Response to a Possible Role of Visceral Fat-Related Inflammation in Linking Obstructive Sleep Apnea to Left Ventricular Hypertrophy
We thank Drs Cereda and Malavazos1 for their comments regarding our article “Left Ventricular Hypertrophy in Severe Obesity. Interactions Among Blood Pressure, Nocturnal Hypoxemia, and Body Mass.”2 They point out a potential role for inflammation mediated by visceral adipose tissue as a contributing factor for the cardiac abnormalities that we observed in our severely obese subjects. They also point out the potential limitations of using body mass index as an index of obesity. We agree that a growing body of literature supports both of these notions. Clearly there is ongoing debate in the scientific community about how to best define obesity and patterns of obesity that impart excessive cardiovascular and pulmonary risk. In our study population, we found that essentially all of the subjects had increased waist circumferences (average for men: 142 cm and women: 132 cm) and elevated waist/hip ratios (men: 1.03 and women: 0.94). This predominance of central adiposity likely reflects the severe degree of obesity in our subjects, as well as the fact that many were seeking bariatric surgery. Subjects with a lesser amount of central obesity might be less likely to consider surgical intervention. We found significant colinearity between body mass index and waist circumference in our population; hence, we did not include waist circumference in our multivariate analysis. Our main conclusions would not have been changed by using waist circumference rather than body mass index in the model. Nonetheless, we strongly endorse further investigation into the role of visceral adipose tissue and adipose-related inflammation in the pathogenesis of obesity-related complications. Newer, clinically useful classification schemes for defining patterns of obesity would be welcome.
Cereda E, Malavazos AE. A possible role of visceral fat-related inflammation in linking obstructive sleep apnea to left ventricular hypertrophy. Hypertension. 2007; 49: e23.
Avelar E, Cloward TV, Walker JM, Farney RJ, Strong M, Pendleton RC, Segerson N, Adams TD, Gress RE, Hunt SC, Litwin SE. Left ventricular hypertrophy in severe obesity. Interactions among blood pressure, nocturnal hypoxemia, and body mass. Hypertension. 2007; 49: 34–39.