Obesity linked to premature death
A meta-analysis of 189 studies including 3.9 million adults across four continents shows that being overweight or obese is associated with an increased risk of premature death. The risks of coronary heart disease, stroke, respiratory disease and cancer are all increased. In addition, the excess risk of premature death before the age of 70 among those who are overweight or obese is about three times as great in men as in women. Participants in the study had never smoked and had no chronic disease at recruitment.
According to the lead author of the study Dr Emanuele Di Angelantonio (University of Cambridge), overweight people (BMI 25-30) lose approximately one year of life expectancy with moderately obese people (BMI30-35) losing about 3 years. The study also showed that overweight and obesity cause approximately one in 7 of all premature deaths in Europe and one in 5 in North America.
Obese men were at a much higher risk of premature death than women, which is consistent with previous observations that obese men have greater insulin resistance, liver fat levels and diabetes risk. In men, the risk of death before the age of 70 in those of normal weight (BMI 20-25) was 19% compared with 29.5% in those who were moderately obese (BMI 30-35). In women these figures were 11% and 14.6%, respectively.
However the study was limited by the only measure of obesity being BMI and there was no assessment of fat distribution in different parts of the body, muscle mass, or obesity-related metabolic factors such as blood sugar or cholesterol.
- The World Health Organisation estimates that 1.3 billion adults worldwide are overweight, and that a further 600 million are obese.
- The prevalence of adult obesity is 20% in Europe and 31% in North America.
|BMI 15-18.5||BMI 22.5-25||BMI 30-35||BMI 40-60|
|HR (95%CI)||1.79 (1.63-1.97)||1.00 (0.97-1.03)||1.52 (1.45-1.58)||3.04 (2.84-3.27)|
Table: Risk of premature death in European subjects (89 studies, 1,135,600 participants) in different BMI categories.
The study highlights the significant impact of obesity on life expectancy as well as quality of life. These finding support strategies to combat excess adiposity but the greatest challenge remains in translating epidemiological evidence into effective guidelines and public health interventions. The Global BMI Mortality Collaboration.
Body-mass index and all-cause mortality: individual participant-data meta-analysis of 239 prospective studies in four continents. Lancet 2016, published online 13 July; http://dx.doi.org/10.1016/S0140-6736(16)30175-1