Gender differences in the prevalence of vitamin D deficiency in a southern Latin American country: a pilot study

Aim: This study aimed to study the prevalence of vitamin D deficiency, assessing the influence of sex, age, and season of the year.Methods: A cross-sectional study was conducted with 1329 healthy subjects (668 women and 661 men) aged 18–89 years in Santiago, Chile. Age (years), body mass index, medical history, working status, sex, and date of blood sample were collected.Results: Men were slightly older than women (53.1 ± 18.2 vs. 50.0 ± 15.6 years; p < 0.01) and a higher percentage worked outside the home (73.1% vs. 51.9%, p < 0.001). The mean serum concentration of 25-hydroxyvitamin D (25(OH)-D) was 23.3 ± 9.3 ng/ml in women and 20.9 ± 9.5 ng/ml in men (p < 0.001). The levels of 25(OH)-D by season were 26.7 ± 9.0, 23.6 ± 9.7, 19.4 ± 8.5, and 19.1 ± 9.5 ng/ml (for summer, fall, winter, and spring, respectively; p < 0.05). The prevalence of vitamin D deficiency increases with age, rising from 36.5% under 40 years to 48.0% over 60 years (p < 0.004). Male sex, winter and spring, and age showed negative correlation with levels of 25(OH)-D (p < 0.05). Multivariate linear regression showed a final model that incorporates: age (coefficient: −0.06; 95% confidence interval [CI]: −0.09 to −0.03; p < 0.001), male sex (coefficient: −2.00; 95% CI: −2.96 to −1.05; p < 0.001), summer (coefficient: 7.30; 95% CI: 6.17 to 8.43; p < 0.001), and fall (coefficient: 4.27; 95% CI: 3.04 to 5.50; p < 0.001).Conclusions: Vitamin D deficiency is more prevalent in men than in women, in the elderly, and during the winter and spring seasons.