We conducted an epigenome-wide association study (EWAS) on obesity in healthy youth and young adults and further examined to what extent identified signals influenced gene expression and were independent of cell type composition and obesity-related cardio-metabolic risk factors. Genome-wide DNA methylation data from leukocytes were obtained from 700 African Americans aged 14–36. We also measured genome-wide DNA methylation data from neutrophils as well as genome-wide gene expression data from leukocytes in a subset of samples (n = 188). The EWAS identified 76 obesity-related CpG sites in leukocytes with p < 1 × 10−7. In silico replication in the ARIC study of 2097 African Americans aged 47–70 validated 54 CpG sites. Out of the 54 CpG sites, 29 associations with obesity were novel and 37 were replicated in neutrophils. Fifty one CpG sites were associated with at least one cardio-metabolic risk factor; however, the number reduced to 9 after adjustment for obesity. Sixteen CpG sites were associated with expression of 17 genes in cis, of which 5 genes displayed differential expression between obese cases and lean controls. We also replicated 71.5% of obesity-related CpG sites previously reported. In this study of youth and young adults, we identified 29 novel CpG sites associated with obesity and replicated the majority of the CpG sites previously identified. We further demonstrated that the majority of the obesity-related CpG sites in leukocytes were not driven by cell composition or obesity-related cardio-metabolic risk factors. We also provided the direct link between DNA methylation-gene expression-obesity for 5 genes.

Clinical trials are scant and equivocal on whether vitamin D can ameliorate arterial stiffness, particularly in populations at high risk for vitamin D deficiency and cardiovascular disease (CVD). This study determined the dose-response effects of vitamin D₃ supplementation on arterial stiffness in overweight African Americans with vitamin D deficiency. Seventy overweight African Americans (aged 13–45 years) with serum 25-hydroxyvitamin D [25(OH)D] levels ≤ 20 ng/mL were randomized to monthly oral supplementation of 18,000 IU (~600 IU/day, n = 17), 60,000 IU (~2000 IU/day, n = 18), or 120,000 IU (~4000 IU/day, n = 18) of vitamin D₃ or placebo (n = 17) for 16-weeks. The arterial stiffness measurements, carotid-femoral pulse wave velocity (PWV) and carotid-radial PWV, were assessed by applanation tonometry at baseline and 16 weeks. Vitamin D₃ supplementation demonstrated a dose-response increase in serum 25(OH)D concentrations between groups (P<0.01). A significant downward linear trend was observed for carotid-femoral PWV (P<0.01), as the mean changes in carotid-femoral PWV across the four treatment groups were 0.13 m/s (95% CI: -0.24, 0.51 m/s) for placebo, 0.02 m/s (95% CI: -0.34, 0.38 m/s) for 600 IU/day group, -0.11 m/s (95% CI: -0.50, 0.27 m/s) for the 2,000 IU/day group, and -0.70 m/s (95% CI: -1.07, -0.32 m/s) for the 4,000 IU/day group. Findings were similar for carotid-radial PWV (P = 0.03), as the mean changes in carotid-radial PWV across the four treatment groups were 0.24 m/s (95% CI: -0.45, 0.92 m/s) for placebo, 0.09 m/s (95% CI: -0.54, 0.73 m/s) for 600 IU/day group, -0.57 m/s (95% CI: -1.20, 0.07 m/s) for the 2,000 IU/day group, and -0.61 m/s (95% CI: -1.25, 0.02 m/s) for the 4,000 IU/day group. Arterial stiffness was improved by vitamin D₃ supplementation in a dose-response manner in overweight African Americans with vitamin D deficiency.

Objective: We aimed to characterize circulating HMGB1 (high-mobility group box-1) levels, one of the better-characterized damage-associated molecular patterns, with respect to age, sex, and race in the general population, and investigate the longitudinal associations of HMGB1 with inflammatory markers, obesity, and preclinical markers of cardiovascular disease. Approach and Results: The analyses included 489 participants (50% Blacks, aged 24.6±3.3 years at the first visit) with up to 4 follow-up visits (1149 samples) over a maximum of 8.5 years. Systolic blood pressure, diastolic blood pressure, carotid-femoral pulse wave velocity, and carotid intima-media thickness together with plasma HMGB1, hs-CRP (high-sensitivity C-reactive protein), IFN-γ (interferon-γ), IL-6 (interleukin-6), IL-10 (interleukin-10), and TNF-α (tumor necrosis factor-α) were measured at each visit. At baseline, plasma HMGB1 concentrations were higher in Blacks compared with Whites (3.86 versus 3.20 ng/mL, P <0.001), and in females compared with males (3.75 versus 3.30 ng/mL, P =0.005). HMGB1 concentrations increased with age ( P =0.007), and higher levels of obesity measures ( P <0.001). Without adjustment for age, sex, race, and body mass index, HMGB1 concentrations were positively associated with hs-CRP, IL-6, TNF-α, systolic blood pressure, diastolic blood pressure, and carotid-femoral pulse wave velocity ( P <0.05) but not IL-10, IFN-γ or carotid intima-media thickness. After covariate adjustments, the associations of HMGB1 with hs-CRP, and carotid-femoral pulse wave velocity remained statistically significant ( P <0.05). Conclusions: This study demonstrates the age, sex, and race differences in circulating HMGB1. The increasing circulating concentrations of HMGB1 with age suggest a potential role of HMGB1 in the pathogenesis of chronic low-grade inflammation, obesity, and subclinical cardiovascular disease risk.

Background: The VITAL study was a nationwide, randomized, double-blind, placebo-controlled, 2 × 2 factorial trial of vitamin D₃ (2000 IU/day) and marine n-3 FAs (1 g/day) supplements. We recently reported that vitamin D supplementation with or without omega 3 fatty acids reduced autoimmune disease by 22% in the VITAL study. Objective: To investigate the effects of vitamin D₃ and/or n-3 FAs on changes in systemic inflammatory biomarkers including pro- and anti-inflammatory cytokines over a 4-year period in the VITAL sub-cohort with in-person evaluations at the Center for Clinical Investigations (CCI) in Boston. Design: Serum levels of four inflammatory biomarkers (high-sensitivity C-reactive protein [hs-CRP], interleukin-6, interleukin-10, and tumor necrosis factor-α) were measured in a total of 2713 samples from those 1054 VITAL/CCI participants (aged 64.9 ± 6.5 years, 49% female, 84% white, and 9% black) at baseline, year 2, and year 4 follow-up visits. Results: In multiple-adjusted models, vitamin D₃ supplementation decreased serum hs-CRP levels by 19% at 2-year follow-up (nominal p = 0.007; p-value after multiple comparison adjustment = 0.028), but not at 4-year follow-up (nominal and adjusted p-values > 0.05). The effects of vitamin D₃ on other inflammatory markers were not statistically significant either at year 2 or year 4 (all adjusted p-values > 0.05). Marine n-3 FAs were not significantly associated with changes of all the above inflammatory markers either at years 2 and 4, after multiple comparison adjustment (all p-values > 0.05). Conclusions: Vitamin D₃ supplementation with or without n-3 FAs decreased hs-CRP by 19% at year 2, but not other inflammatory biomarkers at year 2 or year 4, while n-3 FAs with or without vitamin D₃ did not significantly affect these biomarkers at either time point. Our findings support a potential role of vitamin D supplementation in modulating the chronic inflammatory process, systemic inflammation, and possibly autoimmune disease progression.

Background: A limited number of studies investigated the association between blood pressure variability (BPV) and cognitive impairment in patients with hypertension. This study aimed to identify the longitudinal association between BPV and cognitive decline and the role of blood pressure (BP) control in this association. Methods and Results: Participants with hypertension from the HRS (Health and Retirement Study), the ELSA (English Longitudinal Study of Ageing), and the CHARLS (China Health and Retirement Longitudinal Study) were included. Variation independent of the mean (VIM) was adopted to measure BPV. Cognitive function was measured by standard questionnaires, and a standardized Z score was calculated. Linear mixed‐model and restricted cubic splines were adopted to explore the association between BPV and cognitive decline. The study included 4853, 1616, and 1432 eligible patients with hypertension from the HRS, ELSA, and CHARLS, respectively. After adjusting for covariates, per‐SD increment of VIM of BP was significantly associated with global cognitive function decline in Z scores in both systolic BP (pooled β, −0.045 [95% CI, −0.065 to −0.029]) and diastolic BP (pooled β, −0.022 [95% CI, −0.040 to −0.004]) among hypertensive patients. Similar inverse associations were observed in patients with hypertension taking antihypertensive drugs and in patients with hypertension with well‐controlled BP. Conclusions: High BPV was independently associated with a faster cognitive decline among patients with hypertension, even those with antihypertensive medications or well‐controlled BP. Further studies are needed to confirm our results and determine whether reducing BPV can prevent or delay cognitive decline.

Sphingolipid metabolism plays a critical role in cell growth regulation, lipid regulation, neurodevelopment, type 2 diabetes, and cancer. Animal experiments suggest that vitamin D may be involved in sphingolipid metabolism regulation. In this study, we tested the hypothesis that vitamin D supplementation would alter circulating long-chain ceramides and related metabolites involved in sphingolipid metabolism in humans. We carried out a post-hoc analysis of a previously conducted randomized, placebo-controlled clinical trial in 70 overweight/obese African-Americans, who were randomly assigned into four groups of 600, 2000, 4000 IU/day of vitamin D₃ supplements or placebo for 16 weeks. The metabolites were measured in 64 subjects (aged 26.0 ± 9.4 years, 17% male). Serum levels of N-stearoyl-sphingosine (d18:1/18:0) (C18Cer) and stearoyl sphingomyelin (d18:1/18:0) (C18SM) were significantly increased after vitamin D₃ supplementation (ps < 0.05) in a dose–response fashion. The effects of 600, 2000, and 4000 IU/day vitamin D₃ supplementation on C18Cer were 0.44 (p = 0.049), 0.52 (p = 0.016), and 0.58 (p = 0.008), respectively. The effects of three dosages on C18SM were 0.30 (p = 0.222), 0.61 (p = 0.009), and 0.68 (p = 0.004), respectively. This was accompanied by the significant correlations between serum 25-hydroxyvitamin D₃ [25(OH)D] concentration and those two metabolites (ps < 0.05). Vitamin D₃ supplementations increase serum levels of C18Cer and C18SM in a dose–response fashion among overweight/obese African Americans.