Which of the following statements is/are true of the epidemiology and etiology of melanoma?

D. The per capita incidence of melanoma is highest in Australia.

DISCUSSION: The median age at diagnosis is in the late forties; so, a minority of patients are diagnosed after age 60. The risk of melanoma is closely tied to skin color: Caucasians are at highest risk, and those with a Celtic complexion at even higher risk. Australia has a large Celtic population living near the equator, and it has the highest per capita incidence of melanoma in the world. Sun exposure is believed to be an important cause of melanoma, but the data remain incomplete. Some melanomas arise in sites not exposed to the sun (e.g., mucous membranes), so sun exposure is not the only risk factor.