Department of Dermatology, Stanford University School of Medicine, Pavilion B 2nd Floor, 450 Broadway St, Redwood City, CA 94063, USA.
Cancer Causes Control. 2012 Jan;23(1):133-40. doi: 10.1007/s10552-011-9862-0. Epub 2011 Nov 2.
Sun protection is recommended for skin cancer prevention, yet little is known about the role of sun protection on vitamin D levels. Our aim was to investigate the relationship between different types of sun protective behaviors and serum 25(OH)D levels in the general US population.
Cross-sectional, nationally representative survey of 5,920 adults aged 18-60 years in the US National Health and Nutrition Examination Survey 2003-2006. We analyzed questionnaire responses on sun protective behaviors: staying in the shade, wearing long sleeves, wearing a hat, using sunscreen and SPF level. Analyses were adjusted for multiple confounders of 25(OH)D levels and stratified by race. Our primary outcome measures were serum 25(OH)D levels (ng/ml) measured by radioimmunoassay and vitamin D deficiency, defined as 25(OH)D levels <20 ng/ml.
Staying in the shade and wearing long sleeves were significantly associated with lower 25(OH)D levels. Subjects who reported frequent use of shade on a sunny day had -3.5 ng/ml (p (trend) < 0.001) lower 25(OH)D levels compared to subjects who reported rare use. Subjects who reported frequent use of long sleeves had -2.2 ng/ml (p (trend) = 0.001) lower 25(OH)D levels. These associations were strongest for whites, and did not reach statistical significance among Hispanics or blacks. White participants who reported frequently staying in the shade or wearing long sleeves had double the odds of vitamin D deficiency compared with those who rarely did so. Neither wearing a hat nor using sunscreen was associated with low 25(OH)D levels or vitamin D deficiency.
White individuals who protect themselves from the sun by seeking shade or wearing long sleeves may have lower 25(OH)D levels and be at risk for vitamin D deficiency. Frequent sunscreen use does not appear to be linked to vitamin D deficiency in this population.
防晒被推荐用于预防皮肤癌，但人们对防晒对维生素 D 水平的影响知之甚少。我们的目的是研究不同类型的防晒行为与普通美国人群血清 25（OH）D 水平之间的关系。
这是一项横断面、全国代表性的调查，对象为美国国家健康和营养调查 2003-2006 年期间年龄在 18-60 岁的 5920 名成年人。我们分析了关于防晒行为的问卷回答：待在阴凉处、穿长袖、戴帽子、使用防晒霜和 SPF 级别。分析调整了 25（OH）D 水平的多个混杂因素，并按种族进行分层。我们的主要观察指标是通过放射免疫法测量的血清 25（OH）D 水平（ng/ml）和维生素 D 缺乏症，定义为 25（OH）D 水平<20ng/ml。
待在阴凉处和穿长袖与较低的 25（OH）D 水平显著相关。与很少使用遮阳的人相比，经常在晴天使用遮阳的人血清 25（OH）D 水平低 3.5ng/ml（趋势 p<0.001）。报告经常穿长袖的人血清 25（OH）D 水平低 2.2ng/ml（趋势 p=0.001）。这些关联在白人中最强，在西班牙裔或黑人中则没有达到统计学意义。报告经常待在阴凉处或穿长袖的白人参与者患维生素 D 缺乏症的几率是很少这样做的人的两倍。戴帽子或使用防晒霜与低 25（OH）D 水平或维生素 D 缺乏症无关。
通过寻找阴凉处或穿长袖来保护自己免受阳光照射的白人个体可能会出现 25（OH）D 水平较低，且有患维生素 D 缺乏症的风险。在该人群中，频繁使用防晒霜似乎与维生素 D 缺乏症无关。
