Low and high birth weight as risk factors for obesity among 4 to 5 year old Australian children : does gender matter?

Studies testing whether birth weight and childhood obesity differ by gender are lacking. We aimed to describe the relationship between birth weight and childhood overweight/obesity and investigate the influence that gender has on this relationship among 4 to 5-year-old children. We performed a secondary analysis of an Australian nationally representative cross-sectional study in 4 to 5-year-old children. The main outcome measure was child overweight and obesity. We found that low birth weight (LBW) was associated with lower risk of overweight/obesity among girls at 4–5 years before (OR 0.50, 95%CI 0.32, 0.77) and after adjusting for socio-demographic factors (OR 0.51 95%CI 0.33, 0.80) and ethnicity (OR 0.52, 95%CI 0.33, 0.81) but was not associated with child overweight/obesity among boys before or after adjustment. High birth weight (HBW) was associated with a higher risk of overweight/obesity among both girls (adjusted OR: 1.76, 95%CI 1.12, 2.78) and boys (adjusted OR: 2.42 95% CI 2.06, 2.86). Conclusion: There are gender differences in the association of birth weight with child overweight/obesity. HBW was associated with a higher risk of child overweight/obesity in boys and girls before and after adjustment for socio-demographic factors. However, LBW was associated with a lower risk of child overweight/obesity in girls but not in boys. These gender differences need to be considered when planning interventions to reduce child overweight/obesity.

Relationship of weaning weight to the mature liveweight of cashmere does on Australian farms

Median weaning weight and its relationship with the median mature liveweight of does was quantified for four commercial Australian cashmere farms in various parts of Australia. Individual liveweights, of does of all ages at the time of weaning in December, ranged from 9 to 61 kg. Individual farm means of adult does (>1 year old) ranged from 24.6 to 38.8 kg. The model for the logarithm of liveweight was: log₁₀(liveweight) = a + br ^{(Age + 0.6);} where a, b and r are parameters that are different for each farm. The result that the r parameter differs with farm was statistically significant (P = 9.4 10^-6). The percentage variance accounted for was 84.4% and the residual standard deviation was 0.042. Farms differed greatly in the median mature liveweight with some farms reaching ~44 kg and others only 31 kg. Median weaning weight was 14.1 kg (range 11.4-16.8 kg). Median weaning weight as a percentage of median mature doe liveweight on a particular farm varied from 32 to 42%. These weaning weights appear low in absolute and relative terms and thus are likely to incur production penalties.

Increased energy intake entirely accounts for increase in body weight in women but not in men in the UK between 1986 and 2000

There is debate over the casual factors for the rise in body weight in the UK. The present study investigates whether increases between 1986 and 2000 for men and women were a result of increases in mean total energy intake, decreases in mean physical activity levels or both. Estimates of mean total energy intake in 1986 and 2000 were derived from food availability data adjusted for wastage. Estimates of mean body weight for adults aged 19–64 years were derived from nationally representative dietary surveys conducted in 1986–7 and 2000–1. Predicted body weight in 1986 and 2000 was calculated using an equation relating body weight to total energy intake and sex. Differences in predicted mean body weight and actual mean body weight between the two time points were compared. Monte Carlo simulation methods were used to assess the stability of the estimates. The predicted increase in mean body weight due to changes in total energy intake between 1986 and 2000 was 4·7 (95 % credible interval 4·2, 5·3) kg for men and 6·4 (95 % credible interval 5·9, 7·1) kg for women. Actual mean body weight increased by 7·7 kg for men and 5·4 kg for women between the two time points. We conclude that increases in mean total energy intake are sufficient to explain the increase in mean body weight for women between 1986 and 2000, but for men, the increase in mean body weight is likely to be due to a combination of increased total energy intake and reduced physical activity levels.

Continuity of midwifery care and gestational weight gain in obese women : a randomised controlled trial

Background: The increased prevalence of obesity in pregnant women in Australia and other developed countries is a significant public health concern. Obese women are at increased risk of serious perinatal complications and guidelines recommend weight gain restriction and additional care. There is limited evidence to support the effectiveness of dietary and physical activity lifestyle interventions in preventing adverse perinatal outcomes and new strategies need to be evaluated. The primary aim of this project is to evaluate the effect of continuity of midwifery care on restricting gestational weight gain in obese women to the recommended range. The secondary aims of the study are to assess the impact of continuity of midwifery care on: women’s experience of pregnancy care; women’s satisfaction with care and a range of psychological factors.
Methods/Design: A two arm randomised controlled trial (RCT) will be conducted with primigravid women recruited from maternity services in Victoria, Australia. Participants will be primigravid women, with a BMI≥30 who are less than 17 weeks gestation. Women allocated to the intervention arm will be cared for in a midwifery continuity of care model and receive an informational leaflet on managing weight gain in pregnancy. Women allocated to the control group will receive routine care in addition to the same informational leaflet. Weight gain during pregnancy, standards of care, medical and obstetric information will be extracted from medical records. Data collected at recruitment (self administered survey) and at 36 weeks by postal survey will include sociodemographic information and the use of validated scales to measure secondary outcomes.
Discussion: Continuity of midwifery care models are well aligned with current Victorian, Australian and many international government policies on maternity care. Increasingly, midwifery continuity models of care are being introduced in low risk maternity care, and information on their application in high risk populations is required. There is an identified need to trial alternative antenatal interventions to reduce perinatal risk factors for women who are obese and the findings from this project may have application in other maternity services. In addition this study will inform a larger trial that will focus on birth and postnatal outcomes.

Targeted exercise against osteoporosis : a systematic review and meta-analysis for optimising bone strength throughout life

Background
Exercise is widely recommended to reduce osteoporosis, falls and related fragility fractures, but its effect on whole bone strength has remained inconclusive. The primary purpose of this systematic review and meta-analysis was to evaluate the effects of long-term supervised exercise (≥6 months) on estimates of lower-extremity bone strength from childhood to older age.

Methods
We searched four databases (PubMed, Sport Discus, Physical Education Index, and Embase) up to October 2009 and included 10 randomised controlled trials (RCTs) that assessed the effects of exercise training on whole bone strength. We analysed the results by age groups (childhood, adolescence, and young and older adulthood) and compared the changes to habitually active or sedentary controls. To calculate standardized mean differences (SMD; effect size), we used the follow-up values of bone strength measures adjusted for baseline bone values. An inverse variance-weighted random-effects model was used to pool the results across studies.

Results
Our quality analysis revealed that exercise regimens were heterogeneous; some trials were short in duration and small in sample size, and the weekly training doses varied considerably between trials. We found a small and significant exercise effect among pre- and early pubertal boys [SMD, effect size, 0.17 (95% CI, 0.02-0.32)], but not among pubertal girls [-0.01 (-0.18 to 0.17)], adolescent boys [0.10 (-0.75 to 0.95)], adolescent girls [0.21 (-0.53 to 0.97)], premenopausal women [0.00 (-0.43 to 0.44)] or postmenopausal women [0.00 (-0.15 to 0.15)]. Evidence based on per-protocol analyses of individual trials in children and adolescents indicated that programmes incorporating regular weight-bearing exercise can result in 1% to8% improvements in bone strength at the loaded skeletal sites. In premenopausal women with high exercise compliance, improvements ranging from 0.5% to 2.5% have been reported.

Conclusions
The findings from our meta-analysis of RCTs indicate that exercise can significantly enhance bone strength at loaded sites in children but not in adults. Since few RCTs were conducted to investigate exercise effects on bone strength, there is still a need for further well-designed, long-term RCTs with adequate sample sizes to quantify the effects of exercise on whole bone strength and its structural determinants throughout life.

Associations between parental concern for adolescent weight and the home food environment and dietary intake

Objective: Examine associations between parental concern about adolescent weight and adolescent perceptions of their dietary intake, home food availability, family mealtime environment, and parents' feeding practices.

Design: Cross-sectional study.

Setting: Adolescents, aged 12-15 years from 37 secondary schools in Victoria, Australia, and their parents completed surveys in 2004-2005.

Participants: 1,448 adolescent–parent pairs.

Main Outcome Measures: Parental concern about adolescent weight; adolescent perceptions of their food intake and home food environment.

Analysis: Chi-square tests, exploratory factor analysis, independent t tests (P < .01).

Results: Although 12% of parents perceived their adolescent as overweight, 27% were concerned about their adolescent's weight (under- or overweight). Adolescents of concerned parents reported lower intakes of energy-dense snacks and less home availability of these food items, and they perceived that their parents less often listened to and considered their food preferences when shopping and cooking, than did adolescents of unconcerned parents. Concerned parents were no more likely to provide fruits and vegetables in the home or a positive family mealtime environment than unconcerned parents, at least as reported by their adolescents.

Conclusions and Implications: Parental concern about adolescent weight was associated with lower intakes of energy-dense snacks among adolescents, less home availability of these food items, and less supportive parental feeding practices. Parents should be encouraged to listen to and consider their adolescents' food preferences, and provide supportive family mealtime environments and healthful food in the home.

Patterns of alcohol use and associated physical and lifestyle characteristics according to new Australian guidelines

Objective: To describe the pattern of alcohol consumption and associated physical and lifestyle characteristics in a population-based sample of Australian men.
Method: A community-based age-stratifi ed random sample of 1420 men (median age 56 years, range 20 – 93) participating in the Geelong Osteoporosis Study, an epidemiological study set in south-eastern Australia. Daily alcohol intake was ascertained from a detailed food frequency questionnaire and categorized according to the Australian National Health and Medical Research Council 2009 guidelines (non-drinkers, greater than zero but ≤ 2 drinks per day, > 2 drinks per day), with a standard drink equivalent to 10 g of ethanol. Anthropometry was measured and lifestyle factors self-reported. Body composition was determined using dual energy absorptiometry. Socio-economic status was categorized according to the Australian Bureau of Statistics data. Results were age standardized to the Australian male population figures.
Results: The median daily ethanol consumption was 12 g (IQR 2 – 29) per day with a range of 0 – 117 g/day. The age-standardized proportion of non-drinkers was 8.7%, 51.5% consumed up to two drinks per day ( ≤ 20 g ethanol/day), and 39.9% exceeded 2 standard drinks per day ( > 20 g ethanol/day). Alcohol consumption was positively associated with cigarette smoking, weight, higher SES and inversely with age and physical activity.
Conclusions: Approximately, 40% of Australian men consume alcohol at levels in excess of current recommendations, which in combination with other risk factors may adversely impact upon health.

Cross-sectional geometry of weight-bearing tibia in female athletes subjected to different exercise loadings

Summary The association of long-termsport-specific exercise loading with cross-sectional geometry of the weight-bearing tibia was evaluated among 204 female athletes representing five different exercise loadings and 50 referents. All exercises involving ground impacts (e.g., endurance running, ball games, jumping) were associated with thicker cortex at the distal and diaphyseal sites of the tibia and also with large diaphyseal cross-section, whereas the high-magnitude (powerlifting) and non-impact (swimming) exercises were not. Introduction Bones adapt to the specific loading to which they are habitually subjected. In this cross-sectional study, the association of long-term sport-specific exercise loading with the geometry of the weight-bearing tibia was evaluated among premenopausal female athletes representing 11 different sports.

Methods A total of 204 athletes were divided into five exercise loading groups, and the respective peripheral quantitative computed tomographic data were compared to data obtained from 50 physically active, non-athletic referents. Analysis of covariance was used to estimate the between-group differences.

Results At the distal tibia, the high-impact, odd-impact, and repetitive low-impact exercise loading groups had ~30% to 50% (p<0.05) greater cortical area (CoA) than the referents. At the tibial shaft, these three impact groups had ~15% to 20% (p<0.05) greater total area (ToA) and ~15% to 30% (p<0.05) greater CoA. By contrast, both the high-magnitude and repetitive non-impact groups had similar ToA and CoA values to the reference group at both tibial sites.

Conclusions High-impact, odd-impact, and repetitive lowimpact exercise loadings were associated with thicker cortex at the distal tibia. At the tibial shaft, impact loading was not only associated with thicker cortex, but also a larger cross-sectional area. High-magnitude exercise loading did not show such associations at either site but was comparable to repetitive non-impact loading and reference data. Collectively, the relevance of high strain rate together with moderate-to-high strain magnitude as major determinants of osteogenic loading of the weight-bearing tibia is implicated.

A comparative assessment of austempered ductile iron as a substitute in weight reduction applications

Manufacturing engineering has had to undergo drastic changes in the approach to material selection in order to meet new design challenges. In the automotive industry, researchers in their effort to reduce emissions and satisfy environmental regulations, have shifted their focus to new emerging materials such as high-strength aluminium alloys, metal matrix composites, plastics, polymers and of late, Austempered Ductile Iron (ADI). ADI is a good choice for design where the criterion is high performance at reduced weight and cost. The unique, ausferrite microstructure gives the material desirable material properties and an edge over other materials. A comparative study of ADI in terms of materials properties and machining characteristics with other materials is desirable to highlight the potential of the material. This paper focuses on a comparative assessment of material and machining characteristics of ADI for different applications. The properties under consideration are machinability, weight and cost savings and versatility. ADI has a higher strength-to-weight ratio than aluminium making it a ready alternative for material selection. In terms of machinability, there are some problems associated with machining of ADI due to its work hardening nature. This paper attempts to identify the possible potential applications of ADI, by critically reviewing specific applications such as machinability, overall economics and service.