Association Between Anthropometric Indices and Vitamin D Levels: Results From the Yazd Health Study

Obesity and overweight are widespread health problems affecting many populations. Some studies have shown an inverse association between obesity and vitamin D levels. This study aims to explore the connection between vitamin D levels and various body measurements in Iranian men and women.

This cross-sectional study used data from the Yazd Health Study. The final sample included 1116 men and women aged 20-70. We measured the following anthropometric indices: Body Mass Index (BMI), Waist-to-Hip Ratio, Waist-to-Height Ratio (WHR), conicity index, Body Roundness Index (BRI), body shape index, Abdominal Volume Index (AVI), Body Fat Percentage (BF%), Body Muscle Percentage (BM%), and visceral fat level. We fitted multiple linear regression models in three steps to adjust for confounders.

In men, after adjusting for age, physical activity, hypertension, and diabetes mellitus, vitamin D deficiency showed a positive and nearly borderline significant association with WHtR (β = 0.027, 95% CI: 0.005; 0.048), BRI (β = 0.583, 95% CI: 0.136; 1.030), AVI (β = 1.761, 95% CI: 0.372; 3.150), and BF% (β = 3.614, 95% CI: 0.926; 6.303), and a negative association with BM% (β = -1.978, 95% CI: -3.655; -0.300). The associations of BRI and BF% with vitamin D deficiency remained borderline significant after further adjustment for other potential confounders. In women, vitamin D levels were not significantly associated with any of the anthropometric indices.

Vitamin D levels differentially influence body composition across genders, highlighting potential sex-specific metabolic mechanisms of obesity and vitamin D status, and the need for targeted prevention and intervention strategies.

Vitamin D shows inverse associations with certain body indices in men, highlighting the importance of obesity vulnerability and the need for broader mechanistic studies.