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Biomedical subjects

Claude Bouchard

Publications and source records attributed to Claude Bouchard.

At least 37 records · Page 2Linked to original sources

Impact of abdominal visceral fat, growth hormone, fitness, and insulin on lipids and lipoproteins in older adults.

We examined the relationship between abdominal visceral fat (AVF) and plasma concentrations of lipids and lipoproteins in 19 females (F) (not on estrogen) and 31 males (M) over the age of 60 (age = 66.8 years). In addition, the effects of growth hormone (GH) release, fitness (Vo(2) peak), insulin, and glucose concentrations (both fasting and in response to an oral glucose tolerance test) on lipids were examined. Subjects were categorized by low (L) and high (H) AVF (L < 130 cm(2), H > 130 cm(2)), fat mass (FM) (above or below median value), and AVF corrected for fat mass. Factorial analysis of variance (ANOVA) showed that when subjects were divided by AVF and FM, similar results were observed with H > L (P <.05) for very-low-density lipoprotein-cholesterol (VLDL-C), triglycerides (TG), VLDL-TG, apolipoprotein (apo)-B, apo-B VLDL, cholesterol (Chol)/high-density lipoprotein (HDL), LDL/HDL, apoB/A1 and L > H for HDL, HDL(2), HDL(3), apo A1, and LDL/apo-B LDL. Gender differences were also observed with F > M for Chol, LDL, HDL, and HDL(2). When AVF was corrected for FM, these gender differences were still present. After correcting for FM, differences remained between H and L AVF groups for VLDL, TG, VLDL-TG, apo-B, apo-B LDL, apo-B VLDL, apoB/A1 (P <.05). Twenty-four hour integrated GH concentration (IGHC) was inversely related to VLDL, TG, VLDL TG, LDL TG, apoB, apoB VLDL, apoB LDL, Chol/HDL, LDL/HDL, and apoB/A1 in F, but not M (P <.05). Vo(2) peak was directly related to Chol, LDL, HDL(3), and apoB LDL with stronger relationships observed in F. Fasting insulin was related to lipids and lipoproteins in both men and women. These data suggest that, in older adults, elevated levels of AVF, FM, and AVF corrected for FM are associated with unfavorable lipid-lipoprotein profiles and extend similar findings reported in younger males and females with elevated AVF. These data also support previous findings indicating that AVF is a primary determinant of GH release.

Abdomen↗

Genomic scan of glucose and insulin metabolism phenotypes: the HERITAGE Family Study.

Genetic factors play a role in the regulation of glucose metabolism-related traits such as insulin sensitivity (S(I)), insulin secretion, and glucose effectiveness (S(G)). Several genomic scans have been performed to localize genes involved in glucose metabolism-related traits. However, few of these studies have been performed with phenotypes derived from the frequently sampled intravenous glucose tolerance test (IVGTT) using the minimal modeling (MINMOD) approach. Here, we report on such a scan for glucose metabolism-related traits derived from MINMOD analysis of IVGTT data in 322 sibling pairs from 95 sedentary white families and 75 sibling pairs from 49 sedentary black families from the HERITAGE Family Study. In addition to S(I) and S(G), we also considered acute insulin response to a glucose challenge (AIR(Glucose)), which is an index for insulin secretion, and disposition index (DI, product of S(I) and AIR(Glucose)), which is a measure of the activity of pancreatic beta cells corrected for insulin resistance. These traits were adjusted for age, sex, and body mass index (BMI) in each of 8 sex-by-generation-by-race groups, and then standardized residuals were used as the phenotypes in the linkage analyses. Analyses were with the multipoint variance components linkage method, as implemented in the computer program SEGPATH, using 509 markers. Several regions with promising linkages (LOD score >/= 1.75, P </=.0023) were detected. They include five regions (1q41 and 8p23.2 for S(I), 4q32.1 and 10p15.3 for AIR(Glucose), and 13q32.1 for DI) in whites and 2 regions (9p11.2 for S(G) and 10q26.11 for S(I)) in blacks. Three of these regions (4q32.1, 9p11.2, 10p15.3) are likely to harbor genes that influence interindividual variation in glucose metabolism-related traits as they replicate findings from other studies. Fine mapping and association studies of candidate genes within these genomic regions are warranted.

Adolescent↗

Calcium intake, body composition, and lipoprotein-lipid concentrations in adults.

BACKGROUND: Recent data suggest that variations in calcium intake may influence lipid metabolism and body composition. OBJECTIVE: The association between daily calcium intake and body composition and plasma lipoprotein-lipid concentrations was studied cross-sectionally in adults from phase 2 of the Québec Family Study. DESIGN: Adults aged 20-65 y (235 men, 235 women) were studied. Subjects who consumed vitamin or mineral supplements were excluded. Subjects were divided into 3 groups on the basis of their daily calcium intake: groups A (< 600 mg), B (600-1000 mg), and C (> 1000 mg). RESULTS: Daily calcium intake was negatively correlated with plasma LDL cholesterol, total cholesterol, and total:HDL cholesterol in women and men after adjustment for variations in body fat mass and waist circumference (P < 0.05). In women, a significantly greater ratio of total to HDL cholesterol (P < 0.05) was observed in group A than in group C after correction for body fat mass and waist circumference. In women, body weight, percentage body fat, fat mass, body mass index, waist circumference, and total abdominal adipose tissue area measured by computed tomography were significantly greater (P < 0.05) in group A than in groups B and C, even after adjustments for confounding variables. Comparable trends were observed in men, but not after adjustment for the same covariates. CONCLUSION: A low daily calcium intake is associated with greater adiposity, particularly in women. In both sexes, a high calcium intake is associated with a plasma lipoprotein-lipid profile predictive of a lower risk of coronary heart disease risk compared with a low calcium intake.

Abdomen↗

Increased abdominal obesity, insulin and glucose levels in nondiabetic subjects with a T29C polymorphism of the transforming growth factor-beta1 gene.

BACKGROUND: In humans, a T-->C transition at nucleotide 29 in the region encoding the signal peptide sequence of the transforming growth factor (TGF)-beta(1), which results in a Leu-->Pro substitution at codon 10, has been associated with myocardial infarction. AIMS/METHODS: In the present study, we genotyped 284 unrelated, nondiabetic Swedish men born in 1944 to assess the impact of the Leu10Pro variant on obesity, including abdominal obesity, and estimates of insulin, glucose and lipid metabolism as well as blood pressure. RESULTS: The frequency of the Pro10 variant was 38.9% (95% CI 32.2-46.0%), and the distribution of genotypes was in Hardy-Weinberg equilibrium. Data analysis showed that heterozygotes had significantly higher body mass index compared to homozygous carriers to the Leu10 variant. In addition, homozygous carriers of the Leu10 variant had significantly lower abdominal sagittal diameter than both Leu10Pro and Pro10Pro carriers. We also found that heterozygotes had significantly higher fasting insulin values as well as higher HOMA insulin-resistance index in comparison to homozygous carriers of the Leu10. Fasting glucose levels were significantly higher in subjects with the Pro10Pro variant compared to subjects with either the Leu10Leu or Leu10Pro variant. CONCLUSION: These findings suggest that the Pro10 allele in the TGF-beta(1) gene pathway might contribute to prevalent diseases such as obesity and type 2 diabetes mellitus.

Abdomen↗

Long-term adiposity changes are related to a glucocorticoid receptor polymorphism in young females.

Male and female preadolescents and adolescents who participated in phase 1 of the Québec Family Study, and who were retested about 12 yr later, were recruited and subdivided on the basis of a genetic variant within the intron 2 of the glucocorticoid receptor (GRL IVS2-BclI). The increase in sc adiposity over the 12-yr follow-up period in the 4.5/2.3 genotype female subgroup was more than twice that observed in the 4.5/4.5 and the 2.3/2.3 genotype subgroups (P < 0.01). The statistical significance of this difference was essentially unchanged after adjusting for changes, over time, in percent dietary energy as fat, alcohol consumption, and participation in vigorous physical activity. In male subjects, the same trend was found, but it did not reach statistical significance. In conclusion, this study suggests that a significant interaction effect exists between variation in the glucocorticoid receptor gene and body fat gain in female subjects experiencing the transition between adolescence and adulthood. Further research will, however, be necessary to characterize the lifestyle factors promoting fat accumulation, over time, among genetically susceptible individuals.

Adipose Tissue↗

Genome-wide linkage scan for the metabolic syndrome in the HERITAGE Family Study.

The metabolic syndrome involves multiple and interactive effects of genes and environmental factors. To identify chromosomal regions encoding genes possibly predisposing to the metabolic syndrome, we performed a genome-wide scan with 456 white and 217 black participants from 204 nuclear families of the HERITAGE Family Study, using regression-based, single- and multipoint linkage analyses on 509 markers. A principal component analysis was performed on 7 metabolic syndrome-related phenotypes. Two principal components, PC1 and PC2 (55% of the variance), were used as metabolic syndrome phenotypes. ANOVA was used to quantify the familial aggregation of PC1 and PC2. Family membership contributed significantly (P < 0.0023) to the variance in PC1 (r(2) = 0.38 in whites; r(2) = 0.55 in blacks) and PC2 (r(2) = 0.51; r(2) = 0.48). In whites, promising evidence for linkage (P < 0.0023) was found for PC1 (2 markers on 10p11.2) and PC2 (a marker on 19q13.4). Suggestive evidence of linkage (0.01 > P > 0.0023) appeared for PC1 (1q41 and 9p13.1) and PC2 (2p22.3). In blacks, promising linkage was found for PC2 on 1p34.1, and suggestive linkage was found on 7q31.3 and 9q21.1. The genome-wide scan revealed evidence for quantitative trait loci on chromosomal regions that have been previously linked with individual cardiovascular disease and type 2 diabetes risk factors. Some of these chromosomal regions harbor promising potential candidate genes.

Adolescent↗

Genome-wide linkage scan for physical activity levels in the Quebec Family study.

PURPOSE AND METHODS: It is commonly recognized that there is familial aggregation for physical activity level. However, the genes and sequence variants responsible for the familial clustering have not been investigated. We performed a genome-wide linkage scan based on 432 markers typed in 767 subjects from 207 families of the Quebec Family study with the aim of identifying loci affecting physical activity levels. Four physical activity level phenotypes were used. RESULTS: Promising evidence of linkage (P < 0.0023) was found for physical inactivity on chromosome 2p22-p16. Suggestive linkages (0.0023<P < 0.01) were found for inactivity (7p11.2, 20q13.1), total physical activity (13q22-q31), moderate to strenuous physical activity (4q28.2, 7p11.2, 9q31.1, 13q22-q31), and time spent in physical activity (11p15 and 15q13.3). CONCLUSION: This study identified several chromosomal regions harboring genes that may contribute to the propensity to be physically active or sedentary.

Adult↗

The human gene map for performance and health-related fitness phenotypes: the 2002 update.

This review presents the 2002 update of the human gene map for physical performance and health-related phenotypes. It is based on peer-reviewed papers published by the end of 2002 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 map. The 2001 map includes 71 loci on the autosomes and two on the X chromosome. In contrast, the 2002 human gene map for physical performance and health-related phenotypes includes 90 gene entries and QTL, plus two on the X chromosome. To all these loci, one must add 14 mitochondrial genes in which sequence variants have been shown to influence relevant fitness and performance phenotypes.

Anthropometry↗

Familial resemblance for muscle phenotypes in the HERITAGE Family Study.

INTRODUCTION/PURPOSE: We hypothesized that skeletal muscle histological and biochemical phenotypes aggregate within families. METHODS: Nineteen families (78 Caucasians) from the HERITAGE Family Study participated in the study. Proportions and areas of Type I, IIA, and IIX muscle fibers, capillary density, and maximal enzyme activities were determined in biopsy samples from the vastus lateralis obtained in the sedentary state and after a 20-wk endurance-training program. RESULTS: In the sedentary state, there was evidence for familial resemblance for Type I fiber area (P = 0.007), number of capillaries around Type I and Type IIA fibers (P = 0.04), and Type I and IIA fiber areas per capillary (P = 0.01 and P = 0.04, respectively). Significant familial aggregation (0.05>P > 0.0001) was observed for maximal activities of enzymes of the energy production pathways. With regard to the training response, significant familial aggregation (0.05 > P < 0.0001) was observed for maximal activities of enzymes of the energy production pathways. CONCLUSION: These data provide evidence of familial aggregation for enzyme activities of the main energy metabolism pathways of the skeletal muscle in the sedentary state and in response to regular exercise.

Adaptation, Physiological↗

Targeting the metabolic syndrome with exercise: evidence from the HERITAGE Family Study.

PURPOSE: To determine the efficacy of exercise training in treating the metabolic syndrome. METHODS: The sample included 621 black and white participants from the HERITAGE Family Study, identified as sedentary and apparently healthy (no chronic disease or injury). The metabolic syndrome was defined as having three or more risk factors according to the guidelines of the National Cholesterol Education Program, including elevated waist circumference, blood pressure, triglycerides, blood glucose, and low HDL cholesterol. The presence of the metabolic syndrome and component risk factors were determined before and after 20 wk of supervised aerobic exercise training. RESULTS: The prevalence of the metabolic syndrome was 16.9% in this sample (105/621) of apparently healthy participants. Of the 105 participants with the metabolic syndrome at baseline, 30.5% (32 participants) were no longer classified as having the metabolic syndrome after the exercise training. Among the 32 participants who improved their metabolic profile, 43% decreased triglycerides, 16% improved HDL cholesterol, 38% decreased blood pressure, 9% improved fasting plasma glucose, and 28% decreased their waist circumference. There were no sex or race differences in the efficacy of exercise in treating the metabolic syndrome: 32.7% of men, 28.0% of women, 29.7% of black, and 30.9% of white participants with the metabolic syndrome were no longer classified as having the syndrome after training. CONCLUSION: Aerobic exercise training in patients with the metabolic syndrome can be useful as a treatment strategy and provides support for a role for physical activity in the prevention of chronic disease.

Adult↗

Heart rate versus %VO2max: age, sex, race, initial fitness, and training response--HERITAGE.

PURPOSE: In the HERITAGE Family Study, heart rate (HR) associated with various percentages of maximal oxygen intake (VO2max) was used to prescribe exercise intensity. When fitness improved, HR at the same power output (PO) decreased, and PO was increased to produce the prescribed HR. Although we assumed that subjects were again working at the same %VO2max, there were no studies with a large heterogeneous population to determine whether this was correct. METHODS: Therefore, 653 subjects with complete data were classified by age, sex, race, initial VO2max, and VO2max response after 20 wk of training. RESULTS: All groups had a significant increase in VO2max and a significant decrease in HR at the same absolute PO after training but no difference in HR at the same relative intensity. CONCLUSIONS: Training does not affect HR at a given %VO2max in a heterogeneous population of men and women, blacks and whites aged 17-65 yr with different initial VO2max values and different responses to training.

Adolescent↗

A quantitative trait locus on 7q31 for the changes in plasma insulin in response to exercise training: the HERITAGE Family Study.

Several genome-wide linkage scans have been carried out to identify quantitative trait loci for type 2 diabetes and related metabolic phenotypes. However, no previous linkage scans have focused on the response to exercise training of relevant metabolic traits. We performed a genome-wide linkage scan for baseline fasting glucose, insulin, and C-peptide and their responses to a 20-week exercise training program in nondiabetic white and black men and women from the HERITAGE Family Study. In SIBPAL linkage analyses, the maximum number of sibpairs available was 344 and 93 for baseline phenotypes and 300 and 72 for exercise training response phenotypes in whites and blacks, respectively. A total of 509 markers with an average spacing of 6.0 Mb were used. The strongest linkage was found for the changes in fasting insulin in response to exercise training with a marker in the leptin gene on 7q31 (empirical multipoint P = 0.0004) in whites. In blacks, the strongest linkage was observed for baseline fasting glucose on 12q13-q14 (empirical multipoint P = 0.0006). These regions harbor several potential candidate genes. The present findings may be important in identifying individuals at increased risk of developing type 2 diabetes and who are most likely to benefit from a physically active lifestyle.

Black People↗

Aging per se does not influence glucose homeostasis: in vivo and in vitro evidence.

OBJECTIVE: To assess the effect of age on glucose metabolism by examining 1) glucose metabolism in young and middle-aged subjects when total or regional adiposity is taken into account and 2) in vitro glucose transport in adipose tissue explants from young and middle-aged women paired for total and abdominal adiposity. RESEARCH DESIGN AND METHODS: Study 1: body composition, subcutaneous abdominal and visceral adipose tissue areas, and fasting and oral glucose-stimulated glucose and insulin were measured in 84 young and 81 middle-aged men and in 110 young and 91 middle-aged women. Study 2: glucose uptake in subcutaneous abdominal and visceral adipose tissue explants were measured in eight young and eight middle-aged women. RESULTS: Study 1: young and middle-aged men showed similar subcutaneous abdominal tissue area, whereas fat mass and visceral adipose tissue were greater in middle-aged than in young men (P < 0.01). Fat mass and subcutaneous and visceral adipose tissue areas were greater in middle-aged as compared with young women (P < 0.01). Fasting plasma glucose and the glucose response to an oral glucose tolerance test were significantly higher in middle-aged than in young men and women (P < 0.001). Statistical control for visceral adipose tissue area eliminated the difference seen in glucose response in men and women. Study 2: glucose transport in subcutaneous and omental adipose tissue did not differ between young and middle-aged women. CONCLUSIONS: 1) Visceral obesity, more than age per se, correlates with glucose intolerance in middle-aged subjects; 2) aging does not influence in vitro adipose tissue glucose uptake.

Abdomen↗

Na+-K+-ATPase alpha 2-gene and skeletal muscle characteristics in response to long-term overfeeding.

The role of Na(+)-K(+)-ATPase alpha2-gene BglII polymorphism in the changes of skeletal muscle metabolic properties after a 100-day overfeeding protocol conducted with 12 pairs of monozygotic twins is reported. The activities of oxoglutarate dehydrogenase (OGDH) and phosphofructokinase (PFK) were determined from muscle biopsies. A larger increase in the total fat mass (127 vs. 61%) (P < 0.05) and low-density lipoprotein cholesterol (20 vs. 0.7%) (P = 0.05) in 8.0/8.0-kb [3.3-kb negative (-); n = 7 pairs] than in 8.0/3.3 + 3.3/3.3-kb [3.3-kb positive (+); n = 5 pairs] subjects was observed. OGDH activity decreased in 3.3-kb(-) (-15%), whereas PFK (+26%) as well as the PFK-to-OGDH ratio (90%) increased. In contrast, among 3.3-kb(+), OGDH increased (+54%) together with a decrease in PFK (-1%) and PFK-to-OGDH ratio (-5%). These changes were significantly different between genotypes (P from <0.05 to 0.01). In conclusion, fat mass, low-density lipoprotein cholesterol, and skeletal muscle glycolytic-to-oxidative enzyme ratio increased more in the alpha2-gene 3.3-kb(-) subjects with overfeeding, suggesting more unfavorable metabolic changes compared with the 3.3-kb(+) subjects.

Adipose Tissue↗

Lack of association between the uncoupling protein-2 Ala55Val gene polymorphism and phenotypic features of the Metabolic Syndrome.

The uncoupling protein (UCP) 2 gene is expressed in adipose tissues and skeletal muscles, which are important sites for variations in energy expenditure. The objective of the current study was to examine the potential impact of a C-->T substitution in exon 4, resulting in an alanine to valine substitution at codon 55, on the Metabolic Syndrome in 284 unrelated Swedish men born in 1944. The subjects were genotyped using PCR amplification of the exon 4 region of the UCP2 gene followed by digestion with the restriction enzyme EclHK1. The allelic frequencies were 0.56 for allele Ala and 0.44 for allele Val. No association was found between the Ala55Val SNP and obesity and blood levels of insulin, glucose, and lipids as well as blood pressure and circulating hormones. From these data, we conclude that the C-->T substitution in exon 4 of the UCP2 gene does not contribute to the predisposition to be affected by the Metabolic Syndrome.

Alanine↗

Genome-wide linkage scan for exercise stroke volume and cardiac output in the HERITAGE Family Study.

A genome-wide linkage scan was performed for genes affecting submaximal exercise cardiac output (Q) and stroke volume (SV) in the sedentary state and their responses to a standardized 20-wk endurance training program. A total of 509 polymorphic markers were used, and 328 pairs of siblings from 99 white nuclear families and 102 sibling pairs from 105 black family units were available. Q and SV were measured in relative steady state during exercise at 50 W (Q50 and SV50, respectively). Baseline phenotypes were adjusted for age, sex, and body surface area (BSA), and the training responses (post-training - baseline, Delta) were adjusted for age, sex, baseline BSA, and baseline value of the phenotype. Three analytical strategies were used: a multipoint variance components linkage analysis using all the family data, and regression-based single- and multipoint linkage analyses using pairs of siblings. In whites, baseline SV50 and DeltaSV50 showed promising linkages (P < 0.0023) with markers on chromosomes 14q31.1 and 10p11.2, respectively. Suggestive evidence of linkage (0.01 > P > 0.0023) for DeltaSV50 and Delta Q50 was detected on chromosome 2q31.1 and for baseline SV50 and Q50 on chromosome 9q32-q33. In blacks, markers on 18q11.2 showed promising linkages with baseline Q50. Suggestive evidence of linkage was found in three regions for baseline SV50 (1p21.3, 3q13.3, 12q13.2) and one for baseline SV50 and Q50 (10p14). All these chromosomal regions include several potential candidate genes and therefore warrant further studies in the HERITAGE cohort and other studies.

Adult↗

Physical exercise and blood pressure with reference to the angiotensinogen M235T polymorphism.

We investigated the role of the angiotensinogen (AGT) gene M235T polymorphism in determining blood pressure (BP) response to moderate intensity exercise in a 6-yr randomized controlled trial in 140 middle-aged men. Sitting, supine, and standing blood pressures were measured annually. Of the randomized men, 86% participated in the trial for 6 yr. Submaximal cardiorespiratory fitness increased by 16% in the exercise group. In the M homozygotes, sitting systolic BP decreased by 1.0 mmHg in the exercise but increased by 14.6 mmHg in the reference group (P = 0.007 for net effect). Sitting and supine diastolic BP decreased by 6.2 and 3.3 mmHg in the exercise but increased by 2.8 and 3.2 mmHg in the reference group (P = 0.026 and 0.024 for net effects), respectively. Regular moderate intensity exercise attenuates aging-related increase in systolic BP and decreases diastolic BP among the M homozygotes of the AGT gene M235T polymorphism.

Aging↗

Polymorphism in exon 4 of the human 3 beta-hydroxysteroid dehydrogenase type I gene (HSD3B1) and blood pressure.

There is growing evidence to the effect that steroid hormones are associated with a complex phenotype of metabolic abnormalities usually referred to as the metabolic syndrome. The 3 beta-hydroxysteroid dehydrogenases/Delta(4,5)-isomerase (3 beta-HSD) is crucial to the biosynthesis of hormonal steroids, including aldosterone, cortisol, and testosterone. The objective of the present study was to examine the potential impact of a T-->C substitution at codon Leu(338) of the type I (HSD3B1) 3 beta-HSD gene on obesity, circulating hormones, and estimates of insulin, glucose, and lipid metabolism as well as blood pressure in 284 unrelated Swedish men born in 1944. The subjects were genotyped by using PCR amplification of exon 4 of the HSD3B1 gene followed by digestion with the restriction enzyme BglII. The frequency of allele T was 0.44 and that of allele C 0.56. Homozygotes for the C allele (n=75) had significantly (P<0.05) higher mean systolic and diastolic blood pressures compared to both heterozygotes (n=143) and homozygotes for the T allele (n=45). In addition, the C allele was significantly (P=0.018) more frequent among subjects with grade 1 hypertension (>140/90 mm Hg) compared to normotensive (<130/85 mm Hg) subjects. These results were all adjusted for the potential confounding effect of body mass index (BMI) and waist-to-hip ratio (WHR). Other measurements such as BMI, WHR, abdominal sagittal diameter, salivary cortisol, total testosterone, serum leptin, fasting insulin and glucose, and serum lipids were not different across the HSD3B1 genotype groups. In conclusion, a T-->C polymorphism at codon Leu(338) of exon 4 of the HSD3B1 gene is associated with elevated systolic and diastolic blood pressures. The pathogenic mechanism underlying this association is, however, uncertain from the present data and further studies are warranted.

3-Hydroxysteroid Dehydrogenases↗