Are Ocular Markers of Sun Exposure Associated With Skin Cancer? A Cross‐Sectional Analysis of the Busselton Healthy Ageing Study

Background Higher past sun or ultraviolet radiation exposure increases the risk of skin cancer and three common ocular findings: pterygium, conjunctival ultraviolet autofluorescence (CUVAF) and myopia. We investigated whether ocular markers of past sun exposure are associated with a history of skin cancer. Methods A cross‐sectional study of participants who attended the Phase 2 examination of the Busselton Healthy Ageing Study in Western Australia (2016–2022). Myopia was determined from autorefraction and pterygium and CUVAF from photographs of the anterior eye. Past diagnosis of a skin cancer was obtained from linked hospitalisation and cancer registry data (melanoma) or combining linked and self‐reported data (keratinocyte cancer). Multivariable logistic regression with multiple imputation was used for analysis. Results Of 3888 participants who attended, 3829 (98.5%) had skin cancer history data (mean [standard deviation] age 64.2 [5.4] years). A history of keratinocyte cancer was present in 795 (20.8%) participants and cutaneous melanoma in 59 (1.5%) participants. After adjustments, keratinocyte skin cancer was associated with a current pterygium (odds ratio [OR] = 1.33, 95% confidence interval [CI]: 1.05, 1.69) and a previous self‐reported pterygium excision (OR = 1.85, 95% CI: 1.21, 2.82). Neither CUVAF or myopia was associated with keratinocyte cancer or melanoma diagnoses. Conclusions Having a current pterygium or previous pterygium excision is associated with a diagnosis of keratinocyte skin cancer. While causality cannot be determined, the association may reflect shared risk factors such as chronic ultraviolet radiation exposure, and people with a pterygium should be advised that they are at higher risk of skin cancer.