J. Mark Elwood

Melanoma and sun exposure: An overview of published studies

To assess the association between the incidence of cutaneous melanoma; intermittent, occupational and total sun exposure; and history of sunburn at different ages, we conducted a systematic review using results of all published case‐control studies which have assessed incident melanoma, sun exposure and sunburn. Twenty‐nine studies contributed data on sun exposure and 21 on sunburn. Overall, there was a significant positive association (odds ratio [OR] = 1.71) for intermittent exposure, a significantly reduced risk for heavy occupational exposure (OR = 0.86) and a small, marginally significant excess risk for total exposure (OR = 1.18). There was a significantly increased risk with sunburn at all ages or in adult life (OR = 1.91) and similarly elevated relative risks for sunburn in adolescence (OR = 1.73) and in childhood (OR = 1.95). There was significant heterogeneity with all of these estimates except that of all ages or adult sunburn. These results show the specificity of the positive association between melanoma risk and intermittent sun exposure, in contrast to a reduced risk with high levels of occupational exposure. The association with sunburn also is likely to reflect intermittent exposure; the results do not suggest any strong relationship to age at sunburn. These associations are similar to those reported for basal cell skin cancer but different from those reported for squamous cell cancer. The mechanisms by which intermittent exposure increases risk, while other patterns of exposure do not, remain to be elucidated. Int. J. Cancer 73:198–203, 1997.

Body site distribution of cutaneous malignant melanoma in relationship to patterns of sun exposure

A study of all newly incident melanoma patients in British Columbia in 1991–1992 was undertaken to test the hypothesis raised by an earlier study, which showed that in younger patients the incidence rate of melanoma per unit area of skin was higher on intermittently exposed skin areas than on continuously exposed areas. Using 1,033 patients and a more detailed body site categorisation than was previously possible, our results confirmed that in both men and women under age 50 the highest melanoma density was on the back. At ages over 50, the greatest density occurred on fully exposed sites, such as the face, though the dorsum of the hand and forearm, likely also to have high exposure, show very low melanoma densities. Differences between males and females correlate well with differences in likely exposure patterns. These results were seen for all invasive cutaneous melanomas combined; the patterns were similar for subtypes and for both invasive and in situ melanoma, with the exception of lentigo maligna melanoma (LMM), which occurs almost exclusively on the face, even at younger ages. Comparison with the earlier study (1976–1979) shows that the age‐standardised rates for melanoma excluding LMM have increased by 60%, with the greatest proportional increase being at younger ages; in the recent data, the age‐standardised rate for intermittently exposed sites exceeds that for usually exposed sites. Our results confirm that intermittent sun exposure has a greater potential for producing melanoma than continuous exposure at ages below about 50, though at older ages melanoma is more common on body sites with continuous sun exposure. Int. J. Cancer 78:276–280, 1998.© 1998 Wiley‐Liss, Inc.

Is chronic sunlight exposure important in accounting for increases in melanoma incidence

Most attempts to relate changes in patterns of sunlight exposure to the rise in incidence of malignant melanoma have concentrated on the positive association between intermittent exposure to sunlight and risk of melanoma. The Western Canada Melanoma Study, however, also detected a significant inverse association between melanoma and chronic or longterm occupational sun exposure in men, with the lowest risk (OR = 0.5) in those with maximum occupational exposure, suggesting that chronic exposure may be protective. Data obtained from Canadian census figures indicated that since 1951 there has been a substantial reduction in the number of males engaged in outdoor occupations in Canadian society. These observations suggest that part of the increase in the incidence of melanoma in lowsunlight areas may be due to a reduction over the past 40 years of the size of this group of individuals “protected” by their exposure to UV light.

Epidemiological aspects of cutaneous malignant melanoma

Preface. I: Recent Progress in Melanoma Research. 1. Recent progress in the epidemiology of malignant melanoma R.P. Gallagher, J.M. Elwood. II: Solar and Artificial Ultraviolet Radiation and Melanoma. 2. Sun exposure and the epidemiology of malignant melanoma J.M. Elwood, R.P. Gallagher. 3. Etiological clues from the anatomical distribution of cutaneous melanoma A. Green, R. MacLennan. 4. Tables of ambient solar ultraviolet radiation for use in epidemiological studies of malignant melanoma B.L. Diffey, J.M. Elwood. 5. Non-solar sources of ultraviolet radiation and cutaneous malignant melanoma: a review of the evidence L.D. Marrett. III: Nevi and Melanoma. 6. Risk factors for prevalence of nevi: a review L.K. Dennis, E. White. 7. The atypical mole syndrome -- a definition of phenotype J.A. Newton, V. Bataille. 8. Risk of cutaneous melanoma by number of melanocytic nevi and correlation of nevi by anatomic site E.A. Holly, J.W. Kelly, D.K. Ahn, S.V. Shpall, J.I. Rosen. IV: Occupation and Melanoma. 9. Malignant melanoma of the skin in the telecommunications industry L. de Guire. 10. Petroleum refinery exposure and risk of malignant melanoma M.M. Hornstra, M.J. Klan, D.S. Sharp. 11. Methods for evaluating confounding and effect modification in a small occupational study of cutaneous malignant melanoma J.A. Schwartzbaum, R.W. Setzer, L.L. Kupper. V: Pregnancy and Hormonal Factors and Melanoma. 12. Melanoma and pregnancy E.A. Holly, R.D. Cress. 13. Cutaneous melanoma and oral contraceptives E.A. Holly. VI: Diet and Melanoma. 14. Epidemiology of diet and melanoma incidence -- a brief review C.S. Kirkpatrick. 15. Dietary and other correlates of melanoma in Hawaii: preliminary findings L. le Marchand, J.H. Hankin, L.N. Kolonel, L.R. Wilkens. VII: Prevention and Early Detection of Melanoma. 16. Early detection and lethal melanoma in Connecticut: a preliminary analysis M. Berwick, N. Dubin, G. Roush, R. Barnhill. 17. Risk factors for presentation with thick primary melanoma include older age, male sex, smoking and may include occupation in certain industries P. Hersey, T. Strong, D. Grant, Z. Marish. 18. Skin cancer screening in Massachusetts: the program and methodologic questions H.K. Koh, D.R. Miller, A.C. Geller, R.A. Lew. VIII: Future Directions in Melanoma Research. 19. The epidemiology of melanoma: where do we go from here? B.K. Armstrong. Index Page.

Electromagnetic field exposures and childhood leukaemia in New Zealand

A nationwide case-control study of childhood leukaemia in New Zealand included measurements of electric and magnetic fields in childrens homes. There was no significant association between leukaemia and the time-weighted average of the 50 Hz magnetic or electric fields in the bedroom and living (or daytime) room combined.

Sun exposure and the epidemiology of melanoma

Individual risk of melanoma depends on two sets of factors: characteris tics of each subject such as his or her racial origin, pigmentation, skin reaction to sunlight, nevus and freckle density; and characteristics of the environment in which he or she lives. The only well established environmental causal factor for melanoma is sun exposure, with there being considerable evidence for a complementary effect of artificial ultraviolet radiation (UVR). In this review, the emphasis is on the role of ultraviolet radiation as a modifiable cause of melanoma. This review incorporates and updates material from earlier reports, [1–5], and data from the IARC Monograph on Solar and Ultraviolet Radiation [6]. A number of other very useful reviews are available, [7–19].

Recent progress in the epidemiology of malignant melanoma

Interest in the origin and etiology of malignant melanoma continues to grow as the tumour assumes greater importance as a cause of morbidity in countries with predominantly white populations. Up until 15 years ago most available information came from descriptive data. During the early and mid-1980’s a series of well designed and conducted case-control studies [1–11] made a substantial contribution to elucidating the relationship of melanoma with both pigmentation and constitutional factors and with sunlight.