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Introduction: The cross-sectional association of serum vitamin D levels with blood pressure and hypertension status among a representative sample of U.S. adults was examined.Methods: Participants of the National Health and Nutrition Examination Survey from 2001 to 2010 were included in these analyses. Harmonizing of the vitamin D levels from 2001 to 2006 with vitamin D measurement from 2007 to 2010 was done using regression equations released by the Centers for Disease Control and Prevention. Use of vitamin D supplements was assessed for all participants. Statistical analyses included examination of linear association of vitamin D levels with blood pressure and non-linear cubic splines with hypertension in overall population, by gender, and by race/ethnicity.Results: With every 10 nmol/L higher vitamin D, systolic blood pressure decreased by 0.19 mmHg in this population (p<0.01). In fully adjusted stratified analyses, this association was present among females (-0.25 mmHg, p<0.01) and non-Hispanic whites (0.22 mmHg, p<0.01). After race/ethnic and gender stratification, this association was observed among non-Hispanic white females (0.26 mmHg, p=0.01), non-Hispanic black females (0.65 mmHg, p=0.02), and marginally significant among Hispanic males (0.33 mmHg, p=0.07). Non-parametric assessment with cubic splines show that vitamin D has an inverse association with odds of hypertension up to 100 nmol/L with no apparent benefit at higher levels in overall population, and even lower threshold levels of vitamin D in non-Hispanic blacks (50 nmol/L) and Hispanic Americans (70 nmol/L).Conclusions: Significant race/ethnic and gender differences exist in the association of vitamin D and systolic blood pressure. Odds for hypertension are reduced significantly at higher vitamin D levels, but this benefit plateaus at very high vitamin D levels. [ABSTRACT FROM AUTHOR]

T-helper type 1 (Th1) cells are pro-inflammatory and provide signals to immune cells. Animal models and in vitro human cell culture experiments have indicated that long chain n-3 polyunsaturated fatty acids (LCn3PUFAs) reduce Th1 cell levels; however, the association is unknown in healthy humans. We hypothesized that circulating levels and dietary intake of LCn3PUFAs have an inverse association with circulating levels of Th1 cells and studied 895 participants in the Multi-Ethnic Study of Atherosclerosis (age 61 ± 10 years at exam 1, 52% women, 44% white, 21% African-American, 24% Hispanic-American, 11% Chinese-American). Phospholipid LCn3PUFAs (% of total fatty acids), measured by gas chromatography, and intake of LCn3PUFAs, evaluated by food frequency questionnaire, were evaluated at exam 1 (2000-02) and defined as the sum of eicosapentaenoic and docosahexaenoic acids. Th1 cells were measured by flow cytometry at exam 4 (2005-07), expressed as a percentage of CD4 + lymphocytes that were interferon-γ + (%Th1: CD4 + IFN-γ + ). Median (interquartile range) plasma LCn3PUFA, dietary LCn3PUFA, and %Th1 levels were 4.31% (3.40–5.82%), 0.09 (0.05–0.16) g/day, and 14.4% (9.8–20.0%), respectively. When the association of LCn3PUFA-quartiles with %Th1 was analyzed using general linear models, neither plasma nor dietary LCn3PUFAs were significantly associated with %Th1 ( P -trend = 0.58 and 0.80, respectively), which remained even after adjusting for demographics, lifestyle factors, lipids, season, and cytomegalovirus titers. In this multi-ethnic U.S. population, circulating levels and dietary intake of LCn3PUFAs were not significantly associated with Th1 cell levels. Further research is needed to assess potential benefits of supplementation and much higher dietary consumption of LCn3PUFAs on Th1 cells. [ABSTRACT FROM AUTHOR]