Last data update: May 20, 2024. (Total: 46824 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Lau FK[original query] |
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Could circumcision of HIV-positive males benefit voluntary medical male circumcision programs in Africa? Mathematical modeling analysis
Awad SF , Sgaier SK , Lau FK , Mohamoud YA , Tambatamba BC , Kripke KE , Thomas AG , Bock N , Reed JB , Njeuhmeli E , Abu-Raddad LJ . PLoS One 2017 12 (1) e0170641 BACKGROUND: The epidemiological and programmatic implications of inclusivity of HIV-positive males in voluntary medical male circumcision (VMMC) programs are uncertain. We modeled these implications using Zambia as an illustrative example. METHODS AND FINDINGS: We used the Age-Structured Mathematical (ASM) model to evaluate, over an intermediate horizon (2010-2025), the effectiveness (number of VMMCs needed to avert one HIV infection) of VMMC scale-up scenarios with varying proportions of HIV-positive males. The model was calibrated by fitting to HIV prevalence time trend data from 1990 to 2014. We assumed that inclusivity of HIV positive males may benefit VMMC programs by increasing VMMC uptake among higher risk males, or by circumcision reducing HIV male-to-female transmission risk. All analyses were generated assuming no further antiretroviral therapy (ART) scale-up. The number of VMMCs needed to avert one HIV infection was projected to increase from 12.2 VMMCs per HIV infection averted, in a program that circumcises only HIV-negative males, to 14.0, in a program that includes HIV-positive males. The proportion of HIV-positive males was based on their representation in the population (e.g. 12.6% of those circumcised in 2010 would be HIV-positive based on HIV prevalence among males of 12.6% in 2010). However, if a program that only reaches out to HIV-negative males is associated with 20% lower uptake among higher-risk males, the effectiveness would be 13.2 VMMCs per infection averted. If improved inclusivity of HIV-positive males is associated with 20% higher uptake among higher-risk males, the effectiveness would be 12.4. As the assumed VMMC efficacy against male-to-female HIV transmission was increased from 0% to 20% and 46%, the effectiveness of circumcising regardless of HIV status improved from 14.0 to 11.5 and 9.1, respectively. The reduction in the HIV incidence rate among females increased accordingly, from 24.7% to 34.8% and 50.4%, respectively. CONCLUSION: Improving inclusivity of males in VMMC programs regardless of HIV status increases VMMC effectiveness, if there is moderate increase in VMMC uptake among higher-risk males and/or if there is moderate efficacy for VMMC against male-to-female transmission. In these circumstances, VMMC programs can reduce the HIV incidence rate in males by nearly as much as expected by some ART programs, and additionally, females can benefit from the intervention nearly as much as males. |
Urinary perchlorate as a measure of dietary and drinking water exposure in a representative sample of the United States population 2001-2008
Lau FK , Decastro BR , Mills-Herring L , Tao L , Valentin-Blasini L , Alwis KU , Blount BC . J Expo Sci Environ Epidemiol 2012 23 (2) 207-14 Perchlorate (ClO(4)(-)) is ubiquitous in the environment and inhibits the thyroid's uptake of iodide. Food and tap water are likely sources of environmental exposure to perchlorate. The aim of this study was to identify significant dietary sources of perchlorate using perchlorate measured in urine as an exposure indicator. Sample-weighted, age-stratified linear regression models of National Health and Nutrition Examination Survey (NHANES) 2001-2008 data (n=16,955 participants) characterized the association between urinary perchlorate and the mass consumed in USDA food groups, controlling for urinary creatinine and other potential confounders. Separate models of NHANES 2005-2006 data (n=2841) evaluated the association between urinary perchlorate and perchlorate consumed via residential tap water. Consumption of milk products was associated with statistically significant contributions to urinary perchlorate across all age strata: 2.93 ng ClO(4)(-)/ml per kg consumed for children (6-11 years-old (YO)); 1.54 ng ClO(4)(-)/ml per kg for adolescents (12-19 YO); and 0.69 ng ClO(4)(-)/ml per kg for adults (20-84 YO). Vegetables were a significant contributor for adolescents and adults, whereas fruits and eggs contributed significantly only for adults. Dark-green leafy vegetables contributed the most among all age strata: 30.83 ng ClO(4)(-)/ml per kg for adults. Fats, oils, and salad dressings were significant contributors only for children. Three food groups were negatively associated with urinary perchlorate: grain products for children; sugars, sweets, and beverages for adolescents; and home tap water for adults. In a separate model, however, perchlorate consumed via home tap water contributed significantly to adult urinary perchlorate: 2.11E-4 ng ClO(4)(-)/ml per ng perchlorate in tap water consumed. In a nationally representative sample of the United States 6-84 YO, diet and tap water contributed significantly to urinary perchlorate, with diet contributing substantially more than tap water. (Journal of Exposure Science and Environmental Epidemiology advance online publication, 28 November 2012; doi:10.1038/jes.2012.108.) |
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