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Jonquière, Canada

Haghighi A.,University of Toronto | Schwartz D.H.,Rotman Research Institute | Abrahamowicz M.,McGill University | Leonard G.T.,Montreal Neurological Institute | And 7 more authors.
Archives of General Psychiatry | Year: 2013

Context: Prenatal exposure to maternal cigarette smoking is a well-established risk factor for obesity, but the underlying mechanisms are not known. Preference for fatty foods, regulated in part by the brain reward system, may contribute to the development of obesity. Objective: To examine whether prenatal exposure to maternal cigarette smoking is associated with enhanced fat intake and risk for obesity, and whether these associations may be related to subtle structural variations in brain regions involved in reward processing. Design: Cross-sectional study of a population-based cohort. Setting: The Saguenay Youth Study, Quebec, Canada. Participants: A total of 378 adolescents (aged 13 to 19 years; Tanner stage 4 and 5 of sexual maturation), half of whom were exposed prenatally to maternal cigarette smoking (mean [SD], 11.1 [6.8] cigarettes/d). Main Outcome Measures: Fat intake was assessed with a 24-hour food recall (percentage of energy intake consumed as fat). Body adiposity was measured with anthropometry and multifrequency bioimpedance. Volumes of key brain structures involved in reward processing, namely the amygdala, nucleus accumbens, and orbitofrontal cortex, were measured with magnetic resonance imaging. Results: Exposed vs nonexposed subjects exhibited a higher total body fat (by approximately 1.7 kg; P = .009) and fat intake (by 2.7%; P = .001). They also exhibited a lower volume of the amygdala (by 95 mm3; P < .001) but not of the other 2 brain structures. Consistent with its possible role in limiting fat intake, amygdala volume correlated inversely with fat intake (r = -0.15; P = .006). Conclusions: Prenatal exposure to maternal cigarette smoking may promote obesity by enhancing dietary preference for fat, and this effect may be mediated in part through subtle structural variations in the amygdala. ©2013 American Medical Association. All rights reserved. Source

Syme C.,University of Nottingham | Abrahamowicz M.,McGill University | Mahboubi A.,McGill University | Leonard G.T.,McGill University | And 8 more authors.
Obesity | Year: 2010

In industrialized countries, prenatal exposure to maternal cigarette smoking (PEMCS) is the most common environmental insult to the fetus. Here, we tested the hypothesis that PEMCS amplifies accumulation of abdominal fat during the accelerated weight gain occurring in late puberty. This hypothesis was tested in 508 adolescents (12-18 years, 237 exposed prenatally to maternal cigarette smoking) in whom subcutaneous and intra-abdominal fat were quantified with magnetic resonance imaging (MRI). We found that, in early puberty, exposed and nonexposed adolescents did not differ in MRI-based measures of adiposity. In late puberty, on the other hand, exposed compared with nonexposed adolescents demonstrated markedly higher quantities of both subcutaneous fat (by 26%, P = 0.004) and intra-abdominal fat (by 33%, P = 0.001). These group differences remained virtually unchanged after adjusting for sex and potential confounders, including birth weight and breastfeeding. As such, our results suggest that PEMCS may represent a major risk factor for the development of abdominal obesity at the later stages of puberty. © 2010 The Obesity Society. Source

Paus T.,University of Nottingham | Paus T.,Montreal Neurological Institute | Nawaz-Khan I.,University of Nottingham | Leonard G.,Montreal Neurological Institute | And 8 more authors.
Hormones and Behavior | Year: 2010

Here we examined sex differences in the volumes of grey and white matter, and in grey-matter "density," in a group of typically developing adolescents participating in the Saguenay Youth Study (n = 419; 12-18 years). In male adolescents, we also investigated the role of a functional polymorphism in androgen-receptor gene (AR) in moderating the effect of testosterone on volumes of grey and white matter and grey-matter density. Overall, both absolute and relative volumes of white matter were larger in male vs. females adolescents. The relative grey-matter volumes were slightly larger in female than male adolescents and so was the grey-matter density in a large number of cortical regions. In male adolescents, functional polymorphism of AR moderated the effect of testosterone on relative white- and grey-matter volumes. Following a discussion of several methodological and interpretational issues, we outline future directions in investigating brain-behavior relationships vis-à-vis psychopathology. © 2009 Elsevier Inc. All rights reserved. Source

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