The total death rate is the total number of deaths each from ischemic heart disease, stroke, or chronic obstructive lung disease relative to the total population (usually expressed per 100,00).

Age-specific mortality rates for selected chronic diseases are the annual number of deaths in a given age group from ischemic heart disease, stroke, or chronic obstructive lung disease per the population in that age group.

Age-standardized mortality rates (SRATEs) for selected chronic diseases: the number of deaths from ischemic heart disease, stroke, or chronic obstructive lung disease per the population that would occur if the population had the same age distribution as the 1991 Canadian population.

Standardized mortality ratios (SMRs) for selected chronic diseases: the ratio of observed deaths of ischemic heart disease, stroke, or chronic obstructive lung disease to the number expected if the population had the same age-specific death rates as Ontario, multiplied by 100.

Since mortality reflects the upper limit of the disease severity continuum, this indicator does not capture how many people are living with these conditions. Chronic diseases are sometimes categorized inconsistently. When making comparisons, ensure that indicators are grouped the same way.

Average number of years of life remaining after a given age assuming that observed age-specific mortality rates remain stable for a given period.

Life expectancy at birth is an estimate of the mean length of life of a population. Higher life expectancy is associated with better socioeconomic and health conditions. Life expectancy varies with marital status, sex, income and location. This indicator is not affected by the age structure of the population. Time series permit the assessment of changes in premature mortality. Together with infant mortality, life expectancy is one of the most common indicators of health status.

This indicator provides information only on fatal illness. There is no indication of the number of sick individuals or the importance of diseases that do not result in death. Life expectancy calculated for a given period does not reflect only the mortality for that period. It may also be influenced by past conditions or events and this may cause a temporary increase in mortality in certain age groups. This calculation of life expectancy is based on the assumption that the observed age-specific mortality is stable during a given period. If mortality were to decrease over time then the life expectancy calculation would be an underestimate of the true life expectancy.

It is useful in planning and assessing the effectiveness of health care services

It allows comparisons over time and place to occur.

Leading causes of death expressed as age standardized rates or standardized mortality ratio's. The cause selected is the underlying cause (i.e. the one which initiated the sequence of morbid events leading to death.) The leading causes of death are based on the magnitude of the rate for a given cause relative to the total death rate.

Mortality statistics are often used to obtain an overall picture of the most serious diseases. Mortality levels and causes vary with age, gender, marital status, and socioeconomic status.

At advanced ages, it is difficult to identify the initial cause of death, thus, these rates are usually not calculated after age 85. Mortality reflects only fatal disease burden. It gives no information on the number of sick people or the importance of disease that do not lead to death. Comparisons over time and place may be affected by differences in the methods of reporting, selecting and classifying causes of death. The proportion of all deaths attributable to a single cause has been decreasing. There is an increasing trend toward developing a multiple-cause classification of deaths.

Proportion of infant deaths (under one year of age) per 1000 live births. Stillbirths are excluded from both the numerator and denominator. Infant mortality includes early neonatal (0-6 days), late neonatal (7-27 days) and post-neonatal mortality (28 days – 11 months). When the number of births vary slightly from year to year infant mortality represents the probablitility of dying before the first birthday.

Infant mortality is a good indicator of the level of economic and social development in a region. It is, with life expectancy, the most commonly used health indicator. The infant mortality rate reflects deficiencies in the physical and socioeconomic environment, nutrition, education and health care of a population. Note that even in countries with low rates, there are significant differences between socioeconomic groups.

Mortality only reflects fatal diseases. It gives no information on the number of sick infants or the extent of diseases that do not necessarily lead to death. This rate may depend on the definition of a live birth, which is not uniform from one period and country to another. Advances in medical technology may bring about further changes in the definition. Infant deaths are increasingly concentrated in the first days of life, and consequently, the perinatal mortality rate is an important indicator of the level of care in regions where the infant mortality rate is low.

Proportion of the total stillbirths (fetal death) and early neonatal deaths for a given year relative to the total births for that year. A stillbirth in Ontario is a product of conception weighing 500 grams or more or of 20 or more weeks gestational period which, after being completely delivered, shows no sign of life. An early neonatal death is an infant, born alive, but who dies before their seventh day of life.

The perinatal mortality rate may be considered as the probability of an apparently viable fetus being born dead or dying before the end of the first week of life. The perinatal mortality rate is influenced by the age of the mother, health of the mother, birth order, socioeconomic conditions, birth weight and period of gestation. The perinatal mortality rate is preferred to the infant mortality rate in counties with low infant mortality.

This rate may be inexact since its calculation is based on the weight and gestational period of fetuses and these are not always easy to determine. Since the definition of stillbirth is partly based on fetal weight, the line between spontaneous abortion and stillbirth is not easy to draw. Comparisons over time and place of perinatal mortality rates may be difficult because of the varying definitions used for stillbirth. Some rely on the period of gestation (20 weeks or 28 weeks) others on fetal weight (500 grams or 1000 grams).

Proportion aged 12 and over who have experienced depression in the past 12 months.

Depression is a relatively common mental disorder. It causes substantial suffering and disruption in the lives of those affected and of those around them. Depression is more prevalent among women than men, and among younger than older individuals.

Information collected in surveys may exclude factors, such as genetic make-up and family history, which may increase susceptibility to depression. Depression is measured in the 1996/97 OHS using a scale from question MHC6_2 to MHC6_28. These variables are on the 1996/97 OHS but not the NPHS public use file. The 27 items used are based on the work of Kessler and Mroczek from the University of Michigan. They selected a subset of items from the Composite International Diagnostic Interview (CIDI) that measured major depressive episode (MDE). If the estimate was 0.9 or more, that is 90% likelihood of a positive diagnosis of MDE, the respondent was considered to have experienced depression.

Proportion of annual suicide deaths observed during a given year relative to the total population in that year.

Suicide is an indicator of mental health. This indicator shows only the final consequences of the suicide phenomenon, since those lives lost represent only a proportion of all attempted suicides. High suicide rates are observed among young adults, people living alone, and people of low socioeconomic status. Standardization of rates (age and gender) is necessary to compare total rates over time or total rates in various populations.

Underestimation of suicide is in the order of 18% among women and 12% among men. The majority of suicides that are not identified would fall into the category of causes of undetermined intention (ICD - codes E980 to E989.9). The decision to classify a violent death as suicide is made by a coroner, medical examiner or provincial judge, depending on the province. In making comparisons over time, consideration should be given to the influence of changes in one or another of the following factors: social attitudes regarding suicide, development of forensic medicine methods, and the way suicides and attempted suicides are coded.

The number of deaths attributed to traffic injuries for a given year relative to the total population. A traffic injury is an injury that occurs on a public road. This includes motor vehicle passengers, pedestrians, cyclists and motorcyclists who died as a result of injuries on a public road involving a motor vehicle.

Deaths from traffic injuries are classified according to the external causes codes (E-codes) from the Ninth International Classification of Diseases, Injuries and Causes of Death (ICD-9). This cause of death corresponds to codes ICD-9 E810.0 to E819.0. This is not to be confused with the classification by clinical cause which identifies the nature and site of the injury (ICD-9 with the classification by clinical cause which identifies the nature and site of the injury (ICD-9 800-999). This indicator does not include deaths attributable to injuries involving motor vehicles used in recreational or sporting activities off public roads. In general, the highest traffic mortality rates are observed among young adult males (age 15 – 34) and the socioeconomically disadvantaged. Standardization of rates (age and gender) is necessary to compare total rates over time or total rates in various populations. Alcohol is often a factor in motor vehicle accidents where a fatality occurs. In some areas up to 40% of the motor vehicle fatalities have been related to alcohol. Variations in traffic mortality may be influenced by a number of factors, such as economic conditions (recession), implementation of new laws (seat belts), new technologies (air bags), changes in age structure (aging of the population), development of the health care system, road signs, road conditions and the quality of the highway system.

Deaths occurring several hours after a traffic accident, that did not require hospitalization, may not be classified as a death attributable to a traffic accident.

Number of years of life lost between ages 0 and 74 per 1000 population aged 0 – 74. PYLL are calculated for each deceased person using the difference between age 75 and the age at death. The total years of life lost for all deaths (or for cause specific deaths) during a given year, are then divided by the total population in that year.

PYLL is an indicator of premature mortality. PYLL varies by gender, socioeconomic status, geographic area, and cause of death.

The upper age limit is based on the current level of life expectancy at birth. The relative importance of causes of death varies depending on the age limits chosen.

Number of hospital separations during a given year for a specific cause relative to the total population in that year. The leading cause of hospital separation is based on the magnitude of the rate for a given cause relative to other causes.

Hospital morbidity statistics are calculated based on data on all patients discharged (separated) from public, private, and federal hospitals in Ontario (excluding provincial psychiatric facilities), including acute and chronic care hospitals, and acute psychiatric and rehabilitation units. Hospital separation records are the most comprehensive and accessible source of morbidity information. Other components of morbidity include visits to emergency rooms and physicians, but these data are generally unavailable for analysis. A separation may be due to death, discharge home, or transfer to another facility. The main diagnostic code gives the primary reason for the hospital stay or "most responsible diagnosis". Subsequent diagnosis codes are not as reliable.

Hospitalization statistics may be influenced by factors exogenous to health status. These include availability of care, physical and financial accessibility to care, administrative decisions aimed at limiting the number and length of hospital stays and the specialties offered at certain hospitals. All of these may affect geographical and temporal comparability. Gives an imperfect estimate of the prevalence of a given cause, since the statistics provide information on the number of separations rather than the number of persons hospitalized. Co-morbidity contributes uncertainty to classifying the most responsible diagnosis. Since a person may not be hospitalized or may be hospitalized several times for the same disease or injury event, or discharged from more than one hospital (when transferred) for the same injury event, hospitalization data provide only a crude measure of the prevalence of a cause. Data are influenced by factors that are unrelated to health status such as availability and accessibility of care, and administrative policies and procedures. This may influence comparisons between areas and over time. Data are collected based on location of hospital but are generally analyzed by the residence of the patient. Ontario residents treated outside of the province are excluded. Less than 0.5% of all procedures performed for Ontario residents are out-of-province; however, areas bordering other provinces may be more affected. Rates and proportions based on counts less than 5 must be suppressed.

Number of new cases of notifiable diseases in a given year relative to the total population in that year. Notifiable diseases included diseases designated reportable under the Health Protection and Promotion Act, RSO 1990.

The diseases counted are notifiable diseases reported by physicians or laboratories. This excludes diseases requiring vaccination. Notifiable diseases are considered the diseases most likely to cause epidemics, whether fatal or not, in the population.

The figures represent events and not individuals. More than one disease may be reported per individual. However, for a given episode of the disease, an individual should not be recorded more than once. The level of under reporting of notifiable diseases varies significantly from one area to another depending on the source. When the rate increases between two periods, it may be due to efforts aimed at better reporting or other factors. Therefore, it must be determined whether the increase is due to changes in the specificity or sensitivity of tests, or in the definition of the disease itself. Factors such as time of year and the addition of new sources of reporting (physicians, laboratories) must be considered.

Number of new cases of notifiable diseases requiring vaccination for a given year relative to the total population. They are reported by physicians, laboratories and other sources.

The incidence rates of notifiable diseases requiring vaccination provides an indication of the effectiveness of vaccine coverage. 

The data represents events not individuals. More than one disease may be reported for the same individual. However, for a given episode of the disease, an individual should not be recorded more than once. The level of under reporting of notifiable diseases varies significantly from one area to another depending on the source. When the rate increases between two periods, it may be due to efforts aimed at better reporting or other factors. Therefore, it must be determined whether the increase is due to changes in the specificity or sensitivity of tests, or in the definition of the disease itself. Factors such as time of year and the addition of new sources of reporting (physicians, laboratories) should also be considered when interpreting the data.

Proportion of the screened Grade 7 student population who have been adequately immunized against selected diseases.

The Immunization of School Pupils Act, 1982, requires that the medical officer of health maintain an immunization record on each pupil attending school in their Health Unit area. The Act also authorizes the Medical Officer of Health to suspend pupils who have not completed the prescribed program of immunization and do not have a medical or other exemption to these vaccinations. Medical Officers of Health report regularly to the Ministry of Health on the level of immunization reached within their Health Units. Immunization levels are calculated against each of the six diseases (diphtheria, tetanus, polio, measles, mumps and rubella) for which immunization is required under the Act. The number of students exempted and suspended from school because of failure to comply with the Act is also reported.

Prior to 1993, over half (28) of Ontario Public Health departments maintained immunization records of pupils on the centralized School Health System (SHS), nine maintained their own computer systems, and five maintained manual record systems. This lack of uniformity resulted in artificial differences in coverage between health departments. Note: the Immunization Record Information System (IRIS), a PC based system, has been developed for Public Health Departments and was implemented in the spring of 1993. It has replaced the SHS and several independent manual and computer systems. IRIS will produce coverage reports using standardized immunization schedule logic and will improve the efficiency of immunization records review.

The mean number of teeth or tooth surfaces decayed, missing or filled because of decay among school children.

The index may refer to permanent teeth (DMF) or baby teeth (def).

The index may refer to either the number of teeth (DMFT) or the number of tooth surfaces (DMFS).

The DMF Index is a general indicator of dental health status among children and is felt to be extremely reliable. The lower the index, the better the dental health of the population. This index is influenced by age and socioeconomic status. The index records past history and is cumulative.

The index deals only with tooth decay (the most common dental disease among children). Teeth missing or filled as a result of injury, orthodontic or other treatment are excluded from the index. The index measures both the incidence and the prevalence of decay, when the components are separately recorded. Preventative fillings may lead to an overestimation of the index. The interpretation of the criteria for measuring decay may vary from one study to another.

 The percentage of the children in kindergarten who have never had any cavities.

Children who are absent from school on the day of dental screening, schooled at home or who refuse are excluded. Historical data may not be available from the Ministry of Health for comparison purposes because these data were lost. A change in survey procedures in 1997 shifted screening from all children in kindergarten, Grades 2, 4, 6 and 8 to all children in kindergarten only with subsequent screening in high-risk schools.

Number of people with long-term disability relative to the total population living in private households. Long-term disability is measured by the average number of persons who, at the time of the survey were restricted in the type of quantity of their activities because of a chronic physical or mental disease or health problem. In general, it is estimated that the limitation has lasted or is expected to last at least six months.

Disability is the restriction or lack of ability to perform an activity in the manner considered normal for a human being. It thus reflects each individual’s adaptation to a deficiency and to various specific types of activity (personal hygiene, mobility, communication, etc.). Disability is a general indicator of health status. Values vary with age and sex and socioeconomic status. Long term disability is reported more frequently by those with only primary education and low income. Musculoskeletal conditions such as arthritis and rheumatism are consistently found to be the most common causes of long-term disability.

Reliability problems may result from reporting of the health problem by a third party in surveys, since the interviewer asks the question of one person who answers for the whole household. A recall bias on the part of the respondent is possible when individuals have adjusted to their disability. The measurement and definition of disability varies from one survey to another.

Proportion of people having visited a dentist in the past year.

When was the last time that you went to a dentist?

1) Less than 1 year ago, 2) 1 year to less than 2 years ago, 3) 2 years to less than 3 years ago, 4) 3 years to less than 4 years ago, 5) 4 years to less than 5 years ago, 6) 5 or more years ago, 7) Never

Comparisons with 1990 data may be complicated because of changes to question wording. In 1990 the question (F5-48) asked "How long has it been since you last saw a dentist, dental therapist or other dental care provider"?

Proportion of people 12 and older having at least one visit or call to a general practitioner (GP) or family doctor in the past year.

Higher utilization of health care in certain groups in the form of contacts with health professionals may suggest a greater need for health care services.

Reliability problems may be inherent in these responses because they were garnered by-proxy. The compromise to reliability arises because the interviewer questions a respondent who answers for the entire household. In the interview, one "knowledgeable" member of the household answered the questions for everyone in the household. The number of contacts with health professionals may be driven by factors other than need such as supply of hospital beds and other equipment and number of health professionals. OHS data do not distinguish between telephone consultations and visits. Possible problem of data reliability with responses given by proxy.

Number of people aged 12+ who indicated they used any emergency services in the past 12 months.

The 1996, Ontario Health asked whether, during the past 12 months, Did you use any emergency services in the past 12 months?

Reliability problems may be inherent in these responses because they were garnered by-proxy. The comprimise to reliability arises because the interviewer questions a respondent who answers for the entire household. In the interview, one "knowledgeable" member of the household answered the questions for everyone in the household.

This indicator cannot be compared with the 1990 OHS, which asked only about usage of emergency rooms.

Trends for emergency room use may show decreases in recent years which are related to hospital closings, and not really a reflection of decreased access or use of emergency services. Trends are thus difficult to interpret.

Percent of population age 12 and older that perceive themselves to be in excellent, good or poor health. Respondents were asked to assess their own health status compared to other persons of the same age.

Although the perception of health status is a subjective judgement, there is a strong correlation between it and the presence of actual diagnosed health problems. In addition, studies have found that individuals who perceive their health to be poor have higher mortality rates compared to those who rate their health as good or excellent, when physical health and other factors are controlled.

Social desirability bias may shift individuals to characterize their health as more positive than they feel.

Proportion aged 12+ who reported having a long-term disability or handicap relative to the total population aged 12+.

Since the long-term disability question was on the general component of the 1996/97 OHS rather than the health component, some responses were answered by proxy. In general, 29% (unweighted) of responses on the general component part of the questionnaire were proxy.

The question in the 1990 OHS is different than that in the 1996/97 OHS. It asks: "Compared to other people of the same age in good health, are you limited in the kind or amount of activity you can do because of a long-term physical or mental condition or health problem?" The difference in wording makes it difficult to the two surveys. Prevalence is higher in the 1996/97.

This variable is on the 1996/97 OHS but not the NPHS public use file.

This indicator does not provide a measure of the severity, type, or duration of the limitation (i.e., limitations since birth, for several years, or several months) but other variables on the file can provide more information.

The prevalence of disability varies with age, sex, socioeconomic level, and place of residence.

Disability is a subjective measure.

Total number of people aged 12+ reporting having selected chronic health problems relative to the total population 12+.

Number of live births under 2,500 grams relative to all live births (usually expressed as a percent).

Low birth weight (LBW) is the main determining factor of perinatal and infant mortality and morbidity. Birth weight is an important indicator of the health status of a population and is often used in international comparisons. LBW is influenced by human biology, mother's age, type of birth (multiple), gestational age, parity, the physical and social environment, lifestyle factors, and use of health services.

From 1993-1995, a truncation error in the birth weights over-estimated the low birth weight rate in Ontario. This error has since been corrected. There is a coding problem with the duration variable for gestational age in the birth data for 1991-95. The problem is being corrected. Mortality rates of low birth weight babies cannot easily be determined given the current way the data are set up. Births to women under age 15 are included in the total because the denominator is all live births, not population.

Number of therapeutic abortions (TAs) in hospital and clinic to women in a given age group per population of women in that age group (usually expressed per 1,000).

Since 1988, when the Supreme Court of Canada ruled that the 1969 abortion law was unconstitutional, abortion has been a regulated medical procedure, no different from other procedures under the Canada Health Act.· "Abortion is the termination of pregnancy by any means before the fetus is sufficiently developed to survive." (2)· TAs may be an indicator of unplanned and unwanted pregnancies. Women may have a TA because a serious genetic defect or disorder has been detected in the fetus. In Canada, the abortion rate increased from 1990 to 1995. TAs occurring to women under age 15 are excluded in the total.

Number of multiple live births per total number of live births (usually expressed as a percent).

Since the Registrar General uses the parent registration form to gather data on births, indication of multiple births may be under-estimated. Multiple births are at higher risk of low birth weight. Fertility drugs can increase the chances of having a multiple birth. Multiple births to women under age 15 are included in the total because the denominator is all live births, not population.

Number of babies born with a neural tube defect (anencephalus and similar anomalies, spina bifida, or encephalocele) as detected in the first year of life per live births and stillbirths (usually expressed per 10,000).

Neural tube defects (NTDs) result from a failure of the neural tube to close between 21 and 27 days of gestation.

The three types of congenital anomalies comprising NTDs differ in their incidence and severity. Anencephaly, which results from a lack of skull and brain development, is the most severe; infants are often stillborn or rarely live past a month. Encephalocele results when a distorted portion of the brain hangs outside of the skull in a skin-covered sac; it has the lowest prevalence. Spina bifida is the most common NTD among live births. The degree of disability from spina bifida can vary dramatically, particularly with recent surgical advances.

Randomized control trials have shown that folic acid supplementation before conception and in early pregnancy can prevent NTDs. Health Canada recommends that women of child-bearing age obtain at least 400 micrograms of folic acid per day in their diet or through supplements.

Secondary prevention of NTDs is possible through prenatal screening programs which use maternal serum screening (MSS), ultrasound and amniocentesis to detect NTDs. MSS is a blood test performed between 16 and 18 weeks of pregnancy. Detection of NTDs prenatally give parents the option of terminating the pregnancy or facilitating the child's delivery to reduce subsequent morbidity and trauma.

In 1993, the Ministry of Health established a maternal serum screening program which maintains a database of all maternal serum screens done in Ontario, including information on screening results, use of additional testing, results of follow-up services and pregnancy outcomes.

Rates of NTDs among stillbirths can be examined in more depth using the ICD-9 code provided in the Ontario Stillbirth Database in HELPS. This variable is not available in the Data Warehouse

The CCASS data do not capture the number of fetuses aborted because of a detected neural tube defect. This can be assessed by selecting hospitalization records with ICD-9 codes 635 and 636 (therapeutic abortions) and subsequently those with ICD-9 code 655.0 (suspected fetal anencephaly, spina bifida or hydrocephaly)

Because NTDs are serious congenital anomalies, virtually all babies born with the anomaly would be diagnosed at birth and would be captured by the CCASS

Total number of stillbirths per stillbirths and live births (usually expressed per 1,000).

There may be inconsistencies in the definition of stillbirth with other jurisdictions or over long periods of time; gestation may be based on 20 or 28 weeks and fetal weight can vary from 500 grams or 1,000 grams.

The line between spontaneous abortion and stillbirth is not easy to draw.

Ratio of the number of live births, stillbirths, and therapeutic abortions to women in a given age group per population women in that age group (usually expressed per 1,000).

Since data for the number of therapeutic abortions done in clinic was not available until 1992, data should only be presented for 1992 and later. Not all pregnancies are captured; this indicator does not include ectopic pregnancies nor miscarriages (spontaneous abortions). Many miscarriages occur without the woman's awareness she was pregnant, or are treated in physician offices. The number of miscarriages that require hospitalization (which would be the only feasible way of capturing the information) has been decreasing because of treatment changes; as a result, they were not included in this indicator because of potential bias. Some agencies such as Statistics Canada, have included miscarriages. In this case, the appropriate ICD-9 codes for hospitalization data are: 634 (spontaneous abortion), 636 (illegally induced abortion), and 637 (unspecified abortion). Pregnancies occurring in women under age 15 are excluded in the total pregnancy rate. Multiple births are counted multiple times in the numerator.

Proportion of people aged 12 or older who took medications in the past month.

The 1996 OHS asked In the past month, did you take any of the following medications: pain relievers such as aspirin or Tylenol; tranquillizers such as Valium; diet pills; anti-depressants; codeine, Demerol or morphine; allergy medicine such as Seldane or Chlor-Tripolon; asthma medications such as inhalers or nebulizers; cough or cold remedies; penicillin or other antibiotics; medicine for the heart; medicine for blood pressure; diuretics or water pills; steroids; insulin; pills to control diabetes; sleeping pills; stomach remedies; laxatives;

Possibility of social desirability bias may result in under reporting of certain types, or number of medications.

Caution should be used when comparing with the 1990 OHS because of differences in the medications listed and the methods used (self-completed versus telephone interview).

Proportion of the residents of long-term care facilities who have been adequately immunized against selected diseases.

Proportion of the staff of long-term care facilities who have been adequately immunized against selected diseases.

Influenza is preventable through adequate immunization. High levels of immunization rate results in "herd immunity" whereby unimmunized persons are protected because the chance of an infected person coming in contact with a susceptible person is very low. Immunization against influenza is an annual event. These diseases are all preventable through adequate immunization. High levels of immunization rate results in "herd immunity" whereby unimmunized persons are protected because the chance of an infected person coming in contact with a susceptible person is very low. Immunization with pneumococcal vaccine need only occur once in a person's life while immunization against influenza is an annual event.

The incidence rate is the total number of cases of selected enteric diseases relative to the total population (usually expressed per 100,000).

For enteric diseases, the peak incidence usually occurs among children under the age of 4. Each health unit has its own database called the Reportable Disease Information System (RDIS). Comparisons with Ontario rates are possible. There were some issues around data integrity when RDIS first began operation in 1990. In some cases, case definitions have changed over time.