Sun Exposure in Children: Balancing the Benefits and Harms
Abstract
摘要
英文原文
There is a common belief among the laity and even physicians that sun exposure is a useful source of vitamin D. However, despite the fact that sun exposure occurs almost throughout the year in India, vitamin D deficiency is widely prevalent. Although several authors have reported on the duration of sun exposure required to synthesize adequate amounts of vitamin D in the human body, they have not followed a standard and uniform protocol for measurement of sun exposure and vitamin D synthesis. For these and many other reasons, the results are difficult to interpret. The American Academy of Pediatrics (AAP) has clearly stated that infants should be protected from the sun as much as possible and vitamin D requirements should be met through diet and fortified foods rather than deliberate sun exposure. However, this recommendation is frequently ignored in clinical practice. This review aims to summarize the available literature on benefits and harm of unprotected sun exposure in infants and children with a focus on skin phototype IV to VI. Dermatologists and pediatricians in India should counsel parents about the need for sun protection, especially in fair-skinned infants and children.
对应中文
普通人甚至医生都普遍认为，阳光照射是维生素D的有效来源。然而，尽管印度几乎全年都有阳光照射，但维生素D缺乏症却普遍存在。虽然有几位作者报告了人体合成足量维生素D所需的日照时间，但他们没有遵循标准和统一的方案来测量日晒和维生素D合成。由于这些和许多其他原因，结果很难解释。美国儿科学会（AAP）明确表示，应该尽可能保护婴儿免受阳光照射，并应通过饮食和强化食品来满足维生素D的需求，而不是故意暴露在阳光下。然而，这一建议在临床实践中经常被忽视。本综述旨在总结有关婴儿和儿童无保护阳光照射的益处和危害的现有文献，重点是IV至VI型皮肤。印度的皮肤科医生和儿科医生应向家长建议防晒的必要性，尤其是对于皮肤白皙的婴儿和儿童。
Introduction
介绍
英文原文
It has been a common belief among the laity and medical professionals that sun exposure is the principal source for the synthesis of vitamin D in human body.Vitamin D synthesized in the skin by ultraviolet (UV) rays of the sun has been considered to meet nearly 90% of the daily requirement.It has been suggested that sunlight exposure for approximately 15–30 min twice or thrice a week is sufficient to produce the required amount of vitamin D.However, there is little or no corroboration for this fact. Several other important aspects related to sunlight exposure (e.g., photoaging, predisposition to skin cancer, cataract, retinal injury, and autoimmune diseases) have largely been overlooked. Recent reports on vitamin D status in India have suggested that majority of the population (including neonates, children, adolescents, adults, and pregnant women) has deficient levels.This is probably a reflection of dietary deficiency rather than lack of exposure to sunlight.
对应中文
大众和医学专业人士都普遍认为，阳光照射是人体合成维生素D的主要来源。通过太阳紫外线（UV）在皮肤中合成的维生素D被认为可以满足近90%的日常需求。有人提出，一周两次或三次日光照射大约15-30分钟就足以产生所需的维生素D。然而，这一事实几乎没有或没有得到证实。与阳光暴露有关的其他几个重要方面（例如，光老化、皮肤癌的易感性、白内障、视网膜损伤和自身免疫性疾病）在很大程度上被忽视了。最近关于印度维生素D状况的报告表明，大多数人口（包括新生儿、儿童、青少年、成年人和孕妇）维生素D水平不足。这可能是饮食不足的反映，而不是缺乏阳光照射。
What are the Types of UV Radiation?
紫外线辐射有哪些类型？
英文原文
The UV radiation is classified into three different types based on its wavelength.UV-A (wavelength 320–400 nm) is most abundant of all types of UV radiation, but it causes relatively less skin damage. UV-A rays are potentially carcinogenic.UV-B (wavelength 290–320 nm) is also found in the solar spectrum of the earth. The UV-B rays are erythemogenic and potentially carcinogenic. The daily body exposure to UV-B rays is much less than that of UV-A rays.
UV-C rays (wavelength 200–290 nm) are most dangerous, but fortunately, UV-C rays are absent in the solar spectrum of the earth because of effective filtration by the ozone layer.
对应中文
根据波长的不同，紫外线辐射可分为三种不同的类型。UVA（波长320-400 nm）是所有类型的紫外线辐射中最丰富的，但它对皮肤的损害相对较小，但具有潜在的致癌性。在地球的太阳光谱中也发现了UVB（波长为290-320 nm）。UVB射线会导致红斑，并可能致癌。人体每天暴露在UVB射线下的量比UVA射线要少得多。
UVC射线（波长200-290纳米）是最危险的，但幸运的是，由于臭氧层的有效过滤，UVC射线在地球的太阳光谱中是不存在的。
What are the Harmful Effects of UV Rays?
紫外线的危害是什么？
英文原文
UV rays are immunosuppressive. UV-B rays damage the dendritic cells in the skin and stimulate the regulatory T cells to produce the immunosuppressive cytokine, IL-10.UV radiations lead to DNA strand breaks and pyrimidine dimerization. UV rays also lead to the externalization of nuclear antigens on the cell surface and the synthesis of neoantigens that may flare autoimmune diseases like lupus.Photoaging is another complication of prolonged UV rays exposure. Various epidemiological studies have shown that sunlight exposure is one of the main risk factors for melanoma and nonmelanoma skin cancer (NMSC) development.This risk is highest in the white population, thus, suggesting the protective effect of melanin.It has also been found that the risk of developing skin cancer is higher when there is exposure to UV rays during childhood as compared with the risk when exposure occurs in older age group.Targeting children through schoolbased education and policy strategies for sun protection are being increasingly advocated for melanoma prevention. It has been hypothesized that exposure to UV rays in early age group can damage the DNA of melanocytes, and these melanocytes have the potential of malignant transformation later in life.However, studies advocating childhood sun protection for prevention of melanoma and NMSC were in individuals with skin phototype I–III. Currently, such data about the risk of photodamage, predisposition to develop melanoma and NMSC, and risk reduction with advocacy of childhood photoprotection in pigmented skin phototypes IV–VI is lacking.
对应中文
紫外线具有免疫抑制作用。UV-B射线破坏皮肤中的树突状细胞，刺激调节性T细胞产生免疫抑制细胞因子IL-10。紫外线辐射导致DNA链断裂和嘧啶二聚。紫外线还会导致细胞核抗原在细胞表面外化，并合成新的抗原，从而可能引发狼疮等自身免疫性疾病。光老化是紫外线长期照射的另一个并发症。各种流行病学研究表明，阳光照射是黑色素瘤和非黑色素瘤皮肤癌（NMSC）发展的主要风险因素之一。这种风险在白人人群中最高，因此表明黑色素的保护作用。还发现，与年龄较大的人群暴露在紫外线下相比，儿童时期暴露在紫外线下患皮肤癌的风险更高。越来越多的人主张通过学校为基础的教育和防晒政策策略来预防黑色素瘤。据推测，早期暴露于紫外线会损害黑素细胞的DNA，并且这些黑素细胞在以后的生活中有可能发生恶性转化。然而，提倡儿童防晒以预防黑色素瘤和非黑色素瘤皮肤癌的研究针对的是I-III型皮肤病患者。目前，缺乏关于光损伤风险、发展黑色素瘤和非黑色素瘤的易感性以及支持IV–VI型色素沉着皮肤光保护的儿童期风险降低的此类数据。
What are the Beneficial Effects of UV Rays?
紫外线有什么好处？
英文原文
Sun exposure and vitamin D synthesis;A feeling of well being;Treatment of certain dermatosis like vitiligo and psoriasis.
对应中文
阳光照射和维生素D合成；好情绪；治疗某些皮肤病，如白癜风和银屑病 (牛皮癣)。
How Much Sun Exposure is Sufficient to Synthesize Daily Requirement of Vitamin D in the Body?
日晒多少才足以合成人体每日所需的维生素D？
英文原文
The amount of sun exposure needed to synthesize adequate vitamin D depends upon the type of skin,time of the day, the month of the year, and the latitude.The duration needed in an individual with dark skin is about 10 times that in fair-skinned individuals. It has been suggested that exposure to sunlight for 5 min to 5 h per day (depending upon the above-mentioned factors) may be sufficient to synthesize our daily requirement of vitamin D.However, these studies have serious methodological issues and, consequently, the conclusions that have been drawn may, in fact, be somewhat erroneous.
对应中文
合成足够维生素D所需的日照时间取决于皮肤类型、一天中的时间、一年中的月份和纬度。皮肤黝黑的人所需的时间大约是皮肤白皙的人的10倍。有人提出，每天暴露在阳光下5分钟到5小时(取决于上述因素) 可能足以合成我们每天所需的维生素D。然而，这些研究存在严重的方法学问题，因此，所得出的结论实际上可能是错误的。
Should Infants Ever be Exposed to Sunlight?
婴儿应该暴露在阳光下吗？
英文原文
It is a common practice in India to expose neonates and infants to sunlight, and pediatricians may often encourage it under the mistaken notion that this may help in facilitating the resolution of neonatal jaundice. Though exposure of infants and children has advantages (as listed above), there is some evidence that this practice may be associated with long-term risk of developing skin cancers and the risk is greatest if such exposure occurs in very young children and infants with fair skin.
对应中文
在印度，让新生儿和婴儿暴露在阳光下是一种常见的做法，儿科医生可能经常鼓励这样做，因为他们错误地认为这可能有助于解决新生儿黄疸。虽然婴儿和儿童接触有好处(如上所述)，但有一些证据表明，这种做法可能与患皮肤癌的长期风险有关，如果这种暴露发生在非常年幼的儿童和皮肤白皙的婴儿身上，风险最大。
Do We Need to Apply Sunscreen During Air Travel?
我们在航空旅行中需要涂防晒霜吗？
英文原文
There are no recommendations for the application of sunscreen during air travel. However, there is very high exposure to UV rays in flights primarily because of high altitude. Hence, it may be advisable to use sunscreen throughout the period of air travel, especially, among the frequent travelers and airline crew.
对应中文
在航空旅行中，没有关于使用防晒霜的建议。然而，在飞行中，主要由于海拔高，紫外线的照射量非常大。因此，建议在整个航空旅行期间使用防晒霜，特别是在经常旅客和机组人员中。
What Does the American Academy of Pediatrics Recommend?
美国儿科学会推荐什么？
英文原文
Excess exposure to UV rays (both natural and artificial tanning sources) in children and adolescents may lead to increased risk of skin cancers and some of these may be fatal.Morbidity and mortality resulting from UV exposure are completely preventable.Exposure to excess UV rays should be avoided.Supplemental vitamin D (either from diet or through medicinal preparations) should ideally be given to all children.Pediatricians and dermatologists have an important role in educating parents so that they can teach their children about ways of sun protection from very early on in life. Photo-protection behavior counseling should be included at least once among the many counseling sessions between parents and caregivers.Infants less than 6 months old must be protected from UV rays as much as possible and should preferably be kept away from sunlight.In fact, the American Academy of Pediatrics (AAP) has stated that “Use of deliberate sun exposure to maintain vitamin D sufficiency is not recommended” and “Infants younger than 6 months should be kept out of direct sunlight as much as possible.”There are very strict recommendations on photoprotection in Australia. Under “No hat, no play” policy, children cannot play outdoors if they are not wearing a hat.
对应中文
儿童和青少年过度暴露于紫外线 (天然和人工晒黑来源) 可能会增加患皮肤癌的风险，其中一些可能是致命的。紫外线照射导致的发病率和死亡率是完全可以预防的。应避免暴露在过量的紫外线下。理想情况下，应该给所有儿童补充维生素D (通过饮食或药物制剂)。儿科医生和皮肤科医生在教育父母方面扮演着重要的角色，这样他们就可以从很小的时候就教孩子防晒的方法。在父母和照顾者之间的许多咨询会议中，照片保护行为咨询应该至少包括一次。6个月以下的婴儿必须尽可能地免受紫外线伤害，最好远离阳光。事实上，美国儿科学会（AAP）曾表示，“不建议有意暴露在阳光下以保持维生素D充足”，“6个月以下的婴儿应尽可能避免阳光直射。”澳大利亚对光保护有非常严格的建议。根据 “不戴帽子不玩耍”的政策，如果孩子们不戴帽子，就不能在户外玩耍。
What are Various Methods of Sun-Protection in Children?
儿童防晒的方法有哪些？
英文原文
There are many ways by which one can prevent excessive exposure to UV rays.Sunscreen-Use of sunscreen is perhaps the least costeffective and is the commonly used method to avoid UV rays. Sunscreen is a product designed to protect or shelter viable skin cells against the potentially harmful effects of UV radiation, such as sunburn and skin cancer. Almost all sunscreens have a combination of an organic compound (usually, liquid preparation that absorbs UV rays and dissipates it in the form of heat) and an inorganic compound (usually, minerals that protects from UV rays by reflecting from the surface). The proportion of organic and inorganic compounds in sunscreen lotions varies from preparation to preparation. However, because of the cost and compliance issues, the effective use of sunscreens on Indian patients cannot be generally ascertained. Therefore, avoiding direct sunlight as detailed in the following section becomes important.Avoiding the sun using shades-UV rays are maximally present during the day time (from 10 am to 4 pm); hence, it is recommended to avoid sun exposure during this time. Shades (by using an umbrella or standing under a tree) prevent the direct exposure to sunlight but reflected UV rays can still reach the skin. Moreover, using shades also reduces the heat effect of sunlight, thereby, giving a false sense of security from UV rays. Avoidance of sunlight as much as possible, especially during the peak hours, and use of protective shades is a costeffective measure for protection against UV rays.Use of appropriate clothing, hats, and sunglasses-The UV protection provided by clothing depends upon the texture and porosity of cloth and whether the cloth is dry or wet. Denim has a much higher protection factor as compared to cotton. The wetness of cloth reduces its UV protection capacity and a stretched cloth is less protective than a shrunken one. The protection of a hat for the face and neck depends on the width of the brim. Sunglasses protect against the harmful effects of UV rays on the eyes.
对应中文
有很多方法可以防止人们过度暴露在紫外线下。防晒霜：使用防晒霜可能是最不划算的，但也是最常用的避免紫外线的方法。防晒霜是一种护肤产品，旨在保护活的皮肤细胞免受紫外线辐射的潜在有害影响，如晒伤和皮肤癌。几乎所有的防晒霜都是有机化合物 (通常是液体制剂，吸收紫外线并以热量的形式驱散) 和无机化合物 (通常是通过从表面反射来防止紫外线的矿物质) 的组合。防晒霜中有机和无机化合物的比例因制剂不同而不同。然而，由于成本和依从性问题，通常无法确定印度患者是否有效使用防晒霜。因此，避免阳光直射（详见下一节）变得非常重要。在白天（上午10点至下午4点），最大程度地利用紫外线遮挡阳光；因此，建议在此期间避免阳光照射。阴影（使用伞或站在树下）可以防止阳光直射，但反射的紫外线仍然可以到达皮肤。此外，使用遮光罩还可以减少阳光的热效应，从而产生一种虚假的紫外线安全感。尽可能避免阳光照射，尤其是在高峰时段，使用防护罩是一种经济有效的防紫外线措施。使用合适的衣服、帽子和太阳镜-衣服提供的紫外线防护取决于布料的质地和孔隙率，以及布料是干的还是湿的。与棉布相比，牛仔布的保护系数要高得多。布料的湿润性降低了其防紫外线的能力，拉伸的布料比收缩的布料的防护性要差。帽子对脸部和颈部的保护取决于帽沿的宽度。太阳镜可以防止紫外线对眼睛的有害影响。
Principles of Use of Sunscreen
防晒霜的使用原则
英文原文
The UV protection provided by sunscreen depends upon the sun protection factor (SPF). A sunscreen with an SPF less than 15 is not considered safe for photoprotection. Most sunscreens in clinical use have an SPF between 15 and 50.Sunscreen has to be applied around 30 min prior to anticipated sun exposure. The action of the sunscreen lasts not more than 2 to 3 h and if exposure to UV rays is continuing then it should be reapplied. Sunscreen should be applied after taking a bath or after heavy sweating if sun exposure is anticipated. For best protection, sunscreen should be applied even on a cloudy day as UV rays can penetrate through cloud cover. It should be applied to each uncovered body part, and the amount should be liberal enough to make a protective layer. The recommendation is to apply 2 mg of sunscreen per cm2 of body surface area. Approximately half a teaspoon of sunscreen should be applied over the face and neck and each arm. Approximately one teaspoon of sunscreen should be applied on each leg, chest, and back.
对应中文
防晒霜提供的紫外线防护取决于防晒系数 (SPF)。防晒指数低于15的防晒霜被认为是不安全的。大多数临床使用的防晒霜的SPF值在15到50之间。防晒霜必须在预期的日照前30分钟涂抹。防晒霜的作用时间不超过2至3小时，如果持续暴露在紫外线下，则应重新涂抹。如果预计会暴露在阳光下，则应在沐浴后或大量出汗后涂抹防晒霜。为了达到最好的保护效果，即使在阴天也应该涂抹防晒霜，因为紫外线可以穿透云层。它应适用于每个裸露的身体部位，用量应足够大，以形成一层保护层。建议每平方厘米体表面积涂抹2毫克防晒霜。面部、颈部和手臂上大致需要半茶匙的防晒霜。每条腿、胸部和背部大约涂抹一茶匙防晒霜。
What is so Special About Photoprotection in Indian Children?
印度儿童的光保护有什么特别之处？
英文原文
Exposure to bright sunlight occurs virtually throughout the year.The risk of skin cancer is believed to be low in India because of increased melanin. For the same reason, the dose and duration of UV exposure required to synthesize vitamin D are at least 10 times higher than that in white population.There is a high prevalence of vitamin D deficiency in India.UV rays have a multitude of potential side effects on the skin and hair that have never been evaluated in Indian population.Counseling for photoprotection has not been a priority for dermatologists in India.
对应中文
几乎全年都会暴露在明亮的阳光下。据信，由于黑色素增多，印度患皮肤癌的风险较低。出于同样的原因，合成维生素D所需的紫外线照射剂量和持续时间至少是白人人群的10倍。在印度，维生素D缺乏症的发病率很高。紫外线对皮肤和头发有许多潜在的副作用，这些副作用在印度人群中从未被评估过。在印度，光防护咨询并不是皮肤科医生的首要任务。
What is the Way Forward?
未来的方向是什么？
英文原文
All parents must be explained the risk of excess exposure to sunlight. Moreover, schools must advocate providing a “sun-safe” environment and routines for children, including keeping children indoors during peak sun damage hours and avoiding sports practice during these hours.Photoprotection as per AAP recommendation can be suggested to infants and children, especially to those with skin phototype II and III and in children with blue/green irises, fair skin, and light hair color.While it may not be appropriate to recommend the use of sunscreen in all healthy children, due to lack of evidence, excessive exposure to sun should be avoided by prudent use of shades, hats, full sleeve clothes, and sunscreens.Caution should be observed while exposing infants, especially neonates, to excess sunlight.Exposure to sunlight is probably not enough for meeting the daily requirements of vitamin D in children. Dietary supplementation of vitamin D is necessary.This fact cannot be overemphasized.Wholesome information, education, and communication activities involving parents, teachers, and others involved in child-rearing should be carried out to effectively deliver information regarding the ill effects and benefits of sunlight and easily available vitamin D-rich foods.There is a need to generate data on the ideal supplemental daily dose of vitamin D in Indian children. Till that time, it may be appropriate to continue with the recommendations of prescribing 400–600 IU of vitamin D daily.
对应中文
必须向所有家长解释过度暴露在阳光下的风险。此外，学校必须倡导为孩子们提供一个“防晒”的环境和习惯，包括让孩子们在日照高峰期呆在室内，并避免在这些时间进行体育锻炼。根据美国儿科学会的建议，光防护可推荐给婴儿和儿童，特别是那些皮肤类型II型和III型的人，以及有蓝/绿色虹膜、白皙皮肤和浅色头发的儿童。虽然建议所有健康儿童使用防晒霜可能并不合适，但由于缺乏证据，应谨慎使用墨镜、帽子、长袖衣服和防晒霜，以避免过度暴露在阳光下。将婴儿，尤其是新生儿暴露在过量阳光下时应注意。暴露在阳光下可能不足以满足儿童对维生素D的日常需求。饮食中补充维生素D是必要的。这一事实无论怎样强调都不为过。应该开展健康的信息、教育和交流活动，让父母、老师和其他参与育儿的人参与进来，以便有效地传递有关阳光和富含维生素D的食物的不良影响和益处的信息。需要生成印度儿童维生素D理想补充日剂量的数据。在此之前，继续建议每天服用400-600 IU的维生素D可能是合适的。
REFERENCES
1.Jindal AK, Gupta A, Vinay K, Bishnoi A. Sun Exposure in Children: Balancing the Benefits and Harms. Indian Dermatol Online J. 2020;11(1):94-98.