More precisely, this team from the University of Bristol demonstrates the link between overweight and obesity and mental health or even between BMI and mental well-being. The study, published in the British Medical Journal, details the impact of certain aspects of physical health, such as body weight, heart health and blood pressure, on feelings of happiness and life satisfaction.
Previous studies have shown that people who are happier and more satisfied with their lives tend to have better physical health and live longer than those with lower mental well-being. But these studies leave open the classic question of which factor comes first, health or well-being?
Using a Mendelian randomization technique, the researchers looked at whether poorer physical health led to lower mental wellbeing, or whether people with lower mental wellbeing were more likely to have physical health problems later on. in life. This technique provides evidence for the direction of causation using genetic variants associated with physical health and mental well-being. And unlike previous methods, this technique makes it possible to exclude the influence of other factors that may be the cause of physical and mental health.
The consistent causative effect of a higher BMI: The research team was able to test 11 measures of physical health, including pre-existing coronary heart disease, heart attacks, cholesterol, blood pressure, body fat, and heart rate. body mass index (BMI). The results suggest a consistent causal effect of higher BMI on lower mental well-being. In contrast, the analysis provides little evidence that other physical health characteristics may lead to less happiness and life satisfaction.
The same pattern of results is observed through the analysis of data from 300,000 people aged 40 to 70 from the British Biobank cohort. The researchers looked at different aspects of life satisfaction and found that the main impact of a higher BMI is lower satisfaction especially with health. A “BMI” effect similarly present in men and women.
In testing whether mental well-being could also mediate any of these physical health traits , the authors identify little evidence of a causal impact in this direction. However, this direction remains to be "digged", because there are far fewer genetic variants for mental well-being. As research reveals more genetic variants associated with mental health characteristics, researchers will be better able to test this direction of effects more thoroughly.
Why this link? It's about body satisfaction and self-esteem, the authors suggest.
The findings underscore the pressing need to tackle the obesity crisis also because too high a BMI makes people less happy and less satisfied with their lives. An incentive for clinicians to take back to encourage their patients to maintain a healthy weight.