Identification of hypothalamic genes implicated in the development of obesity in Psammomys obesus using differential display PCR

The hypothalamus is a key central controller of energy homeostasis and is the source and/or site of action of many neuropeptides involved in this process. The aim of this study was to isolate hypothalamic genes differentially expressed between lean and obese Psammomys obesus, a polygenic animal model of obesity and type 2 diabetes. Differential display PCR was used to compare hypothalamic gene expression profiles of lean and healthy, obese and hyperinsulinemic, and obese, diabetic P. obesus in both the fed and fasted states. We conducted differential display with 180 separate primer combinations to amplify approximately 9000 expressed transcripts. Sixty differentially expressed bands were excised. Taqman PCR was performed on 36 of these transcripts to confirm differential gene expression in a larger sample population. Of these 36 transcripts, 9 showed homology to known genes, and 27 were considered to be novel sequences. Gene expression profiles for two of these genes are presented here. In conclusion, differential display PCR was successfully used to isolate several transcripts that may be involved in the central regulation of energy balance. We are currently conducting numerous studies to further investigate the role of these genes in the development of obesity in P. obesus.

Interventions for preventing obesity in childhood. A systematic review

Background The prevalence of obesity and overweight is increasing worldwide. Obesity in children impacts on their health in both short- and long-term. Obesity prevention strategies are poorly understood.

Objective To assess the effectiveness of interventions designed to prevent obesity in childhood.

Search strategy Electronic databases were searched from January 1985 to October 1999.

Selection criteria Data from randomized control trials and non-randomized trials with concurrent control group were included. A priori, studies with follow up of 1 year minimum were selected however, this was subsequently amended to include studies with a minimum follow up of three months.

Data collection & analysis Two reviewers independently extracted data and assessed study quality.

Main results Seven studies were included, three long-term (>1 years) and four short-term (>3 months and <1 years). The studies included were diverse in terms of study design and quality, target population, theoretical underpinning of intervention approach, and outcome measures. As such, it was not appropriate to combine study findings using statistical methods.

Conclusions Two of the long-term studies (one focused on dietary education and physical activity vs. control, and the other only on dietary education vs. control), resulted in a reduction in the prevalence on obesity, but the third, which focused on dietary education and physical activity, found no effect. Of the four short-term studies, three focused simply on physical activity/reduction of sedentary behavious vs. control. Two of these studies resulted in a reduction in the prevalence of obesity in intervention groups compared with control groups, and another study found a non-significant reduction. The fourth study focused on dietary education and physical activity, and did not find an effect on obesity, but did report a reduction in fat intake. Overall, the findings of the review suggest that currently there is limited quality data on the effectiveness of obesity prevention programmes and as such no generalizable conclusions can be drawn. The need for well-designed studies that examine a range of interventions remains a priority.

Risk factors for violence and relational aggression in adolescence

Analyses examined risk factors for seventh- and ninth-grade youth  categorized as nonoffenders, physically violent, relationally aggressive, and both violent and relationally aggressive. Bivariate and multivariate results showed that relationally aggressive youth were elevated on most risks above levels for nonoffenders but lower than those for youth who were violent alone or violent in combination with relational aggression. Youth who were both relationally aggressive and violent did not differ from those who were violent alone on most risk factors examined. Peer, individual, and family risks were among the strongest predictors.

High childhood obesity in an Australian population

Objective: The objective was to determine the prevalences of overweight and obesity in regional Australian children and to examine the association between BMI and indicators of socioeconomic status (SES).

Research Methods and Procedures: Regionally representative cross-sectional survey of 2184 children, 4 to 12 years of age, was conducted, and the socio-demographic characteristics of their parents from regional Victoria, Australia, 2003 to 2004, were obtained.

Results: The prevalences of overweight and obesity were 19.3 plusminus 0.8% (proportion plusminus standard error) and 7.6 plusminus 0.6% , respectively, using international criteria, and the proportion of overweight/obese girls was significantly higher than that of boys (29.6 plusminus 1.4% vs. 23.9 plusminus 1.3% , chi2 = 9.01, p = 0.003). Children from households of lower SES had higher odds of being overweight/obese; lower SES was defined by lower paternal education (adjusted odds ratio, 1.18; 95% confidence interval, 1.08 to 1.30) and lower area-level SES (adjusted odds ratio, 1.13; 95% confidence interval, 1.02 to 1.25), adjusted for age, gender, height, and clustering by school.

Discussion: The prevalences of overweight and obesity are increasing in Australian children by about one percentage point per year. This equates to approx40,000 more overweight children each year, placing Australian children among those at highest risk around the world. In addition, girls are more likely to be overweight, and there is a general trend for children of lower SES to be at even greater risk of overweight and obesity.

Association of key foods and beverages with obesity in Australian schoolchildren

Objective: To examine the pattern of intake of key foods and beverages of children aged 4–12 years and the association with weight status.
Design and setting: A computer-assisted telephone interview was used to determine the intake of fruit, vegetables, packaged snacks, fast foods and sweetened drinks ‘yesterday’ and ‘usually’ as reported by parents/guardians of a representative sample of 2184 children from the Barwon South-Western region of Victoria, Australia.
Results: Children who consumed .2–3, .3–4 and .4 servings of fruit juice/drinks ‘yesterday’ were, respectively, 1.7 (95% confidence interval (CI) 1.2–2.2), 1.7 (95% CI 1.2–2.5) and 2.1 (95% CI 1.5–2.9) times more likely to be overweight/obese compared with those who had no servings of fruit juice/drink ‘yesterday’, adjusted for age, gender and socio-economic status (SES). Further, children who had $3 servings
of soft drink ‘yesterday’ were 2.2 (95% CI 1.3–3.9) times more likely to be
overweight/obese compared with those who had no servings of soft drink ‘yesterday’, adjusted for age, gender and SES. In addition, children who ‘usually’ drank fruit juice/drinks twice or more per day were 1.7 (95% CI 1.2–2.4) times more likely to be overweight/obese compared with those who drank these beverages once or less per week, adjusted for age, gender and SES. Although fast foods and packaged snacks were regularly eaten, there were no associations between weight status and
consumption of these foods.
Conclusions: Intake of sweetened beverages was associated with overweight and obesity in this population of Australian schoolchildren and should be a target for intervention programmes aimed at preventing unhealthy weight gain in children.

Overweight and obesity in Australia: the 1999-2000 Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

Objective:
To measure the prevalence of obesity in Australian adults and to examine the associations of obesity with socioeconomic and lifestyle factors.

Design:
AusDiab, a cross-sectional study conducted between May 1999 and December 2000, involved participants from 42 randomly selected districts throughout Australia.

Participants:
Of 20 347 eligible people aged > 25 years who completed a household interview, 11 247 attended the physical examination at local survey sites (response rate, 55%).

Main outcome measures:
Overweight and obesity defined by body mass index (BMI; kg/m2) and waist circumference (cm); sociodemographic factors (including smoking, physical activity and television viewing time).

Results:
The prevalence of overweight and obesity (BMI > 25.0 kg/m2; waist circumference > 80.0 cm [women] or > 94.0 cm [men]) in both sexes was almost 60%, defined by either BMI or waist circumference. The prevalence of obesity was 2.5 times higher than in 1980. Using waist circumference, the prevalence of obesity was higher in women than men (34.1% v 26.8%; P < 0.01). Lower educational status, higher television viewing time and lower physical activity time were each strongly associated with obesity, with television viewing time showing a stronger relationship than physical activity time.

Conclusions:
The prevalence of obesity in Australia has more than doubled in the past 20 years. Strong positive associations between obesity and each of television viewing time and lower physical activity time confirm the influence of sedentary lifestyles on obesity, and underline the potential benefits of reducing sedentary behaviour, as well as increasing physical activity, to curb the obesity epidemic.

Overweight and obesity in children from Shenzhen, Peoples Republic of China

We describe overweight and obesity prevalence in Shenzhen school children (2146 girls and 2428 boys) aged 7 to 12 years, Guangdong Province, China. Nineteen percent of boys and 11% of girls were overweight or obese. Boys had odds of almost 2 to 1 (1.92, 95% CI 1.62,2.27) of being overweight or obese compared to girls and children aged 9 years and over were at greater odds of being overweight or obese than those aged 7 years (p<0.05). Overweight and obesity prevalence among children from Shenzhen rivals that of children from developed nations. Current obesity levels in Shenzhen may represent future levels for urban China.

Interventions for preventing obesity in children (Review)

Background
Obesity prevention is an international public health priority. The prevalence of obesity and overweight is increasing in child populations throughout the world, impacting on short and long-term health. Obesity prevention strategies for children can change behaviour but efficacy in terms of preventing obesity remains poorly understood.

Objectives
To assess the effectiveness of interventions designed to prevent obesity in childhood through diet, physical activity and/or lifestyle and social support.

Search strategy
MEDLINE, PsycINFO, EMBASE, CINAHL and CENTRAL were searched from 1990 to February 2005. Non-English language papers were included and experts contacted.

Selection criteria
Randomised controlled trials and controlled clinical trials with minimum duration twelve weeks.

Data collection and analysis
Two reviewers independently extracted data and assessed study quality.

Main results
Twenty-two studies were included; ten long-term (at least 12 months) and twelve short-term (12 weeks to 12 months). Nineteen were school/preschool-based interventions, one was a community-based intervention targeting low-income families, and two were family-based interventions targeting non-obese children of obese or overweight parents.

Six of the ten long-term studies combined dietary education and physical activity interventions; five resulted in no difference in overweight status between groups and one resulted in improvements for girls receiving the intervention, but not boys. Two studies focused on physical activity alone. Of these, a multi-media approach appeared to be effective in preventing obesity. Two studies focused on nutrition education alone, but neither were effective in preventing obesity.

Four of the twelve short-term studies focused on interventions to increase physical activity levels, and two of these studies resulted in minor reductions in overweight status in favour of the intervention. The other eight studies combined advice on diet and physical activity, but none had a significant impact.

The studies were heterogeneous in terms of study design, quality, target population, theoretical underpinning, and outcome measures, making it impossible to combine study findings using statistical methods. There was an absence of cost-effectiveness data.

Authors' conclusions
The majority of studies were short-term. Studies that focused on combining dietary and physical activity approaches did not significantly improve BMI, but some studies that focused on dietary or physical activity approaches showed a small but positive impact on BMI status. Nearly all studies included resulted in some improvement in diet or physical activity. Appropriateness of development, design, duration and intensity of interventions to prevent obesity in childhood needs to be reconsidered alongside comprehensive reporting of the intervention scope and process.

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.

The role of peer support in facilitating psychosocial adjustment to chronic illness in adolescence

This article describes a Chronic Illness Peer Support (ChIPS) programme designed to assist young people in their adjustment to life with a chronic medical condition. The ChIPS programme takes a non-categorical approach to participation, recognizing that young people with different medical conditions experience many similar concerns. Support groups are facilitated by a health professional and peer co-leader. Groups meet weekly for 8 weeks and typically include between six and eight young people. Young people can choose to remain involved in broader social, educational and recreational activities following completion of the 8-week programme. We discuss nine psychosocial mechanisms by which peer support groups such as ChIPS might act to improve resilience and well-being among participants. We also discuss some theoretical risks in running support groups for chronically ill young people, which emphasize the importance of training and support of group leaders, including the peer co-leaders. The article concludes with a personal testimony by a ChIPS participant that was prepared for the 2003 Australian and New Zealand Adolescent Health Conference.

Joint associations of multiple leisure-time sedentary behaviours and physical activity with obesity in Australian adults

Background
Television viewing and physical inactivity are independently associated with risk of obesity. However, how the combination of multiple leisure-time sedentary behaviours (LTSB) and physical activity (LTPA) may contribute to the risk of obesity is not well understood. We examined the joint associations of multiple sedentary behaviours and physical activity with the odds of being overweight or obese.

Methods
A mail survey collected the following data from adults living in Adelaide, Australia (n = 2210): self-reported height, weight, six LTSB, LTPA and sociodemographic variables. Participants were categorised into four groups according to their level of LTSB (dichotomised into low and high levels around the median) and LTPA (sufficient: ≥ 2.5 hr/wk; insufficient: < 2.5 hr/wk). Logistic regression analysis examined the odds of being overweight or obese (body mass index ≥ 25 kg/m2) by the combined categories.

Results
The odds of being overweight or obese relative to the reference category (low sedentary behaviour time and sufficient physical activity) were: 1.54 (95% confidence interval [CI]: 1.20–1.98) for the combination of low sedentary behaviour time and insufficient physical activity; 1.55 (95% CI: 1.20–2.02) for the combination of high sedentary behaviour time and sufficient physical activity; and 2.26 (95% CI: 1.75–2.92) for the combination of high sedentary behaviour time and insufficient physical activity.

Conclusion
Those who spent more time in sedentary behaviours (but were sufficiently physically active) and those who were insufficiently active (but spent less time in sedentary behaviour) had a similar risk of being overweight or obese. Reducing leisure-time sedentary behaviours may be as important as increasing leisure-time physical activity as a strategy to fight against obesity in adults.

Neighbourhood fast food outlets and obesity in children and adults : the CLAN study

Objective : We examined associations between density of and proximity to fast food outlets and body weight in a sample of children (137 aged 8-9 years and 243 aged 13-15 years) and their parents (322 fathers and 362 mothers).
Methods : Children's measured and parents' self-reported heights and weights were used to calculate body mass index (BMI). Locations of major fast food outlets were geocoded. Bivariate linear regression analyses examined associations between the presence of any fast food outlet within a 2 km buffer around participants' homes, fast food outlet density within the 2 km buffer, and distance to the nearest outlet and BMI. Each independent variable was also entered into separate bivariate logistic regression analyses to predict the odds of being overweight or obese.
Results : Among older children, those with at least one outlet within 2 km had lower BMI z-scores. The further that fathers lived from an outlet, the higher their BMI. Among 13-15-year-old girls and their fathers, the likelihood of overweight/obesity was reduced by 80% and 50%, respectively, if they had at least one fast food outlet within 2 km of their home. Among older girls, the likelihood of being overweight/obese was reduced by 14% with each additional outlet within 2 km. Fathers' odds of being overweight/obese increased by 13% for each additional kilometre to the nearest outlet.
Conclusions : While consumption of fast food has been shown to be associated with obesity, this study provides little support for the concept that exposure to fast food outlets in the local neighbourhood increases risk of obesity.

Television viewing and abdominal obesity in young adults : is the association mediated by food and beverage consumption during viewing time or reduced leisure-time physical activity?

BACKGROUND:The behavioral pathways through which television (TV) viewing leads to increased adiposity in adults are unclear.

OBJECTIVE:We wanted to determine whether the association between TV viewing and abdominal obesity in young adults is mediated by food and beverage consumption during TV viewing time or by a reduction in overall leisure-time physical activity (LTPA).

DESIGN:This study involved a cross-sectional analysis of data from 2001 Australian adults aged 26–36 y. Waist circumference (WC) was measured at study clinics, and TV viewing time, frequency of food and beverage consumption during TV viewing, LTPA, and demographic characteristics were self-reported.

RESULTS:Women watching TV >3 h/d had a higher prevalence of severe abdominal obesity (WC: =88 cm) compared with women watching =1 h/d [prevalence ratio (PR): 1.89; 95% CI: 1.32, 2.71]. Moderate abdominal obesity (WC: 94–101.9 cm) was more prevalent in men watching TV >3 h/d than in men watching =1 h/d (PR: 2.16; 95% CI: 1.37, 3.41). Adjustment for LTPA made little difference, but adjustment for food and beverage consumption during TV viewing attenuated the associations (PR: 1.48; 95% CI: 1.01, 2.17 for women; PR: 1.73; 95% CI: 1.06, 2.83 for men).

CONCLUSIONS:The association between TV viewing and WC in young adults may be partially explained by food and beverage consumption during TV viewing but was not explained by a reduction in overall LTPA. Other behaviors likely contribute to the association between TV viewing and obesity.