Différence dans la qualité de l’alimentation en relation au risque d’excès de poids chez des populations autochtones canadiennes

Obesity is a public health problem in Canada, particularly among Aboriginal populations where the highest prevalences have been reported. In the literature, several methods have been tried to study the relationship between diet and obesity, but results are inconsistent. The objective of this thesis is to identify differences in selected dimensions of diet quality and quantity across body mass index (BMI) categories for Aboriginal children and adults in Canada. To achieve this goal, we developed a new method by using data from Mohawk children in Kahnawake. The same method was then applied to two other datasets (James Bay Cree adults and off-reserve adults and children from CCHS 2.2). Overall, in each dataset, the results showed no differences in the diets of participants considering indicators such as energy intake, percent fat, fiber intake, energy density and dietary diversity. On the contrary, using the new method based on the most-frequently consumed food items by at least 10% of participants, we found that Mohawk children “at risk of overweight” consume potato chips more frequently (p=0.001) and crackers less frequently (p = 0.015), compared to normal-weight or overweight children. Compared to normal-weight, and after adjusting for age, Mohawk children who consumed more frequently chips increased their probability of being at risk of overweight (Odds ratio : OR = 2.16, 95 % CI : 1.14 - 4.09), while those who consumed crackers more frequently decreased their risk (OR = 0.21; 95 % CI : 0.06 – 0.72). In terms of quantity, and after adjusting for age, overweight children consumed larger portions of french fries (p = 0.027).Among the Cree women (compared to normal-weight, and after adjusting for age), we found out that nondairy creamer was associated to increase risk of being obese (OR = 4.64, 95 % CI : 1.04 - 20.54) while low-fat milk was associated to lower risk of overweight (OR = 0.38, 95 % CI : 0.17 - 0.82). Among Cree men, (after adjusting for age), whole milk was associated to a high risk of the men being overweight (OR = 0.38, 95 % CI : 0.20 - 0.71). Finally, in terms of quantity (after adjusting for age), obese men drank more sweetened fruit drinks compared to men of normal weight or those with overweight (p = 0.015). In the third dataset CCHS2.2, results of the new method show that boys at “risk of overweight” or overweight consumed white bread less frequently (p = 0,048) but in greater quantity when they do so (p = 0,040). They also used more flour (p = 0.006) and yeast (p = 0.002). After adjusting the quantities consumed for age and physical activity, women with overweight or obese used more flour (p < 0.001) than those of normal weight. No differences were found in terms of frequency and quantity for men. The data were not analysed for girls since their Goldberg activity factor was less than 1.2 with greater body weight. The results of this new method could, on one hand, allow us to focus awareness on foods in addition to general recommendations of the Canadian Food Guide. On the other hand, they refer us back to laboratory data to identify components of items that may contribute to the development of obesity.

Keyphrases: Canada, Diet quality, food choices, methods, obesity, body mass index, indigenous peoples