ACCURACY OF EQUATIONS TO PREDICT BASAL METABOLIC-RATE IN OLDER WOMEN

Objective To assess the accuracy of several published equations for pr edicting basal metabolic rate (BMR) in older women. Design BMR was ass essed in 116 healthy, older white women, aged 60 to 82 years, on three successive mornings by indirect calorimetry. Body composition was det ermined by dual energy X-ray absorptiometry or hydrostatic weighing. T he measured BMRs were compared with values obtained from eight publish ed prediction equations that used solely, or in various combinations, measures of height, weight, fat-free mass, age, and menopausal status. Statistical analyses performed The root mean squared prediction error (RMSPE) was used to determine how accurately predicted BMR matched ac tual BMR for each subject. In addition, regression analysis was used t o evaluate accuracy of predicted BMR vs directly measured BMR. Results Predicted mean BMR determined using all eight equations was significa ntly correlated to measured BMR (P=.0001), accounting for 30% to 52% o f the variance of measured BMR. When analyzed by RMSPE, however, the e quations of Owen et al (1986), Fredrix et al (1990), and Harris-Benedi ct (1919) predicted actual BMR for each subject within an average of 1 16 kcal/day, and the equation of Cunningham (1980) resulted in the lar gest prediction error at 208 kcal/day. Applications/conclusions The re gression equations of Owen et al (1986): which used body weight, Fredr ix et al (1990), which used body weight and age, and Harris-Benedict ( 1919), which used age, weight, and height as variables, were most accu rate in predicting BMR in our sample of healthy older women.