Sunscreens used at the beach do not protect against erythema: A new definition of SPF is proposed
Sunscreens used at the beach do not protect against erythema: A new definition of SPF is proposed
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海滩使用的防晒霜不能预防红斑：提出了 SPF 的新定义
DOI：
10.1111/j.1600-0781.1997.tb00215.x
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Jørgen Lock
中科院分区：
文献类型：
--
作者：
H. C. Wulf;I. Stender;Jørgen Lock
由于防晒霜是由医生推荐的，并且在世界各地使用，以防止太阳引起的红斑，因此评估防晒霜是否按建议使用以及是否达到预期效果非常重要。我们参考了几项研究的结果，这些研究是对丹麦哥本哈根附近海滩上有晒伤风险的人进行的。在一个阳光明媚的日子里，在海滩，65%的日光浴者使用了一种或多种防晒霜。其中，46%的人在全身使用防晒霜，使用的防晒系数（SPF）中位数为5-6。日光浴者使用0.5 mg/cm 2的防晒霜，与皮肤类型无关。在防晒霜使用者中，43%在到达海滩后涂抹防晒霜，43%在游泳后重新涂抹防晒霜。防晒霜使用者和非防晒霜使用者的阳光暴露时间和阳光暴露剂量几乎相同。自我评估的皮肤发红表明，防晒霜使用者比非使用者报告在阳光照射后第二天发红，分别为42%和34%。理论计算支持这一发现，并显示出在实现的光保护，如果使用比在测试情况下更薄的层急剧减少。如果不按预期使用，防晒霜不能防止红斑。与其改变人们的习惯，我们建议修改测试方法，将防晒霜的量调整为真实的生活中使用的量，即0.5 mg/cm 2。
Since sunscreens are recommended by doctors and used all over the world to protect against sun induced erythema, it is important to evaluate if sunscreens are used as recommended and if the intended effect is achieved. We refer to the findings of several studies performed on people at risk of sun‐burning at beaches in the vicinity of Copenhagen, Denmark. On a sunny day at the beach 65% of the sunbathers used one or more sunscreens. Of these, 46% used the sunscreen all over the body and a median sun protection factor (SPF) of 5–6 was used. The sunbathers used 0.5 mg/cm2 of sunscreen independent of skin type. Of the sunscreen users, 43%> applied the sunscreen after arriving at the beach and 43% reapplied the sunscreen after swimming. The sun exposure time and the sun exposure dose were almost identical among sunscreen users and non‐users. Self‐assessed redness of the skin demonstrated that more sunscreen users than non‐users reported to be red the day after sun exposure, 42 and 34%, respectively. Theoretical calculations support this finding and show a drastic reduction in the achieved photoprotection if a thinner layer than in the test situation is used. Sunscreens do not protect against erythema if not used as intended. Instead of changing people's habits, we suggest modifying the test method by adjusting the amount of sunscreen to that used in real life situations, 0.5 mg/cm2.