Years of life lost and healthy life-years lost from diabetes and cardiovascular disease in overweight and obese people: a modelling study

Background: Despite the increased risk of cardiovascular disease and type 2 diabetes associated with excess bodyweight, development of a clinically meaningful metric for health professionals remains a challenge. We estimated the years of life lost and the life-years lost from diabetes and cardiovascular disease associated with excess bodyweight.

Methods: We developed a disease-simulation model to estimate the annual risk of diabetes, cardiovascular disease, and mortality for people with BMI of 25-<30 kg/m(2) (overweight), 30-<35 kg/m(2) (obese), or 35 kg/m(2) and higher (very obese), compared with an ideal BMI of 18·5-<25 kg/m(2). We used data from 3992 non-Hispanic white participants in the National Nutrition and Examination Survey (2003-10) for whom complete risk factor data and fasting glucose concentrations were available. After validation of the model projections, we estimated the years of life lost and healthy life-years lost associated with each bodyweight category.

Findings: Excess bodyweight was positively associated with risk factors for cardiovascular disease and type 2 diabetes. The effect of excess weight on years of life lost was greatest for young individuals and decreased with increasing age. The years of life lost for obese men ranged from 0·8 years (95% CI 0·2-1·4) in those aged 60-79 years to 5·9 years (4·4-7·4) in those aged 20-39 years, and years lost for very obese men ranged from 0·9 (0-1·8) years in those aged 60-79 years to 8·4 (7·0-9·8) years in those aged 20-39 years, but losses were smaller and sometimes negligible for men who were only overweight. Similar results were noted for women (eg, 6·1 years [4·6-7·6] lost for very obese women aged 20-39 years; 0·9 years [0·1-1·7] lost for very obese women aged 60-79 years). Healthy life-years lost were two to four times higher than total years of life lost for all age groups and bodyweight categories.

Interpretation: Our estimations for both healthy life-years and total years of life lost show the effect of excess bodyweight on cardiovascular disease and diabetes, and might provide a useful health measure for discussions between health professionals and their patients.

Funding: Canadian Institutes of Health Research.