Abdominal obesity was independently associated with recurrent MI or stroke despite secondary preventive measures, according to a new study.
Abdominal obesity was common in post-myocardial infarction (MI) patients and larger waist circumference-particularly in men-was independently associated with recurrent atherosclerotic cardiovascular disease (ASCVD), according to study results published in the European Journal of Preventive Cardiology.
Abdominal obesity has been shown to be an important risk factor for a fist MI, but this is the first study to demonstrate an association between abdominal obesity and the risk of a subsequent MI or stroke.
“The reason abdominal obesity is very common in patients with a first heart attack is that it is closely linked with conditions that accelerate… atherosclerosis,” said study author Hanieh Mohammadi, MD, of the Karolinska Institute-SÃ¶dersjukhuset in Stockholm in a European Society of Cardiology press release.
But Mohammadi and colleagues observed something more, seeing that “increasing abdominal obesity was independently associated with recurrent heart attacks and strokes” even though patients were receiving secondary prevention with medications that lower the traditional risk factors associated with abdominal obesity. Their results, said Dr Mohammadi, “suggest that there may be other negative mechanisms associated with abdominal obesity that are independent of these risk factors” yet to be identified.
Using the national SWEDEHEART registry, investigators analyzed data from 22,882 patients (16,950 men) aged 35 to 77 years who experienced an MI as the first manifestation of ASCVD; most patients-77% of men, 90% of women-had abdominal obesity (waist circumference ≥94 cm for men and ≥80 cm for women).
Waist circumference was measured during a follow-up visit between 4 and 10 weeks after the first MI; another follow-up visit was conducted between 12 and 14 weeks after MI. Data were collected at both follow-ups on: CV risk factors, smoking, diet, physical activity, employment status, and quality of life. Blood pressure, weight, height, waist circumference, lipids, and ECG rhythm also were recorded.
The primary outcome was recurrent ASCVD, defined as CHD death, nonfatal MI, or fatal or nonfatal ischemic stroke.
A recurrent ASCVD event occurred in 7.3% of men and 7.9% of women during a median follow-up of 3.8 years.
In a univariate analysis, patients in the fifth quintile had an elevated risk for recurrent ASCVD compared with those in the first quintile (hazard ratio 1.22, 95% confidence interval 1.07–1.39). In multivariable-adjusted analysis, risk was elevated in the fourth and fifth quintiles (HR 1.21, 95% CI 1.03–1.43 and HR 1.25, 95% CI 1.04–1.50), respectively. Gender-stratified analyses showed similar associations in men, while U-shaped associations were observed in women and the body mass index analyses.
“Some studies have suggested that abdominal obesity may be more directly associated with the evil visceral fat (fat that sits around your organs) in men compared to women. In women it is thought that a greater portion of the abdominal fat is constituted by subcutaneous fat which is relatively harmless.”
The difference in results between the sexes, according to Dr Mohammadi, could be related to evidence that suggests abdominal obesity may be associated with visceral fat in men vs the more typical, and presumed harmless, subcutaneous fat seen in women.
The authors recommend using waist circumference in clinical settings to identify first-time heart attack patients at increased risk of recurrent events.