Endocrine Abstracts

Vitamin D is a pleotropic hormone with important actions in a wide variety of cell types. Whilst its role in the endocrine control of calcium metabolism via the active circulating metabolite 1,25- dihydroxy cholecalciferol is widely appreciated, other actions in a range of cells and tissues depend on activation of circulating 25-hydroxy vitamin D by intracrine mechanisms and paracrine actions which may be locally controlled. Of particular interest are the roles of vitamin D pertaining to innate immunity, the antimicrobial response and inflammation which are the focus of considerable study and debate. Dietary sources of vitamin D are generally inadequate and most vitamin D is produced by ultraviolet B exposure of the skin which at temperate latitudes is restricted to the summer months. We aimed to study the seasonal variation of vitamin D in our local adult population (>18y) in Preston Lancashire UK by examining vitamin D requests in our laboratory database. Twelve months of anonymised requests from primary care were retrieved from December 2018 to November 2019 and stratified by month and gender. Vitamin D was requested considerably more frequently in women than men. There was a noticeable seasonal variation in both sexes with the highest values in late summer (July to September) and the lowest values in winter (January to March). Except in July and August values were higher in women. Vitamin D deficiency was more common in men than women and more pronounced in the winter months. These observations suggest a hitherto unrecognised gender related health inequality and lend further support to the use of seasonally adjusted ranges when assessing vitamin D status.