The potential impact fraction of population weight reduction scenarios on non-communicable diseases in Belgium: Application of the g-computation approach

Abstract

Abstract Background Overweight is a major risk factor for non-communicable diseases (NCDs) in Europe, affecting almost 60% of all adults. Tackling obesity is therefore a key long-term health challenge and is vital to reduce premature mortality from NCDs. Methodological challenges remain however, to provide actionable evidence on the potential health benefits of population weight reduction interventions. This study aims to demonstrate the use of a g-computation approach to assess the impact of hypothetical weight reduction interventions on NCDs in Belgium in a multi-exposure context.Methods Belgian health interview survey data (2008/2013/2018, n = 27 536) were linked to environmental data at the residential address. A g-computation approach was used to evaluate the potential impact fraction (PIF) of population weight reduction scenarios on four NCDs: diabetes, hypertension, cardiovascular disease (CVD) and musculoskeletal (MSK) disease. Four scenarios were considered: 1) a distribution shift where, for each individual with overweight, a counterfactual weight was drawn from the distribution of individuals with a “normal” BMI 2) a one unit reduction of the BMI of individuals with overweight, 3) a modification of the BMI of individuals with overweight based on a weight loss of 10%, 4) a reduction of the waist circumference (WC) to half of the height among all people with a WC:height ratio greater than 0.5. Regression models were adjusted for socio-demographic, lifestyle and environmental factors.Results The WC/height ratio reduction scenario led to the highest impact, preventing a proportion of cases ranging from 36% for diabetes to 7% for MSK diseases. The shift in BMI distribution also demonstrated a significant impact, preventing a proportion of cases ranging from 32% for diabetes to 6% for MSK diseases. The scenario where BMI was reduced by one unit had the lower impact, with a proportion of prevented cases, ranging from 4.5% for diabetes to 0.8% for MSK diseases.Conclusion Weight reduction scenarios among people with overweight could significantly reduce the prevalence of diabetes, hypertension, CVD and MSK disease in Belgium. The g-computation approach to assess PIF of interventions represents a straightforward approach for drawing causal inferences from observational data while providing useful information for policy makers.