Four unhealthy behaviors -- smoking, lack of physical activity, poor diet and alcohol consumption -- appear to be associated with a substantially increased risk of death when combined, according to a report in the April 26 issue of Archives of Internal Medicine.
"Several studies have shown that specific health behaviors, including cigarette smoking, physical inactivity, higher alcohol intake and, to a lesser extent, diets low in fruits and vegetables, are associated with an increased risk of cardiovascular disease, cancer and premature mortality [death]," the authors write as background information in the article. Most studies that examine the effects of these behaviors control for other unhealthy behaviors to identify independent effects. However, several poor lifestyle choices may coexist in the same individual.
"To fully understand the public health impact of these behaviors, it is necessary to examine both their individual and combined impact on health outcomes," write Elisabeth Kvaavik, Ph.D., of University of Oslo, Norway, and colleagues. The researchers interviewed 4,886 individuals age 18 or older in 1984 to 1985. "A health behavior score was calculated, allocating one point for each poor behavior: smoking; fruits and vegetables consumed less than three times daily; less than two hours physical activity per week; and weekly consumption of more than 14 units [one unit equals 8 grams, or about 0.3 ounces] of alcohol (in women) and more than 21 units (in men)."
During an average of 20 years of follow-up, 1,080 participants died—431 from cardiovascular disease, 318 from cancer and 331 from other causes. When compared with participants who had no poor health behaviors, the risk of death from all causes and from each cause increased with each additional behavior.
Individuals with four compared with zero poor health behaviors had about three times the risk of dying of cardiovascular disease or cancer, four times the risk of dying from other causes and an overall death risk equivalent to being 12 years older.
"Modest but achievable adjustments to lifestyle behaviors are likely to have a considerable impact at both the individual and population level," the authors conclude. "Developing more efficacious methods by which to promote healthy diets and lifestyles across the population should be an important priority of public health policy."
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Arch Intern Med. 2010;170:711-718.