Relationship between muscle strength and dyslipidemia, serum 25(OH)D, and weight status among diverse schoolchildren: a cross-sectional analysis

Abstract Background The relationship between muscle strength and cardiometabolic risk factors in youth, and the potential influence of vitamin D status on this relationship, is not well understood. This study examined associations between muscle strength and dyslipidemia, serum 25-hydroxyvitamin D [25(OH)D], and weight status in diverse schoolchildren. Methods Measures of hand-grip strength (standardized for sex and body weight), anthropometrics (height and weight converted to BMI z-score [BMIz]), sociodemographics, and fasting blood concentrations of plasma HDL-C and triglycerides and serum 25(OH)D were collected from 350 4th-8th grade schoolchildren (11.2 ± 1.3 y, 49.4% female, 56.3% non-white/Caucasian). Logistic regression was used to measure associations between standardized tertiles of grip strength and blood lipids, 25(OH)D, and weight status along with associations between 25(OH)D and dyslipidemia and weight status. Results Children with higher grip strength had lower odds of overweight/obesity (OR: 0.03, 95% CI: 0.01-0.06, in the highest tertile of grip strength vs. lowest, p for trend< 0.0001), borderline/low HDL-C (OR: 0.28, 95% CI: 0.16-0.50, p for trend< 0.0001), and borderline/high triglycerides (OR: 0.48, 95% CI: 0.25-0.92, p for trend< 0.05), adjusting for covariates. Associations between blood lipids and grip strength became non-significant after further adjustment for BMIz. No association was observed between grip strength and 25(OH)D, nor between 25(OH)D and borderline/low HDL-C or weight status; however, vitamin D sufficiency was associated with lower odds of borderline/high triglycerides compared with vitamin D deficiency (OR: 0.26, 95% CI: 0.09-0.74, p for trend< 0.05) before BMIz adjustment. Conclusion Among racially/ethnically diverse children, muscle strength was associated with lower dyslipidemia. Longitudinal studies are needed to explore whether changes in muscle strength impact this relationship in children, independent of weight status. Trial registration This study was registered at www.clinicaltrials.gov (No. NCT01537809) on February 17, 2012

Investigation of the 3-epi-25(OH)D3 of 25-hydroxyvitamin D3 in urban schoolchildren

Background: The physiological relevance C-3 epimer of 25-hydroxyvitamin D [3-epi-25(OH)D] is not well understood among youth. Objective: To assess whether demographic/physiologic characteristics were associated with 3-epi-25(OH)D3 concentrations in youth. Methods: Associations between 3-epi-25(OH)D3 and demographics, 3-epi-25(OH)D3, total 25-hydroxyvitamin (25(OH)D) (25(OH)D2 + 25(OH)D3), total cholesterol, HDL, LDL and triglycerides were examined in racially/ethnically diverse schoolchildren (n=682, 8-15yrs) at Boston-area urban schools. Results: Approximately 50% of participants had detectable 3-epi-25(OH)D3 (range 0.95-3.95 ng/mL). The percentage of 3-epi-25(OH)D3 of total 25(OH)D ranged from 2.5 to 17.0% (median 5.5%). Males were 38% more likely than females to have detectable 3-epi-25(OH)D3 concentrations. Both Asian and black race/ethnicity were associated with lower odds of having detectable 3-epi-25(OH)D3 compared to non-Hispanic white children ((Asian vs. white, OR 0.28, 95%CI 0.14-0.53; black vs. white, OR 0.38, 95%CI 0.23-0.63, pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Vitamin D supplementation and cardiometabolic risk factors among diverse schoolchildren: a randomized clinical trial

BACKGROUND: There remains a lack of evidence demonstrating a potential relationship between vitamin D and cardiometabolic risk among children. OBJECTIVES: We examined the effect of 3 different dosages of vitamin D on cardiometabolic risk factors among children at risk of deficiency. METHODS: Racially diverse schoolchildren aged 8-15 y were randomly assigned in a double-blind fashion to supplementation with 600, 1000, or 2000 IU vitamin D3/d for 6 mo. Changes in HDL cholesterol, triglycerides, LDL cholesterol, total cholesterol, and blood glucose over 6 mo and at 12 mo (6 mo post-supplementation) were assessed. Subgroup analyses were also performed by weight status and race. RESULTS: Among 604 children, 40.9% were vitamin D-inadequate at baseline (\u3c20 ng/mL; mean ± SD: 22.0 ± 6.8 ng/mL), 46.4% were overweight/obese, and 60.9% had ≥1 suboptimal blood lipids or glucose. Over 6 mo, serum 25-hydroxyvitamin D increased in all 3 dosage groups from baseline (mean ± SE change: 4.4 ± 0.6 ng/mL, 5.7 ± 0.7 ng/mL, and 10.7 ± 0.6 ng/mL for 600, 1000, and 2000 IU/d, respectively; P \u3c 0.001). Whereas HDL cholesterol and triglycerides increased in the 600 IU group (P = 0.002 and P = 0.02, respectively), LDL cholesterol and total cholesterol decreased across dosage groups. At 6 mo post-supplementation, HDL cholesterol remained elevated in the 600 and 1000 IU groups ( P \u3c 0.001 and P = 0.02, respectively) whereas triglycerides remained elevated in the 1000 and 2000 IU groups (P = 0.04 and P = 0.006, respectively). The suppression of LDL cholesterol and total cholesterol persisted in the 2000 IU group only (P = 0.04 and P \u3c 0.001, respectively). There were no significant changes in blood glucose and similar responses were observed overall by weight status and racial groups across dosages. CONCLUSIONS: Vitamin D supplementation demonstrated generally positive effects on HDL cholesterol, LDL cholesterol, and total cholesterol, especially at the lower dosage of 600 IU/d, with several significant changes persisting during the post-supplementation period. Increases in triglycerides across dosage groups may be due to natural changes during adolescence warranting further study.This trial was registered at clinicaltrials.gov as NCT01537809

DNA vaccination before conception protects Zika virus-exposed pregnant macaques against prolonged viremia and improves fetal outcomes.

Zika virus (ZIKV) infection of pregnant women is associated with congenital Zika syndrome (CZS) and no vaccine is available, although several are being tested in clinical trials. We tested the efficacy of ZIKV DNA vaccine VRC5283 in a rhesus macaque model of congenital ZIKV infection. Most animal vaccine experiments have a set pathogen exposure several weeks or months after vaccination. In the real world, people encounter pathogens years or decades after vaccination, or may be repeatedly exposed if the virus is endemic. To more accurately mimic how this vaccine would be used, we immunized macaques before conception and then exposed them repeatedly to ZIKV during early and mid-gestation. In comparison to unimmunized animals, vaccinated animals had a significant reduction in peak magnitude and duration of maternal viremia, early fetal loss, fetal infection, and placental and fetal brain pathology. Vaccine-induced neutralizing antibody titers on the day of first ZIKV exposure were negatively associated with the magnitude of maternal viremia, and the absence of prolonged viremia was associated with better fetal outcomes. These data support further clinical development of ZIKV vaccine strategies to protect against negative fetal outcomes