiometry (DXA) scans. We used multivariable linear regression to explore associations between each PFAS and each bone health outcome with adjustment for important confounders such as girls' age at clinic visit, maternal education, and gestational age at sample collection. We also controlled for girls' height and lean mass to explore the role body composition had on observed associations. RESULTS: Prenatal PFOS, PFOA, PFHxS, and PFNA concentrations were associated with inverse effects on bone size and mass after adjusting for important confounders. Conversely, PFNA was positively associated with area-adjusted bone mineral content. However, most significant associations attenuated after additional controlling for height and lean mass. CONCLUSIONS: Prenatal concentrations of some PFAS may be associated with reduced bone mass and size in adolescent girls, although it is not clear whether these associations are driven by body size. |
Multiple bias analysis using logistic regression: an example from the National Birth Defects Prevention Study
Johnson CY , Howards PP , Strickland MJ , Waller DK , Flanders WD . Ann Epidemiol 2018 28 (8) 510-514 PURPOSE: Exposure misclassification, selection bias, and confounding are important biases in epidemiologic studies, yet only confounding is routinely addressed quantitatively. We describe how to combine two previously described methods and adjust for multiple biases using logistic regression. METHODS: Weights were created from selection probabilities and predictive values for exposure classification and applied to multivariable logistic regression models in a case-control study of prepregnancy obesity (body mass index >/=30 vs. <30 kg/m(2)) and cleft lip with or without cleft palate (CL/P) using data from the National Birth Defects Prevention Study (2523 cases, 10,605 controls). RESULTS: Adjusting for confounding by race/ethnicity, prepregnancy obesity, and CL/P were weakly associated (odds ratio [OR]: 1.10; 95% confidence interval: 0.98, 1.23). After weighting the data to account for exposure misclassification, missing exposure data, selection bias, and confounding, multiple bias-adjusted ORs ranged from 0.94 to 1.03 in nonprobabilistic bias analyses and median multiple bias-adjusted ORs ranged from 0.93 to 1.02 in probabilistic analyses. CONCLUSIONS: This approach, adjusting for multiple biases using a logistic regression model, suggested that the observed association between obesity and CL/P could be due to the presence of bias. |
Use of multiple imputation to estimate the proportion of respiratory virus detections among patients hospitalized with community-acquired pneumonia
Bozio CH , Flanders WD , Finelli L , Bramley AM , Reed C , Gandhi NR , Vidal JE , Erdman D , Levine MZ , Lindstrom S , Ampofo K , Arnold SR , Self WH , Williams DJ , Grijalva CG , Anderson EJ , McCullers JA , Edwards KM , Pavia AT , Wunderink RG , Jain S . Open Forum Infect Dis 2018 5 (4) ofy061 Background: Real-time polymerase chain reaction (PCR) on respiratory specimens and serology on paired blood specimens are used to determine the etiology of respiratory illnesses for research studies. However, convalescent serology is often not collected. We used multiple imputation to assign values for missing serology results to estimate virus-specific prevalence among pediatric and adult community-acquired pneumonia hospitalizations using data from an active population-based surveillance study. Methods: Presence of adenoviruses, human metapneumovirus, influenza viruses, parainfluenza virus types 1-3, and respiratory syncytial virus was defined by positive PCR on nasopharyngeal/oropharyngeal specimens or a 4-fold rise in paired serology. We performed multiple imputation by developing a multivariable regression model for each virus using data from patients with available serology results. We calculated absolute and relative differences in the proportion of each virus detected comparing the imputed to observed (nonimputed) results. Results: Among 2222 children and 2259 adults, 98.8% and 99.5% had nasopharyngeal/oropharyngeal specimens and 43.2% and 37.5% had paired serum specimens, respectively. Imputed results increased viral etiology assignments by an absolute difference of 1.6%-4.4% and 0.8%-2.8% in children and adults, respectively; relative differences were 1.1-3.0 times higher. Conclusions: Multiple imputation can be used when serology results are missing, to refine virus-specific prevalence estimates, and these will likely increase estimates. |
The effect of a regimen of antifungal cream use on episodes of acute adenolymphangitis (ADL) among lymphedema patients: An application using marginal structural models
Mues KE , Klein M , Kleinbaum DG , Flanders WD , Fox LM . J Epidemiol Glob Health 2017 8 176-182 Episodes of adenolymphangitis (ADL) are a recurrent clinical aspect of lymphatic filariasis (LF) and a risk factor for progression of lymphedema. Inter-digital entry lesions, often found on the web spaces between the toes of those suffering from lymphedema, have been shown to contribute to the occurrence of ADL episodes. Use of antifungal cream on lesions is often promoted as a critical component of lymphedema management.Our objective was to estimate the observed effect of antifungal cream use on ADL episodes according to treatment regimen among a cohort of lymphedema patients enrolled in a morbidity management program. We estimated this effect using marginal structural models for time varying confounding.In this longitudinal study, we estimate that for every one-unit increase in the number of times one was compliant to cream use through 12 months, there was a 23% (RR = 0.77 (0.62, 0.96)) decrease in the number of ADL episodes at 18 months, however the RR's were not statistically significant at other study time points. Traditionally adjusted models produced a non-significant RR closer to the null at all time points.This is the first study to estimate the effect of a regimen of antifungal cream on the frequency of ADL episodes. This study also highlights the importance of the consideration and proper handling of time-varying confounders in longitudinal observational studies. |
In utero exposure to atrazine analytes and early menarche in the Avon Longitudinal Study of Parents and Children Cohort
Namulanda G , Taylor E , Maisonet M , Boyd Barr D , Flanders WD , Olson D , Qualters JR , Vena J , Northstone K , Naeher L . Environ Res 2017 156 420-425 BACKGROUND: Evidence from experimental studies suggests that atrazine and its analytes alter the timing of puberty in laboratory animals. Such associations have not been investigated in humans. OBJECTIVE: To determine the association between in utero exposure to atrazine analytes and earlier menarche attainment in a nested case-control study of the population-based Avon Longitudinal Study of Parents and Children. METHODS: Cases were girls who reported menarche before 11.5 years while controls were girls who reported menarche at or after 11.5 years. Seven atrazine analyte concentrations were measured in maternal gestational urine samples (sample gestation week median (IQR): 12 (8-17)) during the period 1991-1992, for 174 cases and 195 controls using high performance liquid chromatography-tandem mass spectrometry. We evaluated the study association using multivariate logistic regression, adjusting for potential confounders. We used multiple imputation to impute missing confounder data for 29% of the study participants. RESULTS: Diaminochlorotriazine (DACT) was the most frequently detected analyte (58%>limit of detection [LOD]) followed by desethyl atrazine (6%), desethyl atrazine mercapturate (3%), atrazine mercapturate (1%), hydroxyl atrazine (1%), atrazine (1%) and desisopropyl atrazine (0.5%). Because of low detection of other analytes, only DACT was included in the exposure-outcome analyses. The adjusted odds of early menarche for girls with DACT exposures≥median was 1.13 (95% Confidence Interval [95% CI]:0.82, 1.55) and exposure<median was 1.01 (95% CI: 0.73, 1.42) compared to girls with exposure<LOD (reference). In the subset that excluded girls with missing data, the adjusted odds of early menarche for girls with DACT exposures≥median was 1.86 (95% CI: 1.03, 3.38) and exposure<median was 1.26 (95% CI: 0.65, 2.24) compared to the reference. CONCLUSIONS: This study is the first to examine the association between timing of menarche and atrazine analytes. We found a weak, non-significant association between in-utero exposure to atrazine metabolite DACT and early menarche, though the association was significant in the subset of girls with complete confounder information. Further exploration of the role of these exposures in female reproduction in other cohorts is needed. |
Prenatal exposure to perfluoroalkyl substances and body fatness in girls
Hartman TJ , Calafat AM , Holmes AK , Marcus M , Northstone K , Flanders WD , Kato K , Taylor EV . Child Obes 2017 13 (3) 222-230 BACKGROUND: Perfluoroalkyl substances (PFASs) are used in surface coatings that resist stains, grease, and water. METHODS: The association between in utero PFAS exposure and girls' body fatness at age 9 was analyzed in The Avon Longitudinal Study of Parents and Children (UK). Maternal serum [median 15 weeks: interquartile range (IQR) 10 and 28 weeks of gestation] was analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorononanoate (PFNA). Body composition was measured by dual X-ray emission absorptiometry, and percent total body fat (%BF) was calculated. Associations between PFASs and body fatness were modeled by multivariable linear regression. RESULTS: Among 359 girls, median (IQR) %BF was 27.5 (IQR 21.7-34.6). Median (IQR) concentrations (all ng/mL) were 3.7 (2.9-4.8) for PFOA, 19.8 (15.0-25.3) for PFOS, 1.6 (1.3-2.2) for PFHxS, and 0.5 (0.4-0.7) for PFNA. Maternal PFAS concentrations were not significantly associated with daughters' total %BF overall. Mothers' educational status modified associations for PFOA and PFOS with %BF (P-interactions: 0.005 and 0.02, respectively). %BF was higher [1.4%; 95% confidence interval (95% CI): 0.3 to 2.5] for each one unit (ng/mL) higher PFOA among girls with mothers in the middle education group, but lower (-0.6%; 95% CI: -1.12 to -0.04) for the corresponding comparison among girls with mothers with the highest education. %BF was lower (-0.2%; 95% CI: -0.3 to -0.1) for each one unit higher PFOS among girls with the most educated mothers. CONCLUSIONS: Prenatal exposure to PFOA and PFOS was associated with girls' %BF within some strata of maternal education status. PFHxS and PFNA were not associated with %BF. |
Assessing potential population impact of statin treatment for primary prevention of atherosclerotic cardiovascular diseases in the USA: population-based modelling study
Yang Q , Zhong Y , Gillespie C , Merritt R , Bowman B , George MG , Flanders WD . BMJ Open 2017 7 (1) e011684 OBJECTIVE: New cholesterol treatment guidelines from American College of Cardiology/American Heart Association recommend statin treatment for more of US population to prevent atherosclerotic cardiovascular disease (ASCVD). It is important to assess how new guidelines may affect population-level health. This study assessed the impact of statin use for primary prevention of ASCVD under the new guidelines. METHODS: We used data from 2010 US Multiple Cause Mortality, Third National Health and Nutrition Examination Survey (NHANES III) Linked Mortality File (1988-2006, n=8941) and NHANES 2005-2010 (n=3178) participants 40-75 years of age for the present study. RESULTS: Among 33.0 million adults meeting new guidelines for primary prevention of ASCVD, 8.8 million were taking statins; 24.2 million, including 7.7 million with diabetes, are eligible for statin treatment. If all those with diabetes used a statin, 2514 (95% CI 592 to 4142) predicted ASCVD deaths would be prevented annually with 482 (0 to 2239) predicted annual additional cases of myopathy based on randomised clinical trials (RCTs), and 11 801 (9251 to 14 916) using population-based study. Among 16.5 million without diabetes, 5425 (1276 to 8935) ASCVD deaths would be prevented annually with 16 406 (4922 to 26 250) predicted annual additional cases of diabetes and between 1030 (0 to 4791) and 24 302 (19 363 to 30 292) additional cases of myopathy based on RCTs and population-based study. Assuming 80% eligible population take statins with 80% medication adherence, among those without diabetes, the corresponding numbers were 3472 (817 to 5718) deaths, 10 500 (3150 to 16 800) diabetes, 660 (0 to 3066) myopathy (RCTs), and 15 554 (12 392 to 19 387) myopathy (population-based). The estimated total annual cost of statins use ranged from US$1.65 to US$6.5 billion if 100% of eligible population take statins. CONCLUSIONS: This population-based modelling study focused on impact of statin use on ASCVD mortality. Under the new guidelines, if all those eligible for primary prevention of ASCVD take statins, up to 12.6% of annual ASCVD deaths might be prevented, though additional cases of diabetes and myopathy likely occur. DISCLAIMER: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. |
Maternal exposure to ozone and PM2.5 and the prevalence of orofacial clefts in four U.S. states
Zhou Y , Gilboa SM , Herdt ML , Lupo PJ , Flanders WD , Liu Y , Shin M , Canfield MA , Kirby RS . Environ Res 2016 153 35-40 BACKGROUND: While there is some evidence that maternal exposure to ambient air pollution is associated with orofacial clefts in offspring, the epidemiologic studies have been largely equivocal. We evaluated whether maternal exposure to elevated county-level ambient fine particulate matter with aerodynamic diameter ≤2.5microm (PM2.5) and ozone during early gestation was associated with a higher prevalence of orofacial clefts. METHODS: Birth data consisting of 4.7 million births from 2001 to 2007 were obtained from National Birth Defects Prevention Network for four states - Arizona, Florida, New York (excluding New York City), and Texas. The air pollution exposure assessment for gestational weeks 5-10 was based on county-level average concentrations of PM2.5 and ozone data generated using a Bayesian fusion model available through CDC's Environmental Public Health Tracking Network. Two outcomes were analyzed separately: cleft lip with or without cleft palate, cleft palate alone. In logistic regression analyses, we adjusted for factors that were suspected confounders or modifiers of the association between the prevalence of orofacial clefts and air pollution, i.e., infant sex, race-ethnicity, maternal education, smoking status during pregnancy, whether this was mother's first baby, maternal age. RESULTS: Each 10microg/m3 increase in PM2.5 concentration was significantly associated with cleft palate alone (OR =1.43, 95% CI: 1.11-1.86). There was no significant association between PM2.5 concentration and cleft lip with or without cleft palate. No associations were observed between ozone exposure and the two outcomes of orofacial clefts. CONCLUSIONS: Our study suggests that PM2.5 significantly increased the risk of cleft palate alone, but did not change the incidence of cleft lip with or without palate. Ozone levels did not correlate with incidence of orofacial clefts. |
Outdoor PM2.5, ambient air temperature, and asthma symptoms in the past 14 days among adults with active asthma
Mirabelli MC , Vaidyanathan A , Flanders WD , Qin X , Garbe P . Environ Health Perspect 2016 124 (12) 1882-1890 BACKGROUND: Relationships between air quality and health are well-described, but little information is available about the joint associations between particulate air pollution, ambient temperature, and respiratory morbidity. OBJECTIVES: To evaluate associations between concentrations of particulate matter ≤2.5 microns in diameter (PM2.5) and exacerbation of existing asthma and modification of the associations by ambient air temperature. METHODS: Data from 50,356 adult 2006-2010 Asthma Call-back Survey respondents were linked by interview date and county of residence to estimates of daily averages of PM2.5 and maximum air temperature. Associations between 14-day average PM2.5 and the presence of any asthma symptoms during the 14 days leading up to and including the interview date were evaluated using binomial regression. We explored variation by air temperature using similar models, stratified into quintiles of the 14-day average maximum temperature. RESULTS: Among adults with active asthma, 57.1% reported asthma symptoms within the past 14 days and 14-day average PM2.5 ≥7.07 microg.m-3 was associated with an estimated 4 to 5% higher asthma symptom prevalence. In the range of 4.00 to 7.06 microg.m-3 of PM2.5, each microg.m-3 increase was associated with a 3.4% (95% confidence interval: 1.1, 5.7) increase in symptom prevalence; across categories of temperature from 1.1 to 80.5 degrees F, each microg.m-3 increase was associated with increased symptom prevalence (1.1-44.4 degrees F: 7.9%; 44.5-58.6 degrees F: 6.9%; 58.7-70.1 degrees F: 2.9%; 70.2-80.5 degrees F: 7.3%). CONCLUSIONS: These results suggest that each unit increase in PM2.5 may be associated with an increase in the prevalence of asthma symptoms, even at levels as low as 4.00 to 7.06 microg.m-3. |
In utero exposure to organochlorine pesticides and early menarche in the Avon Longitudinal Study of Parents and Children
Namulanda G , Maisonet M , Taylor E , Flanders WD , Olson D , Sjodin A , Qualters JR , Vena J , Northstone K , Naeher L . Environ Int 2016 94 467-472 INTRODUCTION: Epidemiologic data supporting the role of organochlorine pesticides in pubertal development are limited. METHODS: Using a nested case-control design, serum collected during pregnancy from mothers of 218 girls who reported menarche before 11.5years of age (cases) and 230 girls who reported menarche at or after 11.5years of age (controls) was analyzed for 9 organochlorines and metabolites. We analyzed the association between in utero organochlorine concentrations and early menarche using multivariate logistic regression controlling for mother's age at menarche, or mother's prenatal BMI. RESULTS: We did not observe an association between in utero exposure to HCB, beta-HCH, Upsilon-HCH, p,p'-DDT, p,p'-DDE, oxychlordane or trans-nonachlor and early menarche. CONCLUSIONS: This study is the first to examine the association between in utero exposure to HCB, beta-HCH, Upsilon-HCH, oxychlordane or trans-nonachlor and early menarche. In utero exposure to organochlorine pesticides does not appear to have a role in the timing of menarche in this study. |
Conditions for valid estimation of causal effects on prevalence in cross-sectional and other studies
Flanders WD , Klein M , Mirabelli MC . Ann Epidemiol 2016 26 (6) 389-394 e2 PURPOSE: Causal effects in epidemiology are almost invariably studied by considering disease incidence even when prevalence data are used to estimate the causal effect. For example, if certain conditions are met, a prevalence odds ratio can provide a valid estimate of an incidence rate ratio. Our purpose and main result are conditions that assure causal effects on prevalence can be estimated in cross-sectional studies, even when the prevalence odds ratio does not estimate incidence. METHODS: Using a general causal effect definition in a multivariate counterfactual framework, we define causal contrasts that compare prevalences among survivors from a target population had all been exposed at baseline with that prevalence had all been unexposed. Although prevalence is a measure reflecting a moment in time, we consider the time sequence to study causal effects. RESULTS: Effects defined using a contrast of counterfactual prevalences can be estimated in an experiment and, with conditions provided, in cross-sectional studies. Proper interpretation of the effect includes recognition that the target is the baseline population, defined at the age or time of exposure. CONCLUSIONS: Prevalences are widely reported, readily available measures for assessing disabilities and disease burden. Effects on prevalence are estimable in cross-sectional studies but only if appropriate conditions hold. |
Modification of traffic-related respiratory response by asthma control in a population of car commuters
Mirabelli MC , Golan R , Greenwald R , Raysoni AU , Holguin F , Kewada P , Winquist A , Flanders WD , Sarnat JA . Epidemiology 2015 26 (4) 546-55 BACKGROUND: Effects of traffic-related exposures on respiratory health are well documented, but little information is available about whether asthma control influences individual susceptibility. We analyzed data from the Atlanta Commuter Exposure study to evaluate modification of associations between rush-hour commuting, in-vehicle air pollution, and selected respiratory health outcomes by asthma control status. METHODS: Between 2009 and 2011, 39 adults participated in Atlanta Commuter Exposure, and each conducted two scripted rush-hour highway commutes. In-vehicle particulate components were measured during all commutes. Among adults with asthma, we evaluated asthma control by questionnaire and spirometry. Exhaled nitric oxide, forced expiratory volume in 1 second (FEV1), and other metrics of respiratory health were measured precommute and 0, 1, 2, and 3 hours postcommute. We used mixed effects linear regression to evaluate associations between commute-related exposures and postcommute changes in metrics of respiratory health by level of asthma control. RESULTS: We observed increased exhaled nitric oxide across all levels of asthma control compared with precommute measurements, with largest postcommute increases observed among participants with below-median asthma control (2 hours postcommute: 14.6% [95% confidence interval {CI} = 5.7, 24.2]; 3 hours postcommute: 19.5% [95% CI = 7.8, 32.5]). No associations between in-vehicle pollutants and percent of predicted FEV1 were observed, although higher PM2.5 was associated with lower FEV1 % predicted among participants with below-median asthma control (3 hours postcommute: -7.2 [95% CI = -11.8, -2.7]). CONCLUSIONS: Level of asthma control may influence respiratory response to in-vehicle exposures experienced during rush-hour commuting. |
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