Heat stress as a potential risk factor for vitamin D deficiency

Rising environmental temperatures induced by climate change cause several physiological responses linked to morbidity and mortality. In this context, heat stress may also contribute to vitamin D deficiency (VDD) through its ability to activate the hypothalamus -hypophyseal axis and cortisol release. VDD may be determined by chronic cortisol exposure, becoming an indirect consequence of an imbalance in glucocorticoid metabolism induced by heat stress in living environment. Several studies suggest the ability of cortisol to increase the catabolism of vitamin D by activating the cytochrome P450 enzymes (CYP), especially CYP24A1 and CYP3A1, and to compete with vitamin D at steroid receptor level leading to potential VDD. This phenomenon could also reinforce the weak influence of non-genetic and genetic determinants of change in vitamin D levels.