Night shift, vitamin D and occupational allergies in bakers

Background.Night work can influence vitamin D level and growing evidence connects vitamin D with allergic diseases. Aims. To evaluate the effect of working schedule on vitamin D levels in bakers. Methods.Forty-four bakers, participating in a survey on the prevalence of occupational allergic diseases, underwent a clinical evaluation, including waist-to-hip ratio (WHR) assessment, vitamin D measurement, spirometry, methacholine challenge, SPT to bakery9s allergens, NET evaluation. Results.Thirty-tree bakers were working at night, while 11 during daytime. Normal vitamin D levels (g30 ng/mL) were observed only in 3 bakers, all of them working during daytime. Median vitamin D level was significantly lower in night workers (15.1 ng/mL, range 4.9-26.3) than in daytime workers (27.1 ng/mL, range 17.8-41.7). Vitamin D deficiency (l20 ng/mL) was observed in 27 night working bakers (82%) but only in one daytime working baker. WHR (Spearman9s rho = -0.406, pl0.01) and the presence of occupational allergic diseases (n=31) were significantly associated with vitamin D levels in univariable analysis. In multivariable analysis only working schedule was a significant predictor of vitamin D levels (pl0.001). According to a quantile regression model, median vitamin D level in night working bakers was lower by 9.6 ng/mL (95% CI 16.3 – 2.9) with respect to daytime working bakers (p=0.006). Conclusion.Vitamin D insufficiency is very common in bakers, especially in night workers. The main risk factor of vitamin D deficiency was working at night, while WHR and occupational allergic diseases did not independently affect vitamin D levels in this small sample.