Personal, family, social, and environmental correlates of active commuting to school

Background: Active commuting to school may be an important opportunity for children to accumulate adequate physical activity for improved cardiovascular risk factors, enhanced bone health, and psychosocial well-being. The purpose of this study was to examine personal, family, social, and environmental correlates of active commuting to school among children. Methods: Cross-sectional study of 235 children aged 5 to 6 years and 677 children aged 10 to 12 years from 19 elementary schools in Melbourne, Australia. Self-administered questionnaires were completed by parents, and the older children. The shortest possible routes to school were examined using a geographic information system. Results: Among both age groups, negative correlates of active commuting to school included parental perception of few other children in the neighborhood and no lights or crossings for their child to use, and an objectively assessed busy road barrier en route to school. In younger children, an objectively assessed steep incline en route to school was negatively associated with walking or cycling to school. Good connectivity en route to school was negatively associated with walking or cycling to school among older children. Among both age groups, children were more likely to actively commute to school if their route was <800 meters. There were no associations with perceived energy levels or enjoyment of physical activity, weight status, or family factors. Conclusions: For children, creating child-friendly communities and providing skills to safely negotiate the environment may be important. Environmental correlates of active transport in children and adults may differ and warrant further investigation.

Children's television viewing and objectively measured physical activity: associations with family circumstances

Background: The contribution of family circumstance to physical activity and television viewing has not been widely investigated in pre-adolescents, and available information is inconsistent. This study examines whether television viewing and objectively measured physical activity vary by different indicators of family circumstance.
Methods: Data from the 2001 Children's Leisure Activity Study and the 2002/3 Health, Eating and Play Study, involving Australian children in Grades Prep (mean age 6y) and 5–6 (mean age 11y), were combined. Children wore accelerometers for six consecutive 24 hour periods. Average min/day in low-intensity activity (1.0–1.9 METs) and moderate-to-vigorous-intensity activity (≥3 METs) were calculated. Parents reported children's television viewing and family circumstance. Linear regression analyses were conducted separately for young girls, young boys, older girls and older boys. Results: Complete data were available for 2458 children. Parental education and, to a lesser extent, employment level were inversely associated with television viewing. Children in single-parent families, those whose fathers were not in paid employment, and those without siblings tended to spend more time in low-intensity activity than their peers. Children with siblings spent more time in moderate-to-vigorous-intensity activity; associations were stronger for girls. Maternal education was positively associated with moderate-to-vigorous-intensity activity for younger children. Maternal employment was positively associated with moderate-to-vigorous-intensity activity for older children. Multivariable models did not demonstrate a cumulative explanatory effect.
Conclusion:  Individual measures of family circumstance were differentially associated with television, low-intensity activity and moderate-to-vigorous-intensity activity and associations were often not consistent across age-by-gender groups. Interventions may need to be tailored accordingly.

Family food environment and dietary behaviors likely to promote fatness in 5-6 year-old children

Background: The family food environment (FFE) is likely to exert important influences on young children's eating. Examination of multiple aspects of the FFE may provide useful insights regarding which of these might most effectively be targeted to prevent childhood obesity.

Objective: To assess the associations between the FFE and a range of obesity-promoting dietary behaviors in 5–6-year-old children.

Design: Cross-sectional study.

Subjects: Five hundred and sixty families sampled from three socio-economically distinct areas.

Measurements: Predictors included parental perceptions of their child's diet, food availability, child feeding practices, parental modeling of eating and food preparation and television (TV) exposure. Dietary outcomes included energy intake, vegetable, sweet snack, savory snack and high-energy (non-dairy) fluid consumption.

Results: Multiple linear regression analyses, adjusted for all other predictor variables and maternal education, showed that several aspects of the FFE were associated with dietary outcomes likely to promote fatness in 5–6-year-old children. For example, increased TV viewing time was associated with increased index of energy intake, increased sweet snack and high-energy drink consumption, and deceased vegetable intake. In addition, parent's increased confidence in the adequacy of their child's diet was associated with increased consumption of sweet and savory snacks and decreased vegetable consumption. 

Conclusion:  This study substantially extends previous research in the area, providing important insights with which to guide family-based obesity prevention strategies.

Australian parents` views on their 5-6-year-old children's food choices

The home food environment is central to the development of healthy eating behaviours, but associations between the home food environment and children's food choices are not yet fully understood. The aims of this study were to explore parents' views regarding factors that influence children's food choices and parents' decision-making regarding the food they provide to their children. In-depth one-on-one interviews were conducted using a semi-structured interview schedule. Key concepts and themes were coded independently by two investigators. Participants include seventeen parents (16 mothers and 1 father) of children in their first year of formal schooling (aged 5–6 years). Five main themes emerged from the interviews: food marketing, food availability/food exposure, feeding strategies, modelling of eating and opportunities for food involvement. Parents believed that food marketing influenced their child's food preferences but differed in the ways they managed these influences. The food made available to children was also seen to influence what a child ate. Yet, although some parents believed it was the parents' role to determine what foods were made available to their child, others offered food on the basis of the child's tastes or preferences. The use of food as a reward was a feeding strategy employed by many parents. Family mealtimes were seen as an important opportunity for modelling of eating behaviour by parents. Peers were also seen to influence children's food preferences and eating behaviour. Finally, many parents believed that involving children in the preparation of food had a positive impact on children's food choices. Associations between the home food environment and children's food choices are complex and involve multiple mediators. Parents' views on the promoters and reinforcers of their decision-making regarding food and their child's food choices provide useful insights into these mediating factors. Increased understanding of these relationships is likely to enhance obesity prevention efforts.

Parental concerns about childhood obesity and the strategies employed to prevent unhealthy weight gain in children.

Objectives: To describe parental concerns about their child’s weight, to determine the proportion of parents taking preventive action to avoid obesity in their children and the predictors of taking preventive action, and to describe the strategies adopted by parents.
Design: A cross-sectional survey was conducted. Children’s heights and weights were measured, and parents completed a questionnaire that included measures of their own weight status, perceptions of their child’s weight, concerns about their child’s current weight and future weight as an adolescent and adult, and the strategies used to prevent obesity.
Setting: The study was conducted in Melbourne, Australia.
Subjects: A total of 291 families of children aged 5–6 years and 919 families of children aged 10–12 years participated.
Results: Eighty-nine per cent of parents of overweight 5–6-year-olds and 63% of parents of overweight 10–12-year-olds were unaware their child was overweight. Seventy-one per cent of parents of overweight 5–6-year-olds and 43% of parents of overweight 10–12-year-olds were not concerned about their child’s current weight. Although 31% of parents of 5–6-year-olds and 43% of parents of 10–12-year-olds were taking action to prevent unhealthy weight gain in their children, less-educated parents were less likely to do so.
Conclusions: Public health programmes are required to raise parental recognition of childhood overweight and of related risk behaviours, and to provide parents with practical strategies to prevent unhealthy weight gain in their children.

Public views of the benefits and barriers to the consumption of a plant-based diet

Objective: The aim of this study was to examine consumers' perceived benefits and barriers to the consumption of a plant-based diet. Design: Mail survey that included questions on perceived benefits and barriers to the consumption of a plant-based diet. Setting: Victoria, Australia. Subjects: Four hundred and fifteen randomly selected Victorian adults. Results: The main perceived barrier to adoption of a plant-based diet was a lack of information about plant-based diets (42% agreement). Sex, age and education differences were present in over a quarter of the barrier items. For example, non-university-educated respondents and older people were less willing to change their current eating pattern than were university educated and younger respondents. The main benefits associated with plant-based diets were health benefits, particularly decreased saturated fat intake (79% agreement), increased fibre intake (76%), and disease prevention (70%). Age, sex and education differences with regard to benefits were apparent, although sex differences were more important than age or education differences. Conclusions: The majority of respondents perceived there to be health benefits associated with the consumption of a plant-based diet. Compared with the proportion of respondents who agreed that there were particular benefits of eating a plant-based diet, perceived barriers were relatively low. An understanding of the perceived benefits and barriers of consuming a plant-based diet will help formulate strategies that aim to influence beliefs about plant foods, plant food consumption, and, ultimately, public health.

An investigation of psychological, social and environmental correlates of obesity and weight gain in young women

Objectives: This study explored the biological, psychological, social and environmental correlates of young women's current weight and retrospective 2-year weight change. Methods: A total of 790 young women (mean age 26.8 years), sampled from the Australian Longitudinal Study on Women's Health, provided self-reported data on their height and weight, sociodemographics and a range of biological, psychological, social and environmental variables. Results: Several variables from all domains (biological, psychological, social support and environmental) were correlated with higher body mass index, and less strongly greater 2-year weight change. Key correlates included the tendency to never put on weight, no matter what; self-efficacy for avoiding weight gain, and for healthy eating; attention paid to weight; family support and friends' support/sabotage of physical activity/healthy eating; and perceived difficulty of taking the stairs rather than the elevator as part of the daily routine. Conclusions: Intervention strategies aimed at reducing weight gain and obesity may need to focus on social and environmental, as well as psychological factors; however, further research is necessary to confirm these findings given that a number of hypothesized associations were not observed.

Socio-economic factors in obesity: a case of slim chance in a fat world?

The global obesity pandemic has been well-documented and widely discussed by the public, the media, health officials, the food industry and academic researchers. While the problem is widely recognised, the potential solutions are far less clear. There is only limited evidence to guide decisions as to how best to manage obesity in individuals and in populations. While widely viewed as a clinical and public health problem in developed countries, it is now clear that many developing countries also have to grapple with this problem or face the crippling healthcare costs resulting from obesity-related morbidity. There is also abundant evidence that obesity is socio-economically distributed. In developed countries persons of lower socio-economic position are more likely to be affected, while in developing countries, it is often those of higher socio-economic position who are overweight or obese. The aim of this paper is to briefly review the evidence that links socio-economic position and obesity, to discuss what is known about underlying mechanisms, and to consider the role of social, physical, policy and cultural environments in explaining the relationships between socio-economic position and obesity. We introduce the concept of ‘resilience’ as a potential theoretical construct to guide research efforts aimed at understanding how some socio-economically disadvantaged individuals manage to avoid obesity. We conclude by considering an agenda to guide future research and programs focused on understanding and reducing obesity among those of low socio-economic position.

How can socio-economic differences in physical activity among women be explained? A qualitative study

This qualitative study investigated why women of low socio-economic status (SES) are less physically active than women of higher-SES. Semi-structured interviews were conducted with 19 high-, 19 mid- and 18 low-SES women. A social-ecological framework, taking into account intrapersonal, social and environmental level influences, was adopted to guide the development of interview questions and interpretation of data. Thematic analysis identified a number of key influences on physical activity that varied by SES. These included negative early life/family physical activity experiences (a consistent theme among those of low-/mid-SES); participation in a wider range of physical activities in leisure time (high-SES); greater priority given to television viewing (low-SES); lack of time due to work commitments (low-SES); lack of time due to family commitments (high-SES); and neighbourhood-level barriers (low-SES). Financial costs were not perceived as a key barrier by women in any SES group. Public health strategies aimed at reducing SES

Socio-economic inequalities in women`s fruit and vegetable intakes: a multilevel study of individual, social and environmental mediators

Objective: This study employed a multilevel design to test the contribution of individual, social and environmental factors to mediating socio-economic status (SES) inequalities in fruit and vegetable consumption among women. Design: A cross-sectional survey was linked with objective environmental data. Setting: A community sample involving 45 neighbourhoods. Subjects: In total, 1347 women from 45 neighbourhoods provided survey data on their SES (highest education level), nutrition knowledge, health considerations related to food purchasing, and social support for healthy eating. These data were linked with objective environmental data on the density of supermarkets and fruit and vegetable outlets in local neighbourhoods. Results: Multilevel modelling showed that individual and social factors partly mediated, but did not completely explain, SES variations in fruit and vegetable consumption. Store density did not mediate the relationship of SES with fruit or vegetable consumption. Conclusions: Nutrition promotion interventions should focus on enhancing nutrition knowledge and health considerations underlying food purchasing in order to promote healthy eating, particularly among those who are socio-economically disadvantaged. Further investigation is required to identify additional potential mediators of SES–diet relationships, particularly at the environmental level.

Life-cycle energy analysis of building integrated photovoltaic systems (BiPVs) with heat recovery unit

Building integrated photovoltaic (BiPV) systems generate electricity, but also heat, which is typically wasted and also reduces the efficiency of generation. A heat recovery unit can be combined with a BiPV system to take advantage of this waste heat, thus providing cogeneration. Two different photovoltaic (PV) cell types were combined with a heat recovery unit and analysed in terms of their life-cycle energy consumption to determine the energy payback period. A net energy analysis of these PV systems has previously been performed, but recent improvements in the data used for this study allow for a more comprehensive assessment of the combined energy used throughout the entire life-cycle of these systems to be performed. Energy payback periods between 4 and 16.5 years were found, depending on the BiPV system. The energy embodied in PV systems is significant, emphasised here due to the innovative use of national average input–output (I–O) data to fill gaps in traditional life-cycle inventories, i.e. hybrid analysis. These findings provide an insight into the net energy savings that are possible with a well-designed and managed BiPV system.

Family structure and children's television viewing and physical activity

Objectives: This study aimed to examine how physical activity (PA) and television (TV) viewing time of children varied according to family structure.

Methods: In 2001, 5- to 6-yr-old (N = 296) and 10- to 12-yr-old (N = 919) children and their parents were recruited from 19 state elementary schools in Melbourne, Australia. Children's PA was objectively assessed using accelerometers worn for 8 d. Sociodemographic and family structure information and time spent watching TV was collected via questionnaire completed by parents.

Results: ANCOVA revealed that, after controlling for socioeconomic status and age of child, boys without any siblings spent more minutes per day watching TV (153.2 +/- 71.3) compared with those who have siblings (129.0 +/- 64.4, P < 0.05). There were also significant differences in TV viewing time between boys with one sibling (125.5 +/- 59.9), two siblings (141.9 +/- 70.1), or three or more siblings (111.6 +/- 62.6, P < 0.001). Girls from single-parent families (145.7 +/- 85.1) spent significantly more minutes per day watching TV compared with girls from two-parent families (125.1 +/- 67.7, P < 0.05). Girls with siblings spent more minutes per day in PA (148.3 +/- 67.7) compared with those who were an only child (131.0 +/- 58.9, P < 0.05). There were significant interactions between parental status and having a sibling, with PA, and also with TV viewing for girls and between parental status and having a brother with PA for boys. There were also significant interactions between having an older sibling and child's sex with PA and between number of siblings and sex with TV viewing.

Conclusions: Family structure may be an important source of influence on children's PA and TV viewing time. Aspects of family structure interact differently with PA and TV viewing, suggesting interventions may need to be tailored with consideration of the family structure of children.

Individual, social and home environment determinants of change in children's television viewing: the Switch-Play intervention

Understanding potential determinants of change in television (TV) viewing among children may enhance the effectiveness of programs targeting this behaviour. This study aimed to investigate the contribution of individual, social and home environment factors among 10-year-old Australian children to change in TV viewing over a 21-month period. A total of 164 children (49% boys) completed a 19-lesson (9-month) intervention program to reduce TV viewing time. Children completed self-administered surveys four times over 21 months (pre- and post-intervention, 6- and 12-month follow-up). Baseline factors associated with change in TV viewing during the intervention and follow-up periods were: ‘asking parents ≥once/week to switch off the TV and play with them’ (21.6 min/day more than those reporting <once/week, p = 0.007); being able to ‘watch just 1 h of TV per day’ (26.1 min/day less than those who could not, p = 0.010); ‘watching TV no matter what was on’ (36.6 min/day more than those who did not, p < 0.001); and ‘continuing to watch TV after their program was over’ (33.0 min/day more than those who did not, p = 0.006). With every unit increase in baseline frequency of TV viewing with family and friends, children spent on average 4.0 min/day more watching TV over the 21-month period (p = 0.047). Baseline number and placement of TVs at home did not predict change in children's TV viewing over the 21 months. Greater understanding of the family dynamics and circumstances, as well as the individual and social determinants of TV viewing, will be required if we are to develop effective strategies for reducing TV viewing in children.

Understanding environmental influences on nutrition and physical activity behaviors: where should we look and what should we count?

Research interest in the influence of environmental factors on nutrition and physical activity behaviors has surged internationally in recent years. This is evident from a rapidly expanding literature and facilitated by advances in methodological and analytical approaches to assessing multiple levels of influence on health behaviors. However, a number of conceptual challenges complicate research endeavours in this field. The purpose of this paper is to provide a 'state of the science' overview of evidence regarding environmental influences on nutrition and physical activity behaviors. We focus particularly on a number of key conceptual and methodological issues, including: a consideration of how the environment is defined; the selection and operationalization of environmental exposures; and the importance of integrating existing understanding of individual influences on behavior with the emerging data on the role of the environment. We draw on examples from the published literature including our own research studies to illustrate these issues. We conclude by proposing a research agenda to progress understanding of the influences of the environment on population nutrition and physical activity behaviors.

Television viewing habits associated with obesity risk factors: a survey of Melbourne schoolchildren.

Objectives: To examine whether children’s television viewing may be a useful indicator of risk of obesity-promoting versus healthy eating behaviours, low-level physical activity (PA) and overweight or obesity among children of primary school entry and exit ages. Design: Cross-sectional study, stratified by area-level socioeconomic status. Participants and setting: 1560 children (613 aged 5–6 years [50% boys], and 947 aged 10–12 years [46% boys]) from 24 primary schools in Melbourne, Australia, randomly selected proportionate to school size between 1 November 2002 and 30 December 2003 . Main outcome measures: Parents’ reports of the time their child spends watching television, their participation in organised physical activities (PA), and their food intake; each child’s measured height and weight and their PA levels as assessed by accelerometry for one week. Results: After adjusting for the age and sex of child, the parents’ level of education, clustering by school, and all other health behaviour variables, children who watched television for > 2 h/day were significantly more likely than children who watched television for ≤ 2 h/day to: to have one or more serves/day of high energy drinks (adjusted odds ratio [AOR], 2.31; 95% CI, 1.61–3.32), and to have one or more serves/day of savoury snacks (AOR, 1.50; 95% CI, 1.04–2.17). They were also less likely to have two or more serves/day of fruit (AOR, 0.58; 95% CI, 0.46–0.74), or to participate in any organised PA (AOR, 0.52; 95% CI, 0.34–0.80). Conclusions: Health practitioners in the primary care setting may find that asking whether a child watches television for more than 2 hours daily can be a useful indicator of a child’s risk of poor diet and low physical activity level.