介绍
在加拿大，皮肤癌是最常见的癌症，仅仅非黑色素瘤皮肤癌（NMSC）就至少占新发癌症病例的40%。2014年， 加拿大估计新发了6500例新黑色素瘤病例和76100例NMSC病例。由于人口老龄化，预计未来几十年皮肤癌的发病率将上升。大多数皮肤癌可通过减少自然和人工紫外线照射（UV）来预防，因此，关于防晒的公众教育和宣传至关重要。有关防晒的安全教育的两个关键信息是定期使用防晒霜和物理保护，如衣服、帽子、太阳眼镜和遮光帘。
防晒因子（SPF）是美国FDA于1978年首次采用的防晒因子，防晒效果已被广泛接受。在加拿大，防晒霜由加拿大卫生部批准和管理。
物理防晒
紫外线防护服是否优于常规服装?
防护服是一种简单的光防护方法。加拿大消费者紫外线防护服装指南提到了紫外线防护系数（UPF），这是一种标准化的体外测量方法，用于测量服装的紫外线防护等级。目前，UPF15和20被评为良好的光保护；UPF25、30和35都很好；UPF40、45、50和 50+则被评为优秀。对于理想的最低UPF因子，加拿大没有指导方针，而欧洲标准推荐UPF40+。
UPF等级受到多种异质因素的影响，包括组织密度、成分、颜色、织物厚度、拉伸、湿度和织物状况。两项研究表明，深色厚而重的衣服能提供更多的保护。类似地，一项体外研究发现，一件带有不同厚度的白色垂直条纹的仿英国足球衫的 UPF，其较薄条纹的UPF值为5，较厚条纹的值为11，这凸显了服装厚度的重要性。对于织物成分，大量研究表明，莱卡/弹性纤维织物最有可能具有50或更高的 UPF，其次是塑料、尼龙和聚酯。因此，消费者在选择防紫外线服装时，检查UPF 标签非常重要。如果没有UPF标签，一般来说，消费者应该选择织物重量更大、更厚、编织更紧密、颜色更深的服装，以及由莱卡/聚酯制成的服装，因为这些特点通常会导致更好的光保护。此外，消费者应该意识到，当UPF值随着拉伸、潮湿和多次洗涤而降低时，薄的、湿的或拉伸的服装可能提供降低的紫外线防护。
建议：有充分的证据支持使用光防护服，因为它提供了出色的持续光防护，且具有明确的UPF评分等级，消费者可以清楚地知道其光防护能力的大小。虽然某些常规衣物可能提供类似的光防护，但常规衣物的光防护范围更广，变化更大从不充分到极好，使得消费者很难确切地评估其光防护能力。此外，由于普通服装很难做得很轻，如果价格合理，在炎热的夏天，避光布是消费者的理想选择。当选择没有UPF标签的常规服装时，消费者应该选择编织更紧密、织物重量更重、厚度更厚、颜色更深、由莱卡/聚酯纤维组成并且覆盖更多皮肤的服装。评估普通服装的一个实用技巧是将服装放在光源前，看看光线是否透过。消费者还应该认识到，水分、织物拉伸和织物降解会降低UPF系数。需要进一步的研究来比较不同条件下的各种UPF服装和普通服装的光防护能力。
Minimum Protection in Sunglasses.
太阳镜的最低防护
英文原文
Chronic UV radiation (UVR) is a known risk factor for cataracts, age-related macular degeneration, and pterygium.There is also the risk of skin cancer involving the delicate skin adjacent to the eye that is typically not protected by sunscreen. The Canadian sunglass industry is self-regulated, and manufacturers com- ply with voluntary standards when classifying their sun- glasses as cosmetic (block 0%-60% visible light and UVA and 87.5%-95% of UVB), general purpose for daily activi- ties (block 60%-92% visible and UVA and 95%-99% of UVB), or special purpose, ie, for skiing (block up to 97% of visible light, up to 98.5% of UVA, and at least 99% of UVB rays), as outlined in Health Canada 2010 guidelines. How- ever, Dain et al.demonstrated that 17% of the 646 pairs of sunglasses tested failed to meet voluntary standards, despite being labelled as such.
对应中文
慢性紫外线辐射（UVR）是白内障、老年性黄斑病变和翼状胬肉的一个已知风险因素。还可能增加眼睛附近脆弱皮肤患皮肤癌的风险，这部分皮肤通常没有防晒霜的保护。如加拿大卫生部2010年指南所述，加拿大的太阳镜行业是自我监管的，制造商遵循自愿标准将其生产的太阳镜分为化妆品（阻挡0%-60%可见光和UVA以及87.5%-95%UVB）、日常活动的一般用途（阻挡60%-92%可见光和UVA以及95%-99%UVB）、以及特殊用途如滑雪（阻挡高达97%的可见光，高达98.5%的UVA和至少99%的UVB射线）。然而，Dain等人证明，646副太阳镜中有17%没有达到上述标准，尽管都贴了上述标签。
英文原文
Health Canada 2010 guidelines recommend only general- purpose sunglasses for driving and special-purpose glasses for prolonged sun exposure. General-purpose sunglasses are often marketed as “UV absorption up to 400 nm,” the equiv- alent of 100% UV absorption.
对应中文
加拿大卫生部2010年指南仅建议驾驶时佩戴一般用途太阳镜，长时间阳光照射时则佩戴专用太阳镜。一般用途太阳镜在市场上通常被标榜为“紫外线吸收高达400纳米”，相当于能吸收100%的紫外线。
英文原文
Ophthalmologists and optometrists also recommend the combination of a hat with sunglasses to minimize light from entering from the side or top of sunglass frames and then reflecting off the inner surface of the lens and into the eye.A study by Sliney et al, using simulated ocular geometry, demonstrated that the human eye receives at least 5% of the UVR dose when wearing clear lenses opaque to the UVR because of the lack of protection above and to the sides of sunglasses. This is also why the “wrap-around” style of sun- glasses is often recommended.
对应中文
眼科医生和验光师还建议将帽子和太阳镜结合起来，以尽量减少从太阳镜镜框侧面或顶部进入然后从镜片内表面反射到眼睛的光线。Sliney等人利用模拟的眼睛几何学进行的一项研究表明，由于太阳镜上方和侧面缺乏保护，当佩戴不透过UVR的透明镜片时，到达人眼的UVR剂量为5%以上。这也是为什么经常推荐”环绕式”太阳镜的原因。
英文原文
Patients should be aware that darker sunglasses do not necessarily provide superior ocular UV protection, as darker glasses could result in greater pupil dilation and increased UV exposure to the lens.
对应中文
患者应该意识到，深色太阳镜并不一定能提供更好的眼部紫外线保护，因为深色眼镜可能导致瞳孔更大，对镜片的紫外线暴露增加。
英文原文
Recommendation: For daily activities, patients should wear general-purpose sunglasses in conjunction with a broad-brimmed hat to reduce the amount of UVR reaching the eyes. Better-quality studies are needed to further quan-tify the absolute risk reduction of wearing sunglasses and in combination with broad-brimmed hats. Physicians should specifically emphasize the importance of sun-glasses to groups who are most at risk, namely individuals who experience high-UV occupational exposure as well as men and minorities. Greater efforts should be made to simplify labelling so patients can easily identify the pur-pose of sunglasses (cosmetic, general purpose, or special activity).
对应中文
建议：在日常活动中，患者应戴上通用太阳镜，同时戴上宽边帽，以减少紫外线照射到眼睛的量。需要更高质量的研究来进一步量化戴太阳镜和戴宽边帽的绝对风险降低。医生应特别强调太阳眼镜对高危人群的重要性，即经历高紫外线职业暴露的个人以及男性和少数民族。应尽更大努力简化标签，以便患者能够轻松识别太阳镜的用途（化妆品、一般用途或特殊活动）。
What is the Recommended Sun-Protection Factor of Sunscreens?
防晒霜的防晒系数是多少？
英文原文
Although there is a common misconception that SPF values are multiplicative (SPF 30 sunscreen is in fact not twice as effective compared with SPF 15), there is abun- dant evidence suggesting that higher SPF is indeed more effective at sun protection. A randomized, double-blind, split-face, natural sunlight exposure clinical trial demon- strated that SPF 100+ sunscreen was significantly more effective in protecting against sunburn than SPF 50+ sun- screen, with 55.3% of their participants more sunburned on the SPF 50+ protected side compared with 5% on the SPF 100+ protected side. In addition, 40.7% exhibited increased erythema scores on the SPF 50+ -protected side as compared with 13.6% on the SPF 100+-protected side. Similarly, Russak and colleagues demonstrated statisti- cally significantly lower cases of sunburn with application of SPF 85 sunscreen compared with SPF 50 and Pissavini and Diffey showed that SPF 30 application had only 11% of skin exhibiting erythema as compared with 46% with SPF 15.
对应中文
虽然有一个普遍的误解，即SPF值是倍增的（SPF30防晒霜的防晒效果实际上并不是SPF15的两倍），但有大量证据表明，SPF值越高，防晒效果就越明显。一项随机、双盲、对照、自然阳光照射的临床试验证明SPF100+防晒霜比SPF50+防晒霜更有效地防止晒伤，55.3%的受试者在SPF50+保护的一侧被晒伤的次数比SPF100+保护的一侧多5%。此外，与SPF100+保护侧的13.6%相比，SPF50+保护侧的红斑评分增加了40.7%。类似地，Russak等研究表明，与SPF50相比，使用SPF85防晒霜的晒伤病例在统计上显著降低。Pissavini和Diffey的研究结果显示，SPF30防晒霜只有11%的皮肤出现红斑，而SPF15防晒霜的皮肤红斑发生率为46%。
英文原文
Recommendation: A broad-spectrum sunscreen with UVA as well as UVB filters and SPF of at least 30 should be applied, and even-higher SPF sunscreens may be used to compensate for common underapplication of sunscreen. Patients should be educated on the importance of proper application and other important factors affecting effective- ness of sunscreen apart from the SPF value.
对应中文
建议：应使用含有UVA以及UVB滤光成分和SPF至少为30的广谱防晒霜，甚至可以使用更高SPF的防晒霜来弥补常见的防晒霜使用不足的情况。应教育患者正确使用防晒霜的重要性以及除SPF值外影响防晒霜有效性的其他重要因素。
What is the Preferred Vehicle of Sunscreens?
防晒霜的首选载体是什么？
英文原文
Recommendation: The W/O emulsion is the recom- mended formulation for sunscreens to achieve highest SPF and water resistance. Generally, sunscreens labelled as water resistant with higher SPFs are typically W/O emulsions, whereas those without water-resistant labelling are typically O/W emulsions. However, patient preference for a vehicle with O/W because of its lighter feel and noncomedogenic properties can significantly affect use and therefore may take precedence.
对应中文
推荐：W/O乳液是防晒霜的推荐配方，可获得最高的防晒指数和防水性。一般来说，标有高SPF防水标签的防晒霜通常是W/O乳液，而那些没有防水标签的防晒霜通常是O/W乳液。然而，通常O/W载体更受欢迎，因为它的肤感较轻、且不会导致粉刺，这些特质可能会显著影响人们的使用偏好，因此在对于防晒霜来说这些特质可能会被优先考虑。
Should Inorganic or Organic Sunscreens Be Used?
应该使用无机或有机防晒霜？
英文原文
Inorganic (physical) sunscreens were traditionally thicker and whiter formulations, which were not aesthetically pleasing. In a small study, most people applied only about 65% of the quan- tity of inorganic sunscreens compared with organic sun- screens. As a result, the measured SPF of inorganic sunscreens was less than half the organic (chemical) ones.Since the development of micronized particles, many current micron- ized inorganic sunscreens are much less visible on the skin.
对应中文
无机（物理）防晒霜传统上是更厚、更白的配方，不美观。在一项小型研究中，与有机防晒霜相比，大多数人只使用了约65%的无机防晒霜。结果，无机防晒霜的实测SPF小于有机（化学）防晒霜的一半以上。但由于微粒化技术的发展，目前许多微粒化无机防晒霜在皮肤上的可见度已经低很多了。
When Should Water-Resistant Sunscreens Be Used?
什么时候应该使用防水防晒霜？
英文原文
Water- resistant labelling of a sunscreen is determined by how well it binds to skin and withstands adverse conditions such as swimming, sweating, friction, and removal through other physical contact.Currently, Health Canada’s 2018 primary sunscreen monograph defines a sunscreen product as either water/sweat resistant for 40 or 80 minutes if it retains protec- tive properties for 40minutes and 80 minutes, respectively, following moderate activity in 23°C to 32°C (73°F to 90°F) indoor fresh water. Furthermore, “waterproof” or “sweat- proof” labels are considered misleading and thus should not be used, reflecting the lack of evidence behind claims of pro- longed protection. Stokes and Diffey found that nearly all the protective effect of non–water-resistant products disap- peared after 20 minutes of water immersion, and there were no significant differences between SPF retention in “water- resistant” compared with “waterproof” products.
对应中文
防晒霜的防水标签取决于它与皮肤的结合程度，以及它能经受住游泳、出汗、摩擦和通过其他身体接触去除等不利条件的程度。目前，加拿大卫生部2018年初选防晒霜专著将防晒产品定义为防水/防汗40分钟或80分钟，如果在23°C至32°C（73°F至90°F）的室内淡水中适度活动后，防晒产品分别保持40分钟和80分钟的保护性能。此外，“防水”或“防汗”标签被视为具有误导性，因此不应使用，这反映了长期保护主张背后缺乏证据。Stokes和Diffey发现，在浸水20分钟后，几乎所有非防水产品的保护作用都消失了，与“防水”产品相比，“防水”产品的防晒系数保留率没有明显差异。
英文原文
Other than water resistance, friction- or rub-resistant prop- erties could affect the photoprotective effect of sunscreens as well. Stokes and Diffey measured SPF values prior to and after agitation with sand and found that even after allowing 20 minutes for the sunscreen to dry, 15%-60% of the photopro- tective effect was lost after contact with the sand.
对应中文
除了防水之外，耐磨或耐磨的特性也会影响防晒霜的光保护效果。Stokes和Diffey等测量了沙子搅拌前后防晒霜SPF值的变化，发现即使在防晒霜干燥20分钟后，与沙子的接触和摩擦也会让防晒霜的效果丧失15%-60%。
Lip Protection.
唇部保护
英文原文
Lip protection is an important component of safe-sun practice. UVR has been well demonstrated as a risk factor for the development of lip cancers.UV filters are available in many commercial products such as lip balm, lip gloss, and lipstick. Use of photoprotective lip products among female farmers has been correlated to decreased risk of lip cancers.There are no specific recommendations regarding SPF and application of lip sunscreens from the FDA or Health Canada. When applied to the lip, the SPF value of lipsticks was on average 1.2units lower than the label SPF of 16.
对应中文
唇部保护是安全防晒的重要组成部分。UVR已被证明是唇癌发展的一个危险因素。紫外线过滤器在许多商业产品中都有，如唇膏、唇彩和口红。女性使用光保护唇部产品与降低患唇癌的风险相关。FDA或加拿大卫生部没有关于SPF和使用唇部防晒霜的具体建议。当涂在嘴唇上时，唇膏的SPF值平均比标签SPF16低1.2个单位。
REFERENCES
1.Li H, Colantonio S, Dawson A, Lin X, Beecker J. Sunscreen Application, Safety, and Sun Protection: The Evidence. J Cutan Med Surg. 2019;23(4):357-69.