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- Title
Plasma leptin concentrations, basal metabolic rates and respiratory quotients in young and older adults.
- Authors
Soares, M J; Piers, L S; O'Dea, K; Collier, G R
- Abstract
OBJECTIVE: To-examine the interrelationship of circulating leptin concentrations, basal metabolic rates (BMR) and respiratory quotients (RQ) in young and older adults. DESIGN: Cross sectional study. SUBJECTS: Seventy-six Australian men and women, 48 young (<35 y) and 28 older (≥50 y). MEASUREMENTS: Fasting plasma leptin concentrations by RIA, BMR and RQ by indirect calorimetry, percentage body fat (BF%), fat mass (FM) and fat-free mass (FFM) from total body water (TBW) based on deuterium dilution, waist and hip circumferences from anthropometry. RESULTS: Older subjects had significantly higher BF%, FM and waist-to-hip ratio (WHR), but significantly lower FFM and absolute BMR as compared to younger subjects. Absolute leptin concentrations were 60% higher in older subjects but did not achieve statistical significance. There was, however, a significant gender × age group interaction in leptin concentrations. This was reflected in a significant inverse relationship between age group and leptin in women when data was controlled for waist circumference (r=-0.38, P=0.028), or FM (r=-0.36, P=0.042). A similar relationship was not observed in men on controlling for BF% or FM. Log transformed plasma leptin was best explained by a model that included BF%, gender, age-group, gender × age-group and WHR r=0.75, adjusted r²=0.56, standard error of estimate (SEE)=0.73 ng/ml). BMR was best explained by FFM, FM and age group r=0.94, adjusted r²=0.87; SEE=429 kJ/day). On controlling for BF%, WHR and FFM, leptin was negatively related to RQ only in older men (r=-0.67, P=0.033). There was no relationship of leptin to BMR in the groups studied. CONCLUSION: The study demonstrates an age-related modification of the gender bias in leptin, and a gender-specific inverse relationship between leptin and RQ in older people. The decline in leptin and the lack of a relationship between RQ and leptin in older women may indicate an increased risk of weight gain relative...
- Subjects
AUSTRALIA; LEPTIN; BASAL metabolism; RESPIRATION
- Publication
International Journal of Obesity & Related Metabolic Disorders, 2000, Vol 24, Issue 12, p1592
- ISSN
0307-0565
- Publication type
Article
- DOI
10.1038/sj.ijo.0801450