One third of adults in Western countries present with obesity. Obesity and, to a lesser degree, overweight, have been considered to increase the risk of cardiovascular disease, but controversy exists as most people with overweight or obesity also present with other risk factors such as hypertension, dyslipidaemia, or diabetes. Metabolically healthy obesity (MHO) is a status characterized by obesity devoid of other cardiovascular risk factors. People with MHO tend to be more physically active than people with obesity and other risk factors, but whether other healthy behaviours such as non-smoking, adequate sleep or moderate/no drinking also contribute to MHO status remains an open question.
Using data from almost 600,000 participants of a nationwide cohort of Spanish workers, Valenzuela et al (1) assessed whether
overweight and obesity are associated with the prevalence cardiovascular risk factors (hypertension, dyslipidaemia, and diabetes),
MHO is associated with incidence of the beforementioned risk factors, and
which healthy behaviours (being physically active, refraining from smoking, having enough sleep, and abstaining from drinking alcohol) could prevent the incidence.
In the cross-sectional analysis, participants with overweight had 90%, 48% and 47% higher likelihood of presenting with hypertension, dyslipidaemia, and diabetes, the values increasing to 367%, 71% and 243% in participants with obesity. Being physically active decreased the likelihood of presenting with cardiovascular risk factors by 13%, while no effect was found for refraining from smoking, having enough sleep, or abstaining from drinking alcohol.
After a 2-year follow-up of 300,00 participants, 1.3% developed risk factors. Compared to normal weight participants, those with overweight had 89%, 46% and 46% higher risk of developing hypertension, dyslipidaemia, and diabetes, the values increasing to 363%, 69% and 256% in participants with obesity. Again, being physically active decreased the likelihood of developing cardiovascular risk factors by 13%, while no effect was found for the other lifestyle factors.
The authors conclude that MHO is a transitory condition, and people with overweight or obesity are at higher risk of presenting or developing cardiovascular risk factors than normal weight people. Is thus physical activity THE solution? It isn’t, as it did not prevent physically active participants with overweight or obesity to develop risk factors: the decrease in risk was 13%, compared to a severalfold increase due to overweight or obesity. But as the authors rightfully state, physical activity might partially attenuate the development of other cardiovascular risk factors in the short term.
Although several potential protective factors could not be assessed, such as diet, social networks, and environment, the paper by Valenzuela et al debunks (again) the myth of a persistent healthy overweight or obese status and stresses (again) the importance of physical activity in the primordial prevention of cardiovascular disease. So, the solution might be lose weight, and be active!