Question

For the chronic health disease of obesity determine the following:

Identify and describe data interpretation issues and pertinent knowledge gaps.

Develop an experimental design, including methods of assessing internal and external validity, to address one identified knowledge gap pertaining to the health outcome.

This question will take some time to answer.

Answer 1

It is currently firmly established that obesity, i.e. excess body weight, is increasingly frequent in the population. This phenomenon may be clearly demonstrated for both adults and children by the increase in the body weight of our contemporaries for a given gender, age and height. The evidence is so striking that the health authorities became aware of it at the end of the last century (WHO, 1997). Mobilization in most Western countries resulted. However, the in-depth understanding of the causes of the phenomenon and rational assessment of its consequences in terms of individual and collective health are far from perfect. In parallel with the public health measures to be taken to halt the progression, progress in our understanding of the phenomenon is necessary.

The epidemiological context of the combat against obesity is reviewed in this chapter. An attempt is made to indicate the limitations and interpretation difficulties of the reported findings. The prevalence of obesity and, above all, its recent progression are discussed, as are the current data on the public health consequences, particularly with respect to cardiovascular disease and mortality. Special attention is paid to the role of socioeconomic factors as determinants of obesity in the population.

increase is thus largely secondary to changes affecting all the population rather than the particular behaviors of subjects with a high BMI (Silventoinen et al., 2004). However, certain fine analyses show that the general effect of increasing corpulence is not the only mechanism (Pietinen et al., 1996), suggesting that the profile of the BMI distribution in the population is changing with an increase in variance and skewing toward high values.

In France, the proportion of military service recruits who were overweight or obese also constantly increased over the period 1987–1996, from 11.5 to 16.5% and from 1.5 to 3.1%, respectively, while height continued to increase (Salem et al., 2000). This suggests that the increase in the body weight of 19-year old recruits, secondary to the secular trend towards an increase in height, was accompanied by a supplementary weight gain that could already be measured at the end of adolescence. It is thus remarkable that the increase in the prevalence of obese and overweight adults was also observed in children and adolescents over the same period (Lobstein et al., 2004).

Experimental Design

Objective To test the effectiveness of a non-pharmaceutical programme for obese participants in a rural Eastern Canadian Province using certified health professionals.

Design A prospective quasi-experimental design with repeated premeasure and postmeasure.

Participants 146 participants with obesity (body mass index >30 kg/m²) from rural and urban communities in an Eastern Canadian Province were divided into four groups.

Intervention A 6-month intensive active community-based lifestyle intervention (InI) delivered by Certified Exercise Physiologists, Certified Personal Trainers and Registered Dietitians, followed by 6 months of self-management. A second intervention (InII) was nested in InI and consisted of group-mediated cognitive–behavioral intervention (GMCBI) delivered by an exercise psychologist to two of the four InI groups.

Outcomes (1) Improving health outcomes among the participants’ preactive and postactive 6-month intervention and self-management period, (2) Documenting the impact of InII (GMCBI) and location of the intervention (urban vs rural).

Results The 6-month active InI significantly improved cardiovascular health for participants who completed the intervention. InII (GMCBI) significantly lowered the attrition rate among the participants. The self-management period was challenging for the participants and they did not make further gains; however, most were able to maintain the gains achieved during the active intervention. The location of the intervention, urban or rural, had little impact on outcomes.

Conclusions A community-based programme utilising healthcare professionals other than physicians to treat obese patients was effective based on premeasure and postmeasure. During the self-management phase, the participants were able to maintain the gains. Psychological support is essential to participant retention.

• PRIMARY CARE
• PUBLIC HEALTH
• NUTRITION & DIETETICS