Determinants of Vitamin D Status in Healthy Young Adults from Mexico City

Vitamin D deficiency is a global health problem. The determinants of this deficiency have not been evaluated in developing countries such as Mexico. Thus, this study aimed to determine vitamin D intake and sun exposure and its relationship with plasma concentrations of 25-hydroxyvitamin D -25(OH)D- in young adults from Mexico City.

One hundred fifty five urban adult subjects were enrolled during 2017 and 2018. Sociodemographic, anthropometric, and clinical data, vitamin D intake, and sun exposure habits were collected. Plasma concentrations of 25(OH)D were also determined.

The proportion of vitamin D deficiency was significantly higher in women than in men (65.7 vs. 43.4%, p = 0.012). The overall median dietary vitamin D intake was 112 IU/d (less than 20% of the recommended daily intake; RDI). 25-hydroxyvitamin D correlated directly with vitamin D intake, sun exposure score, waist-to-hip ratio, and age; an inverse significant association was found with body fat percentage. A multiple regression analysis was performed; simultaneous and significant (p <0.01) effects of sun exposure score, dietary vitamin D, the season of the year (spring-summer vs. fall-winter), and age were observed on 25(OH)D levels.

High rates of vitamin D deficiency and insufficiency were observed in young adults from Mexico City. According to the RDI of this vitamin, its consumption, assessed by a 24 h multi-step nutritional questionnaire, was significantly low. A linear multiple regression model identified several predictors of plasma 25(OH)D concentrations. This multiple regression model was statistically validated.