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Biomedical subjects

Claude Bouchard

Publications and source records attributed to Claude Bouchard.

At least 73 records · Page 4Linked to original sources
PubMed2004

A genome-wide linkage scan for dietary energy and nutrient intakes: the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study.

BACKGROUND: A poor diet is a risk factor for chronic diseases such as obesity, cardiovascular disease, hypertension, and some cancers. Twin and family studies suggest that genetic factors potentially influence energy and nutrient intakes. OBJECTIVE: We sought to identify genomic regions harboring genes affecting total energy, carbohydrate, protein, and fat intakes. DESIGN: We performed a genomic scan in 347 white sibling pairs and 99 black sibling pairs. Dietary energy and nutrient intakes were assessed by using Willett's food-frequency questionnaire. Single-point and multipoint Haseman-Elston regression techniques were used to test for linkage. These subjects were part of the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study, a multicenter project undertaken by 5 laboratories. RESULTS: In the whites, the strongest evidence of linkage appeared for dietary energy and nutrient intakes on chromosomes 1p21.2 (P = 0.0002) and 20q13.13 (P = 0.00007), and that for fat intake appeared on chromosome 12q14.1 (P = 0.0013). The linkage evidence on chromosomes 1 and 20 related to total energy intake rather than to the intake of specific macronutrients. In the blacks, promising linkages for macronutrient intakes occurred on chromosomes 12q23-q24.21, 1q32.1, and 7q11.1. Several potential candidate genes are encoded in and around the linkage regions on chromosomes 1p21.2, 12q14.1, and 20q13.13. CONCLUSIONS: These are the first reported human quantitative trait loci for dietary energy and macronutrient intakes. Further study may refine these quantitative trait loci to identify potential candidate genes for energy and specific macronutrient intakes that would be amenable to more detailed molecular studies.

Adolescent↗
PubMed2004

Modifications in food-group consumption are related to long-term body-weight changes.

BACKGROUND: Dietary patterns play an important role in the control of body weight. OBJECTIVE: The aim of this study was to verify whether changes in some dietary patterns over a 6-y follow-up period would be associated with weight changes. DESIGN: A sample of 248 volunteers of the Québec Family Study were measured twice (visit 1: 1989-1994; visit 2: 1995-2000). Body weight, percentage body fat, subcutaneous skinfold thicknesses, and waist circumference measurements as well as 3-d dietary and physical activity records were obtained at each visit. At visit 2, all participants filled out a food-based questionnaire examining changes in the consumption of 10 food categories. To further investigate the relation between changes in food-group consumption and body-weight changes, a total of 51 food subcategories were identified from dietary records. RESULTS: A self-reported decrease in the consumption of food in the fat group or an increase in consumption in the fruit group from the food-based questionnaire predicted a lower increase in body weight and adiposity indicators over time. A more detailed examination of the change in food groups between diet records revealed that increases in the consumption of whole fruit as well as skimmed milk and partly skimmed milk were the 2 food patterns that negatively correlated with the changes of each body weight-related indicator. CONCLUSIONS: These results show that changes in the consumption of some specific food groups are associated with body-weight changes. Such specific eating patterns could help to improve obesity treatment and prevention.

Adolescent↗
PubMed2004

Neuromedin beta: a strong candidate gene linking eating behaviors and susceptibility to obesity.

BACKGROUND: Obesity is frequently associated with eating disorders, and evidence indicates that both conditions are influenced by genetic factors. However, little is known about the genes influencing eating behaviors. OBJECTIVE: The objective was to identify genes associated with eating behaviors. DESIGN: Three eating behaviors were assessed in 660 adults from the Quebec Family Study with the use of the Three-Factor Eating Questionnaire. A genome-wide scan was conducted with a total of 471 genetic markers spanning the 22 autosomes to identify quantitative trait loci for eating behaviors. Body composition and macronutrient and energy intakes were also measured. RESULTS: Four quantitative trait loci were identified for disinhibition and susceptibility to hunger. Of these, the best evidence of linkage was found between a locus on chromosome 15q24-q25 and disinhibition (P <0.0058) and susceptibility to hunger (P <0.0001). After fine-mapping, the peak linkage was found between markers D15S206 and D15S201 surrounding the neuromedin beta (NMB) gene. A missense mutation (p.P73T) located within the NMB gene showed significant associations with eating behaviors and obesity phenotypes. The T73T homozygotes were 2 times as likely to exhibit high levels of disinhibition (odds ratio: 1.8; 95% CI: 1.07, 2.89; P=0.03) and susceptibility to hunger (odds ratio: 1.9; 95% CI: 1.15, 3.06; P=0.01) as were the P73 allele carriers. Six-year follow-up data showed that the amount of body fat gain over time in T73T subjects was >2 times that than in P73P homozygotes (3.6 compared with 1.5 kg; P <0.05). CONCLUSION: The results suggest that NMB is a very strong candidate gene of eating behaviors and predisposition to obesity.

Adult↗
PubMed2004

Calcium intake is associated with adiposity in Black and White men and White women of the HERITAGE Family Study.

Calcium (Ca(2+)) intake may play a role in the regulation of body weight. Increased Ca(2+) intake has been associated with lower body weight, BMI, and adiposity measures in cross-sectional studies. We examined the association between Ca(2+) intake, derived from the Willett FFQ, and overall and abdominal adiposity in Black and White men and women of the HERITAGE Family Study. BMI, the percentage of body fat (%FAT), the sum of 8 skinfold thicknesses, computerized tomography total abdominal fat (TAF), abdominal visceral (AVF) and abdominal subcutaneous (ASF) fat, and waist circumference were measured in 362 men (109 Blacks, 253 Whites) and 462 women (201 Blacks, 261 Whites). Subjects were divided into tertiles of energy-adjusted Ca(2+) intake. Adiposity measures across tertiles were compared by ANOVA and also regressed against the energy-adjusted Ca(2+) intake to test for a linear trend. The strongest inverse associations appeared in Black men and White women. Black men in the high Ca(2+) intake group were leaner than those in the low Ca(2+) intake group: BMI 23.4 +/- 0.9 vs. 26.7 +/- 1.1 kg/m(2) (P = 0.01); for all other adiposity measures, P < 0.05. In White women, regression analyses showed significant inverse associations between Ca(2+) intake and BMI (P = 0.02), %FAT (P = 0.001), TAF (P = 0.006), AVF (P = 0.03), and ASF (P = 0.01). The percentage of fat of White men in the highest Ca(2+) intake group was significantly lower than in the lowest Ca(2+) group (P = 0.04). No significant associations were found in Black women. Low Ca(2+) intake may be associated with higher adiposity, particularly in men and White women.

Adipose Tissue↗
PubMed2004

Race and sex similarities in exercise-induced changes in blood lipids and fatness.

PURPOSE: This study explores sex and race differences in the association between changes in fat mass (FM), abdominal visceral fat (AVF), and abdominal subcutaneous fat (ASF) on blood lipid changes consequent to aerobic exercise training. METHODS: The sample included 613 participants (428 white and 185 black, 46% men) from the HERITAGE Family Study. Total FM was determined by densitometry, whereas AVF and ASF cross-sectional areas were determined by computed tomography at the L4-L5 level. Blood lipid measurements included total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and the TC/HDL-C ratio, which were obtained before and after 20 wk of supervised aerobic exercise. Canonical correlation was used to determine the multivariate associations between body fatness and blood lipids at baseline and the changes induced by exercise training. RESULTS: Body fat accounted for 26-36% of the variance in baseline blood lipids, and changes in body fat accounted for 7-21% of the variance in changes in blood lipids with exercise training. The pattern of loadings indicated similar relationships between body fatness and blood lipids at baseline, and their respective changes with exercise training among the four sex-by-race groups. Greater fat loss, characterized by loss of FM, AVF, and ASF, was associated with a greater blood lipid response characterized by an increase in HDL-C and decreases in LDL-C, TG, TC, and TC/HDL-C. Although the pattern of loadings was similar in all groups, the strength of the association was stronger in blacks than in whites. CONCLUSION: The multivariate associations among fat loss and changes in blood lipids consequent to aerobic exercise training are similar in black and white men and women.

Adipose Tissue↗
PubMed2004

The human gene map for performance and health-related fitness phenotypes: the 2003 update.

This review presents the 2003 update of the human gene map for physical performance and health-related fitness phenotypes. It is based on peer-reviewed papers published by the end of 2003 and includes association studies with candidate genes, genome-wide scans with polymorphic markers, and single-gene defects causing exercise intolerance to variable degrees. The genes and markers with evidence of association or linkage with a performance or fitness phenotype in sedentary or active people, in adaptation to acute exercise, or for training-induced changes are positioned on the genetic map of all autosomes and the X chromosome. Negative studies are reviewed but a gene or locus must be supported by at least one positive study before being inserted on the map. By the end of 2000, 29 loci were depicted on the first edition of the map. In contrast, the 2003 human gene map for physical performance and health-related phenotypes includes 109 autosomal gene entries and QTL, plus two on the X chromosome. Moreover, there are 15 mitochondrial genes in which sequence variants have been shown to influence relevant fitness and performance phenotypes.

Adaptation, Physiological↗
PubMed2004

Body mass index, waist circumference, and clustering of cardiovascular disease risk factors in a biracial sample of children and adolescents.

OBJECTIVE: To derive optimal body mass index (BMI) and waist circumference thresholds for children and adolescents, to predict risk factor clustering. DESIGN: Cross-sectional receiver operating characteristic curve analysis. SETTING: The Bogalusa Heart Study, a community-based study of cardiovascular disease risk factors in early life. PARTICIPANTS: A total of 2597 black and white children and adolescents, 5 to 18 years of age, who were examined between 1992 and 1994. MAIN OUTCOME MEASURES: The presence or absence of > or =3 age-adjusted risk factors (low high-density lipoprotein cholesterol level, high low-density lipoprotein cholesterol level, high triglyceride level, high glucose level, high insulin level, and high blood pressure) was predicted from age-adjusted BMI and waist circumference values. RESULTS: The areas under the receiver operating characteristic curves were significantly different from 0.5 for both BMI and waist circumference for all gender/race groups, ranging from 0.73 to 0.82. The optimal BMI thresholds were at the 53rd and 50th percentiles for white and black male subjects, respectively, and at the 57th and 51st percentiles for white and black female subjects, respectively. Similarly, the optimal waist circumference thresholds were at the 56th and 50th percentiles for white and black male subjects, respectively, and at the 57th and 52nd percentiles for white and black female subjects, respectively. The sensitivity and specificity at the thresholds were similar for all gender/race groups, ranging from 67% to 75%. CONCLUSIONS: The use of BMI and waist circumference for the prediction of risk factor clustering among children and adolescents has significant clinical utility. In this sample, race and gender differences in the optimal thresholds were minimal.

Abdomen↗
PubMed2004

Leptin and leptin receptor gene polymorphisms and changes in glucose homeostasis in response to regular exercise in nondiabetic individuals: the HERITAGE family study.

We recently reported that a genomic region close to the leptin locus was linked to fasting insulin response to exercise training in nondiabetic white subjects. We tested the hypothesis that common exonic variants in the leptin (LEP) and leptin receptor (LEPR) genes modify the effects of regular physical activity on glucose homeostasis in nondiabetic whites (n = 397) and blacks (n = 143). In whites, exercise increased insulin sensitivity index (P = 0.041) and disposition index (P = 0.046) in the LEPR 109R allele carriers but not in the K109K homozygotes, increased glucose disappearance index more in the R109R homozygotes than in the K109 allele carriers (P = 0.039), and decreased fasting glucose only in the 109R allele carriers (P = 0.018). We also found an interaction between the LEP A19G and LEPR K109R polymorphisms on the change in fasting insulin in whites (P = 0.010). The association between the LEP A19G polymorphism and the change in insulin was evident only in the LEPR 109R carriers (P = 0.019). The decrease in insulin was strongest in the LEP A19A homozygotes who carried the LEPR 109R allele. Similar interaction was observed in blacks (P = 0.046). Variations in the LEP and LEPR genes are associated with the magnitude of the effects of regular exercise on glucose homeostasis in nondiabetic individuals.

Adult↗
PubMed2003

Combined effects of PPARgamma2 P12A and PPARalpha L162V polymorphisms on glucose and insulin homeostasis: the Québec Family Study.

Peroxisome proliferator-activated receptors gamma2 and alpha are nuclear factors known to be important regulators of lipid and glucose metabolism. Two polymorphisms, namely PPARgamma2 P12A and PPARalpha L162V, were investigated for their individual and interaction effects on glucose and insulin homeostasis. Genotypes were determined in 663 nondiabetic adults participating in the Québec Family Study and who underwent an oral glucose tolerance test (OGTT). The insulin and C-peptide areas under the curve (AUC) following the OGTT were higher in subjects carrying the PPARalpha V162 allele compared to homozygous for the L162 allele. When subjects were grouped according to both polymorphisms, higher levels of insulin and C-peptide during the OGTT were observed for those carrying the PPARalpha V162 allele except when they carry at the same time the PPARgamma2 A12 allele. Thus, the PPARgamma2 A12 allele seems protective against the deleterious effect of the PPARalpha V162 allele. Furthermore, a significant gene-gene interaction was observed for the acute (0-30 min) (p<0.001) and the total (p=0.05) C-peptide AUC following the OGTT. These results provide evidence of a gene-gene interaction in the regulation of plasma glucose-insulin homeostasis, and emphasize that these interactions need to be taken into account when dissecting the genetic etiology of complex disorders.

Adult↗
PubMed2003

Titin is a candidate gene for stroke volume response to endurance training: the HERITAGE Family Study.

A genome-wide linkage scan for endurance training-induced changes in submaximal exercise stroke volume (DeltaSV50) in the HERITAGE Family Study revealed two chromosomal regions (2q31-q32 and 10p11.2) with at least suggestive evidence of linkage among white families. Here we report a further characterization of the quantitative trait locus (QTL) in chromosome 2q31 and provide evidence that titin (TTN) is likely a candidate gene involved. The original linkage was detected with two markers (D2S335 and D2S1391), and the QTL covered approximately 25 million base pairs (Mb). We added 12 microsatellite markers resulting in an average marker density of one marker per 2.3 Mb. The evidence of linkage increased from P = 0.006 to P = 0.0002 and 0.00002 in the multi- and single-point analyses, respectively. The strongest evidence of linkage was seen with two markers in and near the TTN gene. Transmission/disequilibrium test (TDT) with the same marker set provided evidence for association with one of the TTN markers (D2S385; P = 0.004). TTN is a major contributor to the elasticity of cardiomyocytes and a key regulator of the Frank-Starling mechanism. Since TTN is the largest gene in the human genome, the challenge is to identify the DNA sequence variants contributing to the interindividual differences in cardiac adaptation to endurance training.

Chromosome Mapping↗
PubMed2003

The T111I mutation in the EL gene modulates the impact of dietary fat on the HDL profile in women.

The objective of the present study was to examine the impact of the T111I missense mutation in exon 3 of the endothelial lipase (EL) gene on HDL and its potential interaction effect with dietary fat. The study sample included 281 women and 216 men aged between 17 and 76 years from the Québec Family Study. Plasma HDL3-C levels of I111I homozygote women were higher compared with those of women carrying the wild-type allele (P = 0.03). These differences were not attenuated when adjusted for levels of obesity and were not observed among men. Dietary PUFA interacted with the T111I mutation to modulate apolipoprotein A-I (apoA-I) and HDL3-C levels among women. Specifically, a diet rich in PUFA was associated with increased apoA-I levels among women carriers of the I111 allele and with decreased apoA-I among women homozygotes for the wild-type allele (P = 0.002). A similar interaction was observed with plasma HDL3-C levels (P = 0.003). These interactions were not observed among men. In conclusion, the EL T111I mutation appears to have a modest effect on plasma HDL levels. The gene-diet interaction among women, however, suggests that the T111I missense mutation may confer protection against the lowering effect of a high dietary PUFA intake on plasma apoA-I and HDL3-C levels.

Adipose Tissue↗
PubMed2003

Evidence for a major quantitative trait locus on chromosome 17q21 affecting low-density lipoprotein peak particle diameter.

BACKGROUND: Several lines of evidence suggest that small dense LDL particles are associated with the risk of coronary heart disease. Heritability and segregation studies suggest that LDL particle size is characterized by a large genetic contribution and the presence of a putative major genetic locus. However, association and linkage analyses have thus far been inconclusive in identifying the underlying gene(s). METHODS AND RESULTS: An autosomal genome-wide scan for LDL peak particle diameter (LDL-PPD) was performed in the Québec Family Study. A total of 442 markers were genotyped, with an average intermarker distance of 7.2 cM. LDL-PPD was measured by gradient gel electrophoresis in 681 subjects from 236 nuclear families. Linkage was tested by both sib-pair-based and variance components-based linkage methods. The strongest evidence of linkage was found on chromosome 17q21.33 at marker D17S1301, with an LOD score of 6.76 by the variance-components method for the phenotype adjusted for age, body mass index, and triglyceride levels. Similar results were obtained with the sib-pair method (P<0.0001). Other chromosomal regions harboring markers with highly suggestive evidence of linkage (P< or =0.0023; LOD > or =1.75) include 1p31, 2q33.2, 4p15.2, 5q12.3, and 14q31. Several candidate genes are localized under the peak linkages, including apolipoprotein H on chromosome 17q, the apolipoprotein E receptor 2, and members of the phospholipase A2 family on chromosome 1p as well as HMG-CoA reductase on chromosome 5q. CONCLUSIONS: This genome-wide scan for LDL-PPD indicates the presence of a major quantitative trait locus located on chromosome 17q and others interesting loci influencing the phenotype.

Adult↗
PubMed2003

Heritability of LDL peak particle diameter in the Quebec Family Study.

LDL size has been associated with the risk of coronary heart disease. The objective of the present study was to verify whether familial factors influence LDL peak particle diameter (LDL-PPD), a quantitative trait reflecting the size of the major LDL subclass. LDL-PPD was measured by 2-16% polyacrylamide gradient gel electrophoresis in 681 members of 236 nuclear families participating in the Quebec Family Study. LDL-PPD was adjusted for age (LDL-PPD1), age and body mass index (LDL-PPD2), or age, body mass index, and plasma triglyceride levels (LDL-PPD3) separately in men and women. The residual scores were used to test for familial aggregation, using an ANOVA and to compute maximum likelihood estimates of familial correlations. The ANOVA test revealed that family lines accounted for 47.4%, 46.7%, and 48.9% of the variance in the LDL-PPD1, LDL-PPD2, and LDL-PPD3 phenotypes, respectively. The pattern of familial correlations revealed no significant spouse correlations but significant parent-offspring and sibling correlations for the three LDL-PPD phenotypes, with maximal heritability estimates of 59%, 58%, and 52% for LDL-PPD1, LDL-PPD2, and LDL-PPD3, respectively. These results suggest that LDL-PPD strongly aggregates in families, and that the familial resemblance appears to be primarily attributable to genetic factors. Genes responsible for this genetic contribution remain to be identified.

Adult↗
PubMed2003

Apolipoprotein AI- and AI:AII-containing lipoproteins in white men and women of the HERITAGE Family study: Associations with metabolic risk profile variables.

It is now well established that an increased high-density lipoprotein (HDL) cholesterol level, especially in the HDL(2) subfraction, is associated with a reduced risk of coronary heart disease (CHD). However, little is known about the associations between the apolipoprotein (apo) composition of HDL and CHD metabolic risk factors. In the present study, we examined the gender differences in plasma concentration of HDL containing apo AI only (LpAI) versus both apoAI and apoAII (LpAI/AII), and also compared their associations with body composition, adipose tissue (AT) distribution, and metabolic risk profile variables. For that purpose, we measured fasting plasma lipoprotein-lipid levels including LpAI and LpAI/AII concentrations in a sample of 215 men and 174 women, all Caucasians, of the HERITAGE Family Study. All subjects underwent anthropometric, body fatness (underwater weighing) and abdominal AT accumulation (computed tomography) measurements. We found that, women had higher LpAI and lower LpAI/AII concentrations compared with men. Whereas in women, LpAI levels were correlated to body fat mass and waist circumference, no association between body composition, fat distribution, and LpAI concentrations was noted in men. Increased LpAI concentrations were associated with higher HDL(2) cholesterol levels in both men and women. Overall, elevated LpAI and LpAI/AII concentrations showed contrasting associations with metabolic risk profile variables as high LpAI, but not LpAI/AII concentrations were associated with a more favorable metabolic risk profile. We also found that high HDL cholesterol appeared to be more closely related to a better metabolic risk profile than high LpAI in both genders. Our results suggest that LpAI and HDL cholesterol levels are good correlates of the metabolic profile, but that HDL cholesterol concentrations could still represent a better index in CHD risk assessment.

Adipose Tissue↗
PubMed2003

Mutations in the adiponectin gene in lean and obese subjects from the Swedish obese subjects cohort.

Adiponectin (also called AdipoQ, gelatin-binding protein 28, Acrp30) DNA sequence variants were determined in 96 unrelated female subjects with severe obesity (mean body mass index [BMI], 42.3 kg/m2) and in 96 non-obese female controls (mean BMI, 23.0 kg/m2) from the Swedish Obese Subjects (SOS) cohort. A single base substitution (T45G) at codon 15 of exon 2 resulting in no change in amino acid (Gly15Gly) was found in equal frequencies among obese and control subjects. However, this polymorphism was associated with serum cholesterol and waist circumference (P=.023 and.043, respectively) in the obese group. A IVS2 + G62T sequence variation was also identified, but had similar prevalence rates in obese and control subjects. Blood glucose was highest in the obese female subjects who were homozygotes for the G allele (GG) of the IVS2 + G62T polymorphism (N=56; P=.033) and all the diabetics (n=6) in this sample were in this group. IVS2 + G62T polymorphism was also associated with BMI (P=.014), diastolic blood pressure (P=.009), and sagittal diameter (P=.032). A missense point mutation at codon 111 (Tyr111His) was not associated with any obesity-related phenotypes. In conclusion, adiponectin DNA sequence variations might play a role in the complications of morbid obesity and should be further investigated.

Adiponectin↗
PubMed2003

A dopamine D2 receptor gene polymorphism and physical activity in two family studies.

A role for dopamine neurotransmission in the regulation of motor activity and reinforcement of behavior is supported by considerable evidence. We studied the association between a marker in the dopamine D2 receptor gene (DRD2) and physical activity level in two cohorts. A first cohort consisted of 721 participants from 161 families of the Quebec Family Study (QFS). Physical activity phenotypes were obtained from a three-day diary and a questionnaire probing physical activity during the past year. The second cohort was the HERITAGE Family Study (HERITAGE), which included 275 Black and 497 White participants from 228 families, among whom past year leisure time and occupational physical activity were probed. A fragment length polymorphism in exon 6 of the DRD2 gene was detected by the polymerase chain reaction (PCR) and NcoI digestion. Frequencies for the T and C alleles were 28% and 72% in the QFS. In the QFS, TT homozygote women had 25% and 34% lower age and BMI-adjusted physical activity level during the past year, compared to CC homozygotes and CT heterozygotes (F=4.42, P=.016). The DRD2 genotype was not associated with the QFS phenotypes obtained from the three-day diary. In the HERITAGE, the frequency of the T allele was 30% among Whites and 63% among Blacks. Similarly, the TT homozygote White women had 29-38% lower sports index (F=4.09, P=.023) and 27-33% lower work index (F=6.23, P=.004) than the CC homozygotes and CT heterozygotes. The results suggest that DNA sequence variation in the DRD2 gene is associated with physical activity levels among White women.

Adult↗
PubMed2003

The utility of the international child and adolescent overweight guidelines for predicting coronary heart disease risk factors.

The purpose of this study was to assess the association between the international overweight cutoffs for children and youth and coronary heart disease risk factors. The sample included 410 boys and 337 girls 9-18 years of age from the Québec Family Study. Participants were classified as normal weight or overweight using the international BMI cutoffs, and into normal and elevated risk groups based on the 90th percentile of sex-specific age-adjusted risk factors [blood pressure, fasting total cholesterol (CHOL), LDL-C, HDL-C, CHOL/HDL-C, triglycerides, glucose, and physical work capacity]. Overweight participants had between 1.6 and 9.1 times the risk of elevated risk factors compared to normal-weight participants. Further, boys and girls with four or more risk factors were 19 and 43 times more likely to be overweight, respectively, compared to participants with no risk factors. The results add evidence that the international cutoffs are related to health risks in youth, supporting the adoption of the guidelines.

Adolescent↗