Women who sunbathe are likely to live longer than those who avoid the sun, even though sunbathers are at an increased risk of developing skin cancer. This paradox baffles oncologists and has suggested that the war on sunshine has been unjustified.

An analysis of information on 29,518 Swedish women may provide some answers. The women were followed for 20 years and the data revealed that longer life expectancy among women with active sun exposure habits was related to a decrease in heart disease and non-cancer/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, they note. Still, it is an intriguing idea.

"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," said Dr. Pelle Lindqvist, lead author of the study in the Journal of Internal Medicine. "Guidelines being too restrictive regarding sun exposure may do more harm than good for health."