Target value of intraabdominal fat area for improving coronary heart disease risk factors.

OBJECTIVE: The goal of this study was to determine an intraabdominal fat (IF) area target value for improving coronary heart disease (CHD) risk factors in response to weight reduction. RESEARCH METHODS AND PROCEDURES: Subjects were 279 obese Japanese women, 21 to 66 years old, who were divided into diet-alone and diet-plus-exercise groups and participated in a 14-week weight reduction program. The IF area was measured by computerized tomography scans. Systolic blood pressure > or = 140 mm Hg, diastolic blood pressure > or = 90 mm Hg, total cholesterol > or = 5.70 mM, triglycerides > or = 1.70 mM, and fasting plasma glucose > or = 6.99 mM were defined as CHD risk factors. RESULTS: The best trade-off between sensitivity (probability of correctly detecting true positive) and specificity (probability of correctly detecting true negative) was found at 100 cm2 pretreatment in combined data of the two groups. At posttreatment, although a slight difference was found in the target value between the treatment groups (60 cm2 for diet alone and 50 cm2 for diet plus exercise), the combined data showed that the best trade-off occurred at 60 cm2 (sensitivity and specificity were 0.55 and 0.63, respectively). The percentage of subjects having no CHD risk factors was significantly lower in the group that had large IF areas (> or = 60 cm2) (46%) compared with the group that had normal IF areas (<60 cm2) (65%). However, the percentage of subjects having multiple CHD risk factors was significantly greater in the group that had large IF areas (16%) compared with the group with normal IF areas (7%) at posttreatment. DISCUSSION: Our longitudinal data suggest that obese Japanese women should reduce their IF areas to < 60 cm2 through weight reduction to improve CHD risk factors independent of treatment.

Effects of obesity phenotype on coronary heart disease risk factors in response to weight loss.

OBJECTIVE: To determine whether there is a difference in risk-factor improvement for coronary heart disease (CHD) between the intra-abdominal fat (IF) and subcutaneous fat (SF) obesity phenotypes after weight loss. RESEARCH METHODS AND PROCEDURES: Subjects included 55 mildly obese women (body mass index, 25 to 36 kg/m(2); age range, 34 to 63 years) who had at least two of three CHD risk factors [systolic blood pressure (SBP), >140 mm Hg; total cholesterol (TC), >220 mg/dL; fasting plasma glucose, >110 mg/dL). Using computed tomography, IF obesity was classified as > or =110 cm(2) of the IF area measured; subjects with <110 cm(2) were classified as having SF obesity. The IF and SF obesity groups were divided into diet-only and diet-plus-exercise groups. Assays and measurements were performed before and after a 14-week (98-day) intervention. RESULTS: Weight was reduced by 7 to 10 kg in each group. The IF and SF areas, SBP, diastolic blood pressure, TC, and low-density lipoprotein-cholesterol were significantly reduced in all groups (p < 0.01). Reduction in IF area was greater in IF obesity than in SF obesity, whereas no differences were observed in the improvement of CHD risk factors. Sample sizes needed for observing a significant difference for SBP, TC, triglycerides, and fasting plasma glucose were greater than the number of subjects in this study. DISCUSSION: Our results suggest that the influence of the obesity phenotype on improving CHD risk factors is not apparent. A larger study is needed to prove the validity of this finding.