Malignant melanoma risk by nativity, place of residence at diagnosis, and age at migration

Ambient UVR and Environmental Arsenic Exposure in Relation to Cutaneous Melanoma in Iowa

Intermittent sun exposure is the major environmental risk factor for cutaneous melanoma (CM). Cumulative sun exposure and other environmental agents, such as environmental arsenic exposure, have not shown consistent associations. Ambient ultraviolet radiation (UVR) was used to measure individual total sun exposure as this is thought to be less prone to misclassification and recall bias. Data were analyzed from 1096 CM cases and 1033 controls in the Iowa Study of Skin Cancer and Its Causes, a population-based, case-control study. Self-reported residential histories were linked to satellite-derived ambient UVR, spatially derived environmental soil arsenic concentration, and drinking water arsenic concentrations. In men and women, ambient UVR during childhood and adolescence was not associated with CM but was positively associated during adulthood. Lifetime ambient UVR was positively associated with CM in men (OR for highest vs. lowest quartile: 6.09, 95% confidence interval (CI) 2.21–16.8), but this association was not as strong among women (OR for highest vs. lowest quartile: 2.15, 95% CI 0.84–5.54). No association was detected for environmental soil or drinking water arsenic concentrations and CM. Our findings suggest that lifetime and adulthood sun exposures may be important risk factors for CM.

Temporal Aspects of the Association between Exposure to the World Trade Center Disaster and Risk of Cutaneous Melanoma

Rescue/recovery workers who responded to the World Trade Center (WTC) attacks were exposed to known/suspected carcinogens. Studies have identified a trend toward an elevated risk of cutaneous melanoma in this population; however, few found significant increases. Furthermore, temporal aspects of the association have not been investigated. A total of 44,540 non-Hispanic White workers from the WTC Combined Rescue/Recovery Cohort were studied between March 12, 2002 and December 31, 2015. Cancer data were obtained through linkages with 13 state registries. Poisson regression was used to estimate hazard ratios and 95% confidence intervals using the New York State population as the reference; change points in hazard ratios were estimated using profile likelihood. We observed 247 incident cases of melanoma. No increase in incidence was detected during 2002-2004. From 2005 to 2015, the hazard ratio was 1.34 (95% confidence interval = 1.18-1.52). A dose‒response relationship was observed by arrival time at the WTC site. Risk was elevated just over 3 years after the attacks. Whereas WTC-related exposures to UVR or other agents might have contributed to this result, exposures other than those at the WTC site, enhanced medical surveillance, and lack of a control group with a similar proportion of rescue/recovery workers cannot be discounted. Our results support continued study of this population for melanoma.

Review of Wearable and Portable Sensors for Monitoring Personal Solar UV Exposure

Sunlight is one of the main environmental resources that keeps all the organisms alive on earth. The ultraviolet (UV) radiation from the sun is essential for vitamin D synthesis in the human body, which is crucial for bone and muscle health. In addition, sun exposure also helps to reduce the risk of some cardiovascular diseases and cancers. However, excessive UV exposure can lead to adverse effects, including some eye diseases, premature aging, sunburn and skin cancers. The solar UV irradiance itself depends on many environmental factors. In fact, the UV index reported in weather forecasts is an estimation under cloudless conditions. Personal UV exposure also depends on one's outdoor activities and habits. Furthermore, the UV intake depends on the skin sensitivity. Therefore, there is a need for research into monitoring the optimal daily UV exposure for health benefits, without developing potential health risks. To facilitate the monitoring of solar UV intensity and cumulative dose, a variety of UV sensors have been developed in the past few decades and many are commercially available. Examples of sensors being marketed are: portable UV dosimeter, wearable UV radiometer, personal UV monitor, and handheld Solarmeter®. Some of the UV sensors can be worn as personal health monitors, which promote solar exposure protection. The paper provides a comprehensive review of the wearable and portable UV sensors for monitoring personal UV exposure, including a discussion of their unique advantages and limitations. Proposals are also presented for possible future research into reliable and practical UV sensors for personal UV exposure monitoring.

Re-engaging an inactive cohort of young adults: evaluating recruitment for the Kidskin Young Adult Myopia Study

BACKGROUND

Recent changes in communication technologies, including increased reliance on mobile phones and the internet, may present challenges and/or opportunities to re-engaging inactive study cohorts. We evaluate our ability to recruit participants for the Kidskin Young Adult Myopia Study (KYAMS), a follow-up of the Kidskin Study.

METHODS

KYAMS participants were recruited from the Kidskin Study, a sun exposure-intervention study for 5-6 year-olds running from 1995 to 1999 with most recent follow-up in 2005. From 2015 to 2019, the KYAMS used mail-outs, phone calls and social media to contact Kidskin Study participants. Multivariable logistic regression was used to identify variables associated with successful contact of a Kidskin Study participant or family member and KYAMS participation.

RESULTS

Of 1695 eligible participants, 599 (35.5%) participants (or a family member) were contacted and 303 (17.9%) participated in the KYAMS. KYAMS participation was more likely in those who participated in the 2005 follow-up (odds ratio [OR] = 5.09, 95% confidence interval [CI]: 3.67-7.06) and had a mobile phone number on record (OR = 2.25, CI: 1.57-3.23). Of those contacted, participants who were the first point of contact (OR = 4.84, CI: 2.89-8.10) and who were contacted by letter in the first (OR = 6.53, CI: 3.35-12.75) or second (OR = 5.77, CI: 2.85-11.67) round were more likely to participate in the KYAMS, compared to contact by landline phone.

CONCLUSIONS

We recruited approximately one-fifth of Kidskin Study participants for the KYAMS. Participants were more likely to participate in the KYAMS if they were contacted directly, rather than through a family member, and if they were contacted by invitation letter.

TRIAL REGISTRATION

ACTRN12617000812392.

Ultraviolet radiation and cutaneous melanoma: a historical perspective

In this article, we summarize the research that eventually led to the classification of the full ultraviolet (UV) radiation spectrum as carcinogenic to humans. We recall the pioneering works that led to the formulation of novel hypotheses on the reasons underlying the increasing burden of melanoma in light-skinned populations. It took long before having compelling evidence on the association between UV and melanoma, in particular, the importance of UV exposure during childhood for both the occurrence of melanoma and death. The role of UVA was established only after 2005. If molecular lesions caused by UV radiation are better known, the precise mechanism by which UV exposure drives melanoma occurrence and progression still needs to be elucidated. More research on the UV-melanoma relationships has led to more evidence-based sun-protection recommendations, especially for children, and to effective control of the artificial UV tanning fashion. Since around 1985-1995, the mortality because of melanoma has started to decrease in younger age groups in most light-skinned populations. If sun protection among children remain on top of public health agendas, there is a fairly great chance that melanoma mortality will stabilize and steadily decrease in all light-skinned populations. The introduction of effective therapies against metastatic disease will improve this reversal in mortality trends.

Recalling our day in the sun: comparing long-term recall of childhood sun exposure with prospectively collected parent-reported data

To examine the impact of sun exposure on human health, accurate measures of past sun exposure are required. We investigated how young adults' recall of childhood sun-related behaviours compares with parent-reported measures collected during childhood. The Kidskin-Young Adult Myopia Study (KYAMS) is a follow-up of the Kidskin Study, a sun-protection intervention study conducted from 1995-2001. KYAMS participants, aged 25-30 years, reported time in sun, and use of hats and sunscreen, for each year from ages 5-26 years (n = 244). Using weighted kappa, we assessed agreement between these data and corresponding variables derived from the Kidskin Study parent questionnaires completed when KYAMS participants were aged 6-12 years. Ordinal logistic regression was used to test the association between self-reported sun-behaviours and corresponding parent-reported data. We found slight agreement between self-reported and parent-reported data for all sun-behaviour measures except hat use at 12 years. KYAMS recall of time in sun at 8-12 years was not associated with Kidskin Study parent-reported responses after adjustment for current time in sun. Recall of higher hat and sunscreen use was associated with higher parent-reported hat and sunscreen use (OR[hat] = 1.37, 95% CI: 1.16, 1.62; OR[sunscreen] = 1.23, 95% CI: 1.03, 1.48). However, KYAMS self-reported data were unable to predict corresponding parent-reported responses. Group data from retrospective recall of sun-related behaviours may be of limited value in studying the relationship between sun exposure and health outcomes; however, individual data are likely of little use.

Review of human hair optical properties in possible relation to melanoma development

Immigration and epidemiological studies provide evidence indicating the correlation of high ultraviolet exposure during childhood and increased risks of melanoma in later life. While the explanation of this phenomenon has not been found in the skin, a class of hair has been hypothesized to be involved in this process by transmitting sufficient ultraviolet rays along the hair shaft to possibly cause damage to the stem cells in the hair follicle, ultimately resulting in melanoma in later life. First, the anatomy of hair and its possible contribution to melanoma development, and the tissue optical properties are briefly introduced to provide the necessary background. This paper emphasizes on the review of the experimental studies of the optical properties of human hair, which include the sample preparation, measurement techniques, results, and statistical analysis. The Monte Carlo photon simulation of human hair is next outlined. Finally, current knowledge of the optical studies of hair is discussed in the light of their possible contribution to melanoma development; the necessary future work needed to support this hypothesis is suggested.

Sun Safety Practices Among Schools in the United States

Importance

Exposure to the sun's UV radiation is a leading cause of skin cancer. Positive attitudes and beliefs about sun safety behavior, which would make sun protective behavior more likely, could be promoted and supported by school policies and practices.

Objective

To identify school characteristics associated with having adopted practices that promote sun safety.

Design, Setting, and Participants

School-level data from the February 3 to July 23, 2014, School Health Policies and Practices Study's Healthy and Safe School Environment questionnaire were analyzed. The School Health Policies and Practices Study uses a 2-stage sampling design to select a nationally representative sample of schools. All public, state-administered, Catholic, and non-Catholic private schools with any of the grades from kindergarten through 12 were eligible for inclusion. All analyses were conducted using weighted data.

Main Outcomes and Measures

Prevalence of sun safety practices.

Results

In a nationally representative sample of 828 US schools, representatives of 577 schools (69.7%) responded. Overall, sun safety practices were not common among schools. The most frequent practice was having teachers allow time for students to apply sunscreen at school (47.6%; 95% CI, 42.4%-52.9%). Few schools made sunscreen available for students to use (13.3%; 95% CI, 10.2%-17.0%), almost always or always scheduled outdoor activities to avoid times when the sun was at peak intensity (15.0%; 95% CI, 11.4%-19.6%), or asked parents to ensure that students applied sunscreen before school (16.4%; 95% CI, 12.9%-20.6%). High schools were less likely than elementary schools and middle schools to adopt several practices: for instance, 37.5% of high schools (95% CI, 29.7%-46.0%), 51.6% of middle schools (95% CI, 43.3%-59.7%), and 49.5% of elementary schools (95% CI, 42.0%-57.0%) had teachers allow time for students to apply sunscreen at school, and 11.8% of high schools (95% CI, 7.7%-17.5%), 18.2% of middle schools (95% CI, 13.3%-24.4%), and 14.7% of elementary schools (95% CI, 9.6%-21.8%) almost always or always scheduled outdoor activities to avoid times when the sun was at peak intensity. Other school characteristics were either not significantly associated with the adoption of any of the sun safety school practices studied (eg, metropolitan status) or were inconsistently associated with such policies and practices (eg, region, percentage of students eligible for free or reduced-price lunch, and school enrollment).

Conclusions and Relevance

School practices that could protect children and adolescents from sun exposure and that could change norms about sun safety are not common. Interventions aimed at increasing the adoption of sun safety practices among schools are needed regardless of the level, location, size, and poverty concentration of the school. Such practices would cost little to implement and would support other messages targeted toward children, adolescents, adults, and parents, with an aim to reduce skin cancer morbidity and mortality.

A Validation Method to Determine Missing Years of Birth in a Cohort Study of Shipyard Workers Using Social Security Number

OBJECTIVE

The objective of the study is to evaluate the generalizability and feasibility of a prediction method developed by Block et al (1983) to estimate missing age of workers by using their Social Security Numbers (SSNs).

METHODS

Our study used a retrospective occupational cohort of about 15,000 workers from the Long Beach Naval Shipyard (1978 to 1985).

RESULTS

Our results showed an 89.2% agreement (P < 0.0001) between the predicted and observed years of birth using Block's method. The correlation increased to 93.1% (P < 0.0001) after our modifications by removing workers with SSNs issued in U.S. territories. The method performed better in shipyard workers who obtained their SSNs after 1950.

CONCLUSION

Although the method is useful in imputing missing age, the accuracy is dependent on the year, age, and location of SSN issuance.

Photocarcinogenesis: an epidemiologic perspective on ultraviolet light and skin cancer

Photocarcinogenesis is the result of a complex interplay between ultraviolet radiation, DNA damage, mutation formation, DNA repair, apoptosis, and the immune system. Recent trends show an increase in incidence of both melanoma and nonmelanoma skin cancers. Some individuals have a genetic predisposition toward increased risk for skin cancer, whereas others experience increased risk through ultraviolet exposure and subsequent mutation formation. The initiation and propagation pathways of melanoma and nonmelanoma skin cancers differ but have some elements in common. The increase in incidence of skin cancer has been discovered to vary among age groups and gender.

Berberine in combination with doxorubicin suppresses growth of murine melanoma B16F10 cells in culture and xenograft

Melanoma is very aggressive and major cause of mortality due to skin cancer. Herein, we studied the anticancer effects of berberine, a plant alkaloid, in combination with doxorubicin on murine melanoma B16F10 cells in vitro and in vivo. This drug combination strongly inhibited cell growth and induced cell death, and caused G2/M arrest in cell cycle together with a decrease in Kip1/p27. Berberine showed stronger inhibitory effect on ERK1/2 phosphorylation as compared to Akt phosphorylation, whereas the combination of the drugs showed greater inhibitory effect on Akt phosphorylation. In murine B16F10 xenograft, cells were implanted into mice and treated with vehicle (methyl cellulose) or berberine (100mg/kg of body weight/day by oral gavage) or doxorubicin (4 mg/kg of body weight/week by intraperitoneal injection) or combination of berberine and doxorubicin. Berberine alone did not show any considerable effect on tumor growth as observed with doxorubicin, however, the combination of the two drugs resulted in a significant and strong decrease in tumor volume (85%, p<0.005) and tumor weight (78%, p<0.05) as compared to control. Immunohistochemical analysis of tumor samples showed that drug combination decreased PCNA-positive cells (82%, p<0.001) and increased cleaved caspase-3 positive cells (3-fold, p<0.05) indicating inhibition of proliferation and an increase in apoptosis, respectively. Overall, our findings suggest that berberine and doxorubicin could be a novel combination to inhibit melanoma tumor growth.

Cutaneous melanoma in Latin America: a population-based descriptive study

Cutaneous melanoma incidences vary between geographic regions and are a health concern for Caucasians and for all ethnic populations. In Latin America, data from population-based cancer registries of cutaneous melanoma incidence rates have rarely been reported. We searched the Cancer Incidence in Five Continents volume IX (CI5-IX) database for cutaneous melanoma and select cases by topography (C43) from 11 population-based cancer registries in Latin America. Between 1998 and 2002, a total of 4,465 cutaneous melanoma cases were reported in Latin America. The average age-standardized incidence rates (per 100,000 persons-year) was 4.6 (male) and 4.3 (female). This study presents an overview of cutaneous melanoma incidence in Latin America, highlighting the need to enhance coverage of population-based cancer registries in Latin America, to allow for a better understanding of this neoplasm in the region. Thus it can help in implementing primary prevention programs for the whole Latino population. At this point in time, early detection messages should target young women and older men in Latin America.

Divergent cancer pathways for early-onset and late-onset cutaneous malignant melanoma

BACKGROUND

Emerging data suggest that cutaneous malignant melanomas (CMM) may arise through divergent cancer pathways that are linked to intermittent versus accumulated sun exposure. However, numerous questions remain regarding the timing and/or age of exposure.

METHODS

The authors systematically examined the effect of aging on CMM incidence in data from the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute. Standard descriptive epidemiology was supplemented with mathematical models. The impact of advancing age on CMM incidence was assessed by sex, histopathologic classification (superficial spreading melanoma [SSM] or lentigo maligna melanoma [LMM]), and anatomic site (face, head, and neck [FHN] or lower extremity [LE]).

RESULTS

Sex, histopathology, and anatomic site were age-specific effect modifiers for CMM that indicated divergent (bimodal) early-onset and late-onset cancer pathways. Early-onset melanomas were associated predominantly with women, SSM, and LE. Late-onset melanomas were correlated with men, LMM, and FHN. Early- and late-onset melanoma populations were confirmed with age-period-cohort models that were adjusted for period and cohort effects. Two-component mixture models also fit the data better than a single cancer population.

CONCLUSIONS

The current results were consistent with a divergent and age-dependent solar hypothesis for CMM. Early-onset melanomas may represent gene-sun exposure interactions that occur early (and/or intermittently) in life among susceptible individuals. Late-onset melanomas may reflect accumulated, lifelong sun exposure in comparatively less susceptible individuals. Future analytical studies should be powered adequately to account for this age-dependent effect modification both for acknowledged melanoma risk factors (sex, histopathology, and anatomic site) and for suspected melanoma risk factors, such as constituent genetic variants.

The population dynamics of cancer: a Darwinian perspective

Carcinogenesis, at least for some types of cancer, can be interpreted as the consequence of selection of mutated cells similar to what, in the theory of evolution, occurs at the population level. Instead of considering a population of organisms, we can refer to a population of cells belonging to multicellular organisms. Many carcinogens are mutagens, and the observed geographic distribution of cancer is, at least in part, attributable to environmental mutagens. However, the rapid change in risk for some cancers after migration suggests that carcinogenesis involves--in addition to mutations--some late event that most probably consists of the selection of cells already carrying mutations. We review a few examples of such selective pressures: finasteride in prostate cancer, vitamin supplementation in smokers, acquired resistance to chemotherapy, peripheral resistance to insulin, and sunlight and mutations in melanoma. A disease model for such a hypothesis is represented by Paroxysmal Nocturnal Hemoglobinuria (PNH). Mutations can be present at birth, as in the case of PNH, and can have a frequency much higher than the occurrence of the corresponding disease (PNH or lymphocytic leukaemia in children). However, PNH does not require a mutator phenotype, only a mutant phenotype followed by selection. A characteristic feature of cancer, instead, is likely to be the development of the mutator phenotype. We propose a 'Darwinian' model of carcinogenesis. If the model is correct, it suggests that prevention is more complex than avoiding exposure to mutagens. Mutations and genetic instability can be already present at birth. Mutations can be selected in the course of life if they increase survival advantage of the cell under certain environmental circumstances. In addition, gene-environment interactions cannot be interpreted according to a simplified linear model (based on the 'analysis of variance' concept); experimental work suggests that a more comprehensive non-linear interpretation based on the idea of 'norm of reaction' is needed.

Sun exposure, diet, and melanoma in Hawaii Caucasians

Much uncertainty remains about the type of sunlight exposure that most increases risk of cutaneous melanoma and the role of diet. The authors conducted a population-based case-control study (1986-1992) of Caucasians living on Oahu, Hawaii; included were 278 cases and age- and sex-matched controls. Plasma samples were measured for retinol, carotenoids, and alpha-tocopherol by high-pressure liquid chromatography. Selenium was measured in blood and toenails by neutron activation. Celtic and English ancestries, migration to Hawaii before age 20 years, fair complexion, inability to tan, and family history of skin cancer, as well as height, hours spent in the summer sun, blistering sunburns during adolescence, and moles, all increased melanoma risk. With regard to diet and biomarkers, only alcohol was associated with risk. The odds ratios for increasing tertiles of lifetime ethanol intake were 1.0, 1.2 (95% confidence interval (CI): 0.6, 2.2), and 2.3 (95% CI: 1.2, 4.4) (p for trend = 0.01) for men and 1.0, 1.1 (95% CI: 0.5, 2.4), and 1.7 (95% CI: 0.7, 3.8) (p for trend = 0.19) for women. Dietary lipids were unrelated to risk, but polyunsaturated fat intake appeared to modify the effects of alcohol and toenail selenium on melanoma risk. These data provide additional evidence for the association of constitutional susceptibility factors, intense sun exposure (particularly before age 20 years), and alcohol consumption with melanoma risk.

Slip! Slap! Slop! Cutaneous malignant melanoma incidence and social status in New Zealand, 1995-2000

Numerous studies have noted a strong social gradient in many types of ill health. In particular, people in more deprived areas tend to be less healthy than those in more affluent communities, even once the demographic and socio-economic differences of the people in those areas have been taken into account. The social gradient is evident for many types of health outcomes, including diseases such as cancer. However, this positive relationship is not evident for rates of melanoma incidence and mortality, with rates of the disease tending to decrease with measures of disadvantage. In this study, we assess the relationship between the incidence of melanoma and deprivation in New Zealand, a country with particularly high rates of the disease. In the light of greater public awareness of the risk factors associated with melanoma, through public awareness campaigns such as 'Slip! Slap! Slop' and 'No Suntan is Safe', we analyse small-area data on standardised rates of melanoma for the period 1995-2000. We found that melanoma rates increase with social status, even once other confounding factors are controlled for, but that the relationship is very small. Furthermore, the relationship between melanoma incidence and deprivation is context-dependent. Possible explanations for the relationship between melanoma and deprivation are discussed, including more frequent exposure to intermittent sunshine among less disadvantaged groups and the underreporting of melanoma incidence in the New Zealand cancer registry among individuals in lower social groups.

Population exposure to ultraviolet radiation in Finland 1920-1995: Exposure trends and a time-series analysis of exposure and cutaneous melanoma incidence

Ultraviolet radiation (UVR) is the principal cause of cutaneous malignant melanoma (CMM). However, the relation between CMM and UVR exposure is not clear. We present the trends of population exposure to UVR and conduct a time-series analysis of the relation between UVR exposure and incidence of CMM. Data on CMM incidence were obtained from the Finnish Cancer Registry. Clothing coverage of the body was scored from archival photographs and the proportion of uncovered skin was used as a measure of solar exposure. Information on the number of sunny resort holidays, duration of annual holidays, and sunscreen sales were obtained from various sources. Exposed skin area doubled from 1920 to 1985. The average duration of annual holidays increased 30-fold. The number of sunny resort holidays and the sales of sunscreens increased rapidly from 1980. CMM was most strongly associated with solar exposure of 5-19 years earlier. There is a considerable decrease in clothing coverage during the 20th century. UVR exposure preceding CMM occurrence 4 years or less does not appear relevant, whereas the period 5-19 years prior to CMM occurrence might be the most relevant period. However, findings of ecological studies may not be applicable at the individual level.

Developing epidemic of melanoma in the Hispanic population of California

BACKGROUND

Hispanics comprise almost one-third of the population of California, are the most rapidly increasing racial/ethnic group in the state, and represent almost one-third of all Hispanics in the U.S. California has among the highest rates of melanoma in the world, yet little is known about trends in melanoma in its Hispanic population.

METHODS

Trends in invasive and in situ melanoma incidence data and melanoma mortality data, between 1988 and 2001, from the California Cancer Registry were analyzed. Trends in the Hispanic population were compared with those in the non-Hispanic white population. Time trends in tumors of differing thicknesses and histology were assessed.

RESULTS

There was a statistically significant 1.8% per year increase in incidence of invasive melanomas among Hispanic males and a similar but non-statistically significant increase in invasive melanoma among Hispanic females between 1988 and 2001. Among Hispanic males and females tumors thicker than 1.5 mm at presentation increased at 11.6% per year (95% confidence interval [CI], 8.1, 15.2) and 8.9% per year (95% CI, 4.7, 13.3), respectively.

CONCLUSION

Rates of invasive melanoma have increased markedly among Hispanics in California since 1988. In contrast to trends in the non-Hispanic white population, increases in melanoma in Hispanics have been confined to thicker tumors, whose prognosis is poor. We recommend that efforts be undertaken immediately to target both primary and secondary melanoma prevention messages to Hispanic communities.

Adverse effects of ultraviolet radiation: a brief review

Solar ultraviolet radiation (UVR) has always been part of the environment of man. UVB is required for the conversion of 7-deoxycholesterol to vitamin D, which is critically important in the maintenance of healthy bones and research is making clear that it has other potential roles in maintenance of human health. Exposure to UVR, whether of solar or artificial origin, also carries potential risks to human health. UVR is a known carcinogen and excessive exposure-at least to solar radiation in sunlight-increases risk of cancer of the lip, basal cell, and squamous cell carcinoma of the skin and cutaneous melanoma, particularly in fair skin populations. There is also evidence that solar UVR increases risk of several diseases of the eye, including cortical cataract, some conjunctival neoplasms, and perhaps ocular melanoma. Solar UVR may also be involved in autoimmune and viral diseases although more research is needed in these areas. Artificial UVR from tanning beds, welding torches, and other sources, may contribute to the burden of disease from UVR. This brief review will assess the human evidence for adverse health effects from solar and artificial UVR and will attempt to assign a degree of certainty to the major disease-exposure relationships based on the weight of available scientific evidence.

Sun exposure and risk of melanoma

BACKGROUND

As skin cancer education programmes directed to children and adolescents continue to expand, an epidemiological basis for these programmes is necessary to target efforts and plan for further evaluation.

AIMS

To summarise the epidemiological evidence on sun exposure during childhood and adolescence and melanoma risk.

METHODS

A literature review was conducted using Medline (1966 to December 2004) to identify articles relating to sun exposure and melanoma. The review was restricted to studies that included sun exposure information on subjects 18 years of age or younger.

RESULTS

Migrant studies generally indicate an increased melanoma risk in individuals who spent childhood in sunny geographical locations, and decreasing melanoma risk with older age at arrival. Individuals who resided in geographical locations close to the equator or close to the coast during childhood and/or adolescence have an increased melanoma risk compared to those who lived at higher latitudes or never lived near the coast. The intermittent exposure hypothesis remains controversial; some studies indicate that children and adolescents who received intermittent sun exposure during vacation, recreation, or occupation are at increased melanoma risk as adults, but more recent studies suggest intermittent exposure to have a protective effect. The majority of sunburn studies suggest a positive association between early age sunburn and subsequent risk of melanoma.

CONCLUSION

Future research efforts should focus on: (1) clarifying the relation between sun exposure and melanoma; (2) conducting prospective studies; (3) assessing sun exposure during different time periods of life using a reliable and quantitative method; (4) obtaining information on protective measures; and (5) examining the interrelations between ability to tan, propensity to burn, skin type, history of sunburns, timing and pattern of sun exposure, number of nevi, and other host factors in the child and adolescent populations.

Seasonal variation in the occurrence of cutaneous melanoma in Europe: influence of latitude. An analysis using the EUROCARE group of registries

The aim of our study was to analyse seasonal variations in melanoma incidence in Europe. Data from 28117 cutaneous melanoma cases reported during 1978-1993 to the EUROCARE group of registries were analysed. There is a clear summer peak in incidence in Western countries (summer-winter ratio: 1.31 P < 0.0001; Nam's test), which was not observed in Central Europe (ratio: 1.06; P = 0.0699). The amplitude of seasonality is higher for females (ratio = 1.38, 95% Confidence Interval (CI) [1.31-1.44]) than for males (ratio = 1.21 95%CI [1.14-1.29]). It is also higher for upper and lower limbs (1.44 and 1.46, respectively), than for head and neck or trunk regions (1.09 and 1.20, respectively). The amplitude of seasonality also varies with latitude and increases with time: in a linear regression adjusting for age, gender and anatomical localisation, the date of diagnosis was significantly closer to summer solstice with decreasing latitude (P = 0.0005) and for more recent year of diagnosis (P = 0.0123). The effect of latitude on the amplitude of the seasonal variation in melanoma incidence in Europe may be an indicator of ultraviolet B (UVB) exposure. Furthermore, an increase in intentional sun exposure could lead to an increase in melanoma promotion and thus to an increase in the amplitude of seasonal variation.

Improved survival for melanoma in Northern Ireland: a comparison of two 5-year periods (1984-88 and 1994-98)

BACKGROUND

The incidence of cutaneous malignant melanoma has been rising steadily in Caucasian populations for several decades, with a doubling time of 10-14 years. An increase in incidence of about 5% per year has been reported in most Caucasian populations since the early 1960s.

OBJECTIVES

This study was designed to determine the changing incidence of primary cutaneous malignant melanoma in Northern Ireland and to examine changes in survival rates from cutaneous malignant melanoma in two 5-year periods, 1984-88 and 1994-98.

METHODS

One thousand three hundred and twenty-six patients with invasive primary cutaneous melanoma were included in the study.

RESULTS

The age standardized rate of melanoma rose from 4.3 per 100,000 population per year in men and 8.6 per 100,000 population per year in women to 7.7 and 11.8, respectively, per 100,000 population per year in the 1994-98 period. Overall, the absolute 5-year survival for the 1984-88 period was 71.0% [95% confidence interval (CI) 66.9-75.1%] and 77.4% (95% CI 73.4-81.4%) for the 1994-98 period. Women consistently showed better survival at all ages and within almost all categories of thickness of primary tumour. Younger patients of both sexes showed better survival rates.

CONCLUSIONS

When survival rates between the 1984-88 and 1994-98 periods were compared using multivariate analysis, we found that patients diagnosed in the second period had a one-third lower risk of dying than those in the earlier period. Much of this reduction was explained by changes in the number of melanomas of thin Breslow depth and ulcerated melanomas.

Recent trends in cutaneous melanoma incidence among whites in the United States

BACKGROUND

It is not yet clear whether increasing melanoma incidence is real or whether recent incidence trends mainly reflect improved diagnosis. To address this question, we examined the most recent melanoma incidence patterns among the white population stratified by sex, age, tumor stage, and tumor thickness by use of data from the Surveillance, Epidemiology, and End Results Program.

METHODS

We examined log-transformed age-specific rates for melanoma by 5-year age groups and time periods by year of diagnosis and birth cohort. Melanoma trends were further examined among broader age groups (<40 years, 40-59 years, and > or =60 years) by tumor stage and tumor thickness. Rates were age-adjusted to the 1970 U.S. standard population, and trends were tested by use of a two-sided Student's t test.

RESULTS

Melanoma incidence increased in females born since the 1960s. From 1974-1975 through 1988-1989, upward trends for the incidence of localized tumors and downward trends for the incidence of distant-stage tumors occurred in the age group under 40 years. In the more recent time period, 1990-1991 through 1996-1997, age specific rates among females compared with males generally remained stable or declined more for distant-stage tumors and increased less for local-stage tumors. Thin tumors (<1 mm) increased statistically significantly in all age groups (P<.05 for all), except in men under age 40 years. In contrast, rates for thick tumors (> or =4 mm) increased statistically significantly (P =.0003) only in males aged 60 years and older.

CONCLUSION

Melanoma incidence may well continue to rise in the United States, at least until the majority of the current population in the middle-age groups becomes the oldest population. The recent trends may reflect increased sunlight exposure.

Cancer surveillance series: changing patterns of cutaneous malignant melanoma mortality rates among whites in the United States

BACKGROUND

Mortality from melanoma among whites is still increasing in the United States. In this study, we describe the changing patterns of melanoma mortality rates among whites by demographic factors and geography and further assess the relationship between the geographic patterns and the UV radiation (UV-B) level.

METHODS

Age-adjusted incidence and mortality rates were computed by use of the 1970 U.S. population standard. Annual percent changes of mortality were estimated by fitting regression lines to the logarithm of rates. The relationships between melanoma mortality rates and UV-B level over time were assessed by weighted regressions. All statistical tests were two-sided.

RESULTS

From 1950-1954 through 1990-1994, melanoma mortality rates increased by 191% and 84% among males and females, respectively. Mortality rates peaked in the 1930 through 1950 birth cohorts for females and in the 1935 through 1950 birth cohorts for males. In the 1950 through 1969 study period, melanoma mortality rates showed a strong North-South gradient, but the gradient weakened in recent periods. The absolute change in mortality for a 10% increase in UV-B among females decreased from 0.08 additional deaths per 100 000 person-years in 1950-1959 to 0.01 additional deaths in 1990-1995. In contrast, the absolute change in mortality among males showed little change over time; additional deaths increased from 0.11 to 0.12 per 100 000 person-years.

CONCLUSIONS

Melanoma mortality in the United States reflects the complex interplay of UV radiation levels in each geographic region, the sun-protection behaviors of each generation of males and females in childhood and adulthood, the geographic mobility of the population, and the risk awareness and early detection.

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

Sun exposure in both childhood and adult life represents the main environmental risk determinant for cutaneous melanoma. However, little is known about the joint effects of sun exposure during early and later life on melanoma risk. A case-control study in Belgium, Germany and France conducted in 1991-1992 suggests that the melanoma risks attached to indicators related to sun exposure appear to combine their effects in an additive way. We therefore constructed composite indices of sun exposure during childhood and during adulthood, assuming additive combinations of melanoma risk associated with each indicator of sun exposure. Logistic regression modeling showed that the melanoma risk associated with a given level of sun exposure during adulthood increased with higher sun exposure during childhood, but the increase in risk was higher than the simple addition of melanoma risk associated with sun exposure during childhood or adulthood. In turn, high sun exposure during childhood constituted a significant risk factor for melanoma only if there was substantial sun exposure during adult life. We thus suggest that sun exposure during childhood and during adulthood would be interdependent as far as their impact on melanoma risk is concerned. Our results support the hypothesis by which the important contribution of sun exposure during childhood in melanoma occurrence is not properly assessed by retrospective epidemiologic studies. Sun avoidance during childhood would have a greater impact on melanoma risk than sun avoidance during adulthood.

Familial halo naevi

The incidence of halo naevi in the population has been estimated to be 1%. We now report the simultaneous occurrence of such naevi in four members of a family previously resident in New Zealand.

Melanoma risk and residence in sunny areas. EORTC Melanoma Co-operative Group. European Organization for Research and Treatment of Cancer

Melanoma risk among subjects from Germany, France and Belgium who had lived for 1 year or more in sunny climates was examined in a one-to-one unmatched case-control study conducted among white subjects 20 years old or more. A total of 412 consecutive patients with melanoma diagnosed from 1 January 1991 onwards, were derived from hospital registers; 445 controls were randomly chosen in the same municipality as the cases. After adjustment for host characteristics, melanoma risk associated with residence in a sunny area was 2.7 (95% CI: 1.4-5.2), increasing to 4.7 (95% CI: 1.4-13.5) if subjects sought a suntan when residing in sunny climates, and to 4.3 (95% CI: 1.7-11.1) if subjects arrived before the age of 10 years in the sunny area. Residence in sunny areas and recreational sun exposure seemed to combine their effects on melanoma risk. Increase in melanoma risk conveyed by deliberate sun exposure during adulthood was highest among subjects who had lived in sunny areas as a child or adolescent and lowest among subjects who had never resided in sunny areas. Our results support conclusions from migrant studies that indicated that childhood is a critical period of either vulnerability to solar radiation or more frequent exposures to melanoma risk factors. They also suggest that moderate sun exposure of an adult who was heavily sun exposed in childhood is associated with a higher melanoma risk than that of high sun exposure of an adult who was sun protected in childhood.

Nevi and migration within the United States and Canada: a population-based cross-sectional study

A survey to ascertain factors associated with benign melanocytic nevi or moles was conducted among randomly-selected White adults (aged 18 to 50 years) in Washington State (United States). Participants of the telephone interview in 1990-91 were questioned about lifetime places of residence and constitutional factors. Subjects counted raised nevi on their arms at the end of the survey. Logistic regression was used to examine the risk for two or more nevi compared with no nevi. Individuals who resided in warmer areas and lower latitudes than Washington State were at higher risk of having multiple nevi. This association held for residence at birth, during childhood, adolescence, and over lifetime: an odds ratio (OR) of 2.3 (95 percent confidence interval = 1.2-4.3) for lifetime average daily maximum temperature of > or = 64 degrees F compared with 58.9 degrees F, and similar ORs of 2.1 for adolescence and 1.8 for childhood. These associations remained significant after adjusting for potential confounding effects of constitutional factors and for childhood sunburns as a potential mechanism. Risk of multiple nevi was reduced for both early age at migration and longer duration of stay in Washington. These data are consistent with the importance of childhood and adolescent sun exposure in the etiology of nevi, but also suggest an effect of lifetime sun exposure.

Proportional melanoma incidence and occupation among white males in Los Angeles County (California, United States)

A case-control analysis of cancer registry data was used to examine the hypothesis that occupational exposure to sunlight influences the risk of melanoma. Occupation at diagnosis was available for 3,527 cutaneous melanomas and 53,129 other cancers identified by the Los Angeles County (California, United States) Cancer Surveillance Program among non-Spanish-surnamed White males aged 20 to 65 years between 1972 and 1990. Occupational exposure to sunlight was assessed by blinded expert coding of job titles as indoor, outdoor, and mixed indoor/outdoor. Relative to indoor occupations, proportionate odds ratios (OR) adjusted for age, level of education, and birthplace were 1.16 (95 percent confidence interval [CI] = 1.07-1.27) for indoor/outdoor occupations and 1.15 (CI = 0.94-1.40) for outdoor occupations. However, increasing levels of the education or training required for the occupation was associated more strongly with increased melanoma occurrence (ORs adjusted for age, occupational sun exposure, and birthplace, were 1.0, 1.63, 2.09, 2.23, and 2.99 for low-skill occupation, high school, college, postgraduate, and doctoral levels, respectively). Analysis of melanoma occurrence by job titles confirmed a clear variation by the required education or training level but not by the category of occupational sunlight exposure. The findings suggest that lifestyle factors associated with higher levels of education may be more important determinants of melanoma risk than characteristics of the work environment.

Cancer incidence in England and Wales and New Zealand and in migrants between the two countries

Risks of cancer incidence in people born in England and Wales and New Zealand (non-Maoris) living in their home countries, and after migration between the two countries, were analysed using data from their national cancer registries. Since these populations are of similar genetic origin, any real differences in cancer incidence between them are likely to reflect the action of environmental or behavioural risk factors. The greatest differences in risk between the countries were for cutaneous melanoma and lip cancer. In each sex, relative risks of these malignancies were 4 or greater for the New Zealand-born in New Zealand compared with English and Welsh natives in their home country, and risks for migrants in each direction were generally intermediate between those born in the home country in the two countries. Sizeable significantly raised risks in the New Zealand-born in New Zealand compared with English and Welsh natives in England and Wales also occurred for cancers of the mouth, small intestine, colon, thymus, eye and thyroid, and non-Hodgkin's lymphoma in each sex, and for cancer of the prostate. For all of these sites except mouth, small intestine and colon there were also risks around or above New Zealand-born levels for English and Welsh migrants to New Zealand; for colon cancer these migrants had risks close to those in England and Wales. New Zealand migrants to England and Wales had risks of cancers of the colon and prostate that were similar to or above New Zealand levels. Risks of cancers of the stomach, lung, pleura and bladder, and Hodgkin's disease in each sex, and cancers of the cervix, ovary and scrotum and penis, were substantially and significantly lower in the New Zealand-born living in New Zealand than in English and Welsh natives in England and Wales. In English and Welsh migrants to New Zealand risks of bladder cancer in each sex, and of scrotal and penile and pleural cancer in males, approximated to England and Wales risks; cervical cancer risk approximated to the New Zealand risk; and stomach, lung and ovarian cancers showed intermediate risks. Migrants from New Zealand to England and Wales did not gain the lung cancer or clearly the stomach cancer risk of their host country, but did have bladder cancer risks approximating to those in England and Wales.(ABSTRACT TRUNCATED AT 400 WORDS)

Ultraviolet radiation-induced skin lesions in laboratory opossums (Monodelphis domestica) exposed from the weanling stage

After repeated exposure to ultraviolet radiation, adult laboratory opossums (Monodelphis domestica) may develop hyperplasia and neoplasia of the shaved skin. We exposed opossums from the weanling stage (8-10 weeks after birth) and compared the incidence of lesions at designated time points with those observed following introduction of adults (around 5 months old) to the same irradiation protocol (125 J/m2 of UVB three times each week for up to 40 weeks). The overall incidence of hyperplasia and neoplasia among opossums exposed from the weanling stage was markedly lower than among animals first exposed as adults, and hyperkeratosis and sarcoma were not observed. Although freckling was widespread, cutaneous melanocytic nevi were rare among animals first exposed as weanlings; however, one animal without freckling developed malignant melanoma with presumptive metastasis to the spleen. The basis of the lowered lesion incidence among weanling-introduced animals is not clear; it may be that cutaneous immunity to ultraviolet radiation damage is more efficient in juveniles than in adults.

Solar ultraviolet radiation and ocular disease: a review of the epidemiological and experimental evidence

Exposure to solar ultraviolet radiation has been linked, at some point, with more than a dozen eye diseases. Some of these associations are based solely on anecdotes, while others have been subjected to epidemiological investigations. For each eye disease, the evidence for an association with ultraviolet radiation is presented and evaluated. The only eye disease for which there is sufficient evidence of a causal association in humans is photokeratitis. For several eye diseases (climatic droplet keratopathy, pterygium, cataract) there is limited evidence for an association, while for other diseases (uveal melanoma, macular degeneration) there is either little support for an association or inadequate data on which to base an assessment.

Radiation-induced malignant melanoma: the dog that did not bark

A history of exposure to ultraviolet rays, such as those in sunlight, has been strongly associated with malignant melanoma. Gamma rays consist of much more energetic photons, but yet they have much more tenuous links to melanoma. A literature review suggests that relatively little evidence has been adduced for gamma radiation as a cause of malignant melanoma. An exploration of the reasons behind the paradoxical lack of melanoma induction by gamma radiation may yield clues to the etiology of melanoma.

Latitude gradients in melanoma incidence and mortality in the non-Maori population of New Zealand

The variation with latitude of incidence and mortality for cutaneous malignant melanoma (CMM) in the non-Maori population of New Zealand was assessed. For those aged 20 to 74 years, the effects of age, time period, birth-cohort, gender, and region (latitude), and some interactions between them were evaluated by log-linear regression methods. Increasing age-standardized incidence and mortality rates with increasing proximity to the equator were found for men and women. These latitude gradients were greater for males than females. The relative risk of melanoma in the most southern part of New Zealand (latitude 44 degrees S) compared with the most northern region (latitude 36 degrees S) was 0.63 (95 percent confidence interval [CI] = 0.60-0.67) for incidence and 0.76 (CI = 0.68-0.86) for mortality, both genders combined. The mean percentage change in CMM rates per degree of latitude for males was greater than those reported in other published studies. Differences between men and women in melanoma risk with latitude suggest that regional sun-behavior patterns or other risk factors may contribute to the latitude gradient observed.

Cutaneous malignant melanoma: association with height, weight and body-surface area. a prospective study in Norway

To investigate whether anthropometric indices as body height, body-mass index (BMI) and body-surface area (BSA) have any influence on the risk of cutaneous malignant melanoma (CMM), we analyzed height and weight data from a Norwegian screening survey running between 1963 and 1975 and comprising 1.3 million individuals followed for 14 to 26 years. Among females, CMM was diagnosed in 2814 incident cases, while the number among males was 2144 during 22,988,345 person-years of follow-up. With adjustment for age, birth cohort, geographic region and BMI, the risk for CMM increased significantly with increasing quintiles of height in both sexes. The tallest persons were at greater relative risk than the shortest ones: 1.60 and 1.59 in males and females respectively. This positive association was also found for CMM localized on face and trunk in both sexes, and in the lower limbs only in females. Males in the highest quintile of BMI had a relative risk for CMM of 1.26 compared with the lowest quintile, while a non-significant negative association were found in obese females. This negative association increased and was significant for CMM located on the trunk and lower limbs in females. Among males we observed a consistent association between BSA and risk of CMM similar to that for height. These relationships between anthropometric indices and CMM are discussed according to factors which promote growth, among which nutrition, social class and hormones are the most important.

Melanoma: linked temporal and latitude changes in the United States

The rise in the incidence and mortality from melanoma of the skin is slowing down in younger age groups in the United States. In many White populations, including that of the US, melanoma incidence and mortality rates increase according to proximity of residence to the Equator. Variations with age in this gradient do not seem to have been examined. We examined how the influence of latitude on melanoma rates varied with age. Estimates of age-specific trends by time and by latitude for natural logarithm (Ln) melanoma incidence-rates from the Surveillance, Epidemiology and End Results (SEER) programs, and Ln melanoma mortality rates from the US Vital Statistics were derived from fitted regression equations. Unexpectedly, a decline from old age to youth in the influence of latitude was found for both incidence and mortality from melanoma of the skin in males, and for mortality in females. Further, these changes in the relationship to latitude with age correlated with the changes in time trends with age. The link with exposure suggests that the time trends in melanoma are driven by variations in damage to melanocytes in early life that increases sensitivity to sunlight. This has implications for the general understanding of melanoma etiology and for health education.