Review
Childhood exposure to ultraviolet radiation and harmful skin effects: Epidemiological evidence

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Abstract

We review the general amount and patterns of exposure to solar ultraviolet (UV) radiation that children and teenagers experience and the spectrum of UV-related skin damage that can occur as a result. Data about the amount of solar UV received by children and teenagers are relatively few but suggest that around 40–50% of total UV to age 60 occurs before age 20. Among white children, those with the palest complexions suffer the most damage. Comparisons of prevalence and incidence of outcomes in children and teenagers sharing common ancestry, but living at different latitudes, show that prevalence rates of photoaging and melanocytic naevi are higher in Australian compared with British children, and similarly for melanoma. Genetic risk for the majority of the melanomas in teens is a function of genes controlling naevus propensity and pigmentation in the skin. High numbers of naevi and freckles, red hair, blue eyes, inability to tan, as well as a family history are the primary determinants of melanoma among adolescents. Beyond the signs of skin damage seen in children are the latent effects observed later in adulthood. Childhood is believed to be a susceptible window for long-term harmful effects of UV, as evidenced by clear differences in skin cancer risk between child and adult migrants from high to low latitudes. Effective UV radiation protection from childhood is necessary to control both immediate and long-term harmful effects on children’s skin.

Introduction

Through outdoor activities and recreation children can experience moderate to high levels of exposure to ambient solar ultraviolet (UV) radiation in the course of their daily lives. The organs most susceptible to UV-related damage are the skin and eyes, and this paper reviews available epidemiological evidence regarding harmful skin outcomes of solar UV exposure during childhood and teenage years. Children are at very low risk of UV-related skin damage compared with adults, but the most common UV-related skin diseases occurring in adults may be observed in the first two decades of life as well, namely photoaging (seen as premature mild skin wrinkling in teenagers) and specific pigmentary signs of UV exposure such as freckling and development of melanocytic naevi (moles). After severe UV damage, benign keratinocytic skin tumours, actinic keratoses, and malignant skin tumours: melanoma, and basal cell and squamous cell carcinomas (BCC and SCC) develop, though among skin cancers, only melanoma occurs to any measurable incidence in childhood. On the other hand childhood appears to be a period in life when people are susceptible to initiation of latent harmful effects of UV manifest decades later in adulthood (Balato et al., 2007) (Thomas et al., 2007). Here we review the epidemiology of childhood actinic skin damage and conclude with evidence mostly from migrant studies of the role of childhood UV exposure in the development of adult skin cancers, in particular melanoma.

Section snippets

Ultraviolet radiation exposure in childhood and adolescence

Several epidemiological studies have provided estimates of sun or UV exposure during childhood and adolescent years, and the relative contribution of childhood UV to lifetime exposure. A few of these studies have relied on modelling and most estimates have been obtained from volunteers and/or selected groups.

An extensive review of early life sun exposure which summarised the mean UV exposure, proportion of the ambient UV radiation received and time spent outdoors daily based on 29 studies

Photoaging

In addition to dermatological assessment of the visible clinical signs of skin photoaging (Green et al., 2011), changes can be assessed by skin surface microtopography using silicone casts of the skin of the back of hand reflecting the level of underlying UV-induced deterioration of dermal elastin fibres (Battistutta et al., 2006). Skin damage scores range from 1 (least) to 6 (highest) with progressive flattening and creasing of the skin surface with increasing UV damage.

In otherwise healthy

Skin cancers in children

Since the incidence of BCC and SCC among children and teenagers in general is negligible, only sporadic melanoma in children and teenagers has been considered in detail for the purposes of this paper.

Skin and pigmentary characteristics

As for adults, differences in melanoma risk in children according to racial skin colour are clearly seen. In the National Cancer Database for all US hospital-based oncology patients (1985–2003), non-Hispanic white children comprised around 90 to 95% of all melanoma cases from aged 5 to 19 years (Lange et al., 2007). Within white children up to age 15, there have been very few population-based epidemiological studies of constitutional risk factors for incident primary melanoma. The largest was

Childhood as a susceptible life stage for adult UV radiation effects

Besides UV-induced skin damage manifest in children, harmful longer-term effects occur, that are latent until later in adulthood. It is possible that sunlight exposure during childhood and adolescence confers a greater increase in risk of melanoma compared with risk incurred by exposure at older ages. This theory is based on the plausible notions of heightened susceptibility of young melanocytes to initiation of UV carcinogenesis through alteration of melanocyte DNA by sun exposure and

Primary prevention

Worldwide, strategies for primary prevention have been mainly focused on reducing sunburn and sun exposure overall in white-skinned people of all ages in an attempt to diminish their skin cancer risk. These strategies include encouraging the use of hats, appropriate clothing and sunscreen, as well as avoidance of the sun, particularly at peak hours of the day, and avoidance of artificial forms of UV radiation such as sunbeds (Stanton et al., 2004). Children and adolescents have been major

References (65)

  • E. Thieden et al.

    Proportion of lifetime UV dose received by children, teenagers and adults based on time-stamped personal dosimetry

    J. Invest. Dermatol.

    (2004)
  • N. Zhu et al.

    Cutaneous malignant melanoma in the young

    Br. J. Plastic Surg.

    (1997)
  • P. Autier et al.

    Influence of sun exposures during childhood and during adulthood on melanoma risk. EPIMEL and EORTC Melanoma Cooperative Group. European Organisation for Research and Treatment of Cancer

    Int. J. Cancer

    (1998)
  • P. Autier et al.

    Sunscreen use and duration of sun exposure: a double-blind, randomized trial

    J. Nat. Cancer Inst.

    (1999)
  • P. Baade et al.

    Trends in melanoma incidence among children: possible influence of sun protection programs

    Expert. Rev. Anticancer Ther.

    (2011)
  • P.D. Baade et al.

    Trends in incidence of childhood cancer in Australia, 1983–2006

    Br. J. Cancer

    (2010)
  • S.J. Balk

    Ultraviolet radiation: a hazard to children and adolescents

    Pediatrics

    (2011)
  • D. Battistutta et al.

    Skin surface topography grading is a valid measure of skin photoaging

    Photodermatol. Photoimmunol. Photomed.

    (2006)
  • J. Bauer et al.

    Effect of sunscreen and clothing on the number of melanocytic Nevi in 1,812 German Children Attending Day Care

    Am. J. Epidemiol.

    (2005)
  • P. Berg et al.

    Germline CDKN2A mutations are rare in child and adolescent cutaneous melanoma

    Melanoma Res.

    (2004)
  • C. Boldeman et al.

    Swedish pre-school children’s UVR exposure – a comparison between two outdoor environments

    Photodermatol. Photoimmunol. Photomed.

    (2004)
  • L.A. Crane et al.

    Melanocytic nevus development in Colorado children born in 1998: a longitudinal study

    Arch. Dermatol.

    (2009)
  • K.J. Davis et al.

    Summer sunburn and sun exposure among US youths ages 11 to 18: national prevalence and associated factors

    Pediatrics

    (2002)
  • A.T. Dodd et al.

    Melanocytic nevi and sun exposure in a cohort of colorado children: anatomic distribution and site-specific sunburn

    Cancer Epidemiol. Biomarkers Prev.

    (2007)
  • D. English et al.

    Ultraviolet radiation at places of residence and the development of melanocytic nevi in children (Australia)

    Cancer Causes Control

    (2006)
  • K.J. Fisher et al.

    The Relationship between Australian Student’s Perceptions of Parental Behaviour, School Policies and Sun Protection Behaviour

    (1996)
  • Fritschi, L., 1993. Assessment of sun exposure. PhD, Australian National University, Canberra, pp....
  • L. Fritschi et al.

    A noninvasive measure of photoageing

    Int. J. Epidemiol.

    (1995)
  • L. Fritschi et al.

    Naevi in schoolchildren in Scotland and Australia

    Br. J. Dermatol.

    (1994)
  • Gandini, S., Boniol, M., Autier, P. Meta-analysis on artificial light and skin cancer. Progr. Biophys. Mol. Biol., in...
  • P. Gies et al.

    Solar UVR exposures of primary school children at three locations in Queensland

    Photochem. Photobiol.

    (1998)
  • D.E. Godar

    UV doses worldwide

    Photochem. Photobiol.

    (2005)
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