A de Silva

Combination of polymorphisms in OB-R and the OB gene associated with insulin resistance in Nauruan males

OBJECTIVE: To investigate the relationship between polymorphisms in the OB-R and OB genes and metabolic markers for obesity and glucose intolerance in a population of Nauruan men. In addition, we examined the effect of the simultaneous presence of the three polymorphisms on the phenotype of individuals in this population.DESIGN AND SUBJECTS: This study was conducted in a population from the Pacific Island of Nauru. Populations in this region have some of the highest recorded rates of obesity and type 2 diabetes and are therefore of great interest in the genetic analysis of these diseases. Two hundred and thirty-two male subjects were examined in this cross-sectional study. All subjects were non-diabetic and the group had a mean age of 31 y and a mean body weight of 104 kg.MEASUREMENTS: Several phenotypic measures of body fatness and fat distribution (anthropometry), fasting plasma insulin, glucose and leptin concentrations, blood pressure and 2 h plasma glucose concentration, genotypes of subjects for the Gln223Arg, PRO1019pro (OB-R gene) and OB gene polymorphisms.RESULTS: Individually, the OB gene and Gln223Arg OB-R polymorphisms were not associated with the obese or glucose-intolerant phenotype in this population. Individuals with the PRO1019pro polymorphism were found to have elevated insulin concentrations and diastolic blood pressure (Pc=0.04). In addition, individuals found to simultaneously exhibit homozygosity of the common allele of all three polymorphisms (genotypes: Arg/Arg, pro/pro and II/II) exhibited significantly elevated fasting insulin levels (Pc=0.03).CONCLUSIONS: Pacific Island populations exhibit a remarkably high prevalence rate of obesity and type 2 diabetes and represent a unique population for genetic studies of obesity. In the present study we have revealed that a specific combination of alleles in OB and OB-R, two candidate genes for obesity, may confer an increased risk for the development of insulin resistance in Nauruan males.

Leptin resistance in a polygenic, hyperleptinemic animal model of obesity and NIDDM: Psammomys obesus

OBJECTIVE:To investigate the effects of leptin administration to Psammomys obesus, a polygenic animal model of obesity and type 2 diabetes mellitus.DESIGN:Longitudinal intervention study utilising three separate leptin treatment protocols lasting 7–14 d.MEASUREMENTS:Body weight and food intake were measured daily, body fat and muscle content were estimated by carcass analysis on completion of the study. Blood glucose, plasma insulin, leptin, triglycerides and cholesterol were measured at baseline and twice each week during the study.RESULTS:Relatively high doses of leptin were required to significantly reduce food intake and body fat content in lean Psammomys obesus, but had no discernible effect on their obese littermates.CONCLUSION:As a species, Psammomys obesus appear to be relatively insensitive to the effects of leptin administration, compared with other rodents. Obese Psammomys obesus are leptin resistant relative to their lean littermates.

Practical considerations for conducting dental clinical trials in primary care

There is increasing importance placed on conducting clinical trials in dentistry to provide a robust evidence base for the treatment provided, and models of care delivered. However, providing the evidence upon which to base such decisions is not straightforward, as the conduct of these trials is complex. Currently, only limited information is available about the strategies to deliver successful clinical trials in primary care settings, and even less available on dental clinical trials. Considerable knowledge and experience is lost once a trial is completed as details about effective management of a trial are generally not reported or disseminated to trial managers and researchers. This leads to loss of vital knowledge that could assist with the effective delivery of new trials. The aim of this study is to examine the conduct and delivery of five dental clinical trials across both Australia and the UK and identify the various factors that impacted upon their implementation. Findings suggest that early stakeholder engagement, and well-designed and managed trials, lead to improved outcomes for researchers, clinic staff and patients, and increases the potential for future dissemination and translation of information into practice.

The outcomes of health-promoting communities: being active eating well initiative—a community-based obesity prevention intervention in Victoria, Australia

Objective:The aim of this study is to evaluate the impact of the Health-Promoting Communities: Being Active Eating Well (HPC:BAEW, 2007–2010) initiative, which comprised community-based multi-component interventions adapted to community context in five separate communities. The intervention aimed to promote healthy eating, physical activity and stronger, healthier communities.Methods:A mixed method and multilevel quasi-experimental evaluation of the HPC:BAEW initiative captured process, impact and outcome data. The evaluation involved both cross-sectional (children and adolescents) and longitudinal designs (adults) with data collected pre- and post-intervention in intervention (n=2408 children and adolescents from 18 schools, n=501 adults from 22 workplaces) and comparison groups (n=3163 children and adolescents from 33 schools, n=318 adults from seven workplaces). Anthropometry, obesity-related behavioural and environmental data, information regarding community context and implementation factors were collected. The primary outcomes were differences in anthropometry (weight, waist, body mass index (BMI) and standardised BMI (BMI z-score)) over time compared with comparison communities. Baseline data was collected 2008/2009 and post-intervention collected in 2010 with an average intervention time frame of approximately 12 months.Results:The strategies most commonly implemented were related to social marketing, stakeholder engagement, network and partnership development, community-directed needs assessment and capacity building. Analysis of post-intervention data showed gains in community capacity, but few impacts on environments, policy or individual knowledge, skills, beliefs and perceptions. Relative to the comparison group, one community achieved a lower prevalence of overweight/obesity, lower weight, waist circumference and BMI (P<0.005). One community achieved a higher level of healthy eating policy implementation in schools; two communities achieved improved healthy eating-related behaviours (P<0.03); one community achieved lower sedentary behaviours; and one community achieved higher levels of physical activity in schools (P<0.05). All effect sizes were in the small-to-moderate range.Conclusions:This was a complex and ambitious initiative, which attempted to expand a previously successful community-based intervention in Victoria into five new contexts and communities. Overall, project success was quite inconsistent, and some significant differences were in the unanticipated direction. However, there are many important learnings that should inform future health-promotion activities. The heterogeneity of outcomes of HPC:BAEW communities reflects the reality of life whereby effectiveness of intervention strategies is dependent on individual and community factors. Future health promotion should consider a systems approach whereby existing systems are modified rather than relying heavily on the addition of new activities, with longer time frames for implementation.