Prevalence of metabolic syndrome with different serum vitamin D levels in middle-aged and older adults

Background: The relationship between serum vitamin D levels and metabolic syndrome (MetS) has been controversial. This study focused on the relationship between the prevalence of MetS and serum vitamin D levels in middle-aged and elderly people.

Methods: This study included middle-aged and older adults who participated in the 2023 Zhejiang Provincial Nutrition and Health Survey, which was conducted in 90 districts and counties in Zhejiang Province, China.

Results: A total of 11,305 participants were included in this study. MetS was prevalent in 31.7% of participants. Vitamin D and vitamin D₃ concentrations were inversely associated with MetS prevalence (P_trend<0.05), but not with vitamin D₂, regardless of whether logistic regression models were adjusted for confounding factors. After adjusting for age, sex, physical activity level, smoking status, education level, annual per capita household income, and body mass index residuals, the highest tertile (Q3) of vitamin D (odds ratio [OR], 0.779; 95% confidence interval [CI], 0.702-0.865) and vitamin D₃ (OR, 0.787; 95% CI, 0.709-0.875) concentrations had a lower risk of MetS than the lowest tertile (Q1). We found that vitamin D and D₃ levels were correlated with age (P_interaction<0.05). When age-stratified analyses were performed, vitamin D and vitamin D3 levels were significantly negatively associated with MetS in older adults but not in middle-aged adults.

Conclusions: Low total serum vitamin D and vitamin D₃ levels were associated with a higher risk of MetS in adults aged 60 years and older.