Photobiology Unit, Ninewells Hospital & Medical School, Dundee, UK.
Photodermatol Photoimmunol Photomed. 2012 Apr;28(2):91-6. doi: 10.1111/j.1600-0781.2011.00644.x.
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.
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).
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.
背景/目的：维生素 D 水平较低与健康的不良影响有关。维生素 D 的主要来源是阳光照射时皮肤的合成。避免阳光照射会限制维生素 D 的光合作用，这在对光敏感的患者中是常见的做法。很少有研究检查过这一人群的维生素 D 状况，尤其是在高纬度地区。因此，本研究的目的是调查在苏格兰邓迪的光生物学单位接受三级光诊断服务的患者中维生素 D 状态低下的发生率和可能的预测因素。
对 165 名在苏格兰邓迪的国家光诊断服务处就诊的患者进行了为期 1 年的病历回顾，评估他们在光生物单位的情况（纬度 56°N）。记录了临床信息和血清 25-羟维生素 D（25（OH）D）浓度。采用多元分析来确定维生素 D 状态的预测因素。
平均 25（OH）D 浓度为 41.9 nmol/L（标准差 22.0）。40%的患者维生素 D 水平不足[25（OH）D 25-49 nmol/L]，25%的患者维生素 D 缺乏[25（OH）D<25 nmol/L]。冬季采血是低 25（OH）D 状态的最强预测因素（P<0.001）；严格的光保护（P=0.04）、症状在阳光暴露后 1 小时内出现（P=0.01）和异常单色仪光测试反应（P=0.009）也预测了低维生素 D 水平。即使在严格避免阳光照射的患者中（P=0.03），补充剂的使用也与更高的维生素 D 水平相关（P<0.001）。
生活在高纬度地区的对光敏感的患者维生素 D 水平低的风险很高，尤其是在冬季和春季。提高对这种风险的认识对于确保实施预防策略至关重要，如补充剂。
