A randomized trial investigating an exercise program to prevent reduction of bone mineral density and impairment of motor performance during treatment for childhood acute lymphoblastic leukemia.

BACKGROUND: Reduced bone mineral density (BMD), altered body composition, impaired motor performance and passive ankle dorsiflexion are side effects of acute lymphoblastic leukemia (ALL) treatment. We performed a randomized study investigating whether an exercise program could prevent these side effects. PROCEDURE: At diagnosis we randomized 51 ALL patients (median age: 5.4 years) into a group receiving a 2-year exercise program or a control group receiving standard care. BMD of total body (BMD(TB)), lumbar spine (BMD(LS)) and body composition were measured using dual energy X-ray absorptiometry, motor performance with Bayley Scales of Infant Development or Movement-ABC, and passive ankle dorsiflexion with a goniometer. The investigator was blinded to the randomization. RESULTS: Body fat increased equally during treatment in both groups. One year after cessation of therapy more rapid decline of excessive body fat was observed in the intervention group than in the controls (P = 0.01). Lean body mass, BMD(TB) and BMD(LS) of both groups decreased equally during treatment and increased equally thereafter. Both groups showed a similar decrease in passive ankle dorsiflexion and motor performance during treatment. Adherence to the intervention program varied considerably. Adherence to intervention: 11% of children exercised daily, 37% > once a week, 16% once weekly, 36% < once a week. CONCLUSIONS: The exercise program was not more beneficial than standard care in preventing reduction in BMD, motor performance and passive ankle dorsiflexion than standard care, most likely due to unsatisfactory compliance. Increased BMI and body fat in the intervention group normalized faster after cessation of chemotherapy.

Relationship between fat patterns, physical fitness and blood pressure of rural South African children: Ellisras Longitudinal Growth and Health Study.

The present study investigated the relationship between blood pressure (BP), fat patterns and fitness parameters of Ellisras children aged 7-13 years. Furthermore, an assessment of body fat patterns was done to determine the subjects with the highest risk of overweight, hypertension and waist-to-hip ratio above the 90th percentile. Data were collected from 1,817 subjects (938 boys and 879 girls), aged 7-13 years, participating in the Ellisras Longitudinal Study. Anthropometric measurements were taken according to the standard procedure of the International Society for the Advancement of Kinanthropometry. The EUROFIT test items were used to test the physical fitness of 1,192 subjects (634 boys and 558 girls). Obesity was defined using the international recommended cutoff points for body mass index (BMI) in children. Hypertension was defined as the occurrence of BP levels greater or equal to the 95th percentile of height- and sex-adjusted reference levels. The prevalence of hypertension ranged from 1 to 11.4% and that of overweight 0.6-4.6%. Waist girth, BMI, triceps and subscapular skinfold showed significant (P<0.001-0.05) correlation with other fat pattern parameters (r ranging from -0.157 to 0.978) compared with significant correlations (P<0.001-0.05) with BP (r ranging from -0.071 to 0.164). Children with waist girth greater than the 90th percentile are more likely to have multiple risk factors than the children with a waist girth that is less than or equal to the 90th percentile. Longitudinal studies should verify whether changes in waist girth and skinfolds will indicate changes in cardiovascular risk factors during growth.

Development and tracking of body mass index from preschool age into adolescence in rural South African children: Ellisras Longitudinal Growth and Health Study.

The purpose of this observational prospective cohort study was to investigate the development and tracking of body mass index (BMI) of Ellisras rural children from preschool age into late adolescence from the Ellisras Longitudinal Growth and Health Study. Heights and weights of children were measured according to the standard procedures recommended by the International Society for the Advancement of Kinanthropometry twice a year from 1996 to 2003. In total, 2,225 children--550 preschool and 1,675 primary school--aged 3-10 years (birth cohorts 1993 to 1986) were enrolled at baseline in 1996 and followed through out the eight-year periodic surveys. In 2003, 1,771 children--489 preschool and 1,282 primary school--were still in the study. The prevalence of overweight was significantly higher among girls (range 1.6-15.5%) compared to boys (range 0.3-4.9%) from age 9.1 years to 14.9 years. The prevalence of thinness (severe, moderate, and mild) ranged from 7.1% to 53.7% for preschool children and from 8.0% to 47.6% for primary school children. Both preschool and primary school children showed a significant association between the first measurements of BMI and the subsequent measurement which ranged from B=0.2 (95% confidence interval [CI] 0.1-0.4) to B=0.8 (95% CI 0.6-0.9) for preschool and B=0.2 (95% CI 0.1-0.3) to B=0.7 (95% CI 0.6-0.8) for primary children. A significant tracking of BMI during 4-12 years of life was more consistent for preschool children (B=0.6 (95% CI 0.6-0.7) and for primary school children (B=0.6 (95% CI 0.5-0.6). Investigation of nutritional intake and physical activity patterns will shed light on how healthy these children are and their lifestyle.

The association of fat patterning with blood pressure in rural South African children: the Ellisras Longitudinal Growth and Health Study.

BACKGROUND: Hypertension is one of the major causes of death in developed and underdeveloped nations. Essential hypertension and obesity may have their inception in childhood, with little data in African children to support these findings. Objectives were to determine the prevalence of overweight and hypertension in rural children in South Africa. Additionally, the association between fat-patterning ratios and blood pressure (BP) was investigated. METHODS: Data were collected from 1884 subjects (967 boys and 917 girls), aged 6-13 years, participating in the Ellisras Longitudinal Study. Height; weight; and triceps, biceps, subscapular, and suprailiac skinfolds were measured according to the protocol of the International Society for the Advancement of Kinanthropometry. Skinfold ratio was used as an indicator of the central pattern of body fat. Internationally recommended cut-off points for body mass index (BMI) were used. Hypertension, defined as the average of three separate BP readings where the systolic BP or diastolic BP is >or=95th percentile for age and sex, was determined. RESULTS: The prevalence of hypertension ranged from 1 to 5.8% for boys and 3.1 to 11.4% for girls, and that of overweight from 1.1 to 2.9% for boys and 0.6 to 4.6% for girls. The association between high systolic BP and high BMI was -3.0, while that for high diastolic BP and high BMI was -0.68. CONCLUSIONS: The prevalence of hypertension is evident from the age 6 years for girls, while that of overweight was low. Overweight became evident from the age 10 to 13 years for both sexes. A significant association between high diastolic BP and high BMI was noted, while children with low BMIs were less likely to be hypertensive. Investigating habitual physical activity, fitness and dietary patterns will shed more light on the association of fat patterning and BP in this population.

Relationship of adiposity and cardiorespiratory fitness with resting blood pressure of South African adolescents: the PAHL Study.

Obesity and low level of cardiorespiratory fitness are associated with high blood pressure in both adolescents and adults. The objective of this study was to assess the relationship of adiposity and cardiorespiratory fitness with resting blood pressure in 14-year-old male and female adolescents. Cross-sectional data on 310 adolescents (31.8% boys) from six high schools, who were participating in the on-going Physical Activity and Health Longitudinal Study, were collected. Height, weight, body mass index (BMI), percentage of body fat, waist circumference, waist-to-height ratio, predicted and resting systolic (SBP) and diastolic blood pressure (DBP) were assessed according to standard procedures. The prevalence of elevated SBP and DBP were 4.9% and 6.5%, respectively. The highest prevalence of elevated blood pressure (SBP=10% and DBP=15%) were measured in overweight adolescents, who also performed poorly for predicted VO(2max)(M=26.66 ml kg(-1 )min(-1)±6.44) compared with underweight and normal-weight adolescents. Multiple regression showed that BMI was positively associated with SBP (ß=0.77, P=0.005) and VO(2max) was negatively associated with DBP (ß=-0.43, P=0.001). Overweight adolescents presented with a relatively high prevalence of elevated blood pressure and poor health-related fitness. Fatness and poor cardiorespiratory fitness were positively associated with elevated SBP and DBP, respectively. In view of the health implications of these findings, strategic interventions are needed to promote obesity-reduction programmes and physical activities in adolescents.

Body composition and physical fitness of undernourished South African rural primary school children.

OBJECTIVE: The purpose of this study was to determine the relationships between the body composition characteristics, body mass index (BMI), sum of skinfolds (SSF), % body fat (%BF), fat-free mass (FFM) and waist-to-hip ratio (WHR), and nine physical fitness items in undernourished rural primary school children in Ellisras, South Africa. DESIGN: A cross-sectional study. SETTING: The study consisted of 462 boys and 393 girls who were aged 7-14 y. MEASUREMENTS: Five body composition measures were assessed: BMI, SSF, %BF, FFM and WHR. Nine physical fitness test items were assessed: standing long jump, bent arm hang, sit-ups, 10 x 5 m shuttle run, 50 m sprint, 1600 m run, flamingo balance, sit and reach, plate tapping. RESULTS: BMI was highly correlated with FFM (r = 0.7, P < 0.001). In line with findings from Western countries, regression coefficients (B) showed that children with higher BMI or SSF performed worse in bent arm hang (girls, B = -0.84, P < 0.001, and B = -0.06, P = 0.02, respectively) and in 1600m run (B = 6.68, P < 0.001). BMI was significantly associated with flamingo balance (B = 0.26, P = 0.04). WHR was positively associated with bent arm hang (B = 9.37, P = 0.03), and inversely with sit and reach (B = -7.48, P = 0.01). In contrast, significant relationships were found between BMI and standing long jump (B = 0.74, P = 0.04), sit and reach (B = 0.51, P < 0.001), flamingo balance (B = 0.26, P = 0.04) and plate tapping (B = -19, P = 0.01). SSF was significantly associated with sit and reach (B = 0.04, P = 0.03). Significant inverse associations were found between FFM and bent arm hang (girls, B = -0.06, P = 0.05), 1600 m run (girls, B = -2.33, P = 0.003) and 50 m run (boys, B = -0.11, P = 0.006). FFM was significantly associated with standing long jump (boys, B = 0.99, P < 0.001; girls, B = 0.73, P < 0.001), flamingo balance (B = 0.17, P < 0.001), and with sit and reach (boys, B = 0.59, P = 0.03). CONCLUSION: In the present study in undernourished children, body composition was significantly related to physical fitness, but not always in the expected direction. It is therefore important to note that in this population, BMI should not be interpreted as a measure of fatness/overweight, but rather as an indicator of muscle mass.

Netherlands research programme weight gain prevention (NHF-NRG): rationale, objectives and strategies.

OBJECTIVE: To outline the rationale, objectives and strategies used in a systematically designed research programmme to study specific weight gain-inducing behaviours, their social-psychological as well as environmental determinants, and the effects of interventions aimed at the prevention of weight gain. DESIGN: The evidence for potential behavioural determinants and strategies to prevent weight gain was reviewed, and the methods applied within the Netherlands Research programme weight gain prevention (NHF-NRG) project were described. The project is designed according to the Intervention Mapping protocol. SETTING: The Netherlands. SUBJECTS: The main target groups are (a) adolescents (12-16 y) in secondary school, (b) young adults (20-40 y) at the workplace and (c) recently retired people (55-65 y) at home. INTERVENTIONS: Each intervention includes an individual component, in which computer-tailored information is provided. Additionally, interventions are aimed at changing environmental components. RESULTS: The short-term results of this project can be expected by the beginning of 2005. Guidelines for nationwide weight gain prevention, based on this research programme, will become available in 2007. CONCLUSIONS: Based on the few interventions that were evaluated to date, no robust conclusions can be drawn regarding the effectiveness of obesity prevention. The systematic and multidisciplinary design of the NHF-NRG programme enables the identification of potentially effective methods and strategies for the prevention of weight gain.

Cross-sectional and longitudinal relationships between alcohol consumption and lipids, blood pressure and body weight indices.

OBJECTIVE: Serum lipids, blood pressure and body mass may mediate the U-shaped relationship of alcohol consumption with type 2 diabetes mellitus and coronary heart disease. This study examines the cross-sectional and long-term longitudinal relationships of (changes in) alcohol consumption with (changes in) serum lipids, blood pressure and body mass indices. METHOD: In this prospective, observational cohort study, two measurements of alcohol consumption, serum total and high-density lipoprotein cholesterol, triglycerides, blood pressure, body weight, the thickness of four skinfolds and waist circumference were performed 4 years apart in healthy volunteers (143 men and 174 women, 32 years old at the first measurement). Alcohol consumption from beer, wine and distilled spirits was assessed using an extensive dietary history interview. Linear regression analyses were performed to study the cross-sectional relationships between the amount of alcohol consumed at the age of 32 years and the levels of the lipids, blood pressure and body weight indices, and to study the longitudinal relationships between the changes in the amount of alcohol consumed over the 4 years of follow-up and the concurrent changes in the lipids, blood pressure and body weight indices. Nonlinearity was investigated for the cross-sectional relationships. RESULTS: A 10-g/day difference in alcohol consumption was positively related with a 0.05 mmol/L (1.9 mg/dl) difference in high-density lipoprotein cholesterol in both cross-sectional (p = .004), and longitudinal (p < .0001) analyses. This relationship did not differ for men and women or for the consumption of beer, wine or distilled spirits. Relationships with changes in total cholesterol, triglycerides, systolic, diastolic, and pulse pressure, body weight and the sum of four skinfolds were not significant. A borderline significant inverse longitudinal relationship was found with waist circumference. The other lifestyle behaviors (tobacco smoking, physical activity and dietary habits) were major confounders of most cross-sectional relationships between alcohol and serum lipids, blood pressure and body mass indices. The longitudinal relationships, however, were not confounded by changes in the other lifestyle behaviors. A significant nonlinear relationship was found for systolic blood pressure, in which drinkers of about 30 g/day had the lowest values. CONCLUSIONS: Moderate alcohol consumption and moderate long-term changes in alcohol consumption are positively related with the levels and changes in high-density lipoprotein cholesterol in healthy adult men and women. A moderate inverse association between alcohol and waist circumference may be expected. No relationships were found with triglycerides, blood pressure, body weight and the sum of the thickness of four skinfolds. Other lifestyle behaviors confound the cross-sectional, but not the longitudinal, relationships between alcohol consumption and serum lipids, blood pressure and body mass indices. Gender and type of beverage do not modify the relationships between alcohol consumption and these indices.

Relationship between physical activity and bone mineral status in young adults: the Northern Ireland Young Hearts Project.

Physical activity during the first three decades of life may increase peak bone mass and reduce future osteoporosis risk. The aim of this study was to determine the extent to which different components of physical activity may influence bone mineral status within a representative population sample of young men and women. Bone mineral density (BMD) and content (BMC) were determined at the lumbar spine and femoral neck in 242 men and 212 women, aged 20-25 years, by dual-energy X-ray absorptiometry. Physical activity was assessed by a self-report questionnaire designed to measure the frequency and duration of physical activity and its components (i.e., work, non-sports leisure, sports-related activities, and peak strain sports activities). Potential confounding factors such as height, weight, diet, and smoking habits were also assessed. In multivariate linear regression models, sports activity and peak strain sports activity undertaken by men were strongly associated with both lumbar spine BMD (beta = 0.35 [0.21, 0.49] and beta = 0.31 [0.17, 0.44], respectively) and BMC (beta = 0.33 [0.21, 0.45] and beta = 0.26 [0.14, 0.38], respectively) and femoral neck BMD (beta = 0.35 [0.21, 0.48] and beta = 0.27 [0.14, 0.40], respectively) and BMC (beta = 0.32 [0.19, 0.44] and beta = 0.29 [0.17, 0.41], respectively) (all p < 0.01), but work and non-sports leisure activities were not. In women, there were no associations between bone measurements and any component of physical activity. In models involving all subjects the gender/sports activity, but not the gender/peak strain, interaction term was statistically significant. Sports activity explained 10.4% of the observed variance in lumbar spine BMD in men, but <1% in women. These results demonstrate the importance of sports activities, especially those involving high peak strain, in determining peak bone status in young men. Failure to observe this association in women reflects their lower participation in such activities, but they may have the same capacity to benefit from these activities as men. Intervention studies are warranted to determine whether peak bone density in women can be improved by participating, during childhood and adolescence, in sports activities involving high peak strain.

Computerization of a dietary history interview in a running cohort; evaluation within the Amsterdam Growth and Health Longitudinal Study.

OBJECTIVE: In nutritional research, a growing interest in the use of computer-assisted cross-check dietary history interview methods exists in order to improve cost-effectiveness. The introduction of such a method in an ongoing longitudinal study was evaluated with special emphasis on the effect on interviewer bias. DESIGN: A study for the interviewer bias within and the agreement between a previously used paper-based face-to-face cross-check dietary history interview method and a newly developed interviewer-administered computer-assisted version of this interview method. SUBJECTS: The interviewer bias of 436 face-to-face interviews is compared with that of 352 computer-assisted interviews. A subset of 82 subjects underwent a face-to-face interview at the mean age of 27 and 32 y and a computer-assisted interview at their mean age of 36 y. Energy, three macronutrients (protein, fat and carbohydrate), two micronutrients (calcium and iron) and alcohol intakes obtained by these three measurements are compared to analyse the agreement between the two interview methods. RESULTS: ANOVA showed no interviewer bias for all seven analysed nutrients within the data from the computer-assisted interview, while for the face-to-face interview method, several nutrients varied significantly among the interviewers. Five different measures, used to analyse the agreement (differences, Pearson's correlation, ICC, square weighted kappa and Bland-Altman plots), showed no relevant differences between the two cross-check dietary history interview methods. CONCLUSIONS: It is concluded that the computer-assisted interview caused a reduction of interviewer bias and is of similar quality to the face-to-face interview method. Computerization of a paper-based interview can be implemented in a running cohort if a change in method is unavoidable.

Physical fitness, body fatness, and physical activity: The Amsterdam Growth and Health Study.

The purpose of this study was to examine sex-specific longitudinal relationships between physical fitness (cardiopulmonary and neuromotor fitness) and body fatness (sum of skinfolds) and to examine the influence of physical activity (weighted activity score) on these relationships. The data were obtained from the Amsterdam Growth and Health Study (AGHS), an observational longitudinal study of 98 females and 83 males, with six repeated measurements over a period from 13 to 27 years of age. The longitudinal relationship between body fatness and physical fitness was analyzed using generalized estimating equations (GEE). For each of the eight fitness items used as outcome variables, standardized regression coefficients were calculated for the relationships with body fatness and for the relationships with physical activity with and without correcting for height and weight. In all analyses, body fatness was inversely related to running speed, standing high jump, leg lift speed, and maximal oxygen uptake. Physical activity was positively related to leg lift speed and maximal oxygen uptake, and only in females to the standing high jump. Thus, body fatness is inversely related to most fitness items, while physical activity is positively related to only several fitness items. Further, body fatness and physical activity are independently related to physical fitness. Am. J. Hum. Biol. 12:593-599, 2000. Copyright 2000 Wiley-Liss, Inc.

The prevention and treatment of overweight and obesity. Summary of the advisory report by the Health Council of The Netherlands.

This article presents the highlights of an advisory report on the prevention and treatment of overweight and obesity. The report, which was produced by the Health Council of The Netherlands, incorporates the most recent developments and projected scientific breakthroughs in this field. The prevalence of overweight and obesity has taken on epidemic proportions. In The Netherlands, as elsewhere, there is a steady rise in the number of individuals suffering from overweight or obesity. Since it is associated with serious health problems, obesity (and to a lesser extent overweight) leads to increased costs for the healthcare system. Food consumption surveys and studies on time trends in physical activity patterns have revealed that the increased prevalence of obesity is due to an increasing lack of exercise, combined with relative overconsumption. A healthy diet (including plenty of fruit, vegetables and cereal products) and at least one hour a day of moderate physical activity are recommended for the maintenance of energy balance and for the prevention of weight gain. While genetic factors play a part in the development of overweight and obesity, environmental factors appear to be of overriding importance. The so-called 'obesogenic environment' prompts individuals to eat more and to take less exercise. There are still no effective intervention strategies for the prevention of weight gain. However, the explosive increase in the prevalence of obesity and of its associated serious medical problems demands a common-sense approach involving preventive interventions, which are based on modern views of health promotion. These interventions require a broad coalition of actors, in which local and national authorities, industry, the healthcare system and the population at risk must each shoulder their own share of responsibility. The primary aim of obesity treatment should be a long-lasting weight loss of about 10%. Even this relatively small weight loss can produce significant health gains. Treatment methods must involve an integrated (lifestyle) approach, dependent on the amount of overweight involved and on the presence of comorbidity. Obesity should be treated chronically and prevention of weight regain must be part of any obesity treatment programme.

Motor fitness in Dutch youth: differences over a 26-year period (1980-2006).

This study aimed to compare neuromotor fitness test scores of 9-12-year-old Dutch youth in 2006 with scores of same aged children in 1980. Body height, body weight and performance on neuromotor fitness test items were measured in 2050 Dutch children from 9 to 12 years in 2006 and were compared with data of 2603 same aged Dutch children measured in 1980 with the same neuromotor fitness test battery. Dutch 9-12 year olds in 2006 were significantly taller and heavier than their peers in 1980. Age- and sex-specific performance on almost all neuromotor fitness test items was significantly worse in 2006. Thus, our data suggest that neuromotor fitness of Dutch youth has significantly decreased over the past 26 years.

Somatotype and blood pressure of rural South African children aged 6-13 years: Ellisras longitudinal growth and health study.

BACKGROUND: Physique has been useful in assessing the outcome of underlying growth and maturity processes, which leads to a better understanding of variation in child and adult health. However, a high endomorphy rating has been associated with hypertension in adults, posing a serious threat to their health status, while receiving little attention in children. AIM: The study examined the association between somatotypes, body mass index (BMI) and blood pressure (BP) in 6-13-year-old rural children, in Ellisras, South Africa. SUBJECTS: A total of 1902 subjects (980 boys and 922 girls) aged 6-13 years were studied as part of the Ellisras Longitudinal Study. Height, weight, four skinfold sites, two breadths, and two girths were measured according to the International Society for the Advancement of Kinanthropometry (ISAK). The Heath-Carter method of somatotyping was used, together with internationally recommended cut-off points for BMI in children. Hypertension, defined as the average of three separate BP readings, where the systolic or diastolic BP is greater than or equal to the 95th percentile for age and sex, was determined. RESULTS: The prevalence of hypertension ranges from 1 to 5.8% in boys and 3.4-11.4% in girls. The prevalence of overweight ranges from 1.1 to 2.9% in boys and 0.6-4.6% in girls. Systolic BP and BMI showed a significant positive correlation at age 6 years (r = 0.436) and 10-13 years (r = 0.180-0.246 in boys and r = 0.221-0.271 in girls). Diastolic BP showed an insignificant correlation with the BMI and somatotype components in boys and girls. CONCLUSION: A significant association exists between BP and BMI, and ectomorphy components even after being adjusted for age, gender and height. The need to manage hypertensive individuals is evident in this sample to combat this chronic disease from an early age. Follow-up studies should investigate the relationship between BP and the dietary intake of these children.

Longitudinal follow-up of fitness during childhood: interaction with physical activity.

Health-related fitness values during childhood (from age 11 to 16 years) were analyzed in relation to changes in physical activity level. One hundred fifty-eight children were monitored over a 4-year period. Twice a year, they performed six physical fitness tests: standing broad jump, 10 x 5-meter shuttle run, sit-and-reach, handgrip, number of sit-ups in 30 s, and 20-m shuttle run. Height was measured four times per year to assess age at peak height velocity. Physical activity was assessed with a self-administered questionnaire at baseline and at the end of the follow-up. The physical activity level was defined by the frequency and the time spent in moderate-to-vigorous physical activities. Two groups were constituted: regularly active and sedentary. A multiple linear multilevel regression analysis was used to analyze the longitudinal relationships between changes in physical activity and physical fitness levels. Corrections were made for both time-dependent (time) and time-independent (sex) variables. Except for flexibility, boys' fitness performances increased more than that for the girls. Positive and significant (P < 0.05) regression coefficients were found with the regularly active for standing broad jump, 20-m shuttle run, number of sit-ups, 10 x 5-m shuttle run in both sexes, and for the girls' sit-and-reach performance. Increasing or decreasing physical activity level was not associated with changes in fitness performances over time, except for flexibility for the girls and the 20-m shuttle run for the boys. From childhood to adolescence, increasing physical activity is not sufficient to be more fit. The children who are stayed the most active were the fittest, particularly the girls. Am. J. Hum. Biol. 18:51-58, 2006. (c) 2005 Wiley-Liss, Inc.

Maximal oxygen uptake during cycling is reduced in moving environments; consequences for motion-induced fatigue.

In previous studies on physical fatigue during simulated ship movements, the apparent exhaustion of subjects after experimentation suggested that the traditional index of physical workload, oxygen consumption expressed as the percentage of peak oxygen consumption (VO2-peak) measured in a separate graded exercise test (GXT), underestimates workload in a moving environment. In these studies, the GXT was carried out in a stationary environment, as is standard practice. To explain the underestimation, it was hypothesized that VO2-peak might have been less if the GXT had been carried out in the moving environment. This paper reports on three experimental tests of this hypothesis, performed with a ship motion simulator and aboard a ship at sea. In all three experiments, VO2-peak was indeed significantly reduced when the GXT was carried out in the moving environment. Theoretical reasons for this phenomenon are discussed and investigated, but a clear explanation is still lacking.

The relationship between physical fitness and physical activity during adolescence and cardiovascular disease risk factors at adult age. The Amsterdam Growth and Health Longitudinal Study.

The purpose of this study was to analyse the relationship between physical activity and physical fitness during adolescence (between 13 and 16 years of age) and cardiovascular disease (CVD) risk factors at adult age (32 years). The following CVD risk factors were considered: lipoprotein levels (total serum cholesterol (TC), high density lipoprotein cholesterol (HDL), the TC:HDL ratio, systolic and diastolic blood pressure, and indicators for body fatness and body fat distribution (sum of four skinfolds, waist to hip ratio, waist circumference). The data were derived from the Amsterdam Growth and Health Longitudinal Study, an observational longitudinal study in which eight repeated measurements were carried out over a period of 20 years. Physical fitness (measured by maximal oxygen uptake per kg bodyweight and by maximal slope reached on a treadmill test) during adolescence was related to a healthy CVD risk profile at the age of 32 years (i. e. inversely to the sum of four skinfolds, waist circumference and to total serum cholesterol). Physical activity during adolescence was not related to a healthy CVD risk profile at the age of 32 years.

The influence of climatic factors on non-specific back and neck-shoulder disease.

An epidemiological study was carried out to explore the relationship between climatic factors and non-specific low-back and neck-shoulder symptoms in working populations. In a review of published literature, 27 studies were found which related climatic factors to musculoskeletal symptoms, but none of these studies specifically addressed the subject. It can be concluded that a relationship between climatic factors and musculoskeletal symptoms is considered at least plausible by both researchers, workers and patients, but that the epidemiological evidence appearing from literature is very weak. Questionnaire data which were collected on musculoskeletal symptoms, workload and perceptions of climatic conditions of 2030 workers in 24 different occupations were analysed multi-variately. About one-quarter of the workers related symptoms of the low back and neck-shoulders to climatic factors. They perceived climatic factors in most cases as aggravating factors for their symptoms. No seasonal influence on prevalence rates was reported. For low-back and neck-shoulder symptoms and for sick leave due to neck-shoulder symptoms, an association was found with climatic factors, and in particular with respect to draughts in relation to neck-shoulder symptoms. In addition, neck-shoulder symptoms were negatively related to frequent outdoor work. The findings suggest a relationship between climatic factors and musculoskeletal symptoms and call for further detailed investigations.

Current and adolescent levels of cardiopulmonary fitness are related to large artery properties at age 36: the Amsterdam Growth and Health Longitudinal Study.

BACKGROUND: High levels of cardiopulmonary fitness (VO2max) are associated with reduced risk of cardiovascular morbidity and mortality, but little is known to what extent this is related to the effects of cardiopulmonary fitness on atherosclerosis and arterial stiffness. Moreover, the time course of these relationships needs to be elucidated. We sought to investigate (i) the cross-sectional relationship between VO2max and carotid atherosclerosis and carotid and femoral arterial stiffness at age 36, as well as (ii) the relationship between VO2max during adolescence (13-16 years) and the same arterial properties at age 36 (prospective analyses). DESIGN: Cross-sectional analyses consisted of 351 subjects (183 women) and the prospective analyses of a subpopulation of 154 subjects (79 girls). Arterial properties were assessed noninvasively by ultrasound imaging; VO2max was measured with a maximal running text on a treadmill with direct measurements of oxygen uptake. RESULTS: After adjustment for confounding by other known risk factors, current and adolescent levels of VO2max were independently associated with carotid intima-media thickness (beta = -0.288, P = 0.004 and beta = -0.381, P = 0.012) in men, and with the diameter of the femoral artery (beta = 0.375, P < 0.001 and beta = 0.252, P = 0.026, respectively) in both sexes. Current levels of VO2max were positively associated with the compliance of the carotid and the femoral arteries (beta = 0.186, P = 0.023 and beta = 0.183, P = 0.033, respectively), and with the distensibility of the carotid (beta = 0.162, P = 0.047) but not the femoral artery. CONCLUSION: We conclude that cardiopulmonary fitness is associated with large artery properties at age 36, and that the roots of this association may already be present in adolescence.

Effects of health information in youth and young adulthood on risk factors for chronic diseases--20-year study results from the Amsterdam Growth and Health Longitudinal Study.

In the Amsterdam Growth and Health Longitudinal Study (AGAHLS) biological risk factors for chronic diseases were measured on eight separate occasions over a period of 20 years in a group of apparently healthy males and females (n = 164). Data were first collected from participants at 13 years of age. At each of the eight measurements, a medical checkup was performed and participants were given information about their current health status based on their personal biological risk factor profile (cholesterol, blood pressure, body composition, and physical fitness). A comparable group (n = 113) was measured on two occasions only: at age 13 and again at age 33. It was hypothesized that the group with eight measurements would present a more favorable 20-year development of the risk factors than the group with only two measurements. In the present article the six additional measurements with personal feedback of one's health status were perceived as an "intervention," even though the AGAHLS never intended to improve the lifestyle or health of its subjects. The intervention appeared to have had a positive effect on body fat distribution and, in men, on systolic blood pressure. However, it was expected that these significant results were not true effects of the intervention, but that they were type-I errors. For the other variables, total cholesterol, high-density lipoprotein cholesterol, and the ratio between these two, for the sum of four skinfolds, diastolic blood pressure, neuromotor fitness, and for maximal oxygen uptake, the 20-year development did not differ between the two groups. Thus, the effects of a 20-year health measurement and information intervention begun in youth on biologic risk factors for chronic diseases were limited. The absence of clear significant findings may be due to the low contrast between the two groups, as only six intervention measurements were conducted over a period of 20 years. Another reason may be that the young and relatively healthy population under study here was not amenable to changing their fitness and health.