Intra-abdominal adiposity and individual components of the metabolic syndrome in adolescence: sex differences and underlying mechanisms.
OBJECTIVE
To investigate the association between intra-abdominal adiposity and individual components of the metabolic syndrome (MS) in adolescent males and females.


METHODS
Cross-sectional study of a population-based cohort.


METHODS
Saguenay Youth Study, Quebec, Canada.


METHODS
A total of 324 adolescents, aged 12 to 18 years.


METHODS
Measures were compared between males and females with "high" or "low" intra-abdominal fat (IAF).


METHODS
Intra-abdominal fat was quantified with magnetic resonance imaging. Primary outcome measures were blood pressure (BP) and fasting serum glucose, insulin, lipids, and C-reactive protein levels. Secondary mechanistic measures were cardiovascular variability indexes of autonomic nervous system function, pubertal development, and serum levels of cortisol, leptin, and sex hormones.


RESULTS
The MS was completely absent in adolescents with low IAF and was present in 13.8% of males and 8.3% of females with high IAF. Excess IAF was associated with a higher homeostasis model assessment index (0.5 [95% confidence interval (CI), 0.3 to 0.8]; P < .001) and triglycerides level (17.7 mg/dL [to convert to millimoles per liter, multiply by 0.0113] [95% CI, 9.7 to 25.7 mg/dL]; P < .001), lower high-density lipoprotein cholesterol level (-3.9 mg/dL [to convert to millimoles per liter, multiply by 0.0259] [95% CI, -6.2 to -1.5 mg/dL]; P = .003), and higher C-reactive protein level (0.03 mg/L [to convert to nanomoles per liter, multiply by 9.524] [95% CI, 0.01 to 0.05 mg/L]; P = .003). High IAF was associated with elevations of BP and sympathetic activity in males only (higher systolic BP, 6 mm Hg [95% CI, 1 to 11 mm Hg]; P = .02 and low-frequency power of diastolic BP, 629 mm Hg2 [95% CI, 37 to 1222 mm Hg2]; P = .04).


CONCLUSIONS
Our results suggest that, already in adolescence, accumulation of IAF may promote development of the MS, affecting the metabolic and inflammatory components similarly in both sexes but influencing BP adversely only in males. The latter may be attributed, in part, to the augmentation of sympathetic activity also seen only in males.
Syme
Catriona
C
Brain and Body Centre, University of Nottingham, Nottingham, England.
Abrahamowicz
Michal
M
Leonard
Gabriel T
GT
Perron
Michel
M
Pitiot
Alain
A
Qiu
Xi
X
Richer
Louis
L
Totman
John
J
Veillette
Suzanne
S
Xiao
Yongling
Y
Gaudet
Daniel
D
Paus
Tomas
T
Pausova
Zdenka
Z
D050153:Abdominal Fat; D050154:Adiposity; D000293:Adolescent; D001341:Autonomic Nervous System / Q000502:physiology; D001794:Blood Pressure; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*; D009765:Obesity / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D012727:Sex Characteristics