Impact of body mass index and waist circumference on the cardiovascular risk and all-cause death in a general population: data from the PAMELA study.

BACKGROUND AND AIMS: Elevated values of body mass index (BMI) and waist circumference (WC) are associated with an augmented cardiovascular (CV) risk. It is debated, however, whether and to what extent this depends on the body fat increase 'per se' or on the related cardiometabolic alterations. METHODS AND
RESULTS: In 2005 subjects randomly selected from the general population of Monza (Italy), we assessed BMI, WC, office, home and 24 h blood pressure (BP), heart rate and metabolic variables. The impact of BMI and WC on the incidence of CV events, CV and all-cause mortality was estimated during a 148-month follow-up. Progressively higher values of BMI and WC were associated with a progressive increase in office, home and 24 h BP and in erratic BP variability (P < 0.0001 for trend). Metabolic variables were directly and significantly (P < 0.0001) related to BMI and WC, while an inverse significant relationship was detected with high-density lipoprotein (HDL)-cholesterol. The incidence of CV events, CV and all-cause deaths increased progressively from the lowest to the highest quintile of BMI and WC (P for trend always <0.005). Baseline BMI and WC higher by respectively 1 kg m⁻² and 1 cm were associated with an increased risk of CV events, CV and all-cause death by 8%, 12% and 7% (for baseline BMI) and 4%, 5% and 4% (for baseline WC), respectively. After adjustment for confounders, only the increased risk of CV death related to higher baseline BMI remained significant (hazard ratio (HR) 1.062, confidence interval (CI) 95% 1.003-1.126, P < 0.05).
CONCLUSION: The adverse prognostic impact of the accumulation of body fat is mediated by the associated haemodynamic and metabolic alterations. Baseline values of BMI, however, are an independent predictor of CV mortality.