Abstract

Introduction

According to the "thrifty genotype" theory 6 that attempts to explain the increased occurrence of diabetes, traditional hunter-gatherer and early agricultural populations were genetically adapted to surviving periods when food was scarce, alternating with periods when food was plentiful. They were capable of storing fat efficiently, which helped them through previous periods of food scarcity, but now that food is always available, the genetic trait leads to obesity. Being physically active has been shown to reduce the risk of developing diabetes,7,8 and it is generally recognized that the aboriginal peoples are more sedentary than in the past because of changes in lifestyle imposed on them by the European settlement of North America.

The effect of returning to a more traditional lifestyle on diabetes control was assessed by O'Dea among a group of Australian Aborigines with diabetes.9 She accompanied a group (half men, half women) of middle-aged Aborigines, 10 with diabetes and 4 without diabetes, on a seven-week bush stay during which there was no access to store-bought food or beverages. (A control group was not included in the study.) Initial average weight among persons with diabetes was 81.9 kg, and body mass index (BMI) was 27.2. After seven weeks of eating kangaroo, fish and seafood, birds, reptiles, yams, figs, wild honey, etc. (with animal foods constituting over two-thirds of caloric intake and total fat, 13%), the 10 persons with diabetes lost an average of 8 kg, and their fasting glucose dropped from an average of 11.1 to 6.1 mmol/L (well below the cut-off of 7.8 mmol/L for the diagnosis of diabetes).

A general practitioner and a community health representative working in a northern Quebec First Nations community observed (in the clinical setting) that persons with diabetes who spent several consecutive months living in the bush had better diabetic control on their return than those who had stayed in the village. Our study aimed to document these observations with respect to weight, height, fasting glucose, glycosylated hemoglobin and other variables.

Population
The 10,000 James Bay Cree of northern Quebec live in a territory that lies between the 49th and 55th parallels, covering 300,000 square kilometres of boreal forest. Traditionally, the Cree were hunter-gatherers usually living in extended family groups in the winter and gathering into larger groups in the summer or whenever the food supply permitted. Animals, birds and fish (composed of protein and fat but little carbohydrate) were the main sources of calories in their traditional diet, with plants providing important vitamins and minerals.10 The James Bay Cree are now based in nine scattered communities along the coast of James and Hudson bays and further inland, and 30% of the population is supported by an income security program instituted at the time of the James Bay and northern Quebec agreement.11 This program provides a guaranteed income to families who spend at least four months of the year hunting and trapping "on the land."

By 1989, 5.2% of the population aged 20 or over had been diagnosed with diabetes according to World Health Organization (WHO) criteria.12 Diabetes prevalence showed a north-south gradient with rates varying from 1.9% in the northernmost community to 9.0% in the southernmost.4 The more southern communities are located close to non-native communities by road.

Methods

Persons with diabetes appearing at the clinic in late August or early September 1991 were asked whether they were going into the bush or staying in the village and if they would participate in the study. Among persons with diabetes, 25 were planning to go into the bush till Christmas and all agreed to participate; 26 controls were recruited from among the 75 planning to stay in the village. The inclusion criteria for the study were Cree ethnic status, ages 20-64, residence in the community, known NIDDM according to WHO classification criteria, no history of travel outside the community for three or more months prior to the study and no hospitalization for complications of diabetes in the six months prior to the study.

Baseline measurements in September 1991 (time 1) included weight, height, blood pressure, glycosylated hemoglobin and fasting blood sugar taken in a routine manner at the local clinic; blood tests were sent to the nearest hospital to be analyzed as usual. All measurements were repeated in December 1991 (time 2). Basic demographic information, duration of diabetes, treatment and presence or absence of complications were determined from medical charts. The family physician and community health representative in the local clinic assessed smoking and physical activity levels from interviews.

Body mass index was calculated as weight in kilograms divided by height in meters squared. Physical activity was self-classified by respondents as between 1 and 4, with 1 being inactive (usually sitting and not walking around much) and 4 being heavy work or carrying very heavy loads. Both groups were asked the questions about physical activity in the village at time 1; the bush group was asked about activity while in the bush at time 2.

Statistical analysis was done using the SAS statistical package on an IBM personal computer. Two-tailed t-tests were used throughout. In addition, paired t-tests were used for comparing variables at time 1 and time 2 within each group.

Results

Table 2 shows the results for selected physiologic variables after the bush group had spent three months in the bush (time 2). At this time, the mean BMI of the bush group was lower than the village group (p = 0.024). When the differences between time 1 and time 2 are compared for each group (Table 3), there is a statistically significant difference in weight and BMI in the two groups, largely attributable to weight gain on the part of the village group. The glucose level went down from 14.1 at time 1 to 12.2 at time 2 for the bush group, whereas it went up from 12.7 to 14.0 in the village group. Within the bush group, the reductions in fasting blood glucose and in glycosylated hemoglobin over the three months were statistically significant, but the average weight loss of 0.6 kg was not.

Self-reported activity levels rose significantly for the bush group between time 1 and time 2 (Table 4).

No patients in either group increased their diabetic medication during the study period. Nine of the twenty-one persons taking medication in the bush group and three of nineteen in the control group stopped or reduced their diabetic medication during the three months. Among the bush group, the decision to stop taking medication was the patient's choice as he or she was not in contact with a doctor during this time. The transport and use of insulin in the bush is difficult. However, the difference between the two groups did not reach statistical significance.

All members of the bush group took store-bought groceries into the bush. Although we have not quantified the amount of each item, they all took lard and eggs with them, 84% took cookies, 80% took butter and 48% took sugar. Sixty-four percent of the bush group also reported that they returned to their village for a day at least once, enabling the purchase of more store foods.

Discussion

For practical purposes, this study could not be an experimental one with subjects randomly assigned to the bush or village. In addition, we cannot be sure that the control group was representative of all persons with diabetes who did not go into the bush. Bias in the groups is therefore possible. Despite a lack of significant differences, the bush group appeared to be fitter (less obese and with fewer diabetic complications) to start with.

We believe that the failure to demonstrate a dramatic improvement, as O'Dea did in Australia, is largely due to the quantity of store food consumed in the bush among our population. In O'Dea's study, the subjects had no access to store food, consuming an average of 1200 calories per day, significantly below the recommended maintenance level of 2000 to 3000 kcal for sedentary adults.13 On a long-term basis, insufficient caloric intake can affect immunity and lead to a higher incidence of infectious diseases. Undernourishment was documented in the James Bay area in the first half of this century,14 and stories of starvation in the past are often told; reductions in the occurrence of infectious disease among native peoples may be due in part to the greater availability of calories.

In our study, exercise levels were considerably higher in the bush. This is encouraging, as exercise has been shown to improve insulin sensitivity and glucose homeostasis independently of weight loss,7 and it may also have beneficial effects in the prevention of cardiovascular disease.

The higher level of activity might result in hypoglycemic episodes if medication is maintained at a constant level, and it appears that some of those studied were aware of this. Thus, it is important that people with diabetes continue to be educated about adjusting their diabetic medication if necessary while in the bush.

Bush living, as presently practised by the group in this study, has a small beneficial effect, but weights and blood glucose levels remain well beyond those required for good diabetes control. Studies have shown that the prevalence of serious complications, such as nephropathy, is high among aboriginal persons with diabetes.15,16 In order to control the epidemic of diabetes in native communities, efforts should be aimed both at primary prevention and at education and quality care for people diagnosed with diabetes.

A deeper understanding of the underlying reasons for eating and physical activity patterns observed in aboriginal communities is urgently required in order for health promotion programs to be effective. Aboriginal nutritionists and health educators are essential in the planning and implementation of such programs. Access to diabetes education is presently non-existent for many more remote aboriginal communities, and budgets must be made available. The treatment and prevention of diabetes are major challenges that will continue into the next millennium for all people working and living in aboriginal communities.

Acknowledgements

References

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11. Annual Report, 1990-91, Cree Hunters and Trappers Income Security Board. Québec: L'Office de la sécurité du revenu des chasseurs et piégeurs cris.

12. Harris MJ, Hadden WC, Knowler WC, Bennett PH. International criteria for the diagnosis of diabetes and impaired glucose tolerance. Diabetes Care 1985;8:562-7.

13. Nestle M. Nutrition in clinical practice. Greenbrae (CA): Jones Medical Publications, 1985.

14. Vivian RP, McMillan C, Moore PE, Robertson ED, Sebrell WH, Tisdall FF, et al. The nutrition and health of the James Bay Indian. Can Med Assoc J 1948;59:505-18.

15. Muneta B, Newman J, Stevenson J, Eggers P. Diabetic end-stage renal disease among native Americans. Diabetes Care 1993;16 Suppl 1:346-8.

16. Dyck RF, Tan L. Rates and outcomes of diabetic end-stage renal disease among registered native people in Saskatchewan. Can Med Assoc J 1994;150:203-8.

Author References

This paper is based on an oral presentation made at the 3rd International Conference on Diabetes and Indigenous Peoples: "Theory, Reality and Hope," held in Winnipeg, Manitoba, May 26-30, 1995.

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