Composition of objectively measured physical activity and sedentary behaviour participation across the school-day, influence of gender and weight status: cross-sectional analyses among disadvantaged Victorian school children

BACKGROUND: The after-school period has been described as the 'critical window' for physical activity (PA) participation. However, little is known about the importance of this window compared with the before and during-school period among socioeconomically disadvantaged children, and influence of gender and weight status.

METHODS: 39 out of 156 (RR=25%) invited primary schools across 26 local government areas in Victoria, Australia, consented to participate with 856 children (RR=36%) participating in the wider study. The analysis sample included 298 Grade 4 and Grade 6 children (mean age: 11.2±1.1; 44% male) whom met minimum accelerometry wear-time criteria and had complete height, weight and health-behaviours questionnaire data. Accelerometry measured duration in daily light-intensity PA (LPA), moderate-to-vigorous PA (MVPA) and sedentary time (ST) was calculated for before-school=8-8:59, during-school=9:00-15:29 and after-school=15:30-18:00. Bivariate and multivariable linear regression analyses were conducted.

RESULTS: During-school represented the greatest accumulation of LPA and MVPA compared with the before and after-school periods. Boys engaged in 102 min/day of LPA (95% CI 98.5 to 104.9) and 62 min/day of MVPA (95% CI 58.9 to 64.7) during-school; girls engaged in 103 min/day of LPA (95% CI 99.7 to 106.5) and 45 min/day of MVPA (95% CI 42.9 to 47.4). Linear regression models indicated that girls with overweight or obesity engaged in significantly less LPA, MVPA and more time in ST during-school.

CONCLUSIONS: This study highlights the importance of in-school PA compared with after-school PA among socioeconomically disadvantage children whom may have fewer resources to participate in after-school PA.

Beliefs about the causes of weight change in the Australian population

OBJECTIVE: To describe self-reported weight change and beliefs about the causes of weight change and to examine whether these vary by sex and weight status.
DESIGN: This cross-sectional population study examined data from the 1995 Australian National Health and Nutrition Surveys.
SUBJECTS: A total of 10 624 randomly-selected adults provided data.
MEASURES: Objectively measured height and weight, perceptions of current weight status, self-reported weight change over the past year, and reasons for weight change.
RESULTS: Thirty-five percent of participants reported a weight gain in the last 12 months, with females, and those already overweight more likely to report a recent increase in weight. Approximately one in five participants reported a recent weight loss. Those who had recently gained weight were more likely to perceive themselves as overweight regardless of actual weight status. Commonly reported reasons for weight gain included a change in physical activity level (52% males and 35% females) and a change in the amount of food/drink consumed (30% males, 27% females). Similar reasons were given for weight loss.
CONCLUSIONS: Findings of widespread reported weight gain, particularly among those already overweight, suggest Australia's obesity epidemic may be worsening. Strategies are urgently required to better inform individuals about the factors impacting on their weight in order to prevent further weight gain.

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.

Whose socioeconomic status influences a women's obesity risk: her mother's, her father's, or her own?

Background Evidence on the relative influence of childhood vs adulthood socioeconomic conditions on obesity risk is limited and equivocal. The objective of this study was to investigate associations of several indicators of mothers', fathers', and own socioeconomic status, and intergenerational social mobility, with body mass index (BMI) and weight change in young women.

Methods This population-based cohort study used survey data provided by 8756 women in the young cohort (aged 18–23 years at baseline) of the Australian Longitudinal Study on Women's Health. In 1996 and 2000, women completed mailed surveys in which they reported their height and weight, and their own, mother's, and father's education and occupation.

Results Multiple linear regression models showed that both childhood and adulthood socioeconomic status were associated with women's BMI and weight change, generally in the hypothesized (inverse) direction, but the associations varied according to socioeconomic status and weight indicator. Social mobility was associated with BMI (based on father's socioeconomic status) and weight change (based on mother's socioeconomic status), but results were slightly less consistent.

Conclusions Results suggest lasting effects of childhood socioeconomic status on young women's weight status, independent of adult socioeconomic status, although the effect may be attenuated among those who are upwardly socially mobile. While the mechanisms underlying these associations require further investigation, public health strategies aimed at preventing obesity may need to target families of low socioeconomic status early in children's lives.

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

Family average income and body mass index above the healthy weight range among urban and rural resicents in regional Mainland China

Objective: To explore the relationship between family average income (FAI; an index of socio-economic status) and body mass index (BMI; a widely used, inexpensive indicator of weight status) above the healthy weight range in a region of Mainland China. Design: Population-based cross-sectional study, conducted between October 1999 and March 2000 on a sample of regular local residents aged 35 years or older who were selected by random cluster sampling. Setting: Forty-five administrative villages selected from three urban districts and two rural counties of Nanjing municipality, Mainland China, with a regional population of 5.6 million. Subjects: In total, 29 340 subjects participated; 67.7% from urban and 32.3% from rural areas; 49.8% male and 50.2% female. The response rate among eligible participants was 90.1%. Results: The proportion of participants classified as overweight was 30.5%, while 7.8% were identified as obese. After adjusting for possible confounding variables (age, gender, area of residence, educational level, occupational and leisure-time physical activity, daily vegetable consumption and frequency of red meat intake), urban participants were more likely to be overweight or obese relative to their rural counterparts, more women than men were obese, and participants in the lowest FAI tertile were the least likely to be above the healthy weight range. Conclusions: The proportion of adults with BMI above the healthy weight range was positively related to having a higher socio-economic status (indexed by FAI) in a regional Chinese population.

Family physical activity and sedentary environments and weight change in children

Objective. To examine associations between family physical activity and sedentary environment and changes in body mass index (BMI) z-scores among 10-12-year-old children over three years.
Method. Design. Longitudinal (three-year follow-up). Subjects. In total, 152 boys and 192 girls aged 10-12 years at baseline.
Measurements. Measured height and weight at baseline and follow-up (weight status, BMI z-scores); aspects of the family physical activity and sedentary environment (parental and sibling modelling, reinforcement, social support, family-related barriers, rules/restrictions, home physical environment) measured with a questionnaire completed by parents at baseline.
Results. At baseline, 29.6% of boys and 21.9% of girls were overweight or obese, and mean (standard deviation, SD) BMI z-scores were 0.44 (0.99) and 0.28 (0.89), respectively. There was a significant change in BMI z-score among girls (mean change=0.19, SD=0.55, p<0.001), but not boys. Among boys, the number of items at home able to be used for sedentary behaviour (B=0.11, p=0.037) was associated with relatively greater increases in BMI z-score. Among girls, sibling engagement in physical activity at least three times/wk (B=-0.17, p=0.010) and the number of physical activity equipment items at home (B=-0.05, p=0.018) were associated with relatively greater decreases in BMI z-score.
Conclusion. Sibling physical activity and environmental stimuli for sedentary behaviours and physical activity within the home may be important targets for prevention of weight gain during the transition from childhood to adolescence.

Parents' perceptions and concerns about their children's weight

Background: For parents to address overweight or obesity in their children, they first need to perceive their child to be overweight and to show some level of concern. We aimed to: (1) measure the level of misclassification between children’s actual and parent-perceived weight status, and (2) determine the level of parent concern about their child’s (actual) weight and whether concern varied according to the accuracy of parents’ perceptions.

Methods: Participants were 1711 primary school children aged 5–12 years from the Barwon-South West region of Victoria, Australia. Height and weight were measured and weight status determined using international standards. Parents completed a Computer Assisted Telephone Interview (CATI) that included questions relating to their child’s weight.

Results: 448 children (26.2% of sample) were overweight or obese. Of these, weight status for almost half (48%) was underestimated by parents. This ‘bias’ did not vary according to the child’s gender, parent’s education, or household socio-economic status but did for child’s age and parent-respondent gender. More than half (57%) of the parents of overweight-obese children expressed no concern about their child’s weight. Parents who underestimated the weight status of their overweight child were significantly less concerned (P < 0.001) about their child’s weight than those who correctly perceived their child as overweight.

Conclusions: Parents were relatively poor judges of overweight or obesity in their own child and consequently there was a lack of appropriately directed concern. Education to help parents correctly classify their child’s weight status should be part of efforts to prevent unhealthy weight gain.

Association between weight perception and psychological distress

Background: Obesity is a well-known cause of cardiovascular disease burden and premature death, but effects on depressive symptoms remain equivocal. Depressive symptoms may be more common among the obese individuals who perceive themselves as overweight, rather than those who perceive themselves as having an acceptable weight. Our aim was to determine whether weight status and weight perceptions are independently associated with psychological distress.

Methods: We conducted a cross-sectional study using data from the Australian National Health Survey 2004–2005 (N=17 253). All variables were collected by self-report. Adjusted multinomial logistic regression analysis was conducted to generate prevalence odds ratios with 95% confidence intervals (95% CI) for medium (Kessler Psychological Distress Scale (K10) scores of 20–29) and high (K10 scores of 30–50) psychological distress (compared with K10 scores of 10–19 as the reference) associated with weight status (standard body mass index (BMI) cutoffs for underweight, overweight and obesity vs normal weight), weight perception (perceived underweight and overweight vs acceptable weight) and weight misperception (incorrect with BMI vs correct with BMI) adjusting for numerous important covariates.

Results: Overweight and underweight perception increased the odds of medium (40 and 50%) and high (50 and 120%) psychological distress, whereas weight status and weight misperception were not associated with psychological distress in adjusted analysis. Gender, alcohol consumed per week and post-school education were not significant covariates (at P<0.10 level).

Conclusions: Overweight and underweight perception rather than weight status or weight misperception are significant risk factors associated with medium and high psychological distress prevalence and effects appear to be uniform for men and women. Well-designed prospective studies are still needed to determine whether weight perceptions cause psychological distress, and if so, whether symptoms are significantly reduced following effective intervention.

An observational approach to testing bi-directional parent–child interactions as influential to child eating and weight

Obesity among children has been on the rise globally for the past few decades. Previous research has centred mainly on self/parent-reported measures examining only uni-directional parental feeding styles and practices. Recent discussions in the literature have raised the importance of bi-directional parent–child interactions in influencing children's weight status. The aims of this paper are to highlight the importance of an observational approach when investigating positive bi-directional parent–child interactions during mealtimes and to outline how these interactions may be linked to positive child eating and weight outcomes. We examine the current literature on self-reported parental patterns and argue for the influential roles of responsiveness, affect and parental control dimensions within the parent–child dyad. Information about the ways in which the parent and the child can influence each other on these dimensions, as observed in parent–child interactions around food, is likely to provide greater insights into the aetiology of childhood obesity.

Perceived discrimination and stigmatisation against severely obese women : age and weight loss make a difference

Aims: Patients’ perceptions about weight-related stigma and discrimination were assessed in 2 groups of patients, obese and laparoscopic adjustable gastric banding (LAGB).

Methods: Seven focus group sessions were held including a total of 32 women, 8 obese (body mass index 35+) and 24 who had lost 50&percnt; of excess weight following bariatric surgery. During the sessions, participants were asked to consider their experiences in situations including general, family, friends, work place, medical, and educational settings.

Results: Whilst perceptions of discrimination and stigmatisation were common and affected many life situations, they were less prevalent than previous reports. It appeared that it was not the frequency or number of events which affected an individual but the intensity of the experience. Younger women reported greater discrimination than older women and felt the social consequences of obesity to a greater extent. Older women were more concerned about the consequences of being overweight on their health.

Conclusions: Women who had lost weight considered that aspects of their own behaviours when obese contributed to their experiences of discrimination and stigmatisation. Perceptions of discrimination and stigmatisation appear to be influenced by age and current weight status.

Which measures of adiposity are related to Australian adolescent's perception of their weight?

Aim
To determine which measurement of adiposity – standardised body mass index (BMI-z), waist circumference or body fat percentage – is most closely correlated with adolescents' weight perception and whether this differs by gender.

Methods
Weight and height (used to calculate BMI-z), waist circumference and body fat percentage were measured in 2278 adolescents aged between 12 and 16 and compared with self-reported weight status.

Results
The distribution of subjects across the three weight categories (underweight, healthy weight and overweight) differed significantly between BMI-z, waist circumference and body fat percentage (p < 0.001). BMI-z was most closely aligned with perceived weight status in boys and girls, and waist circumference was also a good correlate of weight perception in boys. Boys were more likely than girls to underestimate their weight when it was defined by BMI-z; however, girls were equally likely to underestimate their weight when it was defined by waist circumference. The majority of adolescents underestimated their weight status when it was defined by BF%.

Conclusion
BMI-z is the closest correlate of self-perceived weight status. In the absence of internationally accepted reference values for waist circumference, BMI-z is the most appropriate measure to verify weight perception.

Small area-level socioeconomic status and all-cause mortality within 10 years in a population-based cohort of women: Data from the Geelong Osteoporosis Study

Background: The social gradient of health and mortality is well-documented. However, data are scarce regarding whether differences in mortality are observed across socio-economic status (SES) measured at the small area-level. We investigated associations between area-level SES and all-cause mortality in Australian women aged ≥. 20. years. Methods: We examined SES, obesity, hypertension, lifestyle behaviors and all-cause mortality within 10. years post-baseline (1994), for 1494 randomly-selected women. Participants' residential addresses were matched to Australian Bureau of Statistics Census data to identify area-level SES, and deaths were ascertained from the Australian National Deaths Index. Logistic regression models were adjusted for age, and subsequent adjustments made for measures of weight status and lifestyle behaviors. Results: We observed 243 (16.3%) deaths within 10. years post-baseline. Females in SES quintiles 2-4 (less disadvantaged) had lower odds of mortality (0.49-0.59) compared to SES quintile 1 (most disadvantaged) under the best model, after adjusting for age, smoking status and low mobility. Conclusions: Compared to the lowest SES quintile (most disadvantaged), females in quintiles 2 to 5 (less disadvantaged) had significantly lower odds ratio of all-cause mortality within 10. years. Associations between extreme social disadvantage and mortality warrant further attention from research, public health and policy arenas.

Classification tree analysis of postal questionnaire data to identify risk of excessive gestational weight gain

OBJECTIVE: overweight/obese weight status during pregnancy increases risk of a range of adverse health outcomes for mother and child. Whereas identification of those who are overweight/obese pre-pregnancy and in early pregnancy is straightforward, prediction of who will experience excessive gestational weight gain (EGWG), and thus be at greater risk of becoming overweight or obese during pregnancy is more challenging. The present study sought to better identify those at risk of EGWG by exploring pre-pregnancy BMI as well as a range of psychosocial risk factors identified as risk factors in prior research. METHODS: 225 pregnant women completed self-reported via postal survey measures of height, weight, and psychosocial variables at 16-18 weeks gestation, and reported their weight again at 32-34 weeks to calculate GWG. Classification and regression tree analysis (CART) was used to find subgroups in the data with increased risk of EGWG based on their pre-pregnancy BMI and psychosocial risk factor scores at Time 1. FINDINGS: CART confirmed that self-reported BMI status was a strong predictor of EGWG risk for women who were overweight/obese pre-pregnancy. Normal weight women with low motivation to maintain a healthy diet and who reported lower levels of partner support were also at considerable risk of EGWG. IMPLICATIONS FOR PRACTICE: present findings offer support for inclusion of psychosocial measures (in addition to BMI) in early antenatal visits to detect risk of EGWG. However, these findings also underscore the need for further consideration of effect modifiers that place women at increased or decreased risk of EGWG. Proposed additional constructs are discussed to direct further theory-driven research.

Validity and reliability of a physical activity recall instrument among overweight and non-overweight men and women

This study examined the validity and reliability of survey items measuring one-week recall of physical activity (PA) and examined differences by weight status. A sub-aim of the study was to objectively assess the intensity of activity that most closely matches self-report. A questionnaire was administered to adults twice, three days apart. It was again administered after subjects wore a MTI/CSA accelerometer for seven days (n = 118). Several metabolic equivalent (MET) thresholds were applied to the accelerometer data. Agreement between test and re- test estimates of sufficient physical activity for health benefits (150 min/week) was high (% agreement > 90%). Correlations (rho) between total reported PA (mins/day) and accelerometer data were 0.29 (p < 0.05) among men and 0.25 (p < 0.05) among women. Among men, self- reported duration of moderate PA (3-5.9 METS) and accelerometer data were significantly correlated (rho = 0.40, p < 0.01), with no differences by weight status. Among women, a significant relationship was found only for those who were not overweight (rho = 0.52, p < 0.001). A significant correlation between self-reported duration of vigorous PA (6+ METS) and accelerometer data was only found for overweight men (rho = 0.40, p < 0.05). When lower MET thresholds were applied to the accelerometer data, women's reported duration of moderate-intensity PA was most strongly correlated with moderate PA (accelerometer) defined as 2.0-5.9 METS (rho = 0.39, p < 0.01). The recall instrument provides a consistent measure of physical activity and validation coefficients were similar to those obtained for other physical activity recall questionnaires. However, the ability to measure PA by self-report may vary by weight status.