No abstract

Lifestyle interventions have resulted in weight loss or improved physical fitness among individuals with obesity, which may lead to improved physical function. This prospective investigation involved participants in the Action for Health in Diabetes (Look AHEAD) trial who reported knee pain at baseline (n = 2,203). The purposes of this investigation were to determine whether an Intensive Lifestyle Intervention (ILI) condition resulted in improvement in self-reported physical function from baseline to 12 months vs. a Diabetes Support and Education (DSE) condition, and whether changes in weight or fitness mediated the effect of the ILI. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and physical function subscales, and WOMAC summary score. ILI participants exhibited greater adjusted mean weight loss (s.e.) vs. DSE participants (−9.02 kg (0.48) vs. −0.78 kg (0.49); P < 0.001)). ILI participants also demonstrated more favorable change in WOMAC summary scores vs. DSE participants (β (s.e.) = −1.81 (0.63); P = 0.004). Multiple regression mediation analyses revealed that weight loss was a mediator of the effect of the ILI intervention on change in WOMAC pain, function, and summary scores (P < 0.001). In separate analyses, increased fitness also mediated the effect of the ILI intervention upon WOMAC summary score (P < 0.001). The ILI condition resulted in significant improvement in physical function among overweight and obese adults with diabetes and knee pain. The ILI condition also resulted in significant weight loss and improved fitness, which are possible mechanisms through which the ILI condition improved physical function.

OBJECTIVE: The purpose of this study was to examine differences in both resting energy expenditure (REE) and respiratory quotient (RQ) between overweight African-American and Caucasian women of comparable age and body mass index (BMI). DESIGN: Cross-sectional. SUBJECTS: REE was assessed in 41 women (22 African-American and 19 Caucasian) who were recruited to participate in this study. The African-American women were aged 36.4 AE 5.7 y with a BMI of 32.6 AE 5.4 kg/m 2 , and the Caucasian women were aged 35.4 AE 5.7 y with a BMI of 31.3 AE 3.4 kg/m 2 . MEASUREMENTS: Body composition was assessed using dual energy x-ray absorptiometry (DEXA). REE was assessed via the dilution technique following an overnight fast. RESULTS: REE was lower in African-Americans (7279 AE 825 kJ/d) compared to Caucasians (7807 AE 854 kJ/d) (P 0.051). Analysis of covariance showed that REE remained signi®cantly lower in African-American women after correcting for body weight and lean body mass. There was no effect of ethnicity on RQ. CONCLUSION: These results indicate that there is a signi®cant difference in REE between Caucasian and AfricanAmerican overweight women. This difference in REE may contribute to the higher rates of obesity found in the African-American population. This difference may also partially explain the smaller weight losses typically seen in African-American women when compared to Caucasian women enrolled in a weight loss program.

OBJECTIVE: To test the hypotheses that the accumulation of 30 min of moderate intensity, intermittent exercise, 5 daweek 71 , for 32 weeks, will increase aerobic capacity, alter body composition and improve blood lipids, insulin and glucose. Secondly, to identify individuals who may respond to moderate intensity, intermittent exercise. SUBJECTS: Thirteen sedentary, moderately obese females, aged 43 AE 11 (y), body mass index (BMI) 32.7 AE 7.7 (kgaM 2 ), body fat 40.6 AE 8.8 (%), VO 2 max 24.0 AE 4.6 (mlakg 71 amin 71 ). MEASUREMENTS: Aerobic capacity, body composition, blood lipids, fasting insulin and glucose, energy intake. RESULTS: Group data showed no signi®cant changes for aerobic capacity, body composition, blood lipids, insulin or glucose. However, 7 of the 13 subjects increased aerobic capacity, lost fat weight and improved insulin. Adherence to the exercise regimen was excellent with 82.6 AE 10.0% of the prescribed exercise completed. CONCLUSIONS: Moderate intensity, intermittent exercise for a total of 30 min, 5 daweek, 71 for 32 weeks duration, was not a suf®cient stimulus to signi®cantly increase aerobic capacity, alter weight, body composition or improve blood lipids, insulin or glucose for the entire group. However, those subjects who increased aerobic capacity and decreased fat weight were signi®cantly older, had lower maximal aerobic capacity and greater body fat at baseline compared to the six subjects who did not increase aerobic capacity and decrease fat weight. For both groups, moderate intensity, intermittent exercise showed excellent adherence and this may be a useful model for future research studies.

OBJECTIVE: To examine whether the accuracy of bioelectrical impedance analysis (BIA) to estimate body composition in overweight women is affected by the ethnicity of the individuals. DESIGN: Cross-sectional design to compare body composition estimated by BIA to body composition measured by dual energy x-ray absorptiometry (DEXA), which was the reference method. SUBJECTS: One hundred twenty three overweight women participated in this study, of which 43 women were African-American (aged 37.2 AE 5.6 y; BMI, 32.3 AE 4.9 kg/m 2 ) and 80 were Caucasian (aged 36.1 AE 5.7 y; BMI, 31.9 AE 3.5 kg/m 2 ). MEASUREMENTS: Body composition was estimated from BIA using both a generalized and an obesity-speci®c equation. These estimations were compared to body composition measured by DEXA, which was the reference method. RESULTS: The generalized BIA equation underestimated lean body mass (LBM) by 2.6 AE 3.1 kg in Caucasian women and 0.4 AE 3.2 kg in African-American women, with the difference between the ethnic groups being signi®cant (P`0.001). The obesity-speci®c equation underestimated LBM in Caucasians by 0.9 AE 3.1 kg and overestimated LBM in African-Americans by 1.2 AE 2.8 kg (P`0.001). An ethnic-speci®c equation is proposed, and cross-validation of this equation indicates that it provides a reasonable estimate of body composition in overweight women. CONCLUSIONS: The accuracy of BIA to estimate body composition appears to be affected by the ethnicity of the individual. Therefore, an ethnic-speci®c equation for overweight women is proposed. However, further validation of this prediction model in an ethnically diverse population is necessary.