Psychological distress leads to reduced physical activity and fitness in children: the Australian longitudinal LOOK study.

Stress and depression can affect an individual's level of physical activity and fitness, which may place them at risk of developing cardiovascular disease. This study investigates the longitudinal effects of stress and depression on physical activity and cardiorespiratory fitness among youth. Six hundred and seventy-six children, initially aged 8 years, from the LOOK study completed a modified version of the Children's Depression Inventory, the Children's Stress Questionnaire, and objective physical activity and cardiorespiratory fitness assessments on three occasions, every 4 years. Depressive symptoms had a direct effect (longitudinal) on the cardiorespiratory fitness of girls, with a similar trend for boys. In cross-sectional analyses, a child who identified with more symptoms of depression and stress was likely to be less fit and less physically active, which in girls extended to less moderate-to-vigorous physical activity. Our findings, that both physical activity and fitness are impacted by depression and stress may contribute to strategies directed towards achieving enhanced physical activity and reductions in obesity.

Interactions between plasma homocysteine and arterial stiffness in chronic kidney disease in community-dwelling individuals: The Maine-Syracuse Study.

Plasma homocysteine (tHcy) is associated with kidney disease. However, few, if any, studies have examined homocysteine in relation to arterial stiffness, with stratification by the presence or absence of early-stage chronic kidney disease (CKD). The aim of this study was to examine prospective associations between tHcy and carotid-femoral pulse wave velocity (PWV) in persons with and without early-stage CKD in a sample of community-living individuals free from end-stage renal disease, dialysis, stroke and dementia. We conducted a prospective study with 498 participants of the Maine-Syracuse Longitudinal Study (mean age 61 years). Levels of tHcy were positively related to PWV measured 4-5 years later for participants with early-stage CKD (estimated glomerular filtration rate <60 ml min(-1) per 1.73 m(2)). Statistical adjustment was made for multiple confounders, including demographic factors, PWV-related variables and cardiovascular risk factors (b=4.27, 95% confidence interval: 0.23-8.31, P=0.04). These associations were not observed in persons free from CKD. Plasma tHcy is an important predictor of arterial stiffness, as indexed by PWV, in community-living individuals with modest CKD.

'Aussie normals': an a priori study to develop clinical chemistry reference intervals in a healthy Australian population.

Development of reference intervals is difficult, time consuming, expensive and beyond the scope of most laboratories. The Aussie Normals study is a direct a priori study to determine reference intervals in healthy Australian adults. All volunteers completed a health and lifestyle questionnaire and exclusion was based on conditions such as pregnancy, diabetes, renal or cardiovascular disease. Up to 91 biochemical analyses were undertaken on a variety of analytical platforms using serum samples collected from 1856 volunteers. We report on our findings for 40 of these analytes and two calculated parameters performed on the Abbott ARCHITECTci8200/ci16200 analysers. Not all samples were analysed for all assays due to volume requirements or assay/instrument availability. Results with elevated interference indices and those deemed unsuitable after clinical evaluation were removed from the database. Reference intervals were partitioned based on the method of Harris and Boyd into three scenarios, combined gender, males and females and age and gender. We have performed a detailed reference interval study on a healthy Australian population considering the effects of sex, age and body mass. These reference intervals may be adapted to other manufacturer's analytical methods using method transference.

Waiting a few extra minutes before measuring blood pressure has potentially important clinical and research ramifications.

Office blood pressure (BP) is recommended to be measured after 5 min of seated rest, but it may decrease for 10 min of seated rest. This study aimed to determine the change (and its clinical relevance) in brachial and central BP from 5 to 10 min of seated rest. Office brachial and central BP (measured after 5 and 10 min), left ventricular (LV) mass index, 7-day home and ambulatory BP were measured in 250 participants with treated hypertension. Office brachial and central BP were significantly lower at 10-min compared with 5-min BP (P<0.001). Seven-day home systolic BP (SBP) was significantly lower than office SBP measured at 5 min (P<0.001), but was similar to office SBP at 10 min (P=0.511). From 5 to 10 min, the percentage of participants with controlled BP increased and the percentage of participants with high central pulse pressure (PP) decreased (P<0.001). Moreover, brachial and central PP were significantly correlated with LV mass index measured at 10 min (r=0.171, P=0.006 and r=0.139, P=0.027, respectively), but not at 5 min (r=0.115, P=0.068 and r=0.084, P=0.185, respectively). BP recorded after 10 min is more representative of true BP control. These findings have relevance to appropriate diagnosis of hypertension and design of clinical trials.

Temporal divergence of percent body fat and body mass index in pre-teenage children: the LOOK longitudinal study.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: The index of body mass related to stature, (body mass index, BMI, kgm(-2) ), is widely used as a proxy for percent body fat (%BF) in cross-sectional and longitudinal investigations. BMI does not distinguish between lean and fat mass and in children, the cross-sectional relationship between %BF and BMI changes with age and sex. WHAT THIS STUDY ADDS: While BMI increases linearly with age from age 8 to 12 years in both boys and girls, %BF plateaus off between 10 and 12 years. Repeated measures in children show a systematic decrease in %BF for any given BMI from age 8 to 10 to 12 years. Because changes in BMI misrepresent changes in %BF, its use as a proxy of %BF should be avoided in longitudinal studies in this age group. BACKGROUND: Body mass index (BMI, kgm(-2) ) is commonly used as an indicator of pediatric adiposity, but with its inability to distinguish changes in lean and fat mass, its use in longitudinal studies of children requires careful consideration. OBJECTIVE: To investigate the suitability of BMI as a surrogate of percent body fat (%BF) in pediatric longitudinal investigations. METHODS: In this longitudinal study, healthy Australian children (256 girls and 278 boys) were measured at ages 8.0 (standard deviation 0.3), 10.0 and 12.0 years for height, weight and percent body fat (%BF) by dual-energy X-ray absorptiometry. RESULTS: The patterns of change in the means of %BF and BMI were different (P < 0.001). While mean BMI increased linearly from 8 to 12 years of age, %BF did not change between 10 and 12 years. Relationships between %BF and BMI in boys and girls were curvilinear and varied with age (P < 0.001) and gender (P < 0.001); any given BMI corresponding with a lower %BF as a child became older. CONCLUSION: Considering the divergence of temporal patterns of %BF and BMI between 10 and 12 years of age, employment of BMI as a proxy for %BF in absolute or age and sex standardized forms in pediatric longitudinal investigations is problematical.

Benefits of early development of eye-hand coordination: evidence from the LOOK longitudinal study.

We investigated longitudinal and cross-sectional relationships between eye-hand coordination (EHC) and cardiorespiratory fitness (multistage run), physical activity (pedometers), percent body fat (%BF, dual energy x-ray absorptiometry), body image, and organized sport participation (questionnaires) in 406 boys and 384 girls at 8 and 10 years of age. EHC was measured by a throw and wall-rebound catch test involving 40 attempts of increasing difficulty. Median EHC improved during two years from 18 to 32 (boys) and 9 to 24 (girls), and gender differences and improvements were both significant (P < 0.001). Cross-sectional analyses showed that boys and girls with better EHC were fitter (P < 0.001), and a longitudinal relationship showed that girls who improved their EHC over the two years became fitter (P < 0.001). There was also evidence that children with better EHC possessed a more positive body image (P = 0.05 for combined sex data), but there was no evidence of any relationships between EHC and %BF or PA (both P > 0.3). Finally, even at age 8 years, boys and girls participating in organized sport possessed better EHC than non-participants. These data provide evidence for the premise that early acquisition of this single motor skill promotes the development of a child's fitness, body image, and participation in sport.

NTproBNP concentrations in healthy children.

INTRODUCTION: There have been limited studies generating BNP and NT-proBNP reference intervals for paediatric populations. We prospectively assessed NT-proBNP levels in a cohort of 854 healthy school children from the Lifestyle of Our Kids (LOOK) prospective longitudinal study. MATERIALS AND METHODS: NT-proBNP analysis was performed on 172 girls and 212 boys with average age 8.1 years, 183 girls and 181 boys, average age 10.1 years and 183 girls and 180 boys with average age 11.9 years. Data were stratified according to age and gender with the median, range of results and 2.5th and 97.5th percentiles calculated RESULTS: There were no significant differences between males and females at any of the 3 study ages. Significant differences were seen between the 8 and 12 year-olds, 10 and 12 year-olds and the 8 and 12 year-old boys. DISCUSSION: Our study demonstrated that NT-proBNP concentrations in healthy children progressively decline between ages 8 and 12 years. Our selection of unambiguously healthy children produced similar median but lower 97.5th percentile NT-proBNP concentrations to previously published studies.

Characteristics of left ventricular diastolic dysfunction in the community: an echocardiographic survey.

OBJECTIVE: To determine the prevalence and predictors of left ventricular (LV) diastolic dysfunction in older adults. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional survey of 1275 randomly selected residents of Canberra, aged 60 to 86 years (mean age 69.4; 50% men), conducted between February 2002 and June 2003. MAIN OUTCOME MEASURES: Prevalence of LV diastolic dysfunction as characterised by comprehensive Doppler echocardiography. RESULTS: The prevalence of any diastolic dysfunction was 34.7% (95% CI 32.1% to 37.4%) and that of moderate to severe diastolic dysfunction was 7.3% (95% CI 5.9% to 8.9%). Of subjects with moderate to severe diastolic dysfunction, 77.4% had an LV ejection fraction (EF) > 50% and 76.3% were in a preclinical stage of disease. Predictors of diastolic dysfunction were higher age (p < 0.0001), reduced EF (p < 0.0001), obesity (p < 0.0001) and a history of hypertension (p < 0.0001), diabetes (p = 0.02) and myocardial infarction (p = 0.003). Moderate to severe diastolic dysfunction with normal EF, although predominantly preclinical, was independently associated with increased LV mass (p < 0.0001), left atrial volume (p < 0.0001), and circulating amino-terminal pro-B-type natriuretic peptide concentrations (p < 0.0001), and with decreased quality of life (p < 0.005). CONCLUSION: Diastolic dysfunction is common in the community and often unaccompanied by overt congestive heart failure. Despite the lack of symptoms, advanced diastolic dysfunction with normal EF is associated with reduced quality of life and structural abnormalities that reflect increased cardiovascular risk.