No association between resting metabolic rate or respiratory exchange ratio and subsequent changes in body mass and fatness: 5 1/2 year follow-up of the Quebec Family Study

Objective: To investigate the relationships between resting metabolic rate (RMR) and respiratory exchange ratio (RER) and subsequent changes in body s ize and fatness. Design: Prospective longitudinal observational study. Participants: A sample of 147 participants (76 males, 71 females) 18-68 y o f age were followed for approximately 51/2 y. Measures: At baseline, post-absorptive RMR and RER were determined by indir ect calorimetry and adjusted for the effects of age, body mass and subcutan eous fatness using regression procedures. Indicators of body size and fatne ss included body mass, waist circumference, and the sum of six skinfolds. C hanges in these indicators (delta scores) were adjusted for age and length of the follow-up period using regression. Results: Correlations between baseline RMR, RER and subsequent changes in t he indicators of body fatness were uniformly low and not significant (range -0.05-0.16). Further, Cox proportional hazards regression analyses indicat ed that neither RMR nor RER were significant predictors of gains in body ma ss, waist circumference, or the sum of six skinfolds. Conclusions: There is no association between RMR or RER and changes in indi cators of body size and fatness over 51/2 y of follow-up in this sample.