The beneficial cutoffs of vitamin D for metabolic syndrome varies by sex among the elderly Chinese population: A cross-sectional study

Metabolic syndrome (MetS) is a risk factor for various diseases with a high prevalence globally. We aimed to investigate the association of serum vitamin D levels with MetS, and we hypothesized that the beneficial cutoffs of vitamin D for MetS might vary by sex among urban people aged ≥60 years in Tianjin, China. This community-based cross-sectional study was conducted in 2 community health centers. We collected lifestyle and anthropometric information and measured serum 25(OH)D3 concentrations by high-performance liquid chromatography. MetS was diagnosed based on the 2009 International Diabetes Federation/American Heart Association/National Heart, Lung, and Blood Institute criterion. Binary logistic regression and stratification analysis were performed to determine the association between MetS and 25(OH)D3 levels. Among 840 eligible participants (347 males and 493 females), 439 (52.3%) were diagnosed with MetS. The prevalence rates of MetS in men and women were 52.7% and 51.9%, respectively (P = .82). In the whole population, no significant association was found between 25(OH)D3 and MetS, regardless of which 25(OH)D3 cutoff was used. After stratification by sex, men with serum 25(OH)D3 ≥40 ng/mL had a significantly lower risk of MetS before and after adjustment, with odds ratios (ORs) and 95% confidence intervals (CIs) of 0.55 (0.31-0.98) and 0.53 (0.29-0.96), respectively. For women, serum 25(OH)D3 ≥20 ng/mL was associated with a lower MetS risk, with unadjusted and adjusted ORs (95% CI) of 0.64 (0.43-0.95) and 0.61 (0.41-0.91), respectively. This association was more significant among females with respect to diastolic pressure and triglycerides. The beneficial cutoffs of serum 25(OH)D3 levels for MetS among men and women might be different.