Trends and associations between maternal characteristics and infant birthweight among Indigenous and non-Indigenous people in Tasmania, Australia: a population-based study.

OBJECTIVE: This study aimed to investigate the trends and associations of maternal characteristics and birthweight among Indigenous and non-Indigenous infants. STUDY DESIGN: This was a retrospective population-based study. METHODS: Fourteen years (2005-2018) of birthweight and perinatal health data of live-born singletons and their mothers obtained from the Tasmanian Data Linkage Unit were used to assess the trends and associations between maternal characteristics and infant birthweight using regression modelling. RESULTS: Compared with non-Indigenous mothers (n = 76,750), Indigenous mothers (n = 3805) had a significantly higher prevalence of risk factors during the 14-year period. Although the prevalence of prepregnancy obesity and gestational diabetes mellitus (GDM) markedly increased in both groups, the rate of increase was higher (P < 0.001) for Indigenous than non-Indigenous mothers. Smoking, alcohol consumption and illegal drug use during pregnancy reduced over the years, and there was no significant difference in the rate of reduction between the groups. Large-for-gestational-age (LGA) births increased while small-for-gestational-age (SGA) births decreased in both groups over time. In addition, high birthweight (HBW) births decreased while low birthweight (LBW) births increased. The rates of increase in LGA and LBW births and the rates of decrease in SGA and HBW births were significantly higher in Indigenous mothers compared with non-Indigenous mothers (P < 0.001 for all). The association between Indigenous ethnicity and LBW and SGA births weakened after adjusting for other confounding maternal and perinatal variables. LBW and SGA were positively associated with Indigenous ethnicity, age <18 years, smoking, alcohol consumption and illegal drug use, pre-eclampsia, underweight prepregnancy body mass index and low socio-economic status. Women with higher parity, pre-existing diabetes and prepregnancy overweight or obesity were more likely to give birth to an infant with HBW or LGA. CONCLUSIONS: The prevalence of risk factors for abnormal birthweight is higher among Tasmanian Indigenous mothers, contributing to a gap in birthweight outcomes between Indigenous and non-Indigenous infants. The dramatic increase in prepregnancy obesity and GDM in both groups highlight the importance of screening and management of GDM during pregnancy. Comprehensive programmes co-designed and co-managed in consultation with Indigenous people are needed to support healthy lifestyle choices among Indigenous women to address the barriers to individuals adopting behaviour change and to help close the health outcomes-related gap between Indigenous and non-Indigenous mothers and infants.

Physical Activity and Food Environments in and around Schools: A Case Study in Regional North-West Tasmania.

A better understanding of the physical activity (PA) infrastructure in schools, the walkability of neighborhoods close to schools, and the food environments around schools, particularly in rural, socioeconomically challenged areas such as the North-West (NW) of Tasmania, could be important in the wider effort to improve the health of school-age children. Accordingly, this research aimed to assess PA resources, walkability, and food environments in and around schools in three socioeconomically disadvantaged, regional/rural Local Government Areas (LGAs) of Tasmania, Australia. A census of schools (including assessment of the PA infrastructure quality within school grounds), a walkability assessment, and a census of food outlets surrounding schools (through geospatial mapping) were executed. Most of the schools in the study region had access to an oval, basketball/volleyball/netball court, and free-standing exercise equipment. In all instances (i.e., regardless of school type), the quality of the available infrastructure was substantially higher than the number of incivilities observed. Most schools also had good (i.e., within the first four deciles) walkability. Numerous food outlets were within the walking zones of all schools in the study region, with an abundance of food outlets that predominantly sold processed unhealthy food.

Effect of severe compared with moderate energy restriction on physical activity among postmenopausal female adults with obesity: a prespecified secondary analysis of the Type of Energy Manipulation for Promoting optimum metabolic health and body composition in Obesity (TEMPO) Diet randomized controlled Trial.

BACKGROUND: An under-explored strategy for increasing physical activity is the dietary treatment of obesity, but empirical evidence is lacking. OBJECTIVES: We aimed to compare the effects of weight loss via severe as opposed to moderate energy restriction on physical activity over 36 mo. METHODS: A total of 101 postmenopausal female adults (45-65 y, BMI 30-40 kg/m2, <180 min/wk of structured exercise) were randomly assigned to either 12 mo of moderate energy restriction (25%-35% of energy requirement) with a food-based diet, or a severe intervention involving 4 mo of severe energy restriction (65%-75% of energy requirement) with a total meal replacement diet, followed by 8 mo of moderate energy restriction. Physical activity was encouraged, but no tailored or supervised exercise prescription was provided. Physical activity was assessed with an accelerometer worn for 7 d before baseline (0 mo) and 0.25, 1, 4, 6, 12, 24, and 36 mo after intervention commencement. RESULTS: Compared with the moderate group, the severe group exhibited greater mean: total volume of physical activity; duration of moderate-to-vigorous-intensity physical activity (MVPA); duration of light-intensity physical activity; step counts, as well as lower mean duration of sedentary time. All these differences (except step counts) were apparent at 6 mo [e.g., 1006 metabolic equivalent of task (MET)-min/wk; 95% CI: 564, 1449 MET-min/wk for total volume of physical activity], and some were also apparent at 4 and/or 12 mo. There were no differences between groups in the 2 other outcomes investigated (self-efficacy to regulate exercise; and proportion of participants meeting the WHO's 2020 Physical Activity Guidelines for MVPA). When the analyses were adjusted for weight at each time point, the differences between groups were either attenuated or abolished. CONCLUSIONS: Among female adults with obesity, including a dietary component to reduce excess body weight-notably one involving severe energy restriction-could potentially enhance the effectiveness of physical activity interventions.This trial was registered at www.anzctr.org.au as ACTRN12612000651886.

A Spatial Analysis of Access to Physical Activity Infrastructure and Healthy Food in Regional Tasmania.

Prevalence of physical inactivity and obesity continues to increase in regional areas such as North-West (NW) Tasmania and show no signs of abating. It is possible that limited access to physical activity infrastructure (PAI) and healthier food options are exacerbating the low levels of habitual physical activity and obesity prevalence in these communities. Despite a burgeoning research base, concomitant exploration of both physical activity and food environments in rural and regional areas remain scarce. This research evaluated access (i.e., coverage, variety, density, and proximity) to physical activity resources and food outlets in relation to socioeconomic status (SES) in three NW Tasmanian communities. In all three study areas, the PAI and food outlets were largely concentrated in the main urban areas with most recreational tracks and natural amenities located along the coastline or river areas. Circular Head had the lowest total number of PAI (n = 43) but a greater proportion (30%) of free-to-access outdoor amenities. There was marked variation in accessibility to infrastructure across different areas of disadvantage within and between sites. For a considerable proportion of the population, free-to-access natural amenities/green spaces and recreational tracks (73 and 57%, respectively) were beyond 800 m from their households. In relation to food accessibility, only a small proportion of the food outlets across the region sells predominantly healthy (i.e., Tier 1) foods (~6, 13, and 10% in Burnie, Circular Head and Devonport, respectively). Similarly, only a small proportion of the residents are within a reasonable walking distance (i.e., 5-10 min walk) from outlets. In contrast, a much larger proportion of residents lived close to food outlets selling predominantly energy-dense, highly processed food (i.e., Tier 2 outlets). Circular Head had at least twice as many Tier 1 food stores per capita than Devonport and Burnie (0.23 vs. 0.10 and 0.06; respectively) despite recording the highest average distance (4.35 and 5.66 km to Tier 2/Tier 1 stores) to a food outlet. As such, it is possible that both food and physical activity environment layouts in each site are contributing to the obesogenic nature of each community.

The current global state of movement and physical activity - the health and economic costs of the inactive phenotype.

Physical inactivity is one of the major contributing factors to the global pandemic of non-communicable diseases. Unfortunately, low levels of habitual movement and physical activity (PA) are seen in an increasing proportion of populations across low- and middle-income countries and high-income countries alike. This new normal - the inactive phenotype - is a significant contributor to multiple health and economic costs. Here we provide a brief historical overview of societal declines in PA, roughly consistent with major transitions in PA and nutrition in recent decades. This is followed by a synthesis of research evidence linking inactivity with poor health outcomes and prevention approaches needed to impact a perpetuation of poor lifestyle behaviors. A major focus of the paper is on the economic/health costs and the reduction of the inactive phenotype. In summary, we demonstrate that the consequences of insufficient PA are manifold, and if sustained, impact short and long-term health and quality of life, along with substantial economic costs.

Physical Activity and Health: "What is Old is New Again".

Much recent interest has focused on the relationship between physical activity and health and supported with an abundance of scientific evidence. However, the concept of Exercise is Medicine™ copromoted by the American College of Sports Medicine and American Medical Association and similar august bodies worldwide is far from new--the importance of exercise for health has been reported for centuries. Participation in regular physical activity and exercise provides numerous benefits for health with such benefits typically varying according to the volume completed as reflected by intensity, duration, and frequency. Evidence suggests a dose-response relationship such that being active, even to a modest level, is preferable to being inactive or sedentary. Greatest benefits are commonly associated with the previously sedentary individual assuming a more active lifestyle. There is an apparent linear relationship between physical activity and health status and as a general rule, increases in physical activity and fitness result in additional improvements in health status. This narrative review provides a selective appraisal of the evidence for the importance of physical activity for health, commencing with a baseline historical perspective followed by a summary of key health benefits associated with an active lifestyle.

Influence of habitual physical activity on gastric emptying in healthy males and relationships with body composition and energy expenditure.

Although a number of studies have examined the role of gastric emptying (GE) in obesity, the influences of habitual physical activity level, body composition and energy expenditure (EE) on GE have received very little consideration. In the present study, we compared GE in active and inactive males, and characterised relationships with body composition (fat mass and fat-free mass) and EE. A total of forty-four males (active n 22, inactive n 22; BMI 21-36 kg/m2; percentage of fat mass 9-42%) were studied, with GE of a standardised (1676 kJ) pancake meal being assessed by the [13C]octanoic acid breath test, body composition by air displacement plethysmography, RMR by indirect calorimetry, and activity EE (AEE) by accelerometry. The results showed that GE was faster in active compared with inactive males (mean half-time (t 1/2): active 157 (sd 18) and inactive 179 (sd 21) min, P< 0.001). When data from both groups were pooled, GE t 1/2 was associated with percentage of fat mass (r 0.39, P< 0.01) and AEE (r - 0.46, P< 0.01). After controlling for habitual physical activity status, the association between AEE and GE remained, but not that for percentage of fat mass and GE. BMI and RMR were not associated with GE. In summary, faster GE is considered to be a marker of a habitually active lifestyle in males, and is associated with a higher AEE level and a lower percentage of fat mass. The possibility that GE contributes to a gross physiological regulation (or dysregulation) of food intake with physical activity level deserves further investigation.

Muscular strength, aerobic capacity, and adipocytokines in obese youth after resistance training: A pilot study.

BACKGROUND: Exercise has shown positive training effects on obesity-related inflammation, however, resistance training has shown mixed results concerning adipocytokine levels. AIMS: The purpose of this pilot study was to explore the effects of resistance training on blood adipocytokine concentrations in obese youth, with specific examination of the relationship between these biomarkers and improved fitness (i.e., aerobic capacity, muscular strength). METHODS: Fourteen obese adolescents (16.1 ±1.6 y; BMI: 32.3 ±3.9 kg/m(2)) participated in a 16-week resistance training intervention. Body composition, fasting blood concentrations of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-ɑ), adiponectin, and leptin were measured pre- and post-training. Aerobic capacity was assessed via a maximal discontinuous exercise test. The rate of gain in muscular strength was calculated as the slope of progression in 1-repetition maximum throughout the intervention. RESULTS: Resistance training increased lean mass (total, trunk) and decreased per cent body fat (total, trunk). The training also caused moderate clear decreases in IL-6 and TNF-ɑ concentrations. A small increase in adiponectin was also observed before and after intervention. When the group was stratified by changes in aerobic capacity, there were substantially larger decreases in leptin levels for those with improved capacity. Correlation analyses also revealed a negative relationship between log-transformed leptin and aerobic capacity at rest. Improvement in quadriceps strength was positively correlated with IL-6 and TNF-ɑ, while improvement in shoulder adductor strength was positively correlated with IL-6 only. CONCLUSION: Resistance training improved adipocytokine markers, which were partially associated with improved physical fitness. Specifically, the relationship between strength improvements and IL-6 and TNF-ɑ suggests an exercise-induced signalling pathway that results in overall adaptive decreases in systemic inflammation in obese youth.

Assessment of physical activity and energy expenditure: an overview of objective measures.

The ability to assess energy expenditure (EE) and estimate physical activity (PA) in free-living individuals is extremely important in the global context of non-communicable diseases including malnutrition, overnutrition (obesity), and diabetes. It is also important to appreciate that PA and EE are different constructs with PA defined as any bodily movement that results in EE and accordingly, energy is expended as a result of PA. However, total energy expenditure, best assessed using the criterion doubly labeled water (DLW) technique, includes components in addition to physical activity energy expenditure, namely resting energy expenditure and the thermic effect of food. Given the large number of assessment techniques currently used to estimate PA in humans, it is imperative to understand the relative merits of each. The goal of this review is to provide information on the utility and limitations of a range of objective measures of PA and their relationship with EE. The measures discussed include those based on EE or oxygen uptake including DLW, activity energy expenditure, physical activity level, and metabolic equivalent; those based on heart rate monitoring and motion sensors; and because of their widespread use, selected subjective measures.

'Small changes' to diet and physical activity behaviors for weight management.

Obesity is associated with numerous short- and long-term health consequences. Low levels of physical activity and poor dietary habits are consistent with an increased risk of obesity in an obesogenic environment. Relatively little research has investigated associations between eating and activity behaviors by using a systems biology approach and by considering the dynamics of the energy balance concept. A significant body of research indicates that a small positive energy balance over time is sufficient to cause weight gain in many individuals. In contrast, small changes in nutrition and physical activity behaviors can prevent weight gain. In the context of weight management, it may be more feasible for most people to make small compared to large short-term changes in diet and activity. This paper presents a case for the use of small and incremental changes in diet and physical activity for improved weight management in the context of a toxic obesogenic environment.

Physical activity and obesity in children.

Globally, obesity is affecting an increasing proportion of children. Physical activity plays an important role in the prevention of becoming overweight and obese in childhood and adolescence, and reducing the risk of obesity in adulthood. Puberty and the following adolescent period are acknowledged as particularly vulnerable times for the development of obesity due to sexual maturation and, in many individuals, a concomitant reduction in physical activity. In many Western settings, a large proportion of children and adolescents do not meet recommended physical activity guidelines and, typically, those who are more physically active have lower levels of body fat than those who are less active. Active behaviours have been displaced by more sedentary pursuits which have contributed to reductions in physical activity energy expenditure. Without appropriate activity engagement there is an increased likelihood that children will live less healthy lives than their parents. Owing to the high risk of overweight adolescents becoming obese adults, the engagement of children and adolescents in physical activity and sport is a fundamental goal of obesity prevention.

Age, muscle fatigue, and walking endurance in pre-menopausal women.

Aging is associated with loss of endurance; however, aging is also associated with decreased fatigue during maximal isometric contractions. The aims of this study were to examine the relationship between age and walking endurance (WE) and maximal isometric fatigue (MIF) and to determine which metabolic/fitness components explain the expected age effects on WE and MIF. Subjects were 96 pre-menopausal women. Oxygen uptake (walking economy) was assessed during a 3-mph walk; aerobic capacity and WE by progressive treadmill test; knee extension strength by isometric contractions, MIF during a 90-s isometric plantar flexion (muscle metabolism measured by (31)P MRS). Age was related to increased walking economy (low VO(2), r = -0.19, P < 0.03) and muscle metabolic economy (force/ATP, 0.34, P = 0.01), and reduced MIF (-0.26, P < 0.03). However, age was associated with reduced WE (-0.28, P < 0.01). Multiple regression showed that muscle metabolic economy explained the age-related decrease in MIF (partial r for MIF and age -0.13, P = 0.35) whereas walking economy did not explain the age-related decrease in WE (partial r for WE and age -0.25, P < 0.02). Inclusion of VO(2max) and knee endurance strength accounted for the age-related decreased WE (partial r for WE and age = 0.03, P > 0.80). In premenopausal women, age is related to WE and MIF. In addition, these results support the hypothesis that age-related increases in metabolic economy may decrease MIF. However, decreased muscle strength and oxidative capacity are related to WE.

Prevention of gestational diabetes: feasibility issues for an exercise intervention in obese pregnant women.

OBJECTIVE: To examine the feasibility of an individualized exercise program to prevent gestational diabetes mellitus (GDM) in obese pregnant women. RESEARCH DESIGN AND METHODS: The study was a pilot randomized controlled trial with obese pregnant women (intervention group, individualized exercise program [n = 25]; control group, usual care [n = 25]). Average weekly energy expenditure (MET hours per week and kilocalories per week) of exercise-specific activity was assessed during pregnancy using the Pregnancy Physical Activity Questionnaire. Fasting glucose and insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed at baseline and 20, 28, and 36 weeks' gestation. RESULTS: Of the women in the intervention group, 16 of 22 (73%) achieved more than 900 kcal/week of exercise-based activity at 28 weeks compared with 8 of 19 women in the control group (42%), P = 0.047. However, insulin resistance (HOMA-IR) did not differ between the groups. CONCLUSION: This intervention was feasible and prompted a modest increase in physical activity. However, we are not confident that this intervention would be sufficient to prevent GDM.

Are Japanese criteria for obesity useful for screening at risk Japanese? Consideration from anthropometric indices-percentage body fat relationships.

Both childhood and adult obesity are of serious public health concern in Japan. While Japan has diagnostic criteria for both childhood and adult obesity and metabolic syndrome, the appropriateness of the proposed criteria has been questioned. The present study aimed to determine screening ability of anthropometric indices relative to estimated percentage body fat (% BF) and to propose gender- and maturation-specific cut-off points using 1,393 Japanese (552 males and 841 females; 7.6-66.3 years old). Between 20%-50% of individuals with high fat deposits were misclassified using body mass index (BMI), abdominal circumference (AC), abdominal to height ratio (AHtR), and sum of two skinfolds (Sigma2SF). Using the WHO public action point of 23 kg/m2, AC of 80 cm, AHtR of 0.5 for all groups and Sigma2SF of 25 mm for males and 40 mm for females were estimated to be potentially useful cut-off points. The results may indicate a need for further research for appropriate screening cut-off points for Japanese.

State of the science: a focus on physical activity.

Diet, exercise, behavioural support and for some obese individuals, pharmacotherapy, represent the set of lifestyle factors necessary for effective management of obesity. An on-going challenge in the prevention, treatment and management of obesity is to arm health professionals in particular, with the necessary knowledge and understanding and time to engage in meaningful weight management counseling. Despite the many barriers to effective management such as lack of relevant education in nutrition and physical activity, perceived patient non-compliance, perceived inability to change patient behaviours, and the cost of specialist behavioural support, there is increasing evidence of the value of behaviour modification techniques to both dietary and exercise counseling, particularly when focusing on current behaviour. Behavioural counseling addresses the barriers to compliance with diet and physical activity goals and also equips the individual with practical strategies and motivation to be more self-responsible. Commonly employed behavioural interventions include stimulus control, reinforcement techniques, self-monitoring, behavioural contracting, and social support programs. This paper addresses one of the key behavioural components in the treatment and management of obesity - physical activity. Higher levels of energy expenditure through increased physical activity are central to successful weight loss and long-term weight maintenance. The specific value derived from physical activity in the context of weight management for the overweight and obese is in large part associated with an appreciation of the role of both physical activity promotion and exercise prescription.

Physical activity and nutritional status of children of low socioeconomic status. Two interrelated problems: undernutrition and overweight.

The aim of this study was to analyse the level of habitual physical activity (HPA) and nutritional status of children attending selected public schools in Brazil. The sample comprised 1719 participants who ranged in age from 11 to 14 yrs with 861 females (F) aged 12.7+/-1.0 yr and 858 males (M) aged 12.7+/-1.0 yr. The short form of the International Physical Activity Questionnaire (IPAQ) was used to measure HPA. Nutritional status was assessed using the body mass index (BMI). Statistical analyses included ANOVA followed by the post-hoc Tukey-test (P<0.05) which showed a statistically significant difference between M and F in time spent in moderate intensity physical activity. F completed more moderate intensity physical activity than M whereas time in vigorous physical activities was higher in M than F. Analyses of BMI and IPAQ categorical score using Pearson product moment correlations with subsequent Fisher Z transformation showed values of Z = 0.49 for females and Z = 0.44 for males, indicating a low relationship between these variables. HPA levels showed 93.7% of the M and 91.1% of the F were at least minimally active. According to BMI values, 7.3% of the cohort was underweight; 83.0% normal weight; 8.3% overweight and 1.3% obese. These results demand attention, particularly for children at the lower end of nutritional status and HPA levels due to the potential negative impact on their growth and development. At the other end of the nutritional spectrum, one needs to be concerned regarding the levels of excess body weight, mainly considering the poor region in which the children live.

Use of [14C]-sodium bicarbonate/urea to measure physical activity induced increases in total energy expenditure in free-living healthy males.

The aim of this study was to evaluate the utility of the [(14)C]-sodium bicarbonate/urea technique to detect physical activity-induced increases in total energy expenditure in free-living healthy men. Thirteen healthy males aged 34.1 +/- 11.7 yrs with body mass index 24.1 +/- 3.1 kg/m(2) were studied on three separate occasions, during which [(14)C]-bicarbonate was infused over 48-hours and urine was collected during the second 24-hours. On three separate occasions and in random order, subjects either remained sedentary, or performed a bout of physical activity on an electro-magnetically braked cycle ergometer sufficient to increase energy expenditure by 7% or 11% above predicted sedentary total energy expenditure. Urine samples were analyzed to evaluate the amount of [(14)C]-bicarbonate incorporated into urinary urea, thereby reflecting the amount of CO(2) produced per day, and upon conversion, the number of kilojoules of energy expended in 24-hours. All 13 subjects successfully completed the two physical activity treatments and there were no adverse events. As measured by the [(14)C]-urea assay, mean total energy expenditure values were not significantly different between sedentary activity (17902 +/- 905 kJ/day), the physical activity treatment designed to increase TEE by 7% (17701 +/- 594 kJ/day) and the physical activity treatment designed to increase TEE by 11% (18538 +/- 485 kJ/day) (P=0.668). In conclusion, although the [(14)C]-sodium bicarbonate/urea technique was well tolerated and did not interfere with normal daily activities, it was not able to accurately measure physical activity-induced increases in EE in the range of 7-11% above predicted sedentary total energy expenditure.