Association of Sun‐Protective Behaviors With Biological Aging: Evidence From Two Nationwide Population‐Based Studies

Background Chronic exposure to ultraviolet (UV) radiation is a well‐established driver of skin aging. However, its potential to accelerate systemic biological aging and the protective role of sun‐protective behaviors at a population level remain largely unexplored. Objective To investigate the association between the frequency of engaging in sun‐protective behaviors and the pace of biological aging. Methods We analyzed data from 5585 participants in the NHANES and 279,664 participants in the UK Biobank, focusing on sun‐protective behaviors and their association with biological aging, as measured by the PhenoAge algorithm. Multivariable linear regression models were employed to assess the impact of sun protection on biological age. Additionally, subgroup analyses were performed to examine the influence of sunburn history and sun sensitivity on this relationship. Results Sun‐protective behaviors were significantly associated with slower biological aging in both datasets. In NHANES, engaging in at least two sun‐protective behaviors was linked to a 0.66‐year reduction in PhenoAge ( β = −0.66, p = 0.012). Moderate and frequent sunscreen use reduced biological aging by 0.47 years and 0.72 years, while frequent long sleeve use was associated with a 0.57‐year reduction. In the UK Biobank, moderate and frequent sun protection use were associated with reductions of 0.51 years ( β = −0.51, p < 0.001) and 0.68 years ( β = −0.68, p < 0.001). Subgroup analyses suggested that this association was more pronounced among individuals without a history of sunburn or high sun sensitivity. Conclusion Sun‐protective behaviors, particularly regular use of sunscreen, are inversely associated with biological aging. These findings underscore the importance of adopting sun protection measures as part of a healthy lifestyle to potentially delay aging and reduce the risk of age‐related diseases.