Today, whites have reservations about spending too much time in the sun. The risk of basal and squamous cell carcinomas and melanomas are, though not spoken of, largely on their minds
In the ‘twenties and ‘thirties it was not only the height of fashion, but it was also considered healthy.
Opinions about ultraviolet light exposure were not static, but evolved with increasing scientific knowledge and changing social mores. A critical interplay occurred between the prevailing medical and nonmedical views on the subject.
The first clinical observations associating long-term sunlight exposure with skin cancer were also reported during this time. The association, however, was poorly understood, and this work was largely ignored by the medical profession and remained essentially unknown to the public.
The 1920s and 1930s represented an extraordinary time in the shaping of modern attitudes towards ultraviolet light. Dermatologists and other physicians today are still confronting the effects of changes in social behavior that occurred at this time. The discovery that ultraviolet wavelengths played a role in vitamin D synthesis in the skin ushered in a period of enormous popularity for ultraviolet light exposure. A variety of other medical claims were soon made for ultraviolet radiation, including that it increased resistance to disease. The field of phototherapy rapidly expanded, and its use was employed by proponents for a host of unlikely medical conditions. Exposure to sunlight or ultraviolet lamps was widely promoted as a form of preventive medicine. Home sunlamps gained popularity and were aggressively marketed to the public. A suntan, which had previously achieved limited popularity, now was viewed as de rigueur in the United States and Europe. The role that medical advocacy of ultraviolet light exposure played in initially advancing the practice of sunbathing is not commonly appreciated today. Ironically, public health recommendations of the time were often diametrically opposed to those being made at present, since sunlight exposure is currently recognized as the major preventable cause of cancer of the skin.
(1) Melanoma was rare before 1950 but subsequently rose to epidemic proportions and now is increasing at a rate of 6 percent annually.
(2) Increased sunbathing and the thinning ozone layer can’t possibly account for all this. (This is more asserted than proved; I haven’t seen scientific studies making these arguments.)
(3) Sunscreen use, as measured in sales revenue, rose sharply after 1970. Lifetime melanoma risk increased sharply during roughly the same period.
(4) Sunscreens protect against UV-B rays, the primary cause of sunburn, but are less effective against UV-A rays, which penetrate more deeply and, some think, cause melanoma.
(5) Sunscreen thus defeats your natural early-warning system against excessive sun exposure–sunburn. Since you don’t burn, you stay out longer, and next thing you know you’ve got a skin tumor the size of Oahu. (Source)
Unfortunately, there are few animal studies to look to, as skin cancer isn’t caused in other animals by the sun as much as it is in humans.
On the other hand, genetics are a big factor in melanoma. You’re at twice the risk for melanoma if you’re a sun worshipper, but six times the risk if you’re fair-skinned or have lots of moles.