DECREASED RESTING METABOLIC-RATE AMONG PERSONS WITH DOWN-SYNDROME

OBJECTIVE: To compare the resting metabolic rates (RMRs) of adults wit h and without DS while controlling for potential confounds. DESIGN: Ob servational, cross-sectional study. SETTING: Outpatient core of the Ne w York Obesity Research Center. SUBJECTS: Thirteen adults (nine males and four females) with DS were compared to 77 adults without DS. MEASU REMENTS: RMR was measured by indirect calorimetry, Fat mass (FM) and f at free mass (FFM) were determined using dual energy X-ray absorptiome try (DXA), Thyroid function (thyroxin, T3 uptake, and free T4) were de termined from fasting blood samples for all DS subjects and a subset o f the controls. RESULTS: An analysis of covariance was conducted in wh ich DS status was the independent variable, Covariates were sex, FFM, FM, age, and T4, After controlling for sex, FFM, FM, age, and height, persons with US had lower RMRs than persons without DS (F(1,83) = 7.69 7, P = 0.007; eta = 0.29), In terms of kcalories, the adjusted means w ere 1333.5 for DS subjects and 1670.1 for non-DS subjects, a differenc e of 20.8% relative to the grand mean, When thyroxine was added to the regression the effect of DS on RMR was of questionable significance. CONCLUSION: This research demonstrates that persons with DS have lower RMRs than do persons without DS, This difference persists after contr olling for obvious confounds and was of a moderate magnitude.