Background: Aboriginal populations in North America are exhibiting an increased prevalence of cardiovascular disease and associated traditional and nontraditional cardiovascular risk factors, trends believed to be due to the influence of Western lifestyle habits. Because these influences are present at an early age, we sought to study the patterns of one such habit, cigarette smoking, among Aboriginal Canadian youths and to assess the associated accrual of cardiovascular risk factors at an early age.
Methods: Patterns of cigarette smoking were assessed in a population-based, cross-sectional study involving 236 youths aged 10-19 (mean 14.9) years in the Oji-Cree community of Sandy lake, in northwestern Ontario. Participants underwent clinical and metabolic evaluation with assessment of cardiovascular risk factors.
Results: The prevalence of cigarette smoking among the study participants was considerably higher than age-specific national averages, with fully 50% of the participants overall and 82% of the adolescent participants (aged 15-19) being current smokers. Compared with their peers, children smoking 6 or more cigarettes per day had an enhanced cardiovascular risk profile consisting of a higher mean systolic blood pressure (111 v. 107.5 mm Hg, p = 0.036), a higher mean plasma homocysteine level (8.7 v. 7.6 micromol/L, p = 0.008) and a lower mean serum folate level (4.5 v. 5.4 mmol/L, p = 0.007), after adjustment for age, sex and body mass index. In separate multiple linear regression analyses, current cigarette exposure (number of cigarettes smoked per day) emerged as an independent determinant of both systolic blood pressure and plasma homocysteine level.
Interpretation: In this Aboriginal community with remarkably high rates of cigarette smoking among its youth, an independent dose-response relation was found between current smoking exposure and both traditional (systolic blood pressure) and nontraditional (homocysteine level) cardiovascular risk factors. The association of cigarette smoking with an enhanced cardiovascular risk profile at an early age may be a factor contributing to the high prevalence of cardiovascular disease in this Aboriginal population.