Sun-Wise Campaigns May Have Reduced Skin Cancer Rates

Liam Davenport

October 14, 2019

The reduction in the incidence of melanoma cases in Australia since the 1980s may be due to the success of sun awareness campaigns in modifying behaviors, particularly among younger adults, indicates an analysis of a series of population-based surveys.

The SunSmart program was launched in Melbourne, Australia, in 1988 and now includes smartphone apps and interactive tools alongside the more traditional posters and publications.

Since its launch, the program has surveyed individuals ages 14 to 69 years over 14 summers about their attitudes toward tanning, their sun protection behavior, and the incidence of sunburn.

Suzanne Dobbinson, PhD, senior research fellow at Cancer Council Victoria in Melbourne, Australia, and colleagues found that, compared with the year before SunSmart was launched, there were marked increases in the use of at least one sun protection method, which were maintained into the 2010s.

The research, published by PLOS Medicine on October 8, also showed that, over the study period, individuals were increasingly less likely to value getting a suntan, and the incidence of sunburn was reduced by almost 40%.

The team writes that, "with an estimated 20-year lag between sun exposure and melanoma incidence, our findings are consistent with SunSmart having contributed to the reduction in melanoma among younger cohorts."

Dobbinson told Medscape Medical News in an email that this conclusion is based on "logical inference", and she and her colleagues are "confident" in their assertion due to "the timing and size of the behavior changes among Melbourne residents."

"However, definitive evidence on the relationship between the SunSmart program impact and the reductions in melanoma remains elusive," she added.

Dobbinson noted that "skin cancer prevention programs are delivered across all states and territories in Australia, precluding comparison with a control population." In addition, she added, the study was cross-sectional and relied on self-reported behavior.

Nevertheless, she said that the success of SunSmart can be attributed to a number of factors, not the least of which was its introduction just as "the scale and cause of the burden of skin cancer for the community was identified."

"Importantly, the program was established from a strong theoretical base and has benefited from relatively stable funding...over more than 30 years."

Dobbinson believes that another strength is that workplaces and schools were among the settings targeted for advocacy as well as policy and environmental changes, alongside the continuous research and evaluation of the program's activities.

She said that other regions with high skin cancer rates have "adopted aspects of the program and its public education messages," although she emphasized that "each region needs to tailor their approach and messages."

"For example, in northern Europe several countries have responded to increasing melanoma rates by developing campaigns for prevention focused more on the behaviors of indoor tanning or travel on holidays to sunnier climates with high UV environments."

Highly Preventable

The incidence of skin cancer in Australia is higher than that of any other type of cancer due to the high ambient levels of ultraviolet radiation (UV) and the large population with susceptible skin types.

However, the researchers note that, with up to 99% of skin cancer cases in the region attributable to UV exposure, the disease is "highly preventable."

SunSmart was established in Victoria, a state in southeastern Australia, as a multicomponent, community-wide prevention program, and is seen as having successfully raised awareness and changed behaviors.

There has been a decrease in melanoma incidence among Australians born from about 1958 onward, which has sparked debate as to whether it is attributable to sun protection programs.

The researchers suggest that the equivocal nature of the evidence from studies conducted so far is due to a focus on the uptake of individual sun protection behaviors rather than changes in behavior as a whole.

They therefore set out to reappraise the effects of the program by looking at a combination of five sun protection behaviors: wearing wide-brimmed hats; wearing sunglasses; using sunscreen; using covering clothing; and staying under shade while outdoors.

For this, they examined surveys of Melbourne residents (carried out by Cancer Council Victory) on their sun-related attitudes and behavior during 14 summers between 1987 and 2017.

Participants aged 14 to 69 years were recruited to take part in telephone interviews on a cross-sectional basis over 12 to 13 weeks during each of the summers, with the same questions used each year.

The researchers asked about the time and location of sun-related behaviors and sunburn experiences over the previous 2 to 4 days, and linked the findings to weather and UV records for Melbourne on the relevant dates.

A total of 13,258 surveys were available for analysis, including 1655 from 1987, the year before SunSmart was launched, 5258 from the 1990s, 3385 from the 2000s, and 2987 from the 2010s.

The team says that the distributions of age and sex across the surveys reflect the population of Melbourne residents aged 14 to 69 years. Approximately three quarters of respondents had moderately or highly sensitive skin.

Compared with 1987, preventive beliefs and attitudes increased in all decades.

For example, the proportion of respondents reporting that they did not like to get a suntan increased from 43.1% at baseline to 66.1% in the 2010s, at an adjusted odds ratio of 2.78 (P < .001).

Conversely, the proportion of individuals who disagreed with the notion that "Most of my friends think a suntan is a good thing" increased from 35.9% to 63.1% in the 1990s, at an odds ratio of 3.43 (P < .001), before falling back by the 2010s to an odds ratio of 2.52 (P < .001).

After taking into account weather conditions, the results also showed that there was a significant reduction in the proportion of respondents being outdoors during peak UV hours on at least one day over the weekend.

Compared with the baseline survey, the odds ratio of being outdoors during peak UV hours was 0.72 in the 1990s, 0.67 in the 2000s, and 0.57 in the 2010s (P < .001 for each).

The average length of time spent outdoors on weekends also decreased from 120 minutes in the 1980s to 118 minutes in the 1990s, 111 minutes in the 2000s, and 101 minutes in the 2010s.

By the 2010s, there was also a notable increase in the use of sunscreen compared with the 1980s, at an odds ratio of 4.73 (P < .001), and there was a more modest increase in the proportion of respondents staying mostly in the shade when outdoors, at an odds ratio of 1.68 (P < .001).

Overall, there was a 3.46-fold increase in the use of at least one sun protection behavior between the 1980s and the 2010s (P < .001).

This was accompanied by a decrease in rates of sunburn, reaching a nadir in the 2010s, at an odds ratio vs baseline of 0.62 (P < .001).

Dobbinson believes that the methodology they used for the study could be used in other contexts, and "may provide insights for public health programs where multiple behaviors offer the desired prevention outcomes."

"For example," she noted "multiple measures are required to adequately assess physical activity and dietary changes for obesity prevention."

She added: "As with the current study, a review of the selected outcome measures periodically may identify gaps in measures, such as for neglected settings or contexts."

The study was funded by Cancer Council Victoria from 1987 to 2002. Since 2003, the study has been conducted as a component of the National Sun Protection Survey, which is funded by Cancer Council Australia and the Australian Government Department of Health and Ageing.

All study authors were supported by Cancer Council Victoria. Melanie Wakefield is supported by an Australian National Health and Medical Research Council Principal Research Fellowship.

PLOS Medicine. Published online October 8, 2019. Full text

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