Prevalence and predictors of low vitamin D status in patients referred to a tertiary photodiagnostic service: a retrospective study

Suzanne M. Reid, Mark Robinson, Alastair C. Kerr, Sally Helen Ibbotson

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    Background/Purpose: Low vitamin D levels have been associated with adverse effects on health. The primary source of vitamin D is cutaneous production during sunlight exposure. Sun avoidance can restrict vitamin D photosynthesis and is common practice amongst patients with photosensitivity. Few studies have examined vitamin D status in this population, particularly those in northern latitudes. The purpose of this study was therefore to investigate the prevalence and possible predictors of low vitamin D status in patients referred to a tertiary photodiagnostic service.

    Methods: A case note review of 165 patients who attended the National Photodiagnostic Service for assessment at the Photobiology Unit in Dundee, Scotland (latitude 56 degrees N) over 1 year was conducted. Clinical information and serum 25-hydroxyvitamin D (25(OH) D) concentration were documented. Multivariate analyses were used to identify predictors of vitamin D status.

    Results: Mean 25(OH) D concentration was 41.9 nmol/L [standard deviation (SD) 22.0]. Forty percent of patients had insufficient vitamin D levels [25(OH) D 25-49 nmol/L] and 25% were vitamin D deficient [25(OH) D < 25 nmol/L]. Blood collection in winter was the strongest predictor of low 25(OH) D status (P < 0.001); strict photoprotection (P = 0.04), onset of symptoms within an hour of sunlight exposure (P = 0.01) and abnormal monochromator phototesting responses (P = 0.009) also predicted low vitamin D levels. Supplement use was associated with higher vitamin D levels (P < 0.001), even amongst patients who strictly avoided sunlight (P = 0.03).

    Conclusions: Patients with photosensitivity who live in northern latitudes are at high risk of low vitamin D levels, particularly in winter and spring. Increased awareness of this risk is crucial to ensure preventative strategies, such as supplementation, are implemented.

    Original languageEnglish
    Pages (from-to)91-96
    Number of pages6
    JournalPhotodermatology, Photoimmunology & Photomedicine
    Issue number2
    Publication statusPublished - Apr 2012


    • Scotland
    • Vitamin D
    • Humans
    • Adult
    • Retrospective Studies
    • Chromatography, Liquid
    • Middle Aged
    • Tandem Mass Spectrometry
    • Male
    • Female
    • Prevalence

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