National Statistics and Opportunities for Improved Surveillance,
Prevention, and Control

GLOSSARY

Age-specific Rate

The number of cases or deaths per 100,000 persons per year for a specified age group. Five-year age groups are commonly used.

Age-standardized Rate

An adjusted rate that represents what the crude rate would have been in the study population (such as a province or a census division) if that population had the same age distribution as the standard population, which in this report is the 1991 Canadian population. However, because standardization produces a summary measure, it may obscure important differences in the age-specific patterns. Also, standardized rates can be compared with each other only when the same standard population has been used to obtain the rate.

Body Mass Index (BMI)

A measure of human body size and proportion. It is defined as the weight in kilograms divided by the square of height in metres (see Obesity).

ICD-9

International Classification of Disease, 9th edition.

Incidence

The number of new instances of illness commencing, or of persons falling ill, during a given period in a specified population.

Leading Causes of Death

The leading causes of death are those diseases that account for a high proportion of the total number of deaths (taking the number of deaths reported for a given disease chapter based on the ICD-9 classification and dividing by the total number of deaths for a given period).

Life Expectancy

Life expectancy is a summary measure of the health status of a population. It is defined as the average number of years an individual of a given age is expected to live if current mortality rates continue to apply.

Mortality

Death from a particular cause.

Mortality Data

Mortality or death data are collected by the provincial registrar of vital statistics for persons resident in that province or territory at the time of death and sent to Statistics Canada for final editing. The death registration covers all deaths of Canadians occurring in Canada and to some extent in the United States. Deaths occurring in countries other than Canada and the United States are not covered.

Non-Proxy (NPHS)

See Proxy/Non-Proxy

Obesity

The National Population Health Survey 1996 (Statistics Canada) uses the following criteria for levels of obesity: (i) "some excess weight" = Body Mass Index 25-27, and (ii) "overweight" = Body Mass Index > 27. The U.S. National Institutes of Health uses the following criteria: (i) "overweight" = Body Mass Index 25-29.9 , (ii) "obesity" = Body Mass Index 30-39.9, and (iii) "extreme obesity" = Body Mass Index ³ 40 (see Body Mass Index).

Physical Inactivity

A relative term that refers to a lack of exercise, the definition of which varies among researchers.

Potential Years of Life Lost (PYLL)

A measure of the relative impact of various diseases and lethal forces on society resulting in youthful or premature deaths. The PYLL due to a particular cause is calculated by a summing, over all persons dying from that cause, of the years that each individual would have lived had they experienced normal life expectation (see Life Expectancy).

Prevalence

The number of existing instances of a given illness, at a given time, in a specified population.

Proxy/Non-Proxy (NPHS)

Proxy: One knowledgeable person in every participating household provided general socio-demographic and health information about each household member.

Non-Proxy: One randomly selected person in each participating household was chosen to provide in-depth information about his or her own health.

Rate

The proportion of a group affected over a period of time, such as a year. It is usually expressed as the number of new cases (deaths, separations etc.) per 1,000 or 100,000 people per year.

Standard Population

A population structure that is used to provide a constant age distribution, so that the rates of different study populations can be adjusted to it and can be properly compared (see Age-Standardized Rates).

Waist-Hip Ratio

The ratio of waist circumference (cm) to hip circumference (cm). It is used as a measurement of obesity (see Obesity).

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