Mid-20th Century
The 1940s to 1970s were characterized by increased travel, greater availability of outdoor activities, and a popular culture that endorsed even more tanning and revealing clothing styles than in previous decades. Coinciding with the tanning trend, however, were mounting laboratory data indicating a direct role of UV radiation in the development of skin tumors in animals and epidemiological studies associating skin cancer with UV exposure.
Growing Knowledge of the Dangers of UV Radiation
Concurrent with heightened knowledge about the dangers of UV radiation, the consumer products industries had increased interest in developing novel sunscreen preparations. In the 1940s to 1960s, dermatologists commonly recommended 2% to 5% para-aminobenzoic acid–containing topical preparations, which were believed to remain in the stratum corneum and provide UV-B radiation protection for several hours. Later in the 1970s, the first water-resistant sunscreens were developed. Similarly, the cosmetic industry began adding sunscreen to makeup products. Whether sunscreen was used primarily as a way to avoid sunburn and increase time outdoors rather than prevent skin cancer during this time, however, remains uncertain.
The Rise of Revealing Fashions
Despite growing warnings, tanned skin remained popular. Actresses, such as Ursula Andress (the first Bond girl), and fashion magazines endorsed tanning because it supported the prevailing notion of sexy, young, healthy, and wealthy women. Likewise, clothing and swimwear styles also became more revealing. The T-shirt became an acceptable outergarment in 1942, allowing arms to be exposed on a daily basis. During World War II, the US government instituted fabric rations for clothing manufacturers in an effort to conserve wool and silk, which were needed to make uniforms and parachutes. In 1943, an order was issued stating that the fabric used in women's swimwear needed to be reduced by 10%; this resulted in the elimination of the midsection and the introduction of the 2-piece bathing suit. Later, in 1946, skin exposure in swimsuits became even more pronounced when French designer Louis Reard invented the bikini, which was widely adopted in the United States by the 1960s. This new swimsuit design increased women's skin exposure from 47% to 80% (Supplemental Figure 3A, available as a supplement to the online version of this article at http://www.ajph.org). Men's swimsuit skin exposure increased from 47% to 89% as the swim tank top was eliminated in favor of a bare chest (Supplemental Figure 3B, available as a supplement to the online version of this article at http://www.ajph.org). Sportswear skin exposure also increased from 27% to 38% in women and from 14% to 38% in men (Supplemental Figures 3C and 3D, available as a supplement to the online version of this article at http://www.ajph.org).
Together with increasingly revealing fashions, women's magazines continued to portray tanning as chic, and cosmetic companies developed and marketed various tanning oil preparations. If deeply tanned skin could not be achieved by these means, the first commercial self-tanning product, the "Man-tan," became available in the 1950s.
American Affluence Promotes Travel and Sport
Besides changes in fashion, the 1940s to 1970s saw increased travel and expanded participation in organized sports. The reduced cost and increased speed of airplanes resulted in a surge of air travel in the post–World War II era. By the 1950s, the number of Americans traveling by airplane per year was in the millions, compared with tens or hundreds of thousands in the prewar years. During this time, automobile travel also doubled and tourism boomed. Travel to national parks and monuments became popular, and boating and camping gear sales rose dramatically. Amusement parks were common travel destinations. Disneyland in California opened in 1954 and recorded its 10-millionth visitor in just 3 years.
An increase in American affluence also enabled families to dedicate more time and money to organized sports. All-American team sports such as football, baseball, and basketball rose in popularity as a means to promote the "American way of life" during the Cold War. It was also during this time that the notion of sports participation as an important factor for the healthy development of children arose as evidenced by the expanding Young Men's Christian Association movement and the development of physical education in public schools.
The Rise of Melanoma
Although it is now well established that UV exposure is linked to melanoma, it was not until the creation of cancer databases that changes in UV exposure could be compared with melanoma incidence rates. The Connecticut Tumor Registry, which started keeping records in 1935, reported the age-adjusted melanoma incidence in both men and women as approximately 3.0 per 100 000 in 1950 (Figure 1). By the late 1970s, the melanoma incidence rate had risen 3-fold in men and 2.5-fold in women to 9.2 and 7.6 per 100 000, respectively (Figure 1).
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Figure 1.
Age-adjusted melanoma incidence rates with estimated swimwear skin exposure calculated with the rules of nines in (a) women and (b) men.
Note. Swimwear skin exposure is based on a review of bathing suit styles as seen in Sears catalogs. A postexposure lag time of 50–60 years was chosen because this reflects the average age at melanoma diagnosis in different decades as described in the Connecticut Tumor Registry and the Surveillance, Epidemiology, and End Results (SEER) national cancer registries. Source. Geller et al.
From the 1930s to the 1960s, the "all site" age-standardized cancer incidence in men and women increased by 69% and 18%, respectively, whereas melanoma incidence increased by more than 300% in men and 400% in women. This increase in melanoma incidence occurred in parallel with changes in fashion, travel, and leisure that resulted in increased skin and UV exposure.