Serum 25-hydroxy vitamin D levels in middle-aged women in relationship to adiposity and height trajectories over three decades.

Abstract

The long-term chronology of the association between low serum concentrations of 25-hydroxy vitamin D (25(OH)D) and weight status is unclear. We examined whether lower 25(OH)D in middle-aged women drives upwards the weight, body mass index (BMI) and waist-hip ratio (WHR) over the next 32 years, and whether higher 25(OH)D might predict less decline in the mid- to late-life height trajectory. The Population Study of Women in Gothenburg started in 1968-1969 (the baseline) in 38-60-year-old women residing in Gothenburg, Sweden. Anthropometric measures were taken at baseline and 4 re-examinations until 2000-2003. Levels of 25(OH)D were analyzed in serum stored since baseline in 1227 (84%) women. Repeated measures analyses were used to model associations between 25(OH)D (dichotomized, cut point 51.45 nmol/l) at baseline and anthropometric trajectories, adjusting for fixed and time-dependent covariates. At baseline, mean BMI was 25.2 kg/m(2) in women with low 25(OH)D and 23.8 kg/m(2) in the remaining women (P<0.001), but this difference did not increase over 32 years and longitudinal differences were explained by the baseline BMI. Similar results were observed for weight and WHR. In contrast, no association was seen for height at baseline or longitudinally. No relationship was observed between 25(OH)D height trajectory, but lower 25(OH)D was associated with higher BMI, weight and WHR differences that were maintained over three decades. This provides no evidence for the direction of causality, but for a life-long difference in adiposity-related measures according to the 25D level in middle-aged women.