Studies had suggested that some obese people may not face an increased risk of cardiovascular disease if their metabolic profile – including levels of blood sugar, cholesterol and other factors – is normal.
But a new meta-analysis has found that having a BMI of 30 for 10 years or more increases the risk of cardiovascular disease or death by a quarter – even among those who are metabolically ‘healthy’.
Authors of the study said clinicians and patients should not see obesity as a harmless condition. Doctors should consider both BMI and metabolic factors when assessing a person’s risk of cardiovascular disease, they said.
'No healthy obesity'
The international team of researchers examined data from eight studies into the effect of weight and metabolic profile on the risk of heart disease and death.
They analysed pooled data from 61,386 patients. There were 3,988 clinical events, including MI, acute coronary syndrome, heart failure, stroke and all-cause mortality.
Compared with metabolically healthy people of normal weight, people with a normal metabolic profile and a BMI over 30 faced a 24% increased relative risk of a cardiovascular event or death. This translates to a 0.7% greater absolute risk over 10-11 years.
In contrast, all metabolically unhealthy people had a similar risk of cardiovascular disease regardless of their BMI. This was more than double the risk of a metabolically healthy, normal-weight person.
Study authors said the concept of ‘benign obesity’ suggested by previous studies may only represent a short-term picture. Data suggests excess weight is linked to the initial development of unseen metabolic and vascular problems that lead to cardiovascular events in the longer term, they said.
The authors said: ‘Our results do not support this concept of "benign obesity" and demonstrate that there is no "healthy" pattern of obesity.’
They added: ‘Our findings highlight the need for comprehensive evaluation of not only BMI but also metabolic factors for the prediction of future morbidity and mortality.’
Particular attention should be given to normal-weight patients with an unhealthy metabolic profile, they advised.