Sunbathers tend to live longer than their shade-seeking counterparts despite their increased risk for skin cancer, but why?

New research suggests that a decrease in heart disease and noncancer/non-heart disease deaths may explain the paradox.

An analysis of information on 29,518 Swedish women who were followed for 20 years revealed that longer life expectancy among women with active sun exposure habits was related to a decrease in heart disease and noncancer/non-heart disease deaths, causing the relative contribution of death due to cancer to increase.

Whether the positive effect of sun exposure demonstrated in this observational study is mediated by vitamin D, another mechanism related to UV radiation, or by unmeasured bias cannot be determined. Therefore, additional research is warranted.

"We found smokers in the highest sun exposure group were at a similar risk as non-smokers avoiding sun exposure, indicating avoidance of sun exposure to be a risk factor of the same magnitude as smoking," says study author Pelle Lindqvist,MD, a senior lecturer at Karolinska Institutet in Stockholm, Sweden, in a news release.

"Guidelines being too restrictive regarding sun exposure may do more harm than good for health."

The new findings appear in the Journal of Internal Medicine.