Body fat distribution and non-insulin dependent diabetes mellitus in North American Indians

Anthropometric characteristics of Mohawk children aged 6 to 11 years: a population perspective

OBJECTIVE

Recent studies have concluded that Native North American children have higher proportions of overweight and obesity than children from the general North American population. This study presents anthropometric data on a representative sample of children from the Mohawk Nation that can be used for comparison with other Native American populations.

DESIGN

This is a cross-sectional study comparing distributions of anthropometric characteristics of Mohawk children to the corresponding age and gender data from the Second National Health and Nutrition Examination Survey (NHANES II). Weight, height, triceps and subscapular skinfold thickness, and waist and hip circumferences were measured in 527 children.

SUBJECTS/SETTING

All children in grades 1 to 6 (aged 6 to 11 years) in the 3 elementary schools of 2 Mohawk communities in Canada, for whom parental consent was obtained, were enrolled in the present study. There were no exclusion criteria. With a participation rate of 83%, the 527 children enrolled in this study represent an unbiased sample of the population from 2 Mohawk territories.

RESULTS

Compared with children studied in NHANES II, Mohawk children were similar in height and triceps skinfolds but were generally heavier, had thicker subscapular skinfolds, and had greater waist and hip circumferences. These differences were greater in older children. Mohawk children who had extreme-high weight values compared with their population means were heavier than their NHANES II counterparts.

APPLICATIONS/CONCLUSIONS

Results indicated that, on average, Mohawk children seem to be slightly heavier than children in NHANES II. Except for those with extreme overweight values, Mohawk children show less variation of weight and body mass index than children in NHANES II. Finally, overweight Mohawk children seem to be more likely to carry their excess body fat truncally, compared with overweight children from NHANES II. Health practitioners working with Native American populations should be careful when assessing childhood obesity. Simple comparisons of weight or body mass index with NHANES standards may lead to inappropriate risk assessments.

Variation by body mass index and age in waist-to-hip ratio associations with glycemic status in an aboriginal population at risk for type 2 diabetes in British Columbia, Canada

BACKGROUND

It is unclear whether obesity and age modify or confound relations between abdominal adiposity and metabolic risk factors for type 2 diabetes.

OBJECTIVE

Our objective was assess the consistency of relations between abdominal adiposity and glycemic variables across discrete categories of obesity and age.

DESIGN

We performed a stratified analysis of prevalence data from a rural screening initiative in British Columbia, Canada. Subjects were Salishan Indians, all healthy relatives of individuals with type 2 diabetes [n = 151; age: 18-80 y; body mass index (BMI, in kg/m2): 17.0-48.2]. We measured waist-to-hip ratio (WHR) (2 categories); insulin, glycated hemoglobin (Hb A1c), and 2-h glucose concentrations (2 categories); and BMI (4 categories). BMI and age-specific odds ratios (ORs) and 95% CIs were calculated.

RESULTS

WHR-glycemic variable relations were not consistent across BMI and age strata. Risks associated with high WHR were: for persons with BMIs from 25 to 29, elevated insulin (OR: 6.71; 95% CI: 1.41, 34.11) and Hb A1c (OR: 16.23; 95% CI: 2.04, 101.73) concentrations; for persons aged 18-34 y, elevated insulin concentrations [OR: indeterminate (+infinity); 95% CI: 1.89, +infinity]; and, for persons aged 35-49 y, elevated Hb A1c (OR: +infinity; 95% CI: 3.17, +infinity) and 2-h glucose (OR: 9.15; 95% CI: 1.74, 59.91) concentrations.

CONCLUSIONS

WHR discriminates risk of type 2 diabetes in overweight but not obese individuals. Abdominal adiposity is associated with elevated insulin concentrations in younger age groups and with impaired glucose control in middle-aged groups, suggesting metabolic staging by age on a continuum from insulin resistance to impaired glucose tolerance.

The Kahnawake Schools Diabetes Prevention Project: intervention, evaluation, and baseline results of a diabetes primary prevention program with a native community in Canada

OBJECTIVES

Kahnawake Schools Diabetes Prevention Project is a 3-year community-based, primary prevention program for non-insulin-dependent diabetes mellitus in a Mohawk community near Montreal, Canada. Objectives are to improve healthy eating and encourage more physical activity among elementary school children.

METHODS

Intervention incorporates behavior change theory, Native learning styles, the Ottawa Charter for Health Promotion, and a health promotion planning model. Evaluation uses a mixed longitudinal and cross-sectional design to measure obesity, fitness, eating habits, and physical activity of elementary school children in the experimental and comparison communities. Intermediate variables are self-efficacy and perceived parental support. Process evaluation provides feedback to the intervention.

RESULTS

During 3 years, 63 distinct interventions that included a Health Education Program reinforced by school events, a new Community Advisory Board, a recreation path, and community-based activities promoting healthy lifestyles were implemented. Baseline consent rates were 87 and 71% in the experimental and comparison schools. As expected, anthropometric data increase with age. Between 9 and 10 years there are increased weight, height, BMI, and skinfold thicknesses; decreased fitness; and increased television watching.

CONCLUSIONS

Implementing a Native community-based diabetes prevention program is feasible through participatory research that incorporates Native culture and local expertise.

Diabetes and Canada's aboriginal peoples: the need for primary prevention

The high prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in Canada's native communities corresponds with high diabetes prevalence rates in other populations of indigenous peoples that have undergone changes associated with acculturation. Behavioural risk factors can be particularly amenable to public health action. There exists a need to develop, implement and test in collaboration with native people, interventions aimed at reducing the incidence and impact of NIDDM, by reducing the risk of its onset, and by early detection and treatment. Intervention programmes should be conceived with sensitivity to the overall health, social, economic, educational and cultural environment within a community. Although this review focuses specifically on diabetes in Canada, many of the points relating to the need for primary prevention of the disease will be appropriate in other situations.