Ultraviolet exposure and mortality among women in Sweden

Ecological studies have reported possible effects of sunlight on the risk of several diseases. Little evidence is available on the association between mortality and solar and artificial UV exposure by individual level from prospective studies.

The Swedish Women's Lifestyle and Health cohort study included women aged 30 to 49 years in 1991-1992. Participants completed a questionnaire and were followed-up through linkages to national registries until the end of 2006. Cox models were used to estimate adjusted HRs and 95% CIs for all-cause mortality and for cancer and cardiovascular disease (CVD) mortality.

During 15 years of follow-up, among the 38,472 women included in the present study, 754 deaths occurred: 457 due to cancer and 100 due to CVD. When combining the information on sun exposure from age 10 to 39 years, women who got sunburned twice or more per year during adolescence had a reduced all-cause mortality, compared with women who had been sunburned once or less. A reduced risk for all-cause and CVD mortality was observed in women who went on sunbathing vacations more than once a year over three decades. Solarium use once or more per month for at least one decade increased the risk of all-cause mortality, when compared with women who never used a solarium.

Solar UV exposure was associated with reduced overall and CVD mortality, whereas artificial UV exposure was associated with increased overall and cancer mortality among Swedish women.

Moderate sun exposure may protect against cause-specific mortality.