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

Abstract

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.

Keywords: Cross-sectional study; Elderly; Metabolic syndrome; Sex difference; Vitamin D.