The 12-year prediction of physical activity level and submaximal aerobic fitness observed during young adulthood was quantified from childhood and parental measures. The sample consisted of 153 children and adolescents of the Quebec Family Study who were evaluated at baseline and reassessed 12 years later, as young adults. Physical work capacity at a heart rate of 150 beats x min(-1) (PWC150) was measured using cycle ergometry. A 3-day activity record was used to estimate daily energy expenditure (DEE), inactive time (IA), and time spent in moderate-to-vigorous activity (MVPA). Spearman partial inter-age correlations, controlling for length of follow-up and age at baseline, indicated better tracking for PWC150 (0.24 and 0.46, males and females, respectively) than for indicators of physical activity (0.07 < or = r < or = 0.25, males; 0.06 < or = r < or = 0.22, females). Multiple regression analyses indicated that parental measurements of activity and PWC150 did not add any predictive value, with the exception of paternal DEE, which accounted for 8% of the variance in males. There is moderately high stability of submaximal work capacity and lower tracking of physical activity from childhood and adolescence into young adulthood.

Adolescent↗

PubMedDate not supplied

Familial risk of high blood pressure in the Canadian population.

Familial risk ratios for high blood pressure were estimated in a representative sample of the Canadian population. The sample consisted of 14,069 participants 7-69 years of age from 5,753 families participating in the 1981 Canada Fitness Survey. Resting systolic (SBP) and diastolic (DBP) blood pressures were adjusted for the effects of body mass index using regression procedures. Varying degrees of high blood pressure were defined as the 75(th), 85(th), and 95(th) percentiles of age- and sex-specific values. Age- and sex-standardized risk ratios (SRRs) were calculated comparing the prevalences in the general population to those in spouses and first-degree relatives of probands with high blood pressure. SRRs for the 95(th) percentile were, for SBP and DBP, respectively, 1.37 and 1.45 in spouses and 1.33 and 2.36 in first-degree relatives of probands. SRRs decrease with decreasing percentile cut-offs used to define high blood pressure (95(th) > 85(th) > 75(th)), and SRRs are generally higher in first-degree relatives than in spouses, particularly for DBP. The results indicate significant familial risk for high blood pressure in the Canadian population, and the pattern of SRRs suggests that genetic factors may be responsible for a portion of the risk.

Adolescent↗

PubMedDate not supplied

Population differences in the pattern of familial aggregation for sex hormone-binding globulin and its response to exercise training: the HERITAGE Family Study.

Familial influences were investigated for baseline sex hormone-binding globulin (SHBG) and its response (post-training minus baseline) to a 20-week endurance exercise training program. One hundred, eighty-four participants from 85 Black families in the HERITAGE Family Study (HERITAGE) were analyzed using a familial correlation model. Baseline SHBG values and the training response were adjusted for the effects of age, baseline BMI, testosterone, estradiol, and fasting insulin levels (plus baseline SHBG values for the training response) within four sex-by-generation groups prior to genetic analysis. Baseline SHBG levels were influenced by appreciable familial effects (maximum heritability h(2) = 54%) with neither spouse resemblance nor sex and generation differences in the correlations. This estimate is only slightly, but not significantly, smaller than the heritability of 64% reported previously in 428 participants from 99 White families in HERITAGE. In contrast to the modest familial effects for the training response in White participants in HERITAGE (h(2) = 25%), there were no evidence of familial resemblance in Blacks in the current study. Furthermore, there was heterogeneity for both baseline SHBG and the training response between Blacks and Whites in the pattern of familial aggregation. In conclusion, baseline SHBG levels are influenced by significant familial effects in both Blacks and Whites, independent of the effects of age, sex, and baseline values of BMI, testosterone, estradiol, and fasting insulin levels. Whereas modest familial effects were detected for the training response in Whites, the lack of similar effects in Blacks may be due to the smaller sample size.

Black People↗

PubMedDate not supplied

Evidence of major genes for plasma HDL, LDL cholesterol and triglyceride levels at baseline and in response to 20 weeks of endurance training: the HERITAGE Family Study.

This study assessed major gene effects for baseline HDL-C, LDL-C, TG, and their training responses (post-training minus baseline) in 527 individuals from 99 White families and 326 individuals from 113 Black families in the HERITAGE Family Study. The baseline phenotypes were adjusted for the effects of age and BMI, and the training response phenotypes were adjusted for the effects of age, BMI, and their respective baseline values, within each of the sex-by-generation-by-race groups, prior to genetic analyses. In Whites, we found that LDL-C at baseline and HDL-C training response were under influence of major recessive genes (accounting for 2--30 % of the variance) and multifactorial (polygenic and familial environmental) effects. Interactions of these major genes with sex, age, and BMI were tested, and found to be nonsignificant. In Blacks, we found that baseline HDL-C was influenced by a major dominant gene without a multifactorial component. This major gene effect accounted for 45 % of the variance, and exhibited no significant genotype-specific interactions with age, sex, and BMI. Evidence of major genes for the remaining phenotypes at baseline and in response to endurance training were not found in both races, though some were influenced by major effects that did not follow Mendelian expectations or were with ambiguous transmission from parents to offspring. In summary, major gene effects that influence baseline plasma HDL-C and LDL-C levels as well as changes in HDL-C levels in response to regular exercise were detected in the current study.

Adaptation, Physiological↗

PubMedDate not supplied

Familial resemblance for physique: heritabilities for somatotype components.

PRIMARY OBJECTIVE: To examine familial resemblance in the Heath-Carter anthropometric somatotype in a sample of 328 participants from 103 nuclear families in Northern Ontario (Canada). METHODS AND PROCEDURES: The three somatotype components (endomorphy, mesomorphy, ectomorphy) were subjected to principal components analysis and the resulting first principal component (PCI) was used as an additional index of physique. The four phenotypes were adjusted for age, sex and generation effects, while each of the three somatotype components was further adjusted for the effects of the other two components using regression procedures. A familial correlation model was fit to the data and used to estimate the degree of familial resemblance in somatotype. MAIN OUTCOME AND RESULTS: For all somatotype variables, the most parsimonious model was one in which there was no spouse resemblance and no sex or generation effects in the familial correlations. Maximal heritabilities were 56%, 68%, 56% and 64% for endomorphy, mesomorphy, ectomorphy and PCI, respectively, indicating significant familial resemblance for the Heath-Carter anthropometric somatotype. Further, the pattern of familial correlations suggests the role of genetic factors in explaining variation in human physique. CONCLUSIONS: In general, a pattern of no spouse but significant parent-child correlations implicates the role of genes on human physique, provided that mating is random with regard to these traits.

Adolescent↗

PubMedDate not supplied

Transient environmental effects detected in sibling correlations.

Detection of environmental effects in sibling correlation is difficult. Mueller (1978) has proposed that transient environmental effects should be associated with a decrease in the sibling correlation with increasing age difference between members of a pair of adult sibs. The present report suggests that an environmental effect can also be detected by partialing out environmental indicators from correlations between sibs measured at the same chronological age. Correlations for 12 variables were computed between 208 pairs of 10-year-old French-Canadian sibs from Montreal. Partialing out seven socio-economic indicators from these correlations resulted in significant changes for three skeletal measurements as well as for body weight and triceps skinfold. These results differ from those reported earlier. The proposed method may be sufficiently sensitive to detect environmental effects, provided simple assumptions are met.

Anthropometry↗

PubMedDate not supplied

Familial resemblance in fatness indicators.

Family resemblance in fatness has been studied in 481 individuals from 114 families of French descent living in the greater Quebec city area. Subjects were measured for the following fatness indicators: triceps, biceps, subscapular, suprailiac, abdominal and medial calf skinfolds. The sum of these six skinfolds as well as a prediction of percent body fat (Durnin and Rahaman 1967) were also considered. Data were standardized for appropriate age and sex classes yielding SS scores. The influence of relevant lifestyle variables (energy intake, energy expenditure and socioeconomic status) were statistically removed from SS yeilding residual scores (RS) that were then submitted to familial analyses. Analyses of variance indicate that there is a larger between family variation than within (P less than or equal to 0.01) for SS when considering either the whole nuclear family or sibships; in these instances, the intra-class correlation ranges from 0.15 to 0.26. There was, however, no significant resemblance among spouses for the SS fatness indicators. Similar values were essentially found for RS fatness indicators. Furthermore, husband-wife inter-class correlations were not significant with the exception of subscapular and calf skinfold RS. Covariations between biological relatives are however significant (0.16 less than or equal to r less than or equal to 0.24, P less than or equal to 0.01) for SS and remain essentially unchanged after statistical control over the lifestyle variables (0.16 less than or equal to r less than or equal to 0.40, P less than or equal to 0.01). The findings that spouses do not covary significantly in fatness, while biological relatives of traditional nuclear families exhibit a significant degree of resemblance even after statistical control over daily energy intake, daily energy expenditure and socioeconomic status provide evidence supporting the hypothesis that there is a substantial genetic effect in human fatness.

Adolescent↗

PubMedDate not supplied

Submaximal power output in adopted and biological siblings.

Submaximal power output was determined in relative steady state on a bicycle ergometer at a heart rate of 150 beats per minute (PWC150). PWC150 was measured in 880 individuals, 9 to 26 years of age, belonging to 46 sibships of adopted sibs, 66 sibships of unrelated individuals including adoptees, 33 sibships of first-degree cousins, 225 sibships of biological sibs, 56 sibships of DZ twins and 54 sibships of MZ twins. PWC150, PWC150/kg of body weight, PWC150/kg lean body mass, PWC150/cm of height and PWC150/m2 of body surface area were submitted to analysis of variance and correlation analysis after statistical control over age and sex of subjects. Few significant resemblances were found in PWC measurements for adoptive siblings, unrelated sibs and cousins. Sibling resemblance was, however, significant for the sibships of biological sibs, and of DZ and MZ twins. Interclass correlations reached significance only in pairs of biological brothers and sisters, and in pairs of DZ and MZ twins. Estimates of total genetic effect in PWC150/kg in a population of free-living children, adolescents and young adults vary from 0.30 to 0.48. It is concluded that submaximal power output is only moderately affected by the genotype.

Adolescent↗

PubMedDate not supplied

Genetic and environmental sources of variation in physical fitness.

The technique of path analysis was used to assess inherited and environmental variance components in physical fitness indicators measured in 1630 subjects from 375 families of French descent living in the greater Québec city area. For that purpose, submaximal power output (PWC150/kg), muscular endurance, muscular strength, reaction time and movement time were evaluated during a visit of the family to the laboratory. Inter-class correlations in various types of relatives were computed from scores adjusted for linear and non-linear effects of age and sex by a regression procedure (Y = age + sex + (age X sex) + age2). Correlations were then used in the path analytic BETA model which allows the partition of transmissible variance (t2) into genetic (h2) and cultural (b2) components. Results indicated that t2 accounted for 18% (movement time) to 63% (muscular strength) of the phenotypic variance. The contribution of genetic factors was found to be negligible for PWC150/kg and movement time, and accounted for about 20% of the phenotypic variance for reaction time and muscular endurance and 30% for muscular strength, while non-transmissible variance (1 - t2) accounted for 37% (muscular strength) to 82% (movement time) of the phenotypic variance. These results suggest that biological variation observed in the physical fitness level of a healthy population is mainly associated with non-transmissible environment factors and that the contribution of heredity is moderate and clearly lower than previously reported.

Adolescent↗

PubMedDate not supplied

Physique and echocardiographic dimensions in children, adolescents and young adults.

Relationships between echocardiographic dimensions and the Heath-Carter anthropometric somatotype were considered in healthy, non-obese children (8-11 year olds, n = 143), adolescents (12 15 year olds, n = 216) and young adults (16-24 years, n = 190). Cardiac dimensions, measured by M-mode echocardiography at end-diastole, included left ventricular internal diameter (LVIDd), posterior wall thickness (PWTd), and interventricular posterior wall thickness (STd). Left ventricular mass (LVM) and left ventricular end-diastolic volume (LVEDV) were estimated. Partial correlations between cardiac dimensions and each somatotype component were calculated, controlling for age and the other two components. Only 9 out of 45 correlations in males and 7 of 45 correlations in females were significant (p < or = 0.05). LVM, LVEDV, and LVIDd were significantly related to somatotype in males, demonstrating significant positive correlations with mesomorphy (r = 0.25, 0.29 and 0.29, respectively) and ectomorphy (r = 0.22. 0.37, and 0.37, respectively), and LVEDV and LVIDd were related to endomorphy (r = 0.24 and 0.25, respectively) in 8-11 year old boys. In 8-11 year old females, endomorphy was related to STd (r = 0.41) and LVM (r = 0.34), while mesomorphy was related to PWTd (r = -0.34) and ectomorphy was related to PWTd (r = -0.36). In 12-15 year old females, mesomorphy was related to STd (r = 0.26) and in 16-24 year old females, endomorphy was related to LVIDd (r = 0.29) and LVEDV (r = 0.32). Overall, the correlations between somatotype and cardiac dimensions were low, ranging from -0.36 to +0.41, with no clear pattern in either sex. Additionally, a backward stepwise regression analysis indicated that body size was more important in predicting echocardiographic dimensions than somatotype. Thus, physique, as estimated with the Heath-Carter anthropometric somatotype, is not related to echocardiographic dimensions in children, youths and young adults.

Adolescent↗

PubMedDate not supplied

Cytologic predictors of cervical intraepithelial neoplasia in women with an ASCUS Pap smear.

OBJECTIVE: To identify cytologic parameters on Pap smears of women with an atypical squamous cells of undetermined significance (ASCUS) diagnosis that could help cytologists to indicate whether a particular ASCUS case is most likely related to cervical intraepithelial neoplasia (CIN) grade 1 or 2/3. STUDY DESIGN: A total of 360 eligible women diagnosed with ASCUS and referred to the colposcopy clinic of Saint-Sacrement Hospital participated in the study. Eligible women were those aged 18-50 years, newly diagnosed with ASCUS, with no history of cervical biopsies or treatment, and not pregnant at the time of the visit. Colposcopically directed biopsies of lesions were obtained. All Pap smears were reviewed according to 36 different cytomorphologic criteria. The regression logistic model was used to estimate the odds ratios (ORs) for the associations between cytologic criteria observed in smears and the diagnosis of CIN made on biopsies. All cytologic criteria significantly (P < .05) associated with CIN were entered in the models, and a backward selection was done to determine independent cytologic predictors of CIN 1 and 2/3. RESULTS: Biopsies revealed that 22.2% of the study population had concurrent CIN. CIN I and 2/3 were identified in 61 (16.9%) and 19 women (5.3%), respectively. Clear perinuclear spaces (OR = 2.5, P = .002) and moderate nuclear atypia (OR = 4.4, P = .02) were two cytologic criteria independently associated with CIN 1. Four independent predictors of CIN 2/3 were identified: the presence of clear perinuclear spaces (OR = 5.9, P = .004), hyperchromasia (OR = 3.9, P = .04), moderate anisokaryosis (OR = 13.1, P = .01 and increased nuclear volume of metaplastic cells (OR = 5.1, P = .007). CONCLUSION: These observations may help cytologists to better categorize ASCUS lesions as intraepithelial ones and will also contribute to improving the Bethesda definition of ASCUS. Further studies are planned to validate these observations.

Adolescent↗

PubMedDate not supplied

Regional distribution of body fat, plasma lipoproteins, and cardiovascular disease.

Several epidemiological studies have reported that the regional distribution of body fat is a significant and independent risk factor for cardiovascular disease (CVD) and related mortality. Although these associations are well established, the causal mechanisms are not fully understood. Numerous studies have, however, shown that specific topographic features of adipose tissue are associated with metabolic complications that are considered as risk factors for CVD such as insulin resistance, hyperinsulinemia, glucose intolerance and type II diabetes mellitus, hypertension, and changes in the concentration of plasma lipids and lipoproteins. The present article summarizes the evidence on the metabolic correlates of body fat distribution. Potential mechanisms for the association between body fat distribution, metabolic complications, and CVD are reviewed, with an emphasis on plasma lipoprotein levels and plasma lipid transport. From the evidence available, it seems likely that subjects with visceral obesity represent the subgroup of obese individuals with the highest risk for CVD. Although body fat distribution is now considered as a more significant risk factor for CVD and related death rate than obesity per se, further research is clearly needed to identify the determinants of body fat distribution and the causal mechanisms involved in the metabolic alterations. It appears certain, however, that an altered plasma lipid transport is a significant component of the relation between body fat distribution and CVD.

Abdomen↗

PubMedDate not supplied

Heredity and changes in plasma lipids and lipoproteins after short-term exercise training in men.

The aims of this controlled experiment were to investigate the effects of short-term aerobic exercise training on plasma lipid and lipoprotein concentrations and the role of heredity in determining the individual variation observed in the lipoprotein-lipid response. Six pairs of male monozygotic (MZ) twins were subjected to an exercise training program that induced a 22,000 kcal energy deficit after 22 consecutive days of training. This program significantly reduced body weight, percent body fat, and subcutaneous fat and significantly increased maximal oxygen consumption (VO2max) (p less than 0.005). The plasma insulin response to an oral glucose challenge was markedly reduced after training (p less than 0.001). Plasma triglyceride concentration decreased and the high density lipoprotein cholesterol (HDL-CHOL)/CHOL ratio increased with training (p less than 0.05). Subjects also displayed substantial individual variation in their response to exercise training, but the changes in plasma CHOL, apolipoprotein (apo) B low density lipoprotein cholesterol (LDL-CHOL), HDL-CHOL, and the HDL-CHOL/CHOL ratio tended to be similar within MZ twin pairs (0.67 less than or equal to ri less than or equal to 0.92; 0.05 greater than p less than 0.0001) thus indicating a significant effect of heredity on the sensitivity of plasma lipids and lipoproteins to exercise training.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗