A skin cancer prevention programme called SunSmart may have contributed to a recent reduction in melanoma among younger residents of Melbourne, according to a study by Suzanne Dobbinson of Cancer Council Victoria in Australia, and colleagues. According to the authors, the findings may have substantial implications for the future delivery of skin cancer prevention programmes.
Recently, melanoma rates among younger Australians have dropped, suggesting that prevention programs such as SunSmart may have contributed to this decline. But measures previously used to monitor change over time in preventive behaviour for this population focused on just single sun protection behaviours, omitting the effect of extent of use of both individual and combined behaviours that reduce exposure to ultraviolet radiation. This may have led to underestimates of behaviour change, given that effective sun protection involves multiple strategies including sun avoidance. To address this issue, Dobbinson and colleagues conducted a population-based survey in Melbourne in the summer before SunSmart commenced (1987-88) and across summers in three subsequent decades (1988-2017). During summer months, residents ranging in age from 14 to 69 years were recruited to participate in weekly telephone interviews assessing their tanning attitudes, sun protection behaviour and sunburn incidence on the weekend prior to the interview.
By analysing trends in sun protection behaviour for 13,285 respondents, the researchers found that the use of sun protection increased rapidly in the decade after SunSmart commenced. The likelihood of using one or more sun protection behaviours on summer weekends was three times higher in the 1990s than before SunSmart (AOR: 3.04, 95% CI: 2.52-3.68, p <0.001). There was a smaller increase in the use of maximal sun protection including shade (AOR: 1.68, 95% CI: 1.44-1.97, p <0.001). These improvements were sustained into the 2000s and continued to increase in the 2010s.
However, inferences on programme effects are limited by self-reported data, the absence of a control population, the cross-sectional study design and not conducting the survey in all years. Other potential confounders may include increasing educational attainment among respondents over time and exposure to other campaigns such as tobacco and obesity prevention efforts.
Although definitive evidence of the impact of the SunSmart programme on skin cancer rates remains elusive, prevention programmes should be supported given that lifelong protection is beneficial in reducing the risk of skin cancer.
Abstract
Background: Australia has one of the highest skin cancer rates in the world. ‘SunSmart’ is a multi-component, internationally recognised community-wide skin cancer prevention program implemented in Melbourne, Australia, since summer 1988–1989. Following recent reductions in melanoma rates among younger Australian cohorts, the extent of behaviour change and the potential contribution of prevention programs to this decline in melanoma rates are of interest. Sun protection is a multifaceted behaviour. Measures previously applied to monitor change over time in preventive behaviour for this population focused on individual behaviours. The omission of multiple behaviours that reduce exposure to ultraviolet radiation (UV) may have led to underestimates of behaviour change, meriting further analysis of long-term trends to contribute to this debate.
Methods and findings: A population-based survey was conducted in Melbourne in the summer before SunSmart commenced (1987–1988) and across summers in 3 subsequent decades (1988–2017). During summer months, residents (14–69 years) were recruited to cross-sectional weekly telephone interviews assessing their tanning attitudes, sun protection behaviour, and sunburn incidence on the weekend prior to interview. Quotas were used to ensure the sample was proportional to the population by age and sex, while younger respondents were oversampled in some years. The majority of the respondents reported their skin was susceptible to sunburn. Changes in sun protection behaviour were analysed for N = 13,285 respondents in multivariable models, cumulating surveys within decades (1987–1988: N = 1,655; 1990s: N = 5,258; 2000s: N = 3,385; 2010s: N = 2,987) and adjusting for relevant ambient weather conditions and UV levels on weekend dates. We analysed specific and composite behaviours including a novel analysis of the use of maximal sun protection, which considered those people who stayed indoors during peak UV hours together with those people well-protected when outdoors. From a low base, use of sun protection increased rapidly in the decade after SunSmart commenced. The odds of use of at least 1 sun protection behaviours on summer weekends was 3 times higher in the 1990s than pre-SunSmart (adjusted odds ratio [AOR] 3.04, 95% CI 2.52–3.68, p < 0.001). There was a smaller increase in use of maximal sun protection including shade (AOR = 1.68, 95% CI 1.44–1.97, p < 0.001). These improvements were sustained into the 2000s and continued to increase in the 2010s. Inferences about program effects are limited by the self-reported data, the absence of a control population, the cross-sectional study design, and the fact that the survey was not conducted in all years. Other potential confounders may include increasing educational attainment among respondents over time and exposure to other campaigns such as tobacco and obesity prevention.
Conclusions: 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.
Authors
Tamara Tabbakh, Angela Volkov, Melanie Wakefield, Suzanne Dobbinson
[link url="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002932"]PLOS Medicine abstract[/link]