Sunlight exposure behaviour and vitamin D status in photosensitive patients: longitudinal comparative study with healthy individuals at U.K. latitude

Summary Background Low vitamin D status is prevalent in wintertime in populations at northerly latitudes. Photosensitive patients are advised to practise sun avoidance, but their sunlight exposure levels, photoprotective measures and resulting vitamin D status are unknown. Objectives To examine seasonal vitamin D status in photosensitive patients relative to healthy individuals and to assess quantitatively behavioural and demographic contributors. Methods This was a longitudinal prospective cohort study (53·5°N) examining year‐round 25‐hydroxyvitamin D [25(OH)D] levels, sun‐exposure behaviour and oral vitamin D intake in photosensitive patients diagnosed at a photoinvestigation unit (n = 53), compared with concurrently assessed healthy adults (n = 109). Results Photosensitive patients achieved seasonal 25(OH)D variation, but insufficient (