Researchers in China have found that sunlight exposure may have no bearing on risk of age-related macular degeneration (AMD) based on current published data. The team analyzed 14 eligible studies that included 43,934 individuals.

In subgroup analyses, the study found only one mildly significant association in the case-control studies but not in the cross-sectional studies. When they stratified the data based on the stage of AMD, method of exposure assessment and study latitude, the researchers observed similar insignificant results. When observing sun-avoidance behaviors, the study found that subjects who used sunglasses or hats regularly didn’t have a decreased risk of AMD.

The researchers did note that it was difficult to quantify sunlight exposure objectively, which was the best way to evaluate the quality of the articles included in the study. Assessments of total sunlight exposure were based on questionnaires, and the accuracy of the data obtained depended heavily on question quality and respondents’ memory. While some studies used sunlight-related factors to assess exposure, the relationship between proxy measures for sunlight exposure and AMD was not conclusive. The study found that the common limitation in the studies was that the correlation between such proxies and true sunlight exposure was overall unknown.