Last data update: Sep 16, 2024. (Total: 47680 publications since 2009)
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Query Trace: Sempos C [original query] |
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Recommendations on the measurement and theclinical useof vitamin D metabolites and vitamin D binding protein - A position paper from the IFCC Committee on Bone Metabolism.
Makris K , Bhattoa HP , Cavalier E , Phinney K , Sempos CT , Ulmer CZ , Vasikaran SD , Vesper H , Heijboer AC . Clin Chim Acta 2021 517 171-197 Vitamin D, an important hormone with a central role in calcium and phosphate homeostasis, is required for bone and muscle development as well as preservation of musculoskeletal function. The most abundant vitamin D metabolite is 25-hydroxyvitamin D [25(OH)D], which is currently considered the best marker to evaluate overall vitamin D status. 25(OH)D is therefore the most commonly measured metabolite in clinical practice. However, several other metabolites, although not broadly measured, are useful in certain clinical situations. Vitamin D and all its metabolites are circulating in blood bound to vitamin D binding protein, (VDBP). This highly polymorphic protein is not only the major transport protein which, along with albumin, binds over 99% of the circulating vitamin D metabolites, but also participates in the transport of the 25(OH)D into the cell via a megalin/cubilin complex. The accurate measurement of 25(OH)D has proved a difficult task. Although a reference method and standardization program are available for 25(OH)D, the other vitamin D metabolites still lack this. Interpretation of results, creation of clinical supplementation, and generation of therapeutic guidelines require not only accurate measurements of vitamin D metabolites, but also the accurate measurements of several other "molecules" related with bone metabolism. IFCC understood this priority and a committee has been established with the task to support and continue the standardization processes of vitamin D metabolites along with other bone-related biomarkers. In this review, we present the position of this IFCC Committee on Bone Metabolism on the latest developments concerning the measurement and standardization of vitamin D metabolites and its binding protein, as well as clinical indications for their measurement and interpretation of the results. |
Development of an improved standard reference material for vitamin D metabolites in human serum
Phinney KW , Tai SS , Bedner M , Camara JE , Chia RRC , Sander LC , Sharpless KE , Wise SA , Yen JH , Schleicher RL , Chaudhary-Webb M , Maw KL , Rahmani Y , Betz JM , Merkel J , Sempos CT , Coates PM , Durazo-Arvizu RA , Sarafin K , Brooks SPJ . Anal Chem 2017 89 (9) 4907-4913 The National Institute of Standards and Technology (NIST) has developed Standard Reference Material (SRM) 972a Vitamin D Metabolites in Frozen Human Serum as a replacement for SRM 972, which is no longer available. SRM 972a was developed in collaboration with the National Institutes of Health's Office of Dietary Supplements. In contrast to the previous reference material, three of the four levels of SRM 972a are composed of unmodified human serum. This SRM has certified and reference values for the following 25-hydroxyvitamin D [25(OH)D] species: 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3. The value assignment and certification process included three isotope-dilution mass spectrometry approaches, with measurements performed at NIST and at the Centers for Disease Control and Prevention (CDC). The value assignment methods employed have been modified from those utilized for the previous SRM, and all three approaches now incorporate chromatographic resolution of the stereoisomers, 25(OH)D3 and 3-epi-25(OH)D3. |
The vitamin D status of the US population from 1988 to 2010 using standardized serum concentrations of 25-hydroxyvitamin D shows recent modest increases
Schleicher RL , Sternberg MR , Lacher DA , Sempos CT , Looker AC , Durazo-Arvizu RA , Yetley EA , Chaudhary-Webb M , Maw KL , Pfeiffer CM , Johnson CL . Am J Clin Nutr 2016 104 (2) 454-61 BACKGROUND: Temporal trends in the US population's vitamin D status have been uncertain because of nonstandardized serum 25-hydroxyvitamin D [25(OH)D] measurements. OBJECTIVE: To accurately assess vitamin D status trends among those aged ≥12 y, we used data from the cross-sectional NHANESs. DESIGN: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring 25(OH)D (sum of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3), calibrated to standard reference materials, was used to predict LC-MS/MS-equivalent concentrations from radioimmunoassay data (1988-2006 surveys; n = 38,700) and to measure LC-MS/MS concentrations (2007-2010 surveys; n = 12,446). Weighted arithmetic means and the prevalence of 25(OH)D above or below cutoff concentrations were calculated to evaluate long-term trends. RESULTS: Overall, mean predicted 25(OH)D showed no time trend from 1988 to 2006, but during 2007-2010 the mean measured 25(OH)D was 5-6 nmol/L higher. Those groups who showed the largest 25(OH)D increases (7-11 nmol/L) were older, female, non-Hispanic white, and vitamin D supplement users. During 1988-2010, the proportions of persons with 25(OH)D <40 nmol/L were 14-18% (overall), 46-60% (non-Hispanic blacks), 21-28% (Mexican Americans), and 6-10% (non-Hispanic whites). CONCLUSIONS: An accurate method for measuring 25(OH)D showed stable mean concentrations in the US population (1988-2006) and recent modest increases (2007-2010). Although it is unclear to what extent supplement usage compared with different laboratory methods explain the increases in 25(OH)D, the use of higher vitamin D supplement dosages coincided with the increase. Marked race-ethnic differences in 25(OH)D concentrations were apparent. These data provide the first standardized information about temporal trends in the vitamin D status of the US population. |
National estimates of serum total 25-hydroxyvitamin D and metabolite concentrations measured by liquid chromatography-tandem mass spectrometry in the US opulation during 2007-2010
Schleicher RL , Sternberg MR , Looker AC , Yetley EA , Lacher DA , Sempos CT , Taylor CL , Durazo-Arvizu RA , Maw KL , Chaudhary-Webb M , Johnson CL , Pfeiffer CM . J Nutr 2016 146 (5) 1051-61 BACKGROUND: The 2007-2010 NHANES provides the first US nationally representative serum 25-hydroxyvitamin D [25(OH)D] concentrations measured by standardized liquid chromatography-tandem mass spectrometry. OBJECTIVE: We describe patterns for total 25(OH)D and individual metabolites in persons aged ≥1 y stratified by race-ethnicity and grouped by demographic, intake, physiologic, and lifestyle variables. METHODS: We measured 25-hydroxycholecalciferol [25(OH)D3], 25-hydroxyergocalciferol [25(OH)D2], and C3-epimer of 25(OH)D3[C3-epi-25(OH)D3] in serum samples (n= 15,652) from the 2007-2010 cross-sectional NHANES [total 25(OH)D = 25(OH)D3+ 25(OH)D2]. RESULTS: Concentrations (median, detection rate) of 25(OH)D3(63.6 nmol/L, 100%) and C3-epi-25(OH)D3(3.40 nmol/L, 86%) were generally detectable; 25(OH)D2was detectable in 19% of the population. Total 25(OH)D, 25(OH)D3, and C3-epi-25(OH)D3displayed similar demographic patterns and were strongly correlated (Spearman'sr> 0.70). Concentrations of 25(OH)D2(90th percentile) were much higher in persons aged ≥60 y (17.3 nmol/L) than in younger age groups (≤4.88 nmol/L). We noted significant race-ethnicity differences in mean total 25(OH)D [non-Hispanic blacks (NHBs), Hispanics, and non-Hispanic whites (NHWs): 46.6, 57.2, and 75.2 nmol/L, respectively] and in the prevalence of total 25(OH)D <30 nmol/L overall (24% of NHBs, 6.4% of Hispanics, and 2.3% of NHWs) as well as stratified by season (winter months: 30% of NHBs, 7.5% of Hispanics, and 3.8% of NHWs; summer months: 17% of NHBs, 4.4% of Hispanics, and 1.6% of NHWs). Persons with higher vitamin D intakes (diet, supplements, or both) and those examined during May-October had significantly higher total 25(OH)D. Significant race-ethnicity interactions in a multiple linear regression model confirmed the necessity of providing race-ethnicity-specific estimates of total 25(OH)D. CONCLUSIONS: Race-ethnicity differences in the prevalence of low total 25(OH)D remained strong even after adjustment for season to account for the NHANES design imbalance between season, latitude, and race-ethnicity. The strong correlation between C3-epi-25(OH)D3and 25(OH)D3may be because the epimer is a metabolite of 25(OH)D3.The presence of 25(OH)D2mainly in older persons is likely a result of high-dose prescription vitamin D2. |
Estimating the population distribution of usual 24-hour sodium excretion from timed urine void specimens using a statistical approach accounting for correlated measurement errors
Wang CY , Carriquiry AL , Chen TC , Loria CM , Pfeiffer CM , Liu K , Sempos CT , Perrine CG , Cogswell ME . J Nutr 2015 145 (5) 1017-24 BACKGROUND: High US sodium intake and national reduction efforts necessitate developing a feasible and valid monitoring method across the distribution of low-to-high sodium intake. OBJECTIVE: We examined a statistical approach using timed urine voids to estimate the population distribution of usual 24-h sodium excretion. METHODS: A sample of 407 adults, aged 18-39 y (54% female, 48% black), collected each void in a separate container for 24 h; 133 repeated the procedure 4-11 d later. Four timed voids (morning, afternoon, evening, overnight) were selected from each 24-h collection. We developed gender-specific equations to calibrate total sodium excreted in each of the one-void (e.g., morning) and combined two-void (e.g., morning + afternoon) urines to 24-h sodium excretion. The calibrated sodium excretions were used to estimate the population distribution of usual 24-h sodium excretion. Participants were then randomly assigned to modeling (n = 160) or validation (n = 247) groups to examine the bias in estimated population percentiles. RESULTS: Median bias in predicting selected percentiles (5th, 25th, 50th, 75th, 95th) of usual 24-h sodium excretion with one-void urines ranged from -367 to 284 mg (-7.7 to 12.2% of the observed usual excretions) for men and -604 to 486 mg (-14.6 to 23.7%) for women, and with two-void urines from -338 to 263 mg (-6.9 to 10.4%) and -166 to 153 mg (-4.1 to 8.1%), respectively. Four of the 6 two-void urine combinations produced no significant bias in predicting selected percentiles. CONCLUSIONS: Our approach to estimate the population usual 24-h sodium excretion, which uses calibrated timed-void sodium to account for day-to-day variation and covariance between measurement errors, produced percentile estimates with relatively low biases across low-to-high sodium excretions. This may provide a low-burden, low-cost alternative to 24-h collections in monitoring population sodium intake among healthy young adults and merits further investigation in other population subgroups. This study was registered at clinicaltrials.gov as NCT01631240. |
Multivitamin-mineral use is associated with reduced risk of cardiovascular disease mortality among women in the United States
Bailey RL , Fakhouri TH , Park Y , Dwyer JT , Thomas PR , Gahche JJ , Miller PE , Dodd KW , Sempos CT , Murray DM . J Nutr 2015 145 (3) 572-8 BACKGROUND: Multivitamin-mineral (MVM) products are the most commonly used supplements in the United States, followed by multivitamin (MV) products. Two randomized clinical trials (RCTs) did not show an effect of MVMs or MVs on cardiovascular disease (CVD) mortality; however, no clinical trial data are available for women with MVM supplement use and CVD mortality. OBJECTIVE: The objective of this research was to examine the association between MVM and MV use and CVD-specific mortality among US adults without CVD. METHODS: A nationally representative sample of adults from the restricted data NHANES III (1988-1994; n = 8678; age ≥40 y) were matched with mortality data reported by the National Death Index through 2011 to examine associations between MVM and MV use and CVD mortality by using Cox proportional hazards models, adjusting for multiple potential confounders. RESULTS: We observed no significant association between CVD mortality and users of MVMs or MVs compared with nonusers; however, when users were classified by the reported length of time products were used, a significant association was found with MVM use of >3 y compared with nonusers (HR: 0.65; 95% CI: 0.49, 0.85). This finding was largely driven by the significant association among women (HR: 0.56; 95% CI: 0.37, 0.85) but not men (HR: 0.79; 95% CI: 0.44, 1.42). No significant association was observed for MV products and CVD mortality in fully adjusted models. CONCLUSIONS: In this nationally representative data set with detailed information on supplement use and CVD mortality data approximately 20 y later, we found an association between MVM use of >3 y and reduced CVD mortality risk for women when models controlled for age, race, education, body mass index, alcohol, aspirin use, serum lipids, blood pressure, and blood glucose/glycated hemoglobin. Our results are consistent with the 1 available RCT in men, indicating no relation with MVM use and CVD mortality. |
Validity of predictive equations for 24-h urinary sodium excretion in adults aged 18-39 y
Cogswell ME , Wang CY , Chen TC , Pfeiffer CM , Elliott P , Gillespie CD , Carriquiry AL , Sempos CT , Liu K , Perrine CG , Swanson CA , Caldwell KL , Loria CM . Am J Clin Nutr 2013 98 (6) 1502-13 BACKGROUND: Collecting a 24-h urine sample is recommended for monitoring the mean population sodium intake, but implementation can be difficult. OBJECTIVE: The objective was to assess the validity of published equations by using spot urinary sodium concentrations to predict 24-h sodium excretion. DESIGN: This was a cross-sectional study, conducted from June to August 2011 in metropolitan Washington, DC, of 407 adults aged 18-39 y, 48% black, who collected each urine void in a separate container for 24 h. Four timed voids (morning, afternoon, evening, and overnight) were selected from each 24-h collection. Published equations were used to predict 24-h sodium excretion with spot urine by specimen timing and race-sex subgroups. We examined mean differences with measured 24-h sodium excretion (bias) and individual differences with the use of Bland-Altman plots. RESULTS: Across equations and specimens, mean bias in predicting 24-h sodium excretion for all participants ranged from -267 to 1300 mg (Kawasaki equation). Bias was least with International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT) equations with morning (-165 mg; 95% CI: -295, 36 mg), afternoon (-90 mg; -208, 28 mg), and evening (-120 mg; -230, -11 mg) specimens. With overnight specimens, mean bias was least when the Tanaka (-23 mg; 95% CI: -141, 95 mg) or Mage (-145 mg; -314, 25 mg) equations were used but was statistically significant when using the Tanaka equations among females (216 to 243 mg) and the Mage equations among races other than black (-554 to -372 mg). Significant over- and underprediction occurred across individual sodium excretion concentrations. CONCLUSIONS: Using a single spot urine, INTERSALT equations may provide the least biased information about population mean sodium intakes among young US adults. None of the equations evaluated provided unbiased estimates of individual 24-h sodium excretion. This trial was registered at clinicaltrials.gov as NCT01631240. |
Modeling a methylmalonic acid-derived change point for serum vitamin B-12 for adults in NHANES
Bailey RL , Durazo-Arvizu RA , Carmel R , Green R , Pfeiffer CM , Sempos CT , Carriquiry A , Yetley EA . Am J Clin Nutr 2013 98 (2) 460-7 BACKGROUND: No consensus exists about which cutoff point should be applied for serum vitamin B-12 (SB-12) concentrations to define vitamin B-12 status in population-based research. OBJECTIVE: The study's aim was to identify whether a change point exists at which the relation between plasma methylmalonic acid (MMA) and SB-12 changes slope to differentiate between inadequate and adequate vitamin B-12 status by using various statistical models. DESIGN: We used data on adults (≥19 y; n = 12,683) from NHANES 1999-2004-a nationally representative, cross-sectional survey. We evaluated 6 piece-wise polynomial and exponential decay models that used different control levels for known covariates. RESULTS: The MMA-defined change point for SB-12 varied depending on the statistical model used. A linear-splines model was determined to best fit the data, as determined by the approximate permutation test; 3 slopes relating SB-12 and MMA and resulting in 2 change points and 3 subgroups were shown. The first group (SB-12 <126 pmol/L) was small and had the highest MMA concentration (median: 281 nmol/L; 95% CI: 245, 366 nmol/L; n = 157, 1.2%); many in this group could be considered at high risk of severe deficiency because combined abnormalities of MMA and homocysteine were very frequent and the concentrations themselves were significantly higher. The highest SB-12 group (SB-12 >287 pmol/L; n = 8569, 67.6%) likely had adequate vitamin B-12 status (median MMA: 120 nmol/L; 95% CI: 119, 125 nmol/L). The vitamin B-12 status of the sizable intermediate group (n = 3957, 33%) was difficult to interpret. CONCLUSIONS: The 3 distinct slopes for the relation between SB-12 and MMA challenges the conventional use of one cutoff point for classifying vitamin B-12 status. In epidemiologic research, the use of one cutoff point would fail to separate the small, severely deficient group from the intermediate group that has neither normal nor clearly deficient vitamin B-12 concentrations (ie, unknown vitamin B-12 status). This intermediate group requires further characterization. |
Is there a reverse J-shaped association between 25-hydroxyvitamin D and all-cause mortality? Results from the U.S. Nationally Representative NHANES
Sempos CT , Durazo-Arvizu RA , Dawson-Hughes B , Yetley EA , Looker AC , Schleicher RL , Cao G , Burt V , Kramer H , Bailey RL , Dwyer JT , Zhang X , Gahche J , Coates PM , Picciano MF . J Clin Endocrinol Metab 2013 98 (7) 3001-9 CONTEXT: A reverse J-shaped association between serum 25-hydroxyvitamin D (25[OH]D) concentration and all-cause mortality was suggested in a 9-year follow-up (1991-2000) analysis of the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). OBJECTIVE: Our objective was to repeat the analyses with 6 years additional follow-up to evaluate whether the association persists through 15 years of follow-up. PARTICIPANTS: The study included 15 099 participants aged ≥20 years with 3784 deaths. MAIN OUTCOME MEASURE: Relative risk (RR) of death from all causes was adjusted for age, sex, race/ethnicity, and season using 2 Poisson regression approaches: traditional categorical and cubic splines. Results were given for 9 25(OH)D levels: <20, 20 to 29, 30 to 39, 40 to 49, 50 to 59, 60 to 74, 75 to 99 (reference), 100 to 119, and ≥120 nmol/L. RESULTS: The reverse J-shaped association became stronger with longer follow-up and was not affected by excluding deaths within the first 3 years of follow-up. Similar results were found from both statistical approaches for levels <20 through 119 nmol/L. Adjusted RR (95% confidence interval [CI]) estimates for all levels <60 nmol/L were significantly >1 compared with the reference group. The nadir of risk was 81 nmol/L (95% CI, 73-90 nmol/L). For 25(OH)D ≥120 nmol/L, results (RR, 95% CI) were slightly different using traditional categorical (1.5, 1.02-2.3) and cubic splines approaches (1.2, 0.9-1.4). The association appeared in men, women, adults ages 20 to 64 years, and non-Hispanic whites but was weaker in older adults. The study was too small to evaluate the association in non-Hispanic black and Mexican-American adults. CONCLUSIONS: A reverse J-shaped association between serum 25(OH)D and all-cause mortality appears to be real. It is uncertain whether the association is causal. |
Prevalence and predictors of children's dietary supplement use: the 2007 National Health Interview Survey
Dwyer J , Nahin RL , Rogers GT , Barnes PM , Jacques PM , Sempos CT , Bailey R . Am J Clin Nutr 2013 97 (6) 1331-7 BACKGROUND: Little is known about the characteristics of US children who are dietary supplement users. OBJECTIVE: We described the prevalence and predictors of and reasons for giving children dietary supplements. DESIGN: The study included children <18 y of age who participated in the Complementary and Alternative Medicine supplement of the National Health Interview Survey of 2007 whose proxies provided complete information on child dietary supplement use. RESULTS: A total of 37% of subjects used dietary supplements, 31% of subjects used multivitamin mineral (MVM) products exclusively, 4% of subjects used single vitamins or minerals solely or in combination with MVMs, and 2% of subjects used nonvitamin, nonmineral products either solely or in combination with other supplements. Users were more likely than nonusers to be Asian, white, or non-Hispanic; belong to families with higher parental education and income levels; reside in areas other than the South; be in good, very good, or excellent health; have private health insurance; and have a usual place at which they received conventional medical care. Children (3%) with the most disease burden and health care were more likely to use supplements than were healthier children. Supplements were given for the prevention or treatment of many illnesses and conditions. Neither the caregiver's reasons nor specific supplements used were consistently associated with particular conditions. CONCLUSIONS: The 37% of US children who used any type of dietary supplements differed from nonusers in family socioeconomic status and many other health-related characteristics. Users were given supplements to prevent or treat many illnesses and conditions for which there is only limited evidence of their efficacy. |
Evaluation of Vitamin D Standardization Program protocols for standardizing serum 25-hydroxyvitamin D data: a case study of the program's potential for national nutrition and health surveys
Cashman KD , Kiely M , Kinsella M , Durazo-Arvizu RA , Tian L , Zhang Y , Lucey A , Flynn A , Gibney MJ , Vesper HW , Phinney KW , Coates PM , Picciano MF , Sempos CT . Am J Clin Nutr 2013 97 (6) 1235-42 BACKGROUND: The Vitamin D Standardization Program (VDSP) has developed protocols for standardizing procedures of 25-hydroxyvitamin D [25(OH)D] measurement in National Health/Nutrition Surveys to promote 25(OH)D measurements that are accurate and comparable over time, location, and laboratory procedure to improve public health practice. OBJECTIVE: We applied VDSP protocols to existing ELISA-derived serum 25(OH)D data from the Irish National Adult Nutrition Survey (NANS) as a case-study survey and evaluated their effectiveness by comparison of the protocol-projected estimates with those from a reanalysis of survey serums by using liquid chromatography-tandem mass spectrometry (LC-tandem MS). DESIGN: The VDSP reference system and protocols were applied to ELISA-based serum 25(OH)D data from the representative NANS sample (n = 1118). A reanalysis of 99 stored serums by using standardized LC-tandem MS and resulting regression equations yielded predicted standardized serum 25(OH)D values, which were then compared with LC-tandem MS reanalyzed values for all serums. RESULTS: Year-round prevalence rates for serum 25(OH)D concentrations <30, <40, and <50 nmol/L were 6.5%, 21.9%, and 40.0%, respectively, via original ELISA measurements and 11.4%, 25.3%, and 43.7%, respectively, when VDSP protocols were applied. Differences in estimates at <30- and <40-nmol/L thresholds, but not at the <50-nmol/L threshold, were significant (P < 0.05). A reanalysis of all serums by using LC-tandem MS confirmed prevalence estimates as 11.2%, 27.2%, and 45.0%, respectively. Prevalences of serum 25(OH)D concentrations >125 nmol/L were 1.2%, 0.3%, and 0.6% by means of ELISA, VDSP protocols, and LC-tandem MS, respectively. CONCLUSION: VDSP protocols hold a major potential for national nutrition and health surveys in terms of the standardization of serum 25(OH)D data. |
Urinary excretion of sodium, potassium, and chloride, but not iodine, varies by timing of collection in a 24-hour calibration study
Wang CY , Cogswell ME , Loria CM , Chen TC , Pfeiffer CM , Swanson CA , Caldwell KL , Perrine CG , Carriquiry AL , Liu K , Sempos CT , Gillespie CD , Burt VL . J Nutr 2013 143 (8) 1276-82 Because of the logistic complexity, excessive respondent burden, and high cost of conducting 24-h urine collections in a national survey, alternative strategies to monitor sodium intake at the population level need to be evaluated. We conducted a calibration study to assess the ability to characterize sodium intake from timed-spot urine samples calibrated to a 24-h urine collection. In this report, we described the overall design and basic results of the study. Adults aged 18-39 y were recruited to collect urine for a 24-h period, placing each void in a separate container. Four timed-spot specimens (morning, afternoon, evening, and overnight) and the 24-h collection were analyzed for sodium, potassium, chloride, creatinine, and iodine. Of 481 eligible persons, 407 (54% female, 48% black) completed a 24-h urine collection. A subsample (n = 133) collected a second 24-h urine 4-11 d later. Mean sodium excretion was 3.54 +/- 1.51 g/d for males and 3.09 +/- 1.26 g/d for females. Sensitivity analysis excluding those who did not meet the expected creatinine excretion criterion showed the same results. Day-to-day variability for sodium, potassium, chloride, and iodine was observed among those collecting two 24-h urine samples (CV = 16-29% for 24-h urine samples and 21-41% for timed-spot specimens). Among all race-gender groups, overnight specimens had larger volumes (P < 0.01) and lower sodium (P < 0.01 -P = 0.26), potassium (P < 0.01), and chloride (P < 0.01) concentrations compared with other timed-spot urine samples, although the differences were not always significant. Urine creatinine and iodine concentrations did not differ by the timing of collection. The observed day-to-day and diurnal variations in sodium excretion illustrate the importance of accounting for these factors when developing calibration equations from this study. |
Estimation of trends in serum and RBC folate in the U.S. population from pre- to postfortification using assay-adjusted data from the NHANES 1988-2010
Pfeiffer CM , Hughes JP , Lacher DA , Bailey RL , Berry RJ , Zhang M , Yetley EA , Rader JI , Sempos CT , Johnson CL . J Nutr 2012 142 (5) 886-93 The NHANES has monitored folate status of the U.S. population from prefortification (1988-1994) to postfortification (1999-2010) by measuring serum and RBC folate concentrations. The Bio-Rad radioassay (BR) was used from 1988 to 2006, and the microbiologic assay (MBA) was used from 2007 to 2010. The MBA produces higher concentrations than the BR and is considered to be more accurate. Thus, to bridge assay differences and to examine folate trends over time, we adjusted the BR results to be comparable to the MBA results. Postfortification, assay-adjusted serum and RBC folate concentrations were 2.5 times and 1.5 times prefortification concentrations, respectively, and showed a significant linear trend (P < 0.001) to slightly lower concentrations during 1999-2010. The postfortification prevalence of low serum (<10 nmol/L) or RBC (<340 nmol/L) folate concentrations was ≤ 1%, regardless of demographic subgroup, compared with 24% for serum folate and 3.5% for RBC folate prefortification, with substantial variation among demographic subgroups. The central 95% reference intervals for serum and RBC folate varied by demographic subgroup during both pre- and postfortification periods. Age and dietary supplement use had the greatest effects on prevalence estimates of low folate concentrations during the prefortification period. In summary, the MBA-equivalent blood folate concentrations in the U.S. population showed first a sharp increase from pre- to postfortification, then showed a slight decrease (17% for serum and 12% for RBC folate) during the 12-y postfortification period. The MBA-equivalent pre- and postfortification reference concentrations will inform countries that plan folic acid fortification or that need to evaluate its impact. |
Changes in measurement procedure from a radioassay to a microbiologic assay necessitate adjustment of serum and RBC folate concentrations in the U.S. population from the NHANES 1988-2010
Pfeiffer CM , Hughes JP , Durazo-Arvizu RA , Lacher DA , Sempos CT , Zhang M , Yetley EA , Johnson CL . J Nutr 2012 142 (5) 894-900 The NHANES measured serum and RBC folate concentrations by using a radioassay during prefortification (1988-1994) and postfortification (1999-2006) periods followed by the use of a microbiologic assay (MBA) from 2007-2010. The MBA produces higher concentrations than does the radioassay and is considered to be more accurate. To allow for accurate long-term trending (1988-2010), we evaluated different regression models (linear, piecewise linear, and fractional polynomial) to assay-adjust the radioassay results to be comparable to the MBA results. The data used to derive the regression models originated from 2 crossover studies in which the 2 assays were applied to a set of 325 serum and 171 whole-blood samples. Fractional polynomial regression of logarithmically transformed data provided the best fit for serum folate. Linear regression of logarithmically transformed whole-blood data provided an equally good fit compared with the other models and was the simplest to apply for RBC folate. Prefortification serum and RBC folate geometric mean concentrations increased after adjustment from 13.0 to 16.7 nmol/L and from 403 to 747 nmol/L, respectively. Postfortification serum folate concentrations increased from ~30 to ~43 nmol/L, and RBC folate concentrations increased from ~600 to ~1100 nmol/L after adjustment, with some variation across survey cycles. The presented regression equations allow the estimation of more accurate prevalence estimates and long-term trends in blood folate concentrations in the U.S. population by using results that are equivalent to the MBA. This information will be useful to public health officials in the United States who are dealing with folic acid fortification issues. |
Monitoring of vitamin B-12 nutritional status in the United States by using plasma methylmalonic acid and serum vitamin B-12
Bailey RL , Carmel R , Green R , Pfeiffer CM , Cogswell ME , Osterloh JD , Sempos CT , Yetley EA . Am J Clin Nutr 2011 94 (2) 552-61 BACKGROUND: Various definitions, criteria, tests, and cutoffs have been used to define vitamin B-12 status; however, a need exists for the systematic study of vitamin B-12 status in the United States because of concerns about high folic acid intakes and the potential for associated adverse effects. OBJECTIVE: The objective was to determine the effect of different cutoff choices on outcomes and of the different degrees of serum vitamin B-12 status, definable by the concurrent use of a functional and circulating marker as the first steps to developing a data-based consensus on the biochemical diagnosis of vitamin B-12 deficiency. DESIGN: Data from NHANES, a nationally representative cross-sectional survey, were examined for adults aged >19 y (mean +/- SD age: 45 +/- 1 y) from 1999 to 2004 (n = 12,612). RESULTS: Commonly used cutoffs had a greater effect on prevalence estimates of low vitamin B-12 status with the use of vitamin B-12 than with the use of methylmalonic acid (MMA; 3-26% and 2-6%, respectively). A cutoff of >148 pmol/L for vitamin B-12 and of ≤210 nmol/L for MMA resulted in significant misclassifications. Approximately 1% of adults had a clear vitamin B-12 deficiency (low vitamin B-12 and elevated MMA); 92% of adults had adequate vitamin B-12 status. A high percentage of younger women characterized the group with low vitamin B-12 and normal MMA (2% of adults) and may have falsely reflected low vitamin B-12. Adults with elevated MMA (5%) only were demographically similar (ie, by age and race) to the deficient group and may have included some individuals with early vitamin B-12 deficiency. CONCLUSIONS: These analyses indicate the challenges of assessing vitamin B-12 status when uncertainties exist about the appropriate cutoffs. Future studies should determine definable endpoints to achieve this goal. |
Biomarkers of folate status in NHANES: a roundtable summary
Yetley EA , Pfeiffer CM , Phinney KW , Fazili Z , Lacher DA , Bailey RL , Blackmore S , Bock JL , Brody LC , Carmel R , Curtin LR , Durazo-Arvizu RA , Eckfeldt JH , Green R , Gregory JF 3rd , Hoofnagle AN , Jacobsen DW , Jacques PF , Molloy AM , Massaro J , Mills JL , Nexo E , Rader JI , Selhub J , Sempos C , Shane B , Stabler S , Stover P , Tamura T , Tedstone A , Thorpe SJ , Coates PM , Johnson CL , Picciano MF . Am J Clin Nutr 2011 94 (1) 303S-312S A roundtable to discuss the measurement of folate status biomarkers in NHANES took place in July 2010. NHANES has measured serum folate since 1974 and red blood cell (RBC) folate since 1978 with the use of several different measurement procedures. Data on serum 5-methyltetrahydrofolate (5MTHF) and folic acid (FA) concentrations in persons aged ≥60 y are available in NHANES 1999-2002. The roundtable reviewed data that showed that folate concentrations from the Bio-Rad Quantaphase II procedure (Bio-Rad Laboratories, Hercules, CA; used in NHANES 1991-1994 and NHANES 1999-2006) were, on average, 29% lower for serum and 45% lower for RBC than were those from the microbiological assay (MA), which was used in NHANES 2007-2010. Roundtable experts agreed that these differences required a data adjustment for time-trend analyses. The roundtable reviewed the possible use of an isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) measurement procedure for future NHANES and agreed that the close agreement between the MA and LC-MS/MS results for serum folate supported conversion to the LC-MS/MS procedure. However, for RBC folate, the MA gave 25% higher concentrations than did the LC-MS/MS procedure. The roundtable agreed that the use of the LC-MS/MS procedure to measure RBC folate is premature at this time. The roundtable reviewed the reference materials available or under development at the National Institute of Standards and Technology and recognized the challenges related to, and the scientific need for, these materials. They noted the need for a commutability study for the available reference materials for serum 5MTHF and FA. |
Dietary supplement use among U.S. adults has increased since NHANES III (1988-1994)
Gahche J , Bailey R , Burt V , Hughes J , Yetley E , Dwyer J , Picciano MF , McDowell M , Sempos C . NCHS Data Brief 2011 (61) 1-8 KEY FINDINGS: Use of dietary supplements is common among the U.S. adult population. Over 40% used supplements in 1988-1994, and over one-half in 2003-2006. Multivitamins/multiminerals are the most commonly used dietary supplements, with approximately 40% of men and women reporting use during 2003-2006. Use of supplemental calcium increased from 28% during 1988-1994 to 61% during 2003-2006 among women aged 60 and over. Use of supplements containing folic acid among women aged 20-39 did not increase since 1988-1994. In 2003-2006, 34% of women aged 20-39 used a dietary supplement containing folic acid. Use of dietary supplements containing vitamin D increased from 1988-1994 through 1999-2002 for men and women in most age groups. |
Dietary supplement use in the United States, 2003-2006
Bailey RL , Gahche JJ , Lentino CV , Dwyer JT , Engel JS , Thomas PR , Betz JM , Sempos CT , Picciano MF . J Nutr 2011 141 (2) 261-6 Dietary supplement use has steadily increased over time since the 1970s; however, no current data exist for the U.S. population. Therefore, the purpose of this analysis was to estimate dietary supplement use using the NHANES 2003-2006, a nationally representative, cross-sectional survey. Dietary supplement use was analyzed for the U.S. population (≥1 y of age) by the DRI age groupings. Supplement use was measured through a questionnaire and was reported by 49% of the U.S. population (44% of males, 53% of females). Multivitamin-multimineral use was the most frequently reported dietary supplement (33%). The majority of people reported taking only 1 dietary supplement and did so on a daily basis. Dietary supplement use was lowest in obese adults and highest among non-Hispanic whites, older adults, and those with more than a high-school education. Between 28 and 30% reported using dietary supplements containing vitamins B-6, B-12, C, A, and E; 18-19% reported using iron, selenium, and chromium; and 26-27% reported using zinc- and magnesium-containing supplements. Botanical supplement use was more common in older than in younger age groups and was lowest in those aged 1-13 y but was reported by ~20% of adults. About one-half of the U.S. population and 70% of adults ≥ 71 y use dietary supplements; one-third use multivitamin-multimineral dietary supplements. Given the widespread use of supplements, data should be included with nutrient intakes from foods to correctly determine total nutrient exposure. |
NHANES monitoring of serum 25-hydroxyvitamin D: a roundtable summary
Yetley EA , Pfeiffer CM , Schleicher RL , Phinney KW , Lacher DA , Christakos S , Eckfeldt JH , Fleet JC , Howard G , Hoofnagle AN , Hui SL , Lensmeyer GL , Massaro J , Peacock M , Rosner B , Wiebe D , Bailey RL , Coates PM , Looker AC , Sempos C , Johnson CL , Picciano MF . J Nutr 2010 140 (11) 2030S-45S A roundtable to discuss monitoring of serum 25-hydroxyvitamin D [25(OH)D] in the NHANES was held in late July 2009. Topics included the following: 1) options for dealing with assay fluctuations in serum 25(OH)D in the NHANES conducted between 1988 and 2006; 2) approaches for transitioning between the RIA used in the NHANES between 1988 and 2006 to the liquid chromatography tandem MS (LC-MS/MS) measurement procedure to be used in NHANES 2007 and later; 3) approaches for integrating the recently available standard reference material for vitamin D in human serum (SRM 972) from the National Institute of Standards and Technology (NIST) into the NHANES; 4) questions regarding whether the C-3 epimer of 25-hydroxyvitamin D3 [3-epi-25(OH)D3] should be measured in NHANES 2007 and later; and 5) identification of research and educational needs. The roundtable experts agreed that the NHANES data needed to be adjusted to control for assay fluctuations and offered several options for addressing this issue. The experts suggested that the LC-MS/MS measurement procedure developed by NIST could serve as a higher order reference measurement procedure. They noted the need for a commutability study for the recently released NIST SRM 972 across a range of measurement procedures. They suggested that federal agencies and professional organizations work with manufacturers to improve the quality and comparability of measurement procedures across all laboratories. The experts noted the preliminary nature of the evidence of the 3-epi-25(OH)D3 but felt that it should be measured in 2007 NHANES and later. |
Estimation of total usual calcium and vitamin D intakes in the United States
Bailey RL , Dodd KW , Goldman JA , Gahche JJ , Dwyer JT , Moshfegh AJ , Sempos CT , Picciano MF . J Nutr 2010 140 (4) 817-22 Our objective in this study was to estimate calcium intakes from food, water, dietary supplements, and antacids for U.S. citizens aged >or=1 y using NHANES 2003-2006 data and the Dietary Reference Intake panel age groupings. Similar estimates were calculated for vitamin D intake from food and dietary supplements using NHANES 2005-2006. Diet was assessed with 2 24-h recalls; dietary supplement and antacid use were determined by questionnaire. The National Cancer Institute method was used to estimate usual nutrient intake from dietary sources. The mean daily nutrient intake from supplemental sources was added to the adjusted dietary intake estimates to produce total usual nutrient intakes for calcium and vitamin D. A total of 53% of the U.S. population reported using any dietary supplement (2003-2006), 43% used calcium (2003-2006), and 37% used vitamin D (2005-2006). For users, dietary supplements provided the adequate intake (AI) recommendation for calcium intake for approximately 12% of those >or=71 y. Males and females aged 1-3 y had the highest prevalence of meeting the AI from dietary and total calcium intakes. For total vitamin D intake, males and females >or=71, and females 14-18 y had the lowest prevalence of meeting the AI. Dietary supplement use is associated with higher prevalence of groups meeting the AI for calcium and vitamin D. Monitoring usual total nutrient intake is necessary to adequately characterize and evaluate the population's nutritional status and adherence to recommendations for nutrient intake. |
Three-phase model harmonizes estimates of the maximal suppression of parathyroid hormone by 25-hydroxyvitamin D in persons 65 years of age and older
Durazo-Arvizu RA , Dawson-Hughes B , Sempos CT , Yetley EA , Looker AC , Cao G , Harris SS , Burt VL , Carriquiry AL , Picciano MF . J Nutr 2010 140 (3) 595-9 The concentration or threshold of 25-hydroxyvitamin D [25(OH)D] needed to maximally suppress intact serum parathyroid hormone (iPTH) has been suggested as a measure of optimal vitamin D status. Depending upon the definition of maximal suppression of iPTH and the 2-phase regression approach used, 2 distinct clusters for a single 25(OH)D threshold have been reported: 16-20 ng/mL (40-50 nmol/L) and 30-32 ng/mL (75-80 nmol/L). To rationalize the apparently disparate published results, we compared thresholds from several regression models including a 3-phase one to estimate simultaneously 2 thresholds before and after adjusting for possible confounding for age, BMI, glomerular filtration rate, dietary calcium, and season (April-September vs. October-March) within a single data set, i.e. data from the Tufts University Sites Testing Osteoporosis Prevention/Intervention Treatment study, consisting of 181 men and 206 women (total n = 387) ages 65-87 y. Plasma 25(OH)D and serum iPTH concentrations were (mean +/- SD) 22.1 +/- 7.44 ng/mL (55.25 +/- 18.6 nmol/L) and 36.6 +/- 16.03 pg/mL (3.88 +/- 1.7 pmol/L), respectively. The 3-phase model identified 2 thresholds of 12 ng/mL (30 nmol/L) and 28 ng/mL (70 nmol/L); similar results were found from the 2-phase models evaluated, i.e. 13-20 and 27-30 ng/mL (32.5-50 and 67.5-75 nmol/L) and with previous results. Adjusting for confounding did not change the results substantially. Accordingly, the 3-phase model appears to be superior to the 2-phase approach, because it simultaneously estimates the 2 threshold clusters found from the 2-phase approaches along with estimating confidence limits. If replicated, it may be of both clinical and public health importance. |
Total folate and folic acid intake from foods and dietary supplements in the United States: 2003-2006
Bailey RL , Dodd KW , Gahche JJ , Dwyer JT , McDowell MA , Yetley EA , Sempos CA , Burt VL , Radimer KL , Picciano MF . Am J Clin Nutr 2010 91 (1) 231-7 BACKGROUND: The term total folate intake is used to represent folate that occurs naturally in food as well as folic acid from fortified foods and dietary supplements. Folic acid has been referred to as a double-edged sword because of its beneficial role in the prevention of neural tube defects and yet possible deleterious effects on certain cancers and cognitive function. Previous monitoring efforts did not include folic acid from dietary supplements and are therefore not complete. OBJECTIVE: Our objective was to combine data on dietary folate (as measured by two 24-h recalls) and folic acid from dietary supplements (collected with a 30-d frequency questionnaire) with the use of the bias-corrected best power method to adjust for within-person variability. DESIGN: The National Health and Nutrition Examination Survey (NHANES) is a nationally representative, cross-sectional survey. Linear contrasts were constructed to determine differences in dietary and total folate intake for age and racial-ethnic groups by sex; prevalence of inadequate and excessive intakes is presented. RESULTS: In 2003-2006, 53% of the US population used dietary supplements; 34.5% used dietary supplements that contained folic acid. Total folate intake (in dietary folate equivalents) was higher for men (813 +/- 14) than for women (724 +/- 16) and higher for non-Hispanic whites (827 +/- 19) than for Mexican Americans (615 +/- 11) and non-Hispanic blacks (597 +/- 12); 29% of non-Hispanic black women had inadequate intakes. Total folate and folic acid intakes are highest for those aged > or =50 y, and 5% exceed the Tolerable Upper Intake Level. CONCLUSIONS: Improved total folate intake is warranted in targeted subgroups, which include women of childbearing age and non-Hispanic black women, whereas other population groups are at risk of excessive intake. |
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