Vitamin D Status of Tehran Taxi Drivers: How Efficient Is the Occupational Exposure to Sun? A Case-control Study

Day-shift taxi drivers have a long duration of direct sun exposure. However, the efficiency of this occupational exposure in vitamin D synthesis has not been addressed yet. The aim of this study was to assess the vitamin D status of taxi drivers in Tehran, and examine vitamin D status association with some anthropometric and circulating biomarkers. In a case control study, 53 taxi drivers and 80 apparently healthy subjects from other occupations were enrolled. Questionnaires for demographic data, supplement use, and duration of sun exposure were completed. Weight, height and waist circumference were measured. Blood samples were taken from all participants for complete blood cell count, fasting blood glucose (FBG), lipid profile, and 25-hydroxycholecalciferol (25 (OH)D) measurements. Taxi drivers, as compared to the controls, had significantly higher body mass index (BMI), waist circumference (WC), serum triglycerides (TG), and 25(OH)D concentrations. Moreover, 56.6% of the drivers had more than 2 hours of sun exposure during a day. Despite having higher circulating concentrations of 25(OH)D, the taxi drivers had higher cardiometabolic risk factors. These findings indicate a need for nutritional education for taxi drivers.