Vitamin D Status in Infancy and Cardiometabolic Health in Adolescence
Abstract Objectives Vitamin D deficiency has been associated with obesity-related conditions, but the role of early life vitamin D status is not clear. We assessed whether serum 25-hydroxy vitamin D [25(OH)D] at age 1 y was related to metabolic health through adolescence. Methods We quantified serum 25(OH)D in samples obtained at age 1 y from 307 participants in a cohort study in Santiago, Chile. Anthropometry was performed at ages 5, 10, and 16 y. At the 16 y assessment we determined body composition using dual-energy X-ray absorptiometry and quantified metabolic parameters in a blood sample. Using linear regression, we examined the associations of infancy 25(OH)D with body mass index-for-age Z (BMIZ) at ages 5, 10, and 16 y; with % fat and % lean body mass at age 16 y; and with a metabolic syndrome (MetS) score at age 16 y. The MetS score was calculated from sex- and age-standardized values of waist circumference (WC), mean arterial pressure, the homeostatic model assessment for insulin resistance (HOMA-IR), and serum triglyceride and high-density lipoprotein concentrations. Results were adjusted for sex, maternal education, breastfeeding, socioeconomic status, and BMIZ at age 1 y. Results Mean ± SD 25(OH)D concentration was 80.6 ± 33.0 nmol/L. The prevalence of 25(OH)D <50 nmol/L was 11.1%. 25(OH)D was inversely, significantly associated with BMIZ at age 5 y; every 25 nmol/L 25(OH)D was related to an adjusted 0.11 units (95% CI: 0.02, 0.20; P = 0.01) lower BMIZ. At age 16 y, every 25 nmol/L 25(OH)D was associated with a mean 1.3 points (95% CI: 0.4, 2.2; P = 0.005) lower % body fat, and a mean 1.4 points (95% CI: 0.4, 2.3; P = 0.005) higher % lean body mass. Also, every 25 nmol/L 25(OH)D in infancy was related to an adjusted 0.03 units (95% CI: 0.01, 0.05; P = 0.01) lower MetS score at age 16 y, through inverse associations with WC (−0.02 units per 25 nmol/L; 95% CI: −0.03, −0.00; P = 0.02) and HOMA-IR (−0.06 units per 25 nmol/L; 95% CI: −0.12, −0.00; P = 0.05). Conclusions Serum 25(OH)D at age 1 y is inversely associated with childhood BMIZ, % body fat at age 16 y, and a MetS score at age 16 y. Intervention studies are warranted to examine the effect of early-life vitamin D supplementation on later cardiometabolic outcomes. Funding Sources This study was funded by grants from the National Institutes of Health and the University of Michigan.