Cardiorespiratory fitness and development of abdominal obesity

Both, cardiorespiratory fitness and abdominal obesity are independently associated with developing cardiovascular disease and its risk factors. However, the relationship between both attributes is unclear. We examine the relationship between cardiorespiratory fitness and the risk of developing abdominal obesity, and secondarily, other adiposity measures. Retrospective observational study of a cohort of 1284 sedentary patients, who had participated in a clinical trial of physical activity promotion carried out in Spain (2003-2007). At baseline, they were free of cardiovascular disease, hypertension, diabetes, dyslipidemia and/or abdominal obesity, with an indirect VO₂max measurement, were 19-80 years old, 62% women, and had completed the two year follow-up. The exposure factor was cardiorespiratory fitness categorized as high, moderate or low, according to tertiles of VO₂max values. The main outcome measure was the risk of developing abdominal obesity, as defined by waist circumference >102 (men) and >88 (women) cm. Secondary outcomes were the risk of developing: general obesity, excess body fat, and their combination ("defined" obesity). At two years, 10.5% of the participants had developed abdominal obesity: 6.1% in the high cardiorespiratory fitness tertile, 9.7% in the moderate tertile (adjusted odds ratio, 1.20; 95% confidence interval 0.68-2.10), and 15.7% in the low tertile (adjusted odds ratio, 2.29; 95% confidence interval 1.34-3.91). Moreover, 2.2% of participants in the high cardiorespiratory fitness tertile developed "defined" obesity as did 5.4% in the low tertile (adjusted odds ratio, 2.90; 95% confidence interval 1.15-7.29). Low cardiorespiratory fitness levels are associated with a higher risk of developing abdominal and "defined" obesity.