Central fatness (excess fat stored around the abdomen) is associated with a higher risk of early death from any cause, regardless of overall body fat, whereas larger hips and thighs are associated with a lower risk, finds a study published in The BMJ.
The results suggest that measuring central fatness may be a more reliable indicator of risk of death from excess weight, and could be used alongside body mass index to help determine the risk of premature death, say the researchers.
Body mass index (BMI) is a simple measure widely used to assess people’s weight. But its reliability is often criticised, as it does not distinguish fat from muscle and does not tell us where body fat is stored.
It is already well known that being overweight or obese is linked to a greater risk of heart disease, certain cancers, kidney disease, and neurological disorders.
Evidence also suggests that central fatness might be more strongly associated with risk of death than overall obesity, but previous data are inconclusive. To explore this further, an international team of researchers set out to examine whether measures of central fatness are associated with risk of all cause mortality in the general population.
Their findings are based on the results of 72 studies involving over 2.5 million participants who were tracked for between 3 and 24 years.
All of the studies reported risk estimates for at least three measures of central fatness. These included waist circumference, hip circumference, thigh circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, body adiposity index (a measure of total body mass made only of fat tissue), and A body shape index (a combined measure of body height, mass and waist circumference).
The researchers found that most measures of abdominal adiposity, including waist circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, and A body shape index were significantly and positively associated with a higher all cause mortality risk.
In contrast, larger hip and thigh circumference were associated with a lower risk of all cause mortality.
Paper: Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies. The BMJ; www.bmj.com/content/370/bmj.m3324