Relationships of ethnicity, physical activity and diet with adiposity development in Aboriginal youth

Abstract

The objective of this research was to study relationship(s) of ethnicity, physical activity and diet with adiposity development in Aboriginal youth. To meet this objective, three separate, yet inter-related studies were undertaken: 1) to comprehensively assess adiposity in Aboriginal youth and their age, sex and maturity matched Caucasian peers; 2) to assess the role of ethnicity and sex on physical activity (PA) levels and identify the proportion of Aboriginal youth meeting international recommendations; and 3) to explore relationships of ethnicity, physical activity and diet with adiposity. In study one, it was hypothesized that Aboriginal youth would have greater adiposity than their Caucasian peers. While much of the research to date has focused on body mass index, this investigation used DXA and waist circumference to show that Aboriginal youth had greater total and central adiposity in comparison to their Caucasian counterparts.

Study two examined physical activity behaviors of Canadian Aboriginal youth in relation to ethnicity and sex. It was hypothesized that the physical activity levels of Aboriginal youth would be lower than their Caucasian peers; that the majority of Aboriginal youth would not meet PA and T.V. viewing recommendations; and that Aboriginal boys would have higher adjusted physical activity energy expenditures than girls. Findings indicated that physical activity levels of the two ethnic groups were generally comparable, that Aboriginal boys had greater activity energy expenditures than girls, and that a greater percentage of boys were meeting the international recommendations for physical activity and T.V. viewing. Study three built upon the first two investigations, to explore relationships of physical activity and diet with adiposity in Aboriginal youth. It was hypothesized that when age, size and maturity, and their interactions were accounted for, diet and physical activity variables would be related to adiposity (waist circumference, total body and trunk fatness). Results indicated physical activity was inversely related to adiposity level, independent of biological factors. Although energy intake was the sole dietary variable related to the adiposity measures, descriptives showed the eating behaviors (i.e., consumption of fruits and vegetables, sugar sweetened beverages and other foods) of the Aboriginal youth were sub-optimal when compared to current recommendations. This research project is unique because it comprehensively assessed adiposity, diet and physical activity, and the relationships between these variables, in a relatively large sample of Aboriginal boys and girls. Furthermore, these relationships were established using a variety of measures (i.e., DXA, waist circumference, height and weight) while controlling for biological confounders. Overall, the results highlight the urgent need to promote physical activity and healthy eating in Aboriginal youth and set the stage for future research.