Biomedical subjects

Han C G Kemper

Publications and source records attributed to Han C G Kemper.

24 records · Page 2Linked to original sources

PubMed2003

A longitudinal study on smoking in relationship to fitness and heart rate response.

PURPOSE: Smoking has been shown to be associated with impaired cardiovascular fitness and reduced heart rate response to exercise. It is not known whether these associations are present in adolescence and young adults, and whether they change over time. METHODS: Maximal oxygen uptake ([OV0312]O(2max)), maximum treadmill slope (Slope(max)), resting heart rate (HR(rest)), heart rate at submaximal exercise (HR(submax)), heart rate reserve (HRR), and maximum heart rate (HR(max)) were measured one to nine times between ages 13 and 36 in 298 male and 334 female participants of the Amsterdam Growth and Health Longitudinal Study. Generalized estimating equation analyses were used to study the longitudinal relationship between smoking and cardiovascular fitness and heart rate response to exercise, whereas linear regression analyses were used to study the reversibility of smoking effects at age 36. RESULTS: Moderate to heavy smoking (>/=10 g of tobacco per day) was longitudinally and negatively related to [OV0312]O(2max), Slope(max), HR(submax), and HR(max). With increasing age, the negative relationship between smoking and [OV0312]O(2max), Slope(max), and HR(max) became stronger in males. Cross-sectional analyses suggested that the adverse effects of smoking were reversible in 36-yr-old males. CONCLUSION: Cardiovascular fitness and heart rate response to exercise are already reduced in young healthy smokers. In men, the adverse effects of smoking become stronger with increasing age but appear to be reversible at age 36.

Adolescent↗

PubMed2003

Longitudinal changes in .VO2max: associations with carotid IMT and arterial stiffness.

PURPOSE: High levels of cardiorespiratory fitness (.VO2max) are associated with reduced risk of cardiovascular morbidity and mortality. However, little is known to what extent longitudinal changes in .VO2max affect arterial wall thickness and stiffness, i.e., two major risk factors for cardiovascular disease. We therefore investigated the relationship between changes in .VO2max from adolescence (13-16 yr) to adulthood (age 36) and from young adulthood (21-32 yr) to age 36, and carotid intima-media thickness (IMT) and stiffness of the carotid, femoral, and brachial arteries, at age 36. METHODS: Analyses of changes in .VO2max from adolescence to age 36 consisted of 154 subjects (79 women), and from young adulthood to age 36 consisted of a subpopulation of 118 subjects (62 women). Throughout the years, .VO2max was measured directly with a maximal running test on a treadmill. When the subjects had the mean age of 36, carotid IMT and large artery stiffness (distensibility and compliance coefficients) were assessed noninvasively by ultrasound imaging methods. RESULTS: Longitudinal changes in .VO2max were not significantly associated with carotid IMT. Changes in .VO2max were inversely and significantly associated with large artery stiffness. These associations were not uniform throughout the arterial tree, being stronger and independent of changes in other risk factors in the muscular (brachial and femoral) arteries but dependent on and possibly mediated by concomitant changes in HDL cholesterol and body weight in the elastic carotid artery. CONCLUSION: Increases in .VO2max that occur from adolescence up to age 36 are associated with less arterial stiffness. Improving .VO2max by increasing physical activity levels may therefore contribute to a reduction in mortality from cardiovascular disease through decreasing arterial stiffness.

Adolescent↗

PubMed2003

Ten-year longitudinal relationship between physical activity and lumbar bone mass in (young) adults.

Little is known about the influence of long-term daily physical activity (PA) on lumbar bone mass after peak bone mass has been reached, that is, during [young] adulthood. The purpose of this study was to investigate the longitudinal relationship between PA and lumbar bone mineral density (LBMD) in healthy subjects over a 10-year period. The data reported here relate to 225 male and 241 female participants in the Amsterdam Growth and Health Longitudinal Study, who were measured at the mean ages of 27, 32, and/or 36. LBMD, habitual daily PA, total body weight, and calcium intake were assessed at each measurement point. The effects of two aspects of PA were analyzed: the mechanical (MECHPA; sum of all ground reaction forces) and metabolic (METPA; weighted metabolic score of intensity, frequency, and duration) components, each within a separate model. Multilevel analysis was used to investigate the relationship between PA and LBMD over the 10-year period. Gender, total body weight, and calcium intake were included in the analysis as covariates. The results indicated that MECHPA was a significant positive linear predictor of LBMD for males (r = 0.09; p < 0.001) but not for females. For the METPA, no linear longitudinal relationship with LBMD was found. The results suggest that there is a metabolic threshold at which extra PA becomes "deleterious" and METPA in its totality becomes ineffective for LBMD. It is concluded that during the (young) adult period, between 27 and 36 years of age, PA causing mechanical loading on the skeleton has a small positive influence on LBMD in males.

Adult↗

PubMed2002

Validation of a physical activity questionnaire to measure the effect of mechanical strain on bone mass.

Most of the questionnaires available to estimate the daily physical activity levels of humans are based on measuring the intensity of these activities as multiples of resting metabolic rate (METs). Metabolic intensity of physical activities is the most important component for evaluating effects on cardiopulmonary fitness. However, animal studies have indicated that for effects on bone mass the intensity in terms of energy expenditure (metabolic component) of physical activities is less important than the intensity of mechanical strain in terms of the forces by the skeletal muscles and/or the ground reaction forces. The physical activity questionnaire (PAQ) used in the Amsterdam Growth and Health Longitudinal Study (AGAHLS) was applied to investigate the long-term effects of habitual physical activity patterns during youth on health and fitness in later adulthood. The PAQ estimates both the metabolic components of physical activities (METPA) and the mechanical components of physical activities (MECHPA). Longitudinal measurements of METPA and MECHPA were made in a young population of males and females ranging in age from 13 to 32 years. This enabled evaluation of the differential effects of physical activities during adolescence (13-16 years), young adulthood (21-28 years), and the total period of 15 years (age 13-28 years) on bone mineral density (BMD) of the lumbar spine, as measured by dual-energy X-ray absorptiometry (DXA) in males (n = 139) and females (n = 163) at a mean age of 32 years. The PAQ used in the AGAHLS during adolescence (13-16 years) and young adulthood (21-28 years) has the ability to measure the physical activity patterns of both genders, which are important for the development of bone mass at the adult age. MECHPA is more important than METPA. The highest coefficient of 0.33 (p < 0.01) was between MECHPA measured over the total period of 15 years (13-28 years) and lumbar BMD at age 32 years. Only during adolescence (12-16 years) was METPA more important with regard to lumbar BMD at age 32 years, with a beta of 0.21 (p < 0.01). The relative validity of the PAQ was established by comparing PAQ scores during four annual measurements in 200 boys and girls with two other objective measures of physical activity: movement counters (pedometers) and heart rate monitoring. These showed significant (p < 0.01) correlations in both genders, varying between 0.16 and 0.20. The small variation indicates, however, that all three instruments measure different aspects of physical activity. The results from the PAQ, with respect to MECHPA, validated in humans the results from animal studies in which bone adaptation during skeletal growth and development continuously adjust skeletal mass and architecture to changing mechanical stimuli caused by physical activity.

Absorptiometry, Photon↗

PubMed2002

Concurrent validity of alcohol consumption measurement in a 'healthy' population; quantity-frequency questionnaire v. dietary history interview.

Self-reports of alcohol consumption account for approximately 50 % of the reported sales of alcohol. In the absence of a gold standard, it is not known how accurately different methods of measurement reflect actual consumption and whether under-reporting varies among different populations. The objective of the present study was to compare the consumption reported by the widely used quantity-frequency questionnaire (QFQ) with that reported in a cross-check dietary history interview (DHI), which has higher face validity. In 171 male and 197 female subjects of the Amsterdam Growth and Health Longitudinal Study (mean age 36 years), alcohol consumption was assessed by both the QFQ and the DHI. Most subjects reported a moderate consumption of alcohol by both measures. Spearman correlation coefficients were high (0.77 and 0.87 in men and women respectively). Overall, greater alcohol consumption was reported using the DHI. The difference between the DHI and QFQ reports was usually greater for wine than for beer. Backward stepwise regression analysis showed that the difference in reporting was positively related to a more irregular drinking pattern, and in wine drinkers to the square of the QFQ report. Sex, drinking alone or with others and the CAGE (acronym for four questions on drinking behaviour) score were not related to the difference in reporting. The precision of DHI estimation from QFQ reports and other factors was low. Serious questions arise as to the validity and precision of alcohol consumption measurements based on the QFQ alone. QFQ information may be improved by incorporating questions on the type of beverage and drinking patterns.

Adult↗

PubMedDate not supplied

Effects of health information in youth on adult physical activity: 20-year study results from the Amsterdam growth and health longitudinal study.

In the Amsterdam Growth and Health Longitudinal Study (AGAHLS), a group of apparently healthy males and females (n = 200) were interviewed about their physical activities on eight separate occasions over a period of 20 years between 13 and 33 years of age (multi-measured group: MM). Information about their health was given based on their personally measured lifestyle (activity, diet, smoking) and biological risk characteristics for chronic diseases (medical check-ups). A comparable group of boys and girls (n = 200) was only measured on two occasions (bi-measured group: BM): at 13 and 33 years. Physical activity was estimated with a structured interview. Total physical activity and sports activity were estimated in three intensity levels (light, moderate, and heavy). It was hypothesized that the eight repeated medical check-ups with health information in the MM group would result in a healthier lifestyle with respect to the determinants and levels of habitual physical activity compared to the BM group. Contrary to the hypothesis, males and females in the BM group showed a significantly higher increase or a lower decrease in physical activities compared to the MM group. This negative effect on the physical activity pattern at 33 years in the MM group may have been caused by more underreporting of physical activities than in the BM group. In conclusion, there does not appear to be a significant effect of long-term (multi-measured) health information with medical check-ups during adolescence and young adulthood on level of physical activity in males and females at 33 years of age.

Adolescent↗