Obesity and the prevalence and management of hypertension in Ontario, Canada.

Background: We evaluated the association of body weight with the prevalence of hypertension by age and sex, as well as the treatment and control rates in obese and nonobese hypertensives among adults in the province of Ontario, Canada.

Methods: Cross-sectional, population-based survey of 2,510 adults, 20-79 years of age representative of the Ontario population of 7,996,653. Height, weight, arm and waist circumference, and blood pressure (BP) were directly measured by a trained nurse.

Results: Prevalence of obesity (body mass index (BMI) > or =30) increased from 16% in the 20-39 years age-group to 33% in the 60-79 years age group, similarly in men and women. Prevalence of hypertension increased as BMI and age increased: in the older age group (60+) from 36% in the lean to 51% for the overweight, 59% in the obese stage I, and 68% in the obese stage II/III. Prevalence of self-reported diabetes followed a similar pattern. Presence of other risk factors (diabetes and dyslipidemia) was independently associated with higher hypertension rates. Treatment and control rates of hypertension varied by BMI and gender. Lean hypertensive males had the lowest control rates (42%) and the highest systolic BPs compared to overweight (79%) and obese (64%) males. This difference was not apparent in females.

Conclusions: Obesity is associated with markedly higher prevalence of hypertension and diabetes with age. If obesity per se is indeed a contributing factor, public health strategies to reduce the obesity epidemic would also markedly reduce the burden of hypertension and diabetes.