Perception of weight status in Australian adolescents

 This thesis examined Australian adolescents’ perception of their weight and the association of weight perception with weight related behaviours. Overall, this thesis indicated that many adolescents misperceive their weight status and that this is related to gender specific body ideals. Accurate perception of weight did not promote positive health behaviours.

Biopsychosocial correlates of weight status perception in Australian adolescents

This study examined the utility of the biopsychosocial model to predict accuracy of weight status perception among Australian adolescents. The factors included in this framework were: age, gender, and BMI-z (biological factors); satisfaction with body weight and shape (psychological factors); socioeconomic status, peer weight (social factors). Cross-sectional data, including measured height and weight, and self-reported weight status, was obtained from 2954 adolescents (mean age = 14.6, 56% male) who participated in the It's Your Move! study. Accuracy of weight status perception was associated with gender, BMI-z, SES, and weight and shape satisfaction. Gender differences in weight status perception were moderated by satisfaction with weight. In boys, weight satisfaction was associated with perceived healthy weight; in girls, it was associated with perceived healthy weight and underweight. Moderately overweight adolescents are most at risk of underestimating their weight status and could benefit from education about the boundaries of the healthy weight range.

Urban–rural comparison of weight status among women and children living in socioeconomically disadvantaged neighbourhoods

Objective: To compare the weight status of women and children living in socioeconomically disadvantaged rural and urban neighbourhoods in Victoria.

Design, setting and participants: Cross-sectional study of data collected between August 2007 and July 2008 as part of the Resilience for Eating and Activity Despite Inequality (READI) study. Women aged 18–45 years living in 40 rural and 40 urban socioeconomically disadvantaged Victorian areas were surveyed by postal questionnaire. Data from a subset of their children aged 5–12 years were also analysed. Weight and height were self-reported for women and measured for children.

Main outcome measures: Women’s weight status based on body mass index (BMI): underweight; healthy; overweight; or obese Class I, II or III; children’s weight status based on International Obesity Taskforce BMI cut-off points.

Results: Of 11 940 women randomly selected, 4934 (41%) replied to a postal invitation to participate. After exclusions for various reasons, data were available on 3879 women and 636 of their children. Twenty-four per cent of urban and 26% of rural women were classified as overweight; a further 19% of urban and 23% of rural women were classified as obese. Twenty per cent of both urban and rural children were classified as overweight; a further 10% of urban and rural children were classified as obese. In crude analyses, rural women had higher odds of Class I and II obesity (odds ratio [OR], 1.34 and 1.72, respectively) compared with urban women. After adjusting for sociodemographic factors (age, number of children, country of birth, education level, employment status and marital status), there was no difference between urban and rural women in odds of overweight or obesity Class I, II or III. No significant urban–rural difference in odds of overweight/obesity was evident among children.

Conclusions: The higher prevalence of obesity in rural women compared with urban women was largely explained by individual-level sociodemographic factors, such as age, number of children, country of birth, education level, employment status and marital status. This suggests that higher obesity levels among women in rural areas may be attributable to the sociodemographic composition of these areas.

The stability of weight status through the early to middle childhood years in Australia: a longitudinal study

OBJECTIVES: To investigate the sociodemographic and behavioural factors associated with incidence, persistence or remission of obesity in a longitudinal sample of Australian children aged 4-10 years. SETTING: Nationally representative Longitudinal Study of Australian Children (LSAC). PARTICIPANTS: The sample for this analysis included all children in the Kinder cohort (aged 4-5 years at wave 1) who participated in all four waves of LSAC (wave 1, 2004, aged 4-5 years; wave 2, 2006, aged 6-7 years; wave 3, 2008, aged 8-9 years and wave 4, 2010, aged 10-11 years). Of the 4983 children who participated in the baseline (wave 1) survey, 4169 (83.7%) children completed all four waves of data collection. PRIMARY AND SECONDARY OUTCOME MEASURES: Movement of children between weight status categories over time and individual-level predictors of weight status change (sociodemographic characteristics, selected dietary and activity behaviours). RESULTS: The study found tracking of weight status across this period of childhood. There was an inverse association observed between socioeconomic position and persistence of overweight/obesity. Sugar-sweetened beverages and fruit and vegetable intake and screen time appeared to be important predictors of stronger tracking. CONCLUSIONS: Overweight and obesity established early in childhood tracks strongly to the middle childhood years in Australia, particularly among children of lower socioeconomic position and children participating in some unhealthy behaviour patterns.

Sociodemographic and behavioural correlates of weight status among women with children living in socioeconomically disadvantaged neighbourhoods

Objective: To investigate sociodemographic and behavioural characteristics associated with weight status among women with children living in socioeconomically disadvantaged neighbourhoods.
Methods and procedures: A total of 1680 women aged 18–46 years, living in socioeconomically disadvantaged neighbourhoods with dependent children (aged 0–18 years), provided self-report data on height and weight and a range of sociodemographic and behavioural (for example, dietary intake, physical activity and time spent sitting) characteristics.
Results: Half of the women were classified as having a healthy weight (body mass index=18.5–25). Bivariable ordinal logistic regression analyses indicated that a healthy weight status was associated with a range of sociodemographic and behavioural characteristics. In a multivariable model, a healthy weight status among women was associated with being younger and unmarried, speaking a language other than English at home, having a medium or high level of education, and a partner with a high level of education, having a high household income, spending more time engaged in leisure-time physical activity and less time spent sitting, and having a lower consumption of soft drink.
Discussion: The present findings highlight that a considerable proportion of women with children living in disadvantaged neighbourhoods manage to maintain a healthy weight. Acknowledging the cross-sectional nature of this study, strategies aimed at helping women with children in socioeconomically disadvantaged areas to maintain their weight should focus on increasing physical activity, and reducing sitting time and soft drink consumption.

The relationship between quality of life and perceived body weight an dieting history in Dutch men and women

OBJECTIVES: (1) To study the relationship between quality of life (QoL) and measured and perceived weight and dieting history in Dutch men and women; (2) to assess the effect of weight loss over a 5 y period on QoL.

DESIGN: A cross-sectional study, in a sub-sample longitudinal over 5 y.

SUBJECTS: A total of 2155 men and 2446 women, aged 20-59 and recruited from the general population from three towns in The Netherlands.

MEASUREMENTS: Body weight, height, self-administered questionnaire including questions concerning demographic variables and weight loss practices as part of the Dutch Monitoring project on Risk Factors for Chronic Disease (MORGEN). The Rand-36 questionnaire was used as the QoL measure.

RESULTS: In men, measured overweight (body mass index, BMI>25 kg=m2) was not associated with any dimension of QoL after adjustment for age, educational level and perceived overweight. Perceived overweight was related to reduced scores for general health and vitality. This relationship was independent of measured obesity. A history of repeated weight loss was associated with reduced scores for role functioning due to both physical and emotional problems. In women, measured overweight was significantly associated with lower scores for five out of eight QoL dimensions and perceived overweight with three: general health, vitality and physical functioning. A history of frequent weight loss was related to significantly reduced scores in six dimensions. However, only with history of frequent weight loss, and uniquely in women, was there a significant reduction in
scores on mental health and limited emotional role functioning. Measured and perceived overweight and frequent weight loss were all related to reduced scores for physical functioning. Longitudinal data indicate that in older women weight gain of 10% body weight or more was associated with a significant deterioration in QoL.

CONCLUSIONS: When looking at measures of QoL in relation to overweight it is important to separate the effects of perception of weight status and history of weight loss. We observed that the latter two factors were associated with reduced scores on several dimensions of QoL, particularly in women. These associations were observed to be independent of body weight. International Journal of Obesity (2001) 25, 1386 – 1392

Weight status and perception barriers to healthy physical activity and diet behavior

Background : Physical inactivity and insufficient fruit and vegetable consumption are key risk factors for obesity and noncommunicable diseases. Weight perceptions may affect physical activity and diet behaviors. We report current prevalence estimates of Australian adults meeting recommended levels of leisure-time physical activity (LTPA) (150 min/week or more of at least moderate-intensity physical activity (including walking) on 5 days/week) and fruit (2 servings/day) and vegetable (5 servings/day) consumption for health benefits, by weight status and perceptions.
Methods : We conducted a cross-sectional survey analysis of data for 16 314 adults from the Australian National Health Survey 2004–2005. All variables were collected by self-report. Weighted estimates were age- and gender-specific, and data were analyzed using logistic regression with acceptable weight referent categories, adjusting for covariates.
Results : Among acceptable, overweight and obese adults, the prevalence of LTPA was 26.8, 26.1 and 19.3% for men, and 27.7, 23.7 and 19.7% for women, respectively. Approximately 55 and 15% of adults consumed sufficient fruit servings/day and vegetable servings/day, respectively, and less than 5% of adults met combined LTPA and diet guidelines. Overweight decreased the odds ratio for LTPA among women but not men, and obesity decreased the odds ratio for LTPA among both men and women. Overweight perception conferred odds ratios of 0.83 (95% CI 0.70–0.97, P=0.021) for overweight men, and of 0.74 (95% CI 0.62–0.88, P=0.001) and 0.69 (95% CI 0.59–0.80, P<0.001) for obese men and women, respectively; for LTPA, whereas no significant associations were found for acceptable weight perception. No consistent associations between weight status or perceptions and diet behaviors were found.
Conclusions : Overweight perception may be another barrier to physical activity participation among men and women with excess body weight. Public health strategies might need to focus on overcoming weight perception as well as weight status barriers to adopting healthy physical activity behaviors.

Childhood overweight and obesity: paternal influences on preschool aged children's eating and weight status

This thesis explored the role of paternal parenting styles, paternal child feeding practices, and father-child interactions in the development of preschool aged children’s eating behaviours and weight. Fathers parenting style and feeding practices were not directly associated with child BMI. However, fathers parenting style was predictive of child eating behaviours over time, and children's eating behaviours were associated with higher BMI, which suggests that there may be an indirect effect of parenting style on child BMI via child eating behaviour.

Which aspects of socioeconomic status are related to obesity among men and women?

OBJECTIVE: This study aimed to investigate the relationships between body weight and fat distribution, and four empirically derived domains of socioeconomic status: employment, housing, migration status and family unit.

DESIGN: A population-based study was used.

PARTICIPANTS: A total of 8667 randomly-selected adults (4167 men; 4500 women) who participated in the 1995 Australian National Health and Nutrition Surveys provided data on a range of health factors including objective height, weight and body fat distribution, and a range of sociodemographic indicators.

RESULTS: Results demonstrated associations for women, after controlling for age, between the employment domain, and body mass index and waist-to-hip ratio. Low status employed women were 1.4 times as likely to be overweight as high status employed women. There were less consistent relationships observed among these factors for men. Relationships between family unit and indicators of body weight and body fat distribution were observed for both men and women, with those who were married, particularly men (OR=1.6, 95% CI 1.4-2.0), at higher risk of overweight. The migration and housing socioeconomic status domains were not consistently associated with body mass index or waist-to-hip ratio.

CONCLUSIONS: These findings indicate that different components of socioeconomic status may be important in predicting obesity, and thus should be examined separately. Future research would benefit from investigating the underlying mechanisms governing the relationships between socioeconomic status domains further, particularly those related to employment and family unit and obesity

Trends in children`s physical activity and weight status in high and low socio-economic status areas of Melbourne, Victoria, 1985-2001

Objective:
To examine trends in active transport to and from school, in school sport and physical education (PE), and in weight status among children from high and low socio-economic status (SES) areas in Melbourne, Victoria, between 1985 and 2001.

Methods:
Cross-sectional survey data and measured height and weight from 1985 (n=557) and 2001 (n=926) were compared for children aged between 9–13 years within high and low SES areas.

Results:
From 1985 to 2001, the frequency of walking to or from school declined (4.38±4.3 vs. 3.61 ± 3.8 trips/wk, p<0.001), cycling to or from school also declined (1.22±2.9 vs. 0.36±1.5 trips/wk, p<0.001), and the frequency of PE lessons declined (1.64±1.1 vs. 1.18±0.9 lessons/wk, p<0.001). However, the frequency of school sport increased (0.9±1.22 vs. 1.24±0.8 sessions/wk, p<0.001). In 1985, 11.7% of children were overweight or obese compared with 28.7% in 2001 (p<0.001). Apart from walking to school and school sport, there were greater relative declines in cycling to school and PE, and increases in overweight and obesity among children attending schools in low SES areas compared with those attending schools in high SES areas.

Conclusions:
Declines in active school transport and PE have occurred at the same time as increases in overweight and obesity among Australian children.

Implications:
Promoting active school transport and maintaining school sport and PE should be important public health priorities in Australia. Current inequities in school sport and PE and in prevalence of overweight and obesity by area-level SES also need to be addressed.

Associations between family circumstance and weight status of Australian children

To examine associations between weight status and multiple indicators of family circumstance in Australian elementary school children. Data were combined from the 2001 Children's Leisure Activities Study (CLAS Study) and 2002/3 Health, Eating and Play Study (HEAP Study), involving 2520 children in Grades Prep (mean age 6 years) and 5-6 (mean age 11 years) in Melbourne, Australia. Children's body mass index (BMI) was calculated from measured height and weight. Weight status (non-overweight or overweight) was determined according to International Obesity Taskforce cut-off points and BMI was transformed to z-scores based on the 2000 US growth chart data. Parents reported family circumstance (number of parents in the home, marital status, presence of siblings, parental education, parental employment status, parental work hours [HEAP Study only]) and parental BMI. Regression analyses were conducted for the sample overall and separately for young girls, young boys, older girls and older boys. Children in single-parent homes, those without siblings, and those with less educated mothers and fathers tended to have higher z-BMIs (p=0.002, p=0.003, p<0.001 and p<0.001, respectively) and were more likely to be overweight (p=0.003, p<0.001, p<0.001 and p=0.02, respectively). Associations were stronger for older children. Parental employment and work hours were not consistently associated with child weight status. The multivariable models did not demonstrate a cumulative explanatory effect (R2=0.02), except when maternal BMI was included (R2=0.07). Individual measures of family circumstance were differentially associated with child weight status and appeared to be largely independent of other measures of family circumstance. Childhood overweight interventions may need to be tailored based on the age, gender, maternal BMI and family circumstances of the target group.

Weight and place: a multilevel cross-sectional survey of area-level social disadvantage and overweight/obesity in Australia

Objective: To estimate variation between small areas in adult body mass index (BMI), and assess the importance of area level socioeconomic disadvantage in predicting BMI.

Methods: We identified all census collector districts (CCDs) in the 20 innermost Local Government Areas in metropolitan Melbourne, Australia, and ranked them by the percentage of low income households (<$400/week). In all, 50 CCDs were randomly selected from the least, middle and most disadvantaged septiles of the ranked list and 4913 residents (61.4% participation rate) completed one of two surveys. Multilevel linear regression was used to estimate area level variance in BMI and the importance of area level socioeconomic disadvantage in predicting BMI.

Results: There were significant variations in BMI between CCDs for women, even after adjustment for individual and area SES (P=0.012); significant area variation was not found for men. Living in the most versus least disadvantaged areas was associated with an average difference in BMI of 1.08 kg/m² (95% CI: 0.48–1.68 kg/m²) for women, and of 0.93 kg/m² (95% CI: 0.32–1.55 kg/m²) for men. Living in the mid versus least disadvantaged areas were associated with an average difference in BMI of 0.67 kg/m² (95% CI: 0.09–1.26 kg/m²) for women, and 0.43 kg/m² for men (95% CI: -0.16–1.01).

Conclusion: These findings suggest that area disadvantage is an important predictor of adult BMI, and support the need to focus on improving local environments to reduce socioeconomic inequalities in overweight and obesity.