Three clinical studies investigating the relationship between aspects of cardiovascular health - including disease risk and cardiorespiratory fitness - and obesity were presented at this week’s annual meeting of the North American Association for the Study of Obesity (NAASO) in Las Vegas, Nevada. The studies were conducted and presented by investigators from the Rippe Lifestyle Institute, a leading research, communications and health promotion organization, and supported by a research grant from Weight Watchers International.
Body Mass Index (BMI) vs. Waist Circumference
In the study, “Does Body Mass Index (BMI) or Waist Circumference Correlate Better with Risk Factors Associated with Obesity?,” (833-P) researchers investigated the relationship between various cardiovascular disease risk factors linked to obesity - including total cholesterol ratio of cholesterol to HDL (TC/HDL), HDL and glucose levels - with body mass index (BMI) and waist circumference to determine if either was more strongly related to these cardiovascular risk factors over the other. BMI uses a weight-to-height ratio to measure body fat and waist circumference and is the accepted standard to diagnose obesity.
Study results found significantly stronger relationships between waist circumference and weight (p<0.001), HDL (p<0.01) and TC/HDL (p<0.05), compared to BMI.
Only VO2max, a measure of cardiovascular fitness based on the rate of maximal oxygen uptake, and percentage of body fat had a stronger relationship to BMI than waist circumference (p<0.001). While these results conclude an association between measures of fat and a range of cardiovascular disease risk factors, they further demonstrate that abdominal fat has a higher risk associated with it than overall fatness due to the stronger correlation between risk factors and waist circumference than with BMI. Furthermore, waist circumference can be used as strong diagnostic criteria for metabolic syndrome - a cluster of medical conditions characterized by insulin resistance and the presence of obesity, abdominal fat, high blood sugar and triglycerides, high blood cholesterol, and high blood pressure.
"Clearly, physicians need to assess overall cardiovascular risk by routinely measuring both BMI and waist circumference in obese patients," said James M. Rippe, M.D., Founder, Director, Rippe Lifestyle Institute, Associate Professor of Cardiology, Tufts University School of Medicine. "However, the measurement of waist circumference is particularly important in the diagnosis of metabolic syndrome, since this study shows it has quite a strong relationship with cardiovascular risk factors typically found in the condition."
Link Between High-sensitive CRP, Cardiovascular Disease Risk Factors and Cardiorespiratory Fitness
High sensitive C-reactive protein (hs-CRP) is a protein in the blood that, when elevated, is a strong indicator of cardiovascular risk. While past studies have proven that hs-CRP is elevated in obese individuals, two new studies from the Rippe Lifestyle Institute have separately evaluated the relationship between hs-CRP and diagnostic risk factors for metabolic syndrome and CRP and overall cardiovascular fitness.
In the first study, "The Relationship of hs-CRP to Metabolic Syndrome Diagnostic Criteria and Cardiovascular Risk Factors," (835-P) data were collected from 250 sedentary, overweight/obese volunteers to better understand the relationship between hs-CRP and the diagnostic criteria for metabolic syndrome and cardiovascular risk factors. While hs-CRP was excluded if above 10 mg/dL to account for acute inflammation, mean hs-CRP was elevated in these obese individuals with an average 2.68 +/- 2.35 mg/dL.
Data were analyzed by calculating Pearson's correlation coefficients. Results show that hs-CRP is associated with several independent risk factors of cardiovascular disease including cholesterol, LDL cholesterol and diastolic blood pressure, BMI and percentage of fat. And, although a significant relationship is observed with only one aspect of metabolic syndrome - diastolic blood pressure - these results clearly demonstrate that measurement of hs-CRP may be useful to practitioners in the assessment of risk for metabolic syndrome and cardiovascular disease. This study lends further support to the concept that obesity stimulates an inflammatory response in the body which may contribute to chronic diseases.
The second study, "The Association of Serum C-Reactive Protein with Cardiorespiratory Fitness in Middle-Aged, Sedentary, Overweight/Obese Adults," (836-P) evaluated an association between hs-CRP and overall cardiovascular health with regard to VO2 max - a measure of cardiovascular fitness based on the rate of maximal oxygen uptake - in 270 overweight/obese adults. Results show that V02max was inversely correlated to CRP (p<0.001), supporting previous clinical findings that an elevated concentration of CRP in obese individuals demonstrated a negative association between CRP and cardiovascular fitness. This finding emphasizes that physical activity may be particularly important in obese individuals to lower their risk of heart disease.
"All of this research shows that people who are obese need to be concerned about their risk of developing metabolic syndrome. The only known treatment for the syndrome is weight loss and when it comes to health, a sustainable weight loss achieved through a comprehensive program that includes sound nutrition, behavior modification, exercise and a supportive environment is recommended," said Karen Miller-Kovach, Chief Scientific Officer, Weight Watchers International.
Weight Watchers International collaborated with the Rippe Lifestyle Institute to together produce high-quality research, such as these three studies, about the link between sustained weight loss and disease prevention, study the specific behaviors associated with long-term weight loss and quantify the health benefits associated with exercise and the Weight Watchers program.
Founded by James M. Rippe, M.D., Rippe Lifestyle Institute is one of the leading research, communication and health promotion organizations in the world. Through research, publishing and partnering in health promotion and disease prevention projects, the various divisions and two locations of Rippe Lifestyle Institute are helping empower people to lead healthier lifestyles with the passion, commitment and performance that have made RLI a leading authority on lifestyle and health.
Weight Watchers is America's trusted name in weight loss and the global leader in weight-loss services, with approximately 46,000 weekly meetings in 30 countries. Weight Watchers mission is to help people reach and maintain a healthy weight. At the heart of Weight Watchers are weekly meetings which provide the coaching and tools to help people make the positive changes required to lose weight and keep it off. Weight Watchers also offers two subscription products for people wanting to follow Weight Watchers online. To learn more about Weight Watchers services, products and publications, visit http://www.weightwatchers.com/ .
Rippe Lifestyle Institute