Linking environmental exposures and sunburn incidence among beach users at East Fork Lake, Ohio, USA

Sunburn rates have not changed significantly in recent decades. Furthermore, in the midst of a changing climate, it is important to better understand environmental determinants of sunburn in at-risk populations as sunburn is strongly linked to melanoma and other skin cancers.  To address this research and surveillance need, we investigated sunburn as it related to swimming beach activities and environmental determinants (e.g. UV index, air temperature, etc.) using data from our 2009 prospective cohort study at East Fork Lake (Cincinnati, Ohio).  Participants were enrolled at the beach, and their activities were self-reported prior to leaving the beach area.  After 8-9 days post-enrollment, a follow-up interview occurred via telephone.  In total, health and paired exposure data were collected from 296 households representing 947 individuals. At the time of follow-up, new cases of sunburn were reported in 7% of nonswimmers and 18% of swimmers. Upon adjusting for age, swimming activity, arrival time at the beach, and total number of beach visits per year, significant associations (p < 0.05) were observed between sunburn frequency and maximum daily temperature, UV index, and maximum daily ground-level ozone.  The multivariable logistic regression model incorporating maximum daily temperature outperformed the UV index-based model with respect to model fit.  The temperature-based model exhibited outstanding fit by the Hosmer-Lemeshow goodness-of-fit test (p = 0.918); whereas the UV index-based model exhibited poor fit (p = 0.007).  Model discrimination results were equal for both models (area under the curve = 0.76).  These findings have implications for climate-based modeling of sunburn and skin cancer as well as informing sunburn risk communication strategies.