New risk score identifies link between lifestyle risk factors and mortality

A new lifestyle risk score based on six health behaviors identified two new risk factors (sedentary behavior and sleep) that can be used in addition to traditional risk factors, such as smoking and excessive alcohol use to predict risk of mortality. These findings by Ding Ding and colleagues from the University of Sydney, Australia, are published in this week's PLOS Medicine.

The researchers used mortality registration data over a 6-year follow-up period among 231,048 Australians aged 45 years or older who had completed a lifestyle questionnaire at baseline. Higher scores on the lifestyle risk score, created by summing the six health behavior measures (smoking, alcohol use, dietary behavior, physical inactivity, sedentary behavior, and sleep) for each participant, were associated with greater risk of mortality. The researchers estimated that the population attributable risk was 31.3%, suggesting that a third of the person-years lost due to death could have been avoided if all the study participants had a risk score of zero—provided all six risk factors are causal (responsible for illness and death). Furthermore, combinations involving physical inactivity, prolonged sitting, and/or long sleep duration and combinations involving smoking and high alcohol use were among the most strongly associated with all-cause mortality.

The accuracy of the findings may be limited by the potential for confounding (people who reported exposure to a specific risk factor may have shared another characteristic that was actually responsible for their illness or death) and reverse causation (the reported risk factor may have been caused by an underlying illness rather than the factor causing that illness).

The authors say "This large study reaffirms the importance of healthy lifestyles, here evidenced for adults aged 45 and older."