Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort.
Level 3 - non-randomized controlled study
Prospective observational cohort study with 20-year follow-up.
PubMed 24697969 · doi:10.1111/joim.12251
What was done
Researchers evaluated the association between sun exposure habits and all-cause mortality in the prospective Melanoma in Southern Sweden (MISS) cohort. A total of 29,518 Swedish women aged 25 to 64 years were recruited between 1990 and 1992. Baseline questionnaires collected information on sun exposure habits and potential confounders. Participants were followed for 20 years, and data were analyzed using multivariable flexible parametric survival models.
What was found
During the 20-year follow-up, 2,545 deaths occurred. All-cause mortality was inversely related to sun exposure habits. Women who avoided sun exposure had an approximately twofold higher mortality rate compared with women in the highest sun exposure group, representing excess mortality with a population attributable risk of 3%.
Why it matters
These findings suggest that strict avoidance of sun exposure in regions with low solar intensity may be associated with increased mortality risk, cautioning against overly restrictive sun protection guidelines for women in such climates.
Limits
The study is observational, leaving open the possibility of residual confounding such as baseline health status, physical activity, or outdoor lifestyle factors that could limit sun exposure. Sun exposure was self-reported at baseline and not tracked dynamically over time. The cohort consisted exclusively of Swedish women, limiting generalizability to men, other ethnic backgrounds, or populations in regions with higher UV radiation.
Cited by
- supports A large-scale study from Sweden found that greater sunlight exposure was associated with increased lifespan, with smokers who received more sunlight living longer on average than non-smokers who received less sunlight.