Publications

The objective of this study was to determine the relative contributions of physical activity and physical fitness to the coronary heart disease (CHD) risk factor profile. The sample consisted of 253 males and 226 females 30–59 y of age from the Québec Family Study. The sum of six skinfolds, submaximal work capacity (PWC150), quadriceps muscle strength and the number of sit-ups performed in 60 seconds were used as indicators of physical fitness. Estimates of physical activity, including daily energy expenditure, moderate-to-vigorous physical activity, and time spent watching television were derived from a three-day activity record. The risk factor profile consisted of fasting HDL-C, LDL-C, triglycerides, glycemia, and mean arterial blood pressure. Bivariate correlations between physical activity and physical fitness variables and each component of the CHD risk profile were low to moderate. Canonical correlation was used to determine the multivariate association among physical activity, physical fitness and the risk factor profile. Canonical correlations reveal that in men 23.0% (r = 0.48, p < 0.0001) of the variation in the CHD risk profile was accounted for by physical fitness, and 6.5% (r = 0.26, p = 0.12) by physical activity. In women 22.9% (r = 0.48, p < 0.0001) and 7.9% (r = 0.28, p = 0.053) of the variance in the CHD risk profile was accounted for by physical fitness and physical activity, respectively. Thus, the results suggest that physical fitness is more related to the CHD risk factor profile than physical activity in both men and women. The difference in the strength of the relationships could potentially be explained by differences in measurement error, as physical fitness is typically more accurately measured than physical activity. Further research should be aimed at ascertaining the best predictors of the CHD risk profile, using more precise measures of physical activity and other lifestyle components. The Québec Family Study is currently supported by the Medical Research Council of Canada.

Background The small, dense LDL phenotype is associated with an increased cardiovascular disease risk. A genome-wide scan performed on 236 nuclear families of the Quebec Family Study (QFS) revealed a quantitative trait locus (QTL) affecting LDL peak particle size (LDL-PPD) and density on the 17q21 region. This region contains the phosphatidylcholine transfer protein gene (PCTP). In the liver, phosphatidylcholine transfer protein binds specifically phosphatidylcholine suggesting a role for this protein in the formation of HDL and possibly VLDL phospholipid membranes. Objectives To test the association between two coding polymorphisms (c.29A>C (Glu10Ala) and c.188G>A (Cys63Tyr)) in PCTP gene and the LDL-PPD. Methods LDL-PPD was measured by non-denaturating 2–16% polyacrylamide gradient gel electrophoresis on 623 QFS subjects. Results After adjustment for age and sex, carriers of the c.29C allele showed larger LDL-PPD than A/A homozygotes (p <0.05). These results remained significant when LDL-PPD was further adjusted for the effects of BMI and triglyceride levels (p <0.04). We also observed a three-fold lower risk of having the small (LDL-PPD <256Å), dense LDL phenotype in subjects carrying the c.29C allele, when compared to A/A homozygotes (OR=0.35 (95% CI: 0.14–0.91; p =0.03)). Conclusion PCTP gene variants are associated with LDL-PPD.

The purposes of this study were 1) to describe a maximal aerobic capacity (MAC) test and 2) to report on its reliability. Thirty subjects (16 males and 14 females) were tested for maximal aerobic power (MAP) with a progressive bicycle ergometer test and the ventilatory anaerobic threshold (VANT) was determined. MAC was measured as the amount of work that could be performed in 90 min on a bicycle ergometer at an intensity set individually from VANT. Subjects were asked to perform as much work as possible during this non-stop 90 min period. For females and males respectively, MAP reached 42.9 +/- 5.9 (mean +/- SD) and 56.0 +/- 4.7 ml O2/kg X min-1 (p less than .01), VANT 36.3 +/- 6.1 and 46.0 +/- 5.2 ml O2/kg X min-1 (p less than .01), max HR 198 +/- 8 and 195 +/- 9 (p greater than .05) and HR at VANT 187 +/- 9 and 180 +/- 10 (p greater than .05). The same subjects were tested twice for MAC within 7 days. Results expressed in kJ/kg reached 10.6 +/- 2.1 and 10.8 +/- 2.4 for females, 14.7 +/- 2.1 and 14.9 +/- 2.2 for males. Mean HR maintained during MAC were 174 +/- 11 and 174 +/- 9 for females and 169 +/- 10 and 170 +/- 10 for males. There was a non significant difference between means (p greater than .05) of the first and second test in total work performed in kJ/kg. This difference reached about 2% of the first test score, 32.7% of this difference occurring in the first 10 min.(ABSTRACT TRUNCATED AT 250 WORDS)

The present study investigated the interaction of genotype and short-term overfeeding on adipose tissue metabolism of six pairs of male monozygotic twins. The sedentary nonobese twins were submitted to a 22-day overfeeding period in which their normal daily intake was supplemented by an additional 1,000 kcal/day. A fat tissue biopsy was performed in the suprailiac region before and after overfeeding to determine fat cell diameter and basal and maximal stimulated epinephrine, norepinephrine, and isoproterenol lipolysis from collagenase-isolated fat cells. Fat cell basal and maximal insulin-stimulated glucose conversion into triglycerides (basal and stimulated lipogenesis) were measured using [14C]glucose. Adipose tissue heparin-releasable lipoprotein lipase activity (LPL) was also determined. A repeated measures analysis of variance revealed overfeeding induced significant elevations in basal lipogenesis (P less than 0.05) and fat cell diameter (P less than 0.05). No significant group changes were noted in basal, epinephrine-, norepinephrine-, and isoproterenol-stimulated lipolysis, insulin-stimulated lipogenesis, and LPL activity due to large individual variation in the response to overfeeding. However, significant intrapair resemblance was noted in the changes of the aforementioned variables, suggesting a coherent within-twin pair response, despite large between-pair variation in response. Less within-pair similarity was noted in changes in basal lipogenesis and fat cell diameter. The results of the present study suggest that overfeeding induced a large range of adipose tissue metabolic responses and that the genotype plays a role in determining the sensitivity of adipose tissue adaptation to caloric affluence.

This update of the human gene map for physical performance and health-related fitness phenotypes covers the research advances reported in 2006 and 2007. The genes and markers with evidence of association or linkage with a performance or a fitness phenotype in sedentary or active people, in responses to acute exercise, or for training-induced adaptations are positioned on the map of all autosomes and sex chromosomes. Negative studies are reviewed, but a gene or a locus must be supported by at least one positive study before being inserted on the map. A brief discussion on the nature of the evidence and on what to look for in assessing human genetic studies of relevance to fitness and performance is offered in the introduction, followed by a review of all studies published in 2006 and 2007. The findings from these new studies are added to the appropriate tables that are designed to serve as the cumulative summary of all publications with positive genetic associations available to date for a given phenotype and study design. The fitness and performance map now includes 214 autosomal gene entries and quantitative trait loci plus seven others on the X chromosome. Moreover, there are 18 mitochondrial genes that have been shown to influence fitness and performance phenotypes. Thus,the map is growing in complexity. Although the map is exhaustive for currently published accounts of genes and exercise associations and linkages, there are undoubtedly many more gene-exercise interaction effects that have not even been considered thus far. Finally, it should be appreciated that most studies reported to date are based on small sample sizes and cannot therefore provide definitive evidence that DNA sequence variants in a given gene are reliably associated with human variation in fitness and performance traits.

Background: Sequence variation at chromosome 9p21.3 accounts for 20% of myocardial infarctions (MIs) in several populations. Whereas the risk conferred by the 9p21.3 locus appears to act independen...

The purpose of this study was to examine the relationship between theα 2 (exon 1 and exon 21–22 with BglII) and β1 (MspI and PvuII) genes of the sodium potassium adenosine triphosphatase and resting metabolic rate (RMR) and respiratory quotient (RQ). The sample included 582 participants from 171 families of the Québec Family Study. RMR and RQ were adjusted for age, sex, fat mass, and fat free mass. Sib-pair analyses indicated a significant linkage between RQ and theα 2 exon 1 marker (P = 0.03) and the α2 exon 21–22 marker (P = 0.02). No linkage was detected between the β1 markers and either RMR or RQ, whereas RMR was not linked with the α2 makers. There was a significant interaction (P < 0.0003) between α2 exon 1 carrier status and age group [younger (<45 yr) vs. older (≥45 yr) adults] for RQ. The association between carrier status and RQ was significant in younger adults (RQ = 0.76 in carriers vs. 0.80 in noncarriers, P < 0.0001) but was not in older adults (RQ = 0.81 in carriers vs. 0.80 in noncarriers). The α2 exon 1 gene accounted for approximately 9.1% and 0.3% of the variance in RQ in younger and older adults, respectively. The results suggest that the sodium potassium adenosine triphosphatase α2 gene may play a role in fuel oxidation, particularly in younger individuals.

In order to quantify genetic and environmental determinants of physical activity level, 1,610 subjects from 375 families who lived in the greater Québec city area completed a three-day activity record in 1978-1981. Level of habitual physical activity, which includes all the usual activities of life, and exercise participation, which includes activities requiring at least five times the resting oxygen consumption and more, were derived from this record. Familial correlations were computed in several pairs of biologic relatives and relatives by adoption after adjustment for the effects of age, sex, physical fitness, body mass index, and socioeconomic status, and analyzed with a model of path analysis that allows the separation of the transmissible effect between generations (t2) into genetic (h2) and cultural (b2) components of inheritance. The transmission was found to be statistically significant, but was accounted for by genetic factors for level of habitual physical activity (t2 = h2 = 29%), and by cultural factors for exercise participation (t2 = b2 = 12%). Although non-transmissible environmental factors remain the major determinants of these two physical activity indicators in this population, the results suggest that children can acquire from their parents certain customs regarding exercise behavior and that the propensity toward being spontaneously active could be partly influenced by the genotype.

The aim of this study was to investigate the potential interaction between the lipoprotein lipase (LPL) Hin dIII polymorphism and visceral adipose tissue (AT) accumulation in the modulation of triglyceride levels in visceral obesity. The LPL- Hin dIII genotype was determined by polymerase chain reaction in 52 men. Twenty-three subjects were heterozygous (+/−) and 28 were homozygous (+/+) for the presence of the restriction site. One subject who was homozygous for the − allele was excluded from analysis. Body mass index (BMI), fasting insulin level, and visceral AT area as measured by computed tomography were positively correlated with triglyceride levels only in subjects homozygous for the + allele. Furthermore, whereas these variables were negatively correlated with plasma HDL 2 cholesterol concentrations in the +/+ group, these associations were not found in +/− heterozygotes, with the exception of BMI. To further investigate the interaction of the LPL- Hin dIII polymorphism with visceral obesity and hyperinsulinemia, the two genotype groups were further subdivided on the basis of BMI (low versus high), fasting insulin level (low versus high), and visceral AT area (low versus high), and their lipoprotein profiles were compared. Elevated levels of abdominal visceral AT were significantly associated with increased triglyceride concentrations in +/+ homozygous men, suggesting that visceral obesity may lead to hypertriglyceridemia in the presence of the +/+ genotype. In the +/− group, variation in the amount of visceral AT was not associated with differences in triglyceride concentration. However, hypertriglyceridemia and an increased cholesterol-to–HDL cholesterol ratio were observed in the hyperinsulinemic state irrespective of LPL- Hin dIII genotype status. Finally, similar positive correlations were observed between visceral AT accumulation and plasma insulin level in the homozygous (+/+) and heterozygous (+/−) groups, suggesting that the hyperinsulinemic–insulin-resistant state that is frequently associated with visceral obesity is independent of LPL- Hin dIII genotype. These results suggest that the Hin dIII polymorphism may modulate the magnitude of the dyslipidemic state associated with visceral obesity.

Despite numerous attempts to discover genetic variants associated with elite athletic performance, injury predisposition, and elite/world-class athletic status, there has been limited progress to date. Past reliance on candidate gene studies predominantly focusing on genotyping a limited number of single nucleotide polymorphisms or the insertion/deletion variants in small, often heterogeneous cohorts (i.e., made up of athletes of quite different sport specialties) have not generated the kind of results that could offer solid opportunities to bridge the gap between basic research in exercise sciences and deliverables in biomedicine. A retrospective view of genetic association studies with complex disease traits indicates that transition to hypothesis-free genome-wide approaches will be more fruitful. In studies of complex disease, it is well recognized that the magnitude of genetic association is often smaller than initially anticipated, and, as such, large sample sizes are required to identify the gene effects robustly. A symposium was held in Athens and on the Greek island of Santorini from 14–17 May 2015 to review the main findings in exercise genetics and genomics and to explore promising trends and possibilities. The symposium also offered a forum for the development of a position stand (the Santorini Declaration). Among the participants, many were involved in ongoing collaborative studies (e.g., ELITE, GAMES, Gene SMART, GENESIS, and POWERGENE). A consensus emerged among participants that it would be advantageous to bring together all current studies and those recently launched into one new large collaborative initiative, which was subsequently named the Athlome Project Consortium.