Mark Hamer and team explained that previous studies had identified obese individuals who did not have the burden of adiposity-associated cardiometabolic risk factors. However, what their short- and long-term health prospects were remained unclear.
The researchers set out to determine what link, if any, there might be between metabolically healthy obesity and cardiovascular disease risk, as well as all-cause mortality. In other words, whether obese people with no illnesses, such as diabetes, have a higher risk of developing cardiovascular diseases, or dying early.
They looked at the mortality and medical records of 22,203 adult males (45.2%) and females from various parts of England and Scotland. None of them had any known history of cardiovascular disease (CVD).
The authors gathered data on the participants' diabetes status, waist circumference, low-grade inflammation (C-reactive protein ≥ 3 mg/liter), high-density lipoprotein-cholesterol level, and blood pressure.
Those deemed to be metabolically healthy had a score of 0 or 1 metabolic abnormality, while the unhealthy ones had a score of at least 2. They defined obesity as those with a BMI of at least 30kg/m2.
The participants were followed up for an average of at least 7 years for cause-specific mortality.
Below are some of their findings:
- There were 604 cases of cardiovascular disease related deaths
- There were 1,868 all-cause deaths
- Obese individuals with no current illnesses did not have a higher risk of cardiovascular disease than their non-obese counterparts
- Non-obese and obese people with at least two metabolic abnormalities had a higher risk of death
- Metabolically unhealthy people had a higher risk of all-cause mortality, compared with their healthy obese counterparts
"Metabolically healthy obese participants were not at increased risk of CVD and all-cause mortality over 7 years."