Statistical analysis
Normality of data was assessed via kurtosis, skewness, Q-Q plots and the Kolmogorov-Smirnov test (with Lilliefors significance correction). Heteroscedasticity was assessed with Levene’s inferential test. All statistical analyses were completed using IBM’s Statistical
Package for Social Sciences (SPSS, Ver. 27.0) and included demographics, independent
sample t-tests, Chi-square tests and ANOVA (Bonferroni post-hoc test) were used to determine significance between groups. Multivariate analysis was conducted to control for selected confounding variables. A bivariate (two-tailed) Pearson correlation coefficient was used to determine relationships between selected outcome variables. Alpha was set a priori at P < .05 to determine significance between groups.
Point prevalence was determined by the number of surfers or swimmers with a AK, BCC, SCC, SCC in situ or MSC divided by those in the same group without. The standardized rate per 100,000 was calculated as, for example, the number of surfers or swimmer participants identified with a particular skin cancer multiplied by 100,000 then divided by the total number of surfers or swimmers, respectively.20 Odds ratios (OR), a ratio of two sets of odds, were determined with scale data and calculated as the odds of those in the exposed group (for example surfers with a BCC) divided by all surfers. The OR of surfers to swimmers was then determined by the odds in surfers divided by the odds in swimmers. Comparative OR for the Australia general population were identified within the literature.8,9,21