Sun Exposure Linked With Lower Risk of Follicular Lymphoma

High sun exposure in warmer months may protect against the development of follicular lymphoma, according to a study published in the journal Cancer Epidemiology, Biomarkers & Prevention.

“The precise mechanism through which sun exposure might reduce follicular lymphoma risk is unknown,” wrote corresponding author Claire M. Vajdic, PhD, of the University of New South Wales, Sydney, Australia, and study coauthors. “Plausible biological pathways are through the anti-inflammatory activities of vitamin D and the activation of signaling pathways that regulate B-cell proliferation.”

The Australian population-based study included 666 patients with follicular lymphoma and 459 family controls (288 were siblings and 171 were spouses or partners). Researchers questioned participants on factors including outdoor hours in the warmer and cooler months at ages 10, 20, 30, and 40 years and types of clothing worn in warmer weather.

The study found an inverse association between follicular lymphoma risk and several measures of high lifetime sun exposure, particularly for intermittent exposure such as weekends and holidays.

Reduced follicular lymphoma risk was associated with increasing time outdoors on holidays in the warmer months, high outdoor hours on weekends in the warmer months, and increasing time outdoors in the warmer and cooler months combined, according to the study. Risk was also reduced for people who maintained a trajectory of high total outdoor hours in the warmer months across decades compared with moderate-to-low total outdoor hours.

“Despite these findings, sun exposure is not recommended as a cancer control policy given that solar ultraviolet radiation is an established carcinogen for skin cancer,” researchers wrote. “Prospective studies are needed to affirm our findings.”

Reference

Odutola MK, van Leeuwen MT, Bruinsma F, et al. A population-based family case-control study of sun exposure and follicular lymphoma risk. Cancer Epidemiol Biomarkers Prev. 2024;33(1):106-116. doi:10.1158/1055-9965.EPI-23-0578