Here’s something nice to start the new year. It’s big data, just published a few weeks ago, about age-specific incidence of melanoma in the United States.* Melanoma is a dangerous form of skin cancer. Its likelihood of forming increases directly with exposure to UV radiation, particularly if there’s been a childhood sunburn. We’ve written a lot about it in these Snapmed pages, admonishing all our friends to cover up in the summer, and not go to sunbeds in the winter.
Sun-safety campaigns are pretty clearly getting people to cover up more. We know this from other studies. But is this having an effect on people actually getting melanomas?
This new paper says it begins to look so. Overall rates have increased a little across the larger population. But in young people – and this is gratifying, because it’s they who like to sun-worship – the rates are decreasing.
Here’s what the paper says
This was an observational study, based on cancer registry data collected from a combined database covering 15 years in North America. The team crunched data from 988,103 cases of invasive melanoma, and looked for annual rates in pediatric, adolescent, young adult, and adult age groups. They did sub-group analysis for sex and age-adjusted for population increase. The math was fairly complicated, this being a big, longitudinal project, but the numbers they got were nice and clear.
Between 2006 and 2015, overall incidence increased from 200.1 to 229.1 cases per million person-years. In people 40 years old or more, melanoma cases went up by an annual percentage rate of 1.8%, the same for men as for women. For adolescents, however, the rates dropped, by -4.4% for males and -5.4% for females. For young adult males, too, there was a drop, of -3.7%, and -3.6% for female young adults.
Those sex numbers conceal an important statistic. Young adult women have twice the risk of getting a melanoma than young men do. This means the girls really are covering up. They didn’t used to.
Vexingly, the study did not contain data about sun protection. Nor did it contain data about skin pigmentation. We just don’t know about racial prevalence of melanoma in this study cohort, and that would be good to know.
What’s the big punchline, though?
It’s that young people, contrary to the general population, do appear to be getting the message about protecting themselves from melanoma. It’s hard to imagine why else the rates would be so consistently – and for the first time – down. If this is a new age of sun-sensibility among younger people, and if these people extend the same prudence to their own children in time, it certainly bodes well for the future!
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