Sorry, sunbathing doesn’t extend your lifespan

    29 March 2016

    Women who sunbathe are likely to live longer than those who avoid the sun, despite a higher risk of skin cancer, according to research published in the Journal of Internal Medicine.

    The study, carried out by medics and researchers at Lund University in Sweden, looked at data on almost 30,000 women who were followed for 20 years, and concluded that increased life expectancy among women who sunbathed was due to a decreased risk of heart disease and non-cancer deaths.

    However, the idea that life expectancy is actually lengthened by sunbathing — as reported by the Independent for instance — does not seem to be borne out by the evidence (see our expert verdict below).

    The researchers urged caution, saying: ‘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 from our results.’

    Dr Pelle Lindqvist, the study’s lead author, said: ‘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. Guidelines being too restrictive regarding sun exposure may do more harm than good for health.’

    Instant analysis
    The paper raises many questions. The crucial point is that the apparent link between sun exposure and longevity in the women studied could be explained by any number of other factors.

    It comes as no surprise, for instance, that women with a high disposable income were disproportionately included as sunbathers rather than sun avoiders. It may be that more affluent people have less cardiovascular disease.

    The fact that the authors published a very similar paper making the same point two years ago suggests they have an argument to make. This approach seems susceptible to bias.

    Two other weak points: the data is drawn from a questionnaire about sunbathing habits and vitamin D levels are only inferred; and the sun avoiding group is about a 15th of the size of the sunbathing group, which has big implications for the data.

    The study does not show, unfortunately, that if you sunbathe and smoke to your heart’s content you’re just as fine as someone who is afraid of the sun.
    Research rating: 1.5/5