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Photosensitivity strongly associated with low vitamin D levels – March 2012

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

Suzanne M. Reid1,
Mark Robinson2,
Alastair C. Kerr1,
Sally Helen Ibbotson1,.h.ibbotson@dundee.ac.uk
1 Photobiology Unit, Ninewells Hospital & Medical School, Dundee, UK
2 Public Health Observatory Division, NHS Health Scotland, Glasgow, UK
DOI: 10.1111/j.1600-0781.2011.00644.x
© 2012 John Wiley & Sons A/S
Photodermatology, Photoimmunology & Photomedicine, Volume 28, Issue 2, pages 91–96, April 2012

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.

A case note review of 165 patients who attended the National Photodiagnostic Service for assessment at the Photobiology Unit in Dundee, Scotland (latitude 56°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.

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.

For people who were photosensitive the annual concentrations (much worse in winter) were:

  • 65 % had less than 20 nanograms
  • 25 % had less than 10 nanograms

Yes, people staying out of the sun are expected to have low levels of vitamin D
Previously there have been hints that increasing vitamin D levels will reduce photosensitivity.
This abstract has nothing which supports nor denies those hints.

See also VitaminDWiki