Body mass index and health

Abstract

Objectives: This article describes the prevalence of the four international body mass index (BMI) categories--underweight (18.5 or less), acceptable weight (18.6 to 24.9), overweight (25 to 29.9) and obese (30 or more)--by selected socio-demographic and lifestyle characteristics. It also examines the association between BMI and selected health problems.

Data source: The data are from the household component of the 1996/97 National Population Health Survey, conducted by Statistics Canada. Results are based on a sample of 50,347 respondents aged 20 to 64.

Analytical techniques: Prevalence estimates of BMI categories were calculated. Multivariate analyses were used to examine associations between BMI and various health conditions by smoking status, while controlling for age and sex.

Main results: In 1996/97, about half of Canadian adults were in the acceptable weight range; 34% were overweight; 12%, obese; and 2%, underweight. Being overweight or obese was associated with asthma, arthritis, back problems, high blood pressure, diabetes and thyroid disorders, although this varied with smoking status. Underweight smokers had high odds of reporting cancer, bowel disorders, ulcers, and migraine.