Increasing Risk of Melanoma With Increasing Age

To the Editor: Melanoma incidence is increasing faster than any other cancer in the United States, with an estimated 41,600 new melanoma cases diagnosed in 1998.¹ The increase may be explained by lifestyle changes to sun exposure in subsequent generations that affect each generation throughout their life. Such generation or birth-cohort trends have been observed for melanoma.² The associations between melanoma and childhood migration to sunny areas, childhood sunburns, and increased nevi support the importance of exposure early in life. However, it is unclear how birth-cohort trends affect the age-specific incidence rates of melanoma. Dermatologic textbooks^3- 4 often report that melanoma rates increase into middle age and then level off. However, melanoma rates would be expected to increase with age due to cumulative effects on the immune system and damage due to UV exposure. In an attempt to better understand melanoma incidence by age, we compared the crude incidence of melanoma with incidence adjusted for birth-cohort effects.