Familial influences and obesity-associated metabolic risk factors contribute to the variation in resting energy expenditure: the Kiel Obesity Prevention Study.
BACKGROUND
A low metabolic rate may be inherited and predispose to obesity, whereas a higher metabolic rate in obesity may be acquired by obesity-associated cardiometabolic risk.


OBJECTIVE
We aimed to explain the interindividual variation in resting energy expenditure (REE) by assessing 1) the association between REE and body composition, thyroid hormones, and obesity-related cardiometabolic risk factors, and 2) the familial (genetic and environmental) contribution to REE.


METHODS
REE and metabolic risk factors (ie, blood pressure and plasma insulin, glucose, and C-reactive protein concentrations) were assessed in 149 two- or three-generation families, including at least one overweight or obese member. Heritability of REE, respiratory quotient (RQ), thyroid hormones [thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4)], and body composition (fat-free mass and fat mass) were estimated by using variance components-based quantitative genetic models.


RESULTS
REE adjusted for body composition, sex, and age (REEadj) significantly correlated with systolic and diastolic blood pressure, plasma insulin and glucose concentrations, and the homeostasis model assessment (HOMA) (r = 0.14-0.31, P < 0.05). Thyroid hormones had a modest influence on REE variance only. Heritability was 0.30 +/- 0.07 for REEadj and 0.29 +/- 0.08 for REE after additional adjustment for thyroid hormones and metabolic risk. Furthermore, heritability was estimated to be 0.22 +/- 0.08 for RQ, 0.37 +/- 0.08 for TSH, 0.68 +/- 0.06 for FT4, and 0.69 +/- 0.05 for FT3 (all significantly larger than zero).


CONCLUSIONS
Obesity-related cardiometabolic risk factors contribute to interindividual variation in REE, with hypertension and insulin resistance being associated with a higher REE. REE was moderately heritable, independent of body composition, sex, age, thyroid function, and cardiometabolic risk.
Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-Universität, Kiel, Germany.
Anja
A
Bosy-Westphal
Andreas
A
Wolf
Frederike
F
Bührens
Britta
B
Hitze
Norbert
N
Czech
Heiner
H
Mönig
Oliver
O
Selberg
Uta
U
Settler
Maria
M
Pfeuffer
Jürgen
J
Schrezenmeir
Michael
M
Krawczak
Manfred J
MJ
Müller
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002648:Child; D004734:Energy Metabolism; D005190:Family; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate / Q000235:genetics / Q000502:physiology; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D050177:Overweight / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology; D015995:Prevalence; D012146:Rest; D012307:Risk Factors