Coronary artery disease and body mass index: What is the relationship?

Nowadays, obesity is considered an independent risk factor for the development of cardiovascular diseases (CVD), which has been presented as an important cause of worldwide morbidity and mortality, especially coronary artery disease (CAD). The objective of the study was to verify the association between body mass index (BMI) and severity of CAD, its risk factors and surgical and percutaneous treatment in patients hospitalized in cardiological units.

An ambispective, cross-sectional study was performed with patients older than 18 years attended by nutrition in the cardiology units, who underwent coronary angiography. The severity of CAD was categorized into two distinct classifications (CAD Class I and II), considering the presence of CAD as lesions ≥50% and ≥70%. The nutritional status of the patient was established based on BMI according to the World Health Organization (WHO) for the total sample and group of adults, and according to the Pan American Health Organization (PAHO) for the elderly. Age, gender, presence of associated comorbidities, history of smoking, and performed procedures were collected in patients' records. For statistical analysis Kruskal Wallis and Chi-square tests were used, and Hodges-Lehmann estimate was used for the median. Comparisons and associations were considered significant when p < 0.05.

A total of 703 patients were included, of which 495 had arterial lesions ≥70% and 513 patients' lesions ≥50%. The average age was 61 years, women were older (63 vs 61; p = 0.008), had a higher BMI (28.16 kg/m² vs 26.68 kg/m², p = 0.001) and were more likely to have diabetes mellitus (DM) (p < 0.001), dyslipidemia (DSLP) (p < 0.001), and hypertension (HTN) (p = 0.001). The majority of the sample consisted of men, who more often underwent percutaneous coronary intervention (PCI) (53,9% vs 39%, p < 0.001), and were more likely to present more severe CAD (p < 0.001 and p = 0.003). In patients diagnosed with CAD the increase in BMI was positively associated with the presence of DM (p < 0.001), DSLP (p < 0.001) and HTN (p < 0.001), and negatively with age (p = 0.007). Patients with obesity III, were diagnosed with CAD, in average, 11 years earlier than patients with normal BMI (p = 0.05). Therefore, the higher the BMI, the lower the age at the moment of the examination in the total sample, and in the group of elderly, and this association was not found in adults. There was no significant association of BMI with the severity of CAD, or with PCI and coronary artery bypass grafting (CABG). The greater severity of CAD was positively associated with the presence of DM (p = 0.012 and p = 0.001), HTN (p = 0.033 and p = 0.003) and older age (p = 0.005 and p = 0.015). Patients who underwent CABG had a higher incidence of and HTN (p = 0.003), DM (p = 0.006), whereas patients who had PCI had a lower incidence of HTN (p = 0.021) and DM (p = 0.004).

Obesity was showed to be as an independent risk factor for the early incidence of CAD, which is strongly associated with the presence of comorbidities such as DM, HTN and DSLP. The greater severity of CAD and coronary interventions were associated with the presence of risk factors for CAD.