Vitamin D receptors have been mapped throughout the brain suggesting a role for vitamin D in psychosomatic disorders. Results from previous epidemiological studies on relation between vitamin D status and depression are equivocal. Also, limited information is available relating vitamin D status with depression in young adult US population.

Background: The effect of assay drifts over time on serum 25-hydroxyvitamin D [25(OH)D] concentrations were not accounted for in previous national survey studies. Thus, previously reported associations between 25(OH)D with cardiometabolic risk factors using data from NHANES were likely over- or underestimated. Moreover, associations between serum 25(OH)D and metabolic syndrome (MetSyn), insulin resistance (IR), and inflammation are unclear in children.

Prevalence of hypovitaminosis D from previous NHANES reports did not account for assay changes and drifts over time. Thus, published NHANES reports o

Background: Elevated serum total homocysteine (tHcy) is an independent risk factor for vascular diseases. Objective: Associations between serum tHcy and demographics, health and lifestyle factors, and blood vitamin concentrations were investigated. Design: Data from the third National Health and Nutrition Examination Survey, 1988–1994 were used to examine associations in men (n = 2965) and women (n = 3580) between tHcy and age, sex, race-ethnicity, body mass index, systolic and diastolic blood pressures, alcohol consumption, supplement use, red blood cell (RBC) folate, and serum creatinine, folate, vitamin B-12, and cotinine (a measure of cigarette smoking). Results: The unadjusted mean tHcy was 21.5% (≈1.9 μmol/L) higher in men than in women, 11.8% (≈1.1 μmol/L) higher in non-Hispanic whites than in Mexican Americans, 42% (≈3.7 μmol/L) higher in persons aged ≥ 70 y than in persons aged < 30 y, and 10.9% (≈1.0 μmol/L) higher in supplement nonusers than in supplement users. The tHcy concentration was negatively associated with serum folate (P < 0.0001 for trend), RBC folate (P < 0.0001 for trend), and serum vitamin B-12 (P < 0.0036 for trend) and was positively associated with alcohol consumption (P < 0.0001 for trend), serum cotinine (P < 0.0001 for trend), and systolic blood pressure (P < 0.0001 for trend). Consumption of hard liquor (but not of beer or wine) was positively associated with tHcy concentration (P < 0.0001 for trend). Conclusions: In this population-based study, the significant predictors of tHcy concentration were sex, age, race-ethnicity, serum creatinine, systolic blood pressure, body mass index, hard-liquor consumption, smoking, supplement use, serum folate, RBC folate, and serum vitamin B-12.

Folate intakes increased dramatically after folic acid fortification. We investigated the changes in serum folate, RBC folate, and total homocysteine (tHcy) concentrations utilizing data from National Health and Nutrition Examination Surveys (NHANES) 1988–2002. NHANES 1988–2002 were based on a stratified, multistage, probability sampling design conducted among civilian U.S. residents. The current study included 17,144, 17,213, and 11,415 measurements for serum folate, RBC folate, and tHcy, respectively. Overall, geometric mean serum folate concentrations were 149.6 and 129.8% higher in 1999–2000 and 2001–2002, respectively, than in 1988–1994 (P < 0.0001). Sex-, age-, and race-ethnicity–adjusted serum folate was significantly lower in 2001–2002 than in 1999–2000 (10.4%, P < 0.0002). The prevalence of low serum folate decreased from 18.4% in 1988–1994 to 0.8% in 1999–2000 and to 0.2% in 2001–2002 (P < 0.0001). RBC folate increased from 391 nmol/L in 1988–1994 to 618 nmol/L in 1999–2000, and to 611 nmol/L in 2001–2002. Consequently, the prevalence of low RBC folate decreased from 45.8% in 1988–1994 to 7.3% in 1999–2000 and to 7.1% in 2001–2002 (P < 0.0001). Although, RBC folate status improved after folic acid fortification in all race-ethnicities, the prevalence of low RBC folate (∼20.5%) continues to be high in non-Hispanic blacks. Age-, sex-, and race-ethnicity–adjusted tHcy declined from 9.5 μmol/L in 1988–1994 to 7.6 μmol/L in 1999–2000 and to 7.9 μmol/L in 2001–2002. Although folic acid fortification contributed to significant improvement in folate status, serum folate concentrations have declined recently. This may be attributable to lower folic acid intakes.