The Association Between Active Transportation and Serum Total 25-Hydroxyvitamin D Levels Among US Childbearing-Aged Women

Abstract

Background: Serum total 25-hydroxyvitamin D (25[OH]D) and physical activity (PA) both play important roles in maternal–fetal health. However, a high prevalence of vitamin D and PA insufficiency has been observed in women of childbearing age. Active transportation may increase overall PA levels and potentially boost serum 25(OH)D levels. Methods: Data from the National Health and Nutrition Examination Survey between 2007 and 2014 were used. A total of 5601 women aged 18–49 years were included. Transportation PA (TPA) was quantified as metabolic equivalents of task and serum 25(OH)D levels was measured. Multivariable logistic regression models adjusted for potential confounders were conducted. Results: The corresponding adjusted odds ratios associated with vitamin D insufficiency (<50 nmol/L) were 1.09 (95% confidence interval, 0.87–1.37) for 1 to 499 MET minutes per week of TPA, 0.69 (0.52–0.91) for 500 to 1000 MET minutes per week of TPA, and 0.95 (0.72–1.26) for >1000 MET minutes per week of TPA, respectively, compared with no TPA. Using vitamin D deficiency (<30 nmol/L) as the outcome led to similar results. The association between TPA and serum 25(OH)D levels was more robust in high sedentary time. Conclusions: A moderate level of TPA is related to lower odds of suboptimal vitamin D status among women of childbearing age.