Obesity and loss of disease-free years owing to major non-communicable diseases

Obesity is known to be associated with an increased risk of several major non-communicable diseases including type-2 diabetes, coronary heart disease, stroke, asthma and several cancers. It was previously thought that metabolically healthy obese (MHO) individuals were at no increased risk of these conditions.  MHO is characterised by a healthy blood pressure, low cholesterol, normal insulin regulation and reasonable levels of physical fitness. However, more recent longitudinal studies have found that these individuals show a strong tendency to progress to an unhealthy obese state. What has been relatively understudied is the degree to which obesity is associated with the development of these major non-communicable conditions.

In this large study, published in The Lancet, the health data from 120,181 participants was analysed in order to determine how many disease-free years were lost to obesity. The participants were of a range of BMIs, but free of other comorbidities. They found that overweight patients lost 1 disease free-year, mildly obese patients 3-4 years and the severely obese 7-8 years compared with normal weight participants. Severe obesity was associated with the loss of 7-10 disease-free years in active and inactive individuals; current, past and never-smokers; and those of high and low socioeconomic position. The paper suggests that obesity, even in those with a healthy metabolic profile, leads to a substantial loss of disease-free years, across the social hierarchy and irrespective of lifestyle factors such as physical activity and smoking.