A detailed cardiovascular characterization of obesity without the metabolic syndrome

Although obesity without metabolic disturbances has been regarded as harmless, we have recently shown that obese subjects without the metabolic syndrome (MetS) has an increased risk of cardiovascular (CV) disorders and mortality during long-term follow-up. To investigate the basis for that increased risk, we studied the impact of obesity without MetS on multiple markers of subclinical CV disease.

At age 70, 1016 subjects were investigated in the Prospective Investigation of the Vasculature in Uppsala Seniors study. According to body mass index (BMI)/MetS status, they were categorized as normal weight (BMI <25 kg/m(2)) without MetS (National Cholesterol Education Program criteria, n=319), normal weight with MetS (n=19), overweight (BMI 25 to 29.9 kg/m(2)) without MetS (n=333), overweight with MetS (n=94), obese (BMI ≥30 kg/m(2)) without MetS (n=102), and obese with MetS (n=118). Several different measurements of endothelial reactivity, arterial compliance (plethysmography and ultrasound), carotid artery atherosclerosis, and echocardiography were performed, and 7 markers of coagulation/fibrinolysis were measured. Subjects with obesity without MetS showed impaired vasoreactivity, a more echolucent carotid artery wall, increased left ventricular mass and function together with impaired coagulation/fibrinolysis compared with normal-weight subjects without the MetS (P<0.05 to 0.001). The majority of these disturbances were also seen in overweight subjects without the MetS.

In contrast to some previous studies, our data do not support that obesity without MetS is a benign condition, because obesity without MetS was associated with impairments in multiple markers of subclinical CV disease. This was also the case for overweight subjects without the MetS.