Resting metabolic rate in elderly nursing home patients with multiple diagnoses.
BACKGROUND
In the diseased elderly weight loss and malnutrition are common. It is unclear to what degree this is caused by an elevated resting metabolic rate (RMR), a decreased energy intake or a combination of the two.


OBJECTIVE
To measure RMR and nutrient induced thermogenesis (NIT) in chronically diseased elderly living in a nursing home and test for a correlation with fat free mass (FFM), age, energy intake and activities of daily living (ADL).


METHODS
Explorative study performed in the residents' own apartments. RMR was measured by indirect calorimetry, and NIT was tested by giving the subjects an oral fluid test meal, then measuring metabolic rate again one hour later. Body composition was measured anthropometrically and FFM was calculated. Energy intake was calculated from a five-day record of weighed food. BMR was calculated using four different prediction equations and compared with measured RMR.


RESULTS
RMR was 1,174 kcal/d (29.3 kcal/kg FFM/d). The variation in RMR was significantly related to FFM (p < 0.0001). Energy intake was 1,474 kcal/d, (36.5 kcal/kg FFM/d). The energy intake/RMR ratio, was 1.27, and NIT was 15% (0-33%). NIT was not correlated to any of the parameters tested. The equation of Harris and Benedict underestimated BMR by 4%; the WHO/FAO overestimated BMR by 7%; Schofield and an estimate of 20 kcal/kg/d did not significantly differ from the measured mean.


CONCLUSIONS
RMR was closely correlated to FFM. Variations in NIT could not be explained by any tested parameters. Predicted BMR differed from measured RMR by less than 8% in all methods, but individual variations were large.
Lammes
E
E
Nutrition and Pharmacotherapy Unit, Research and Development Unit for the Elderly North West, Karolinska Institute, Senior Staden Hallen, Lovgatan 43-45, 16932 Solna, Sweden, eva.lammes@nlpo.sll.se
Akner
G
G
D000203:Activities of Daily Living; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D001481:Basal Metabolism / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect; D002149:Energy Intake / Q000502:physiology; D005260:Female; D006707:Homes for the Aged; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D009735:Nursing Homes; D011237:Predictive Value of Tests; D022722:Thermogenesis / Q000502:physiology*; D015431:Weight Loss