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INDEX

TERMS, METHODS, AND COMPUTATIONAL EXAMPLES



ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)

(See HIV Disease.)


AGE-SPECIFIC FERTILITY RATE (ASFR)

The rate of live births per 1,000 women for the specific age group. This is a more detailed measure than the crude birth rate, as it reflects variations in the birth rate by age groups of the female population.
(See Statistical Computation under Fertility Rate for an example.)


AGE STANDARDIZATION

Age standardized is a method of calculation which adjusts a statistical measure for differences in the age/gender structures between populations. With standardized measures, more meaningful comparisons can be made between genders, different time periods, or geographic areas, because the age standardized statistic is calculated as if all populations had the same age/gender population distribution.
(See Age Standardized Mortality Rate (ASMR), Standardized Mortality Ratio (SMR), Potential Years of Life Lost Standardized Rate (PYLLSR), and Potential Years of Life Lost Index (PYLLI); for an example, see Statistical Computation.)


AGE STANDARDIZED MORTALITY RATE (ASMR)

A summary of age adjusted death rates by age and gender, which have been standardized to a "standard" population (1991 Canada Census) for the purpose of rate comparisons between genders, different time periods or different geographic locations. The ASMR is the theoretical number of deaths that would occur per 10,000 population, if the specific population had the same age structure as the standard population.
(See Age Standardization and Standard Population; for an example, see Statistical Computation.)


AIDS

(See HIV Disease.)


ALCOHOL-RELATED DEATHS

Alcohol-related deaths are based on the ICD-10 diagnostic categories listed below, for which the resulting deaths are directly attributed to the use or abuse of alcohol.

Directly Related to Alcohol
Cause of Death		 ICD-10 Code(s)
Alcoholic intoxication F10.0
Alcoholic psychoses and dependence F10.1-F10.9
Alcoholic liver disease K70
Alcoholic neurological disorders G31.2, G62.1, G72.1
Alcoholic cardiomyopathy I42.6
Alcoholic gastritis K29.2
Alcoholic chronic pancreatitis K86.0
Alcoholic poisoning X45, X65
Other causes E24.2, O35.4, O99.3, P04.3, Q86.0, R78.0,
T51.0-T51.2, T51.9


Alcohol is considered to be a direct cause of death if one of the above conditions is listed as the underlying cause of death on the medical certification of death. If, however, any of the above conditions are listed on the certificate as antecedent causes giving rise to the underlying cause or other significant conditions contributing to the death, the death is considered to be indirectly related to alcohol. ICD-10 codes for deaths indirectly related to alcohol are listed below:

Indirectly Related to Alcohol
(excludes codes for directly related to alcohol)
Cause of Death		 ICD-10 Code(s)
Infectious/parasitic diseases A00-B99
Neoplasms C00-D48
Endocrine/nutritional/metabolic diseases E00-E24.3, E24.8-E89
Mental and behavioural disorders F00-F09, F11-F99
Nervous system diseases G00-G31.1, G31.8-G62.0, G62.2-G72.0, G72.2-G99
Circulatory system diseases I00-I42.5, I42.7-I99
Respiratory system diseases J00-J99
Digestive system diseases K00-K29.1, K29.3-K69, K71.0-K85, K86.1-K92
Genitourinary system diseases N00-N39, N99.0-N99.1, N99.5
Unintentional injury/accidents V01-X44, X46-X59, Y40-Y86, Y88
Suicide X60-X64, X66-X84, Y87.0
Homicide X85-Y09, Y87.1
Other causes  

Refer to Glossary in previous annual reports for ICD-9 codes.
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ASFR

(See Age Specific Fertility Rate.)


ASMR

(See Age Standardized Mortality Rate.)


AVERAGE AGE

The average ages of brides, grooms, and mothers of newborns in this annual report are calculated based on information provided on marriage or birth registration forms. The average ages of the population living in data dissemination areas are based on the mid-year population estimates for five year age groups.


BIRTH ORDER

Denotes the number position of the present birth relative to previous live births. That is, whether the live birth being counted is the 1st, 2nd, 3rd, etc. live born infant to a particular mother.


BIRTH RATE

(See Crude Rates.)


BIRTH WEIGHT

The first weight of the fetus or newborn after birth. For live births this weight should be measured within the first hour of life before significant postnatal weight loss has occurred. Hospitals in B.C. measure weight in grams; the approximate equivalents in imperial measures are included below for comparisons to other jurisdictions. For statistical and risk assessment purposes, birth weights are grouped as:
Extremely Low Birth Weight: weight less than 500 grams (<1lb 2oz).
Very Low Birth Weight:weight less than 1,500 grams (<3lb 5oz).
Low Birth Weight (LBW):weight less than 2,500 grams (<5lb 8oz).
"Normal" Birth Weight:weight from 2,500 to 4,499 grams (5lb 8oz to 9lb 15oz).
High Birth Weight: weight of 4,500 grams or more (>91b 15 oz).

BIRTHS

(See Total Births.)


BREECH

(See Mode of Delivery.)


CESAREAN

(See Mode of Delivery.)


COMMUNITY

A geographic area defined by a municipal (city, town, village, or district municipality) boundary. In this report, data are provided only for those communities that are incorporated.


CONFIDENCE INTERVAL

(See Statistical Test.)


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CONGENITAL ANOMALIES

Physical defects that existed or date from birth.


CRUDE RATES

  • For live births: the crude rate is the number of births divided by the mid-year population and converted to a rate per 1,000 population.
  • For birth-related statistics (teenage mother, elderly gravida, C-section, low birth weight, and pre-term): the rate is the number of these births divided by the number of live births and converted to a rate per 1,000 live births.
  • For stillbirths and perinatal deaths: the rate is the number of stillbirths and perinatal deaths divided by the number of total births (live births plus stillbirths) and converted to a rate per 1,000 total births.
  • For infant deaths: the crude rate is the number of infant deaths divided by the number of live births and converted to a rate per 1,000 live births.
  • For maternal deaths: the rate is the number of maternal deaths divided by the number of live births, and converted to a rate per 10,000 live births.
  • For deaths and mortality statistics: the crude rate is the number of deaths divided by the mid-year population and converted to a rate per 1,000 population.
  • For marriages: the crude rate is the number of marriages divided by the mid-year population and converted to a rate per 1,000 population.

DEATH RATE

(See Crude Rates.)


DRUG-INDUCED DEATHS

Deaths due to drug-induced causes. This category of deaths excludes accidents, homicides, and other causes indirectly related to drug use, as well as alcohol-related deaths and smoking-attributable mortality. The causes of death classified as being drug-induced (as shown below) are based on those used by the National Center for Health Statistics1.

Cause of Death ICD-10 Code(s)
Psychoactive substance and drug use/abuse F11-F16, F19
Accidental poisoning by drugs and medicaments X40-X44
Suicide by drugs and medicaments X60-X64
Assault by drugs and medicaments X85
Poisoning by drugs and medicaments, undetermined if accident or unintentional Y10-Y14
Adverse effects of drugs and medicaments Y40-Y56, Y57.0-Y57.4, Y57.7-Y57.9, Y88.0

Refer to Glossary in previous annual reports for ICD-9 codes.

1 (National Center for Health Statistics (1993). Technical notes. Monthly Vital Statistics Report. 41 (Suppl. 7), 48).

EARLY NEONATAL DEATH

Death of a child under seven days of age.


ELDERLY GRAVIDA

Any woman who was 35 years of age or older at the time of delivery of a live born infant.


EXPECTED DEATHS

The number of deaths expected for residents of a sub-provincial geographic area, based on the age-specific mortality rates for the province as a whole and the population age structure of the sub-provincial geographic area.
(See Statistical Computation for an example.)


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EXPECTED LOW BIRTH WEIGHT

The number of live births with low birth weight (less than 2,500 grams) that would be expected to be born to residents of a sub-provincial geographic area, based on the low birth weight rate for the province as a whole, and the number of births in the sub-provincial geographic area.
(See Statistical Computation under Low Birth Weight Live Births for an example.)


EXPECTED POTENTIAL YEARS OF LIFE LOST

The number of potential years of life lost (to age 75, as in this report) expected for residents of a sub-provincial geographic area based on the age-specific mortality rates for the province as a whole and the population age structure of the sub-provincial geographic area.
(See Statistical Computation under Potential Years of Life Lost Index for an example.)


FERTILITY RATE

The number of live births occurring in a given time period divided by the number of women of child-bearing age for residents of a geographic area. B.C. rates are per 1,000 women aged 15 to 44. Canadian rates are per 1,000 women aged 15 to 49.
(See Total Fertility Rate.)


FORCEPS

(See Mode of Delivery.)


GESTATIONAL AGE

Fetal age or duration of pregnancy measured from the first day of the last normal menstrual period. Gestational age is expressed in completed days or completed weeks (e.g., events occurring 280 to 286 days after the onset of the last normal menstrual period are considered to have occurred at 40 weeks of gestation).

Measurements of fetal growth, as they represent continuous variables, are expressed in relation to a specific week of gestational age as follows:

  • Extremely premature: gestational age of less than 28 weeks.
  • Moderately premature: gestational age of 28 to 36 weeks.
  • Pre-term/Premature: gestational age of less than 37 weeks.
  • Term: gestational age of 37 to 41 weeks.
  • Post-term/Postmature: gestational age of 42 weeks or more.

HEALTH REGION (HR)

A geographic subdivision of the province used by the Ministry of Health for data dissemination purposes. This publication includes data by 20 health regions, Figure 2 presents a map of the province by health regions.


HIV DISEASE

In 1987, the World Health Organization added new codes to the International Classification of Diseases (ICD) to identify Acquired Immunodeficiency Syndrome (AIDS) and Human Immunodeficiency Virus (HIV). In ICD-10, these conditions are coded to B20-B24 and are called HIV disease.

Refer to Glossary in previous annual reports for ICD-9 codes.


HUMAN IMMUNODEFICIENCY VIRUS (HIV)

The virus that causes HIV disease.


ICD-9 CODES

The World Health Organization's International Classification of Diseases, Ninth Revision. This version of ICD was used by the B.C. Vital Statistics Agency for coding of birth complications and causes of death from 1979 until 1999.


ICD-10 CODES

The World Health Organization's International Classification of Diseases and Related Health Problems, Tenth Revision, implemented by the B.C. Vital Statistics Agency on January 1, 2000. The Preamble to Appendix 2 presents a summary of ICD-10.


INFANT MORTALITY

Death of children under one year of age.


INFANT MORTALITY RATE

The number of deaths of children under one year of age expressed as a rate per 1,000 live births. The infant mortality rate is an internationally accepted indicator of the health status of a population.


LBW

(See Low Birth Weight.)


LHA

(See Local Health Area.)


LIFE EXPECTANCY

Life expectancy at age 0 represents the mean number of years a birth cohort (persons born in the same year) may expect to live given the present mortality experience of a population. The life expectancy for a population is a summary measure that reflects the mortality rates for all ages combined, weighted in accordance with a life-table population structure. Life expectancy is an internationally accepted indicator of the health status of a population.


LIVE BIRTH

The Vital Statistics Act defines a live birth as "The complete expulsion or extraction from its mother, irrespective of the duration of the pregnancy, of a product of conception in which, after the expulsion or extraction, there is:
    (a) breathing;
    (b) beating of the heart;
    (c) pulsation of the umbilical cord; or
    (d) unmistakable movement of voluntary muscle, whether or not the umbilical cord has been cut or the placenta attached."

LOCAL HEALTH AREA

A geographic subdivision of the province used by the Ministry of Health for data dissemination purposes, which can be aggregated into health regions (HR), or established Regional Health Boards, Community Health Service Societies, and Community Health Councils. In the tables in this report, four pairs of LHAs have been combined so their boundaries correspond to those of Community Health Councils.

Figure 1 presents a map of the province by local health areas.


LOW BIRTH WEIGHT (LBW)

A birth weight of less than 2,500 grams. Low birth weight babies have increased risks of morbidity and premature death.


LOW BIRTH WEIGHT RATE

The number of low birth weight live born babies per 1,000 live births.


MARRIAGE RATE

(See Crude Rates.)


MEDICALLY TREATABLE DISEASES, DEATHS DUE TO

Deaths due to medically treatable diseases are based on Charlton's2 classification. The disease categories (shown below) are ones for which mortality could potentially have been avoided through appropriate medical intervention. The calculation of this measure is based on deaths of a specified age where the underlying cause stated on the medical certificate of death falls into one of these categories.

Cause of Death (Age) ICD-10 Code(s)
Hypertensive disease (5-64) I10-I15
Cervical cancer (5-64) C53
Pneumonia and unqualified bronchitis (5-49) J12-J18.1, J18.8-J18.9, J40
Tuberculosis (5-64) A15-A19, B90
Asthma (5-49) J45, J46
Chronic rheumatic heart disease (5-44) I05-I09
Acute respiratory infections and influenza (age 5-49) J00-J06, J20-J22, J10-J11
Bacterial infections (5-64) A00-A05, A20-A49, B95-B96, G00,
H66, H70, H95.0-95.1, I00-I01, I02.0,
I02.9, L01-L08, M00, M02.8, M02.9,
M46.2, M86, M87.1
Hodgkin's disease (5-34) C81
Abdominal hernias, cholecystitis and cholelithiasis, appendicitis (5-64) K40-K46, K80-K81, K35-K37
Deficiency nutritional anemias (5-64) D50-D53
Refer to Glossary in previous annual reports for ICD-9 codes.

2 Charlton, J.R.H. (1987). Avoidable Deaths and Diseases as Monitors of Health Promotion. In Abelin,T., Z.J. Brzezinski, & V. Carstairs (Eds.), Measurement in Health Promotion and Protection (pp. 467-479). Copenhagen, Denmark: World Health Organization, Regional Office for Europe.

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MODE OF DELIVERY

  • Cesarean:
    A delivery involving the surgical incision of the abdomen and uterine walls.
  • Forceps:
    An assisted delivery employing forceps.
  • Spontaneous Breech:
    An unassisted (spontaneous) delivery in which the buttocks or feet of the fetus appear first.
  • Spontaneous Vertex:
    An unassisted (spontaneous) delivery in which the head of the fetus appears first.
  • Vacuum:
    An assisted delivery employing suction or vacuum.

MVA DEATHS

Motor Vehicle Accidental Deaths.


NATURAL POPULATION INCREASE

The component increase in a population due to the number of live births less deaths. This increase may often be expressed as a rate, such as per 1,000 population.


NEONATAL DEATH

Death of a child under 28 days of age.

OBSERVED DEATHS

The actual number of deaths that occurred in the province to residents of a geographic area in a specified time period.


OBSERVED LOW BIRTH WEIGHT LIVE BIRTHS

The actual number of low birth weight live births that occurred in the province to residents of a geographic area in a specified time period.


OBSERVED PYLL

The actual number of potential years of life lost (to age 75) from deaths that occurred in the province to residents of a geographic area in a specified time period.


OUT-OF-WEDLOCK BIRTHS

Births where the mother of the baby is not lawfully married to the father of the baby.


P-VALUE

(See Statistical Test.)

PERINATAL

Pertaining to or occurring in the period shortly before, during, and after birth.


POPULATION

Mid-year population estimates used in the preparation of this report were obtained from BC STATS, Ministry of Finance and Corporate Relations.


POST NEONATAL DEATH

Death of a child between the ages of 28 days and less than one year.


POST-TERM

(See Gestational Age.)


POTENTIAL YEARS OF LIFE LOST (PYLL)

The number of years of life lost when a person dies before a specified age (75 years). In this report, all deaths are assumed to occur at the midpoint of five-year age groups.
(See Statistical Computation for an example.)


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PRE-TERM

(See Gestational Age.)


PYLL INDEX (PYLLI)

The ratio of an area's observed PYLL to its expected PYLL. This is a health status indicator.
(See Statistical Computation for an example.)


PYLL STANDARDIZED RATE (PYLLSR)

An age-standardized measure of an area's PYLL, expressed in terms of a rate per 1,000 population, adjusted to a standard population (1991 Canada Census). This is a health status indicator.
(See Statistical Computation for an example.)


PYLLI

(See PYLL Index.)


PYLLSR

(See PYLL Standardized Rate.)


QUINTILE

A ranking is derived by dividing a group (e.g., LHAs within British Columbia) into five subgroups, each with equal numbers of LHAs. These divisions are derived from a ranking of the group members according to the value of a measure, such as the SMR or the PYLLI.


SAM

(See Smoking-attributable Mortality.)


SAM(%)

(See Smoking-attributable Mortality.)


SIDS

Sudden Infant Death Syndrome.


SMOKING-ATTRIBUTABLE MORTALITY (SAM)

The absence on death certifications of complete and reliable data on smoking as a contributing factor requires that estimation or other techniques be used to approximate the extent of smoking-attributable deaths. Estimation methods, while not precise, may at least provide a general indication of the extent of such deaths. The method used here is based on the concept of attributable risk.

To define attributable risk mathematically, consider d0 and d1 respectively to represent the death rates, in a given time period, in two cohorts from a population - those not exposed and those exposed to a given risk factor. The attributable risk of this factor, AR1 , would then be:

Image

Where:

    r1 = d1/d0 is the relative risk of the exposed cohort.
    The relative risk of the unexposed cohort is r0 = 1; the attributable risk of this cohort is AR0 = 0.
    The attributable risk (AR) for the population as a whole (exposed plus unexposed cohorts) is given by:

Image

Where:
    p1 = the proportion or fraction of the population exposed to the risk factor; and
    1-p1 = the proportion or fraction of the population not exposed to the risk factor.
This may be extended to account for multiple levels of exposure as follows:

Image

Where:
    pi = the proportion (prevalence) of the population in the ith level of exposure group;
    ri = the relative risk at the ith level of exposure; and
    i = the ith risk category
    .
When applied to smoking-attributable mortality (SAM), the attributable risk is often expressed as a percentage:

SAM (%) = AR x 100

The number of adult (35+ years of age) smoking deaths in British Columbia were estimated for 19 diseases. Smoking-attributable deaths are derived by multiplying the smoking-attributable mortality percentage expressed as a decimal fraction by the number of deaths in each cause of death category listed below.

Cause of Death ICD-10 Code(s)
Malignant Neoplasms  
Malignant neoplasms of lip, oral cavity, and pharynx C00-C14
Malignant neoplasm of esophagus C15
     Malignant neoplasm of pancreas C25
     Malignant neoplasm of larynx C32
     Malignant neoplasm of trachea, lung, and bronchus C33-C34
     Malignant neoplasm of cervix, uterus C53-C55
     Malignant neoplasm of urinary bladder C67
     Malignant neoplasm of kidney and other
     unspecified urinary organs 		C64-C66, C68
Circulatory System Diseases  
Hypertension I10-I13
Ischaemic heart disease I20-I25
Other heart diseases I01-I09, I27, I30-I52
Cerebrovascular disease I60-I69
Atherosclerosis I70
Aortic aneurysm I71
Other arterial disease I26, I28, I72-I78
Respiratory System Diseases  
Pneumonia/influenza J10-J18.1, J18.8-J18.9
Bronchitis, emphysema J40-J43
Chronic obstructive pulmonary disease J44
Other respiratory diseases A15-A19, J45-J46

Relative-risk data from the American Society's Cancer Prevention Study (CPS) II (1982-1988)3 were selected for use, as they have been widely used for similar analyses. The data from the CPS-II established the age groups and the classification of smokers (current, former, and never) for which smoking prevalence data were required. The relative risk age categories were for 35+, or 35-64 and 65+. B.C. prevalence rates for smoking were provided in the Tobacco Use in BC (1997) survey commissioned by the BC and Yukon Health and Stroke Foundation4.

Refer to Glossary in previous annual reports for ICD-9 codes.

3 Centres for Disease Control. (1990). Smoking and health: A national status report. (DHSS publication no. (CDC) 87-8396). 2nd Edition. Rockville, MD: U.S. Department of Health and Human Services.

4 Detailed information from the Tobacco Use in B.C., ANGUS REID GROUP survey results, September 1997.

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SMR

(See Standardized Mortality Ratio.)


STANDARD POPULATION

A reference population of known age distribution used in the calculation of standardized indicators to adjust for variations in population age structures in different geographic areas or time periods. For SMR and PYLLI calculations the standard population is the British Columbia population for the year(s) concerned. The 1991 Canadian Census is used as the standard population in the calculation of ASMR and PYLLSR.


STANDARDIZED MORTALITY RATIO (SMR)

The ratio of the number of deaths occurring to residents of a geographic area (e.g., LHA) to the expected number of deaths in that area based on provincial age-specific mortality rates. The SMR is a good measure for comparing mortality data that are based on a small number of cases or for readily comparing mortality data by geographical area. SMR is an internationally recognized health status indicator.
(See Age Standardization and Standard Population ; for an example see Statistical Computation.)


STATISTICAL COMPUTATION

The following provides the reader with computational examples of how various measures are calculated. In the examples, LHAs have been employed as the geographic unit of analysis. All data shown in the examples are hypothetical.
  • Age Standardized Mortality Rate (ASMR):


LHA
AgeStandardEstimatedDeath Observed
GroupPopulationPopulationRate/10,000 Deaths
(i)Image(pi)(mi)(di)
< 1403,0611,33922.43
1-41,550,2855,4831.81
.....
.....
.....
80-84382,3031,198701.284
85 +287,8779081596.9 145
TOTAL28,120,06581,016 561

For the Local Health Area:

Image


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LHA
AgeLiveFemaleAge Specific
GroupBirthsPopulationFertility Rate
(i)(bi)(wi)(ASFRi)
15-191959831.8
20-2446440104.5
25-2974498148.6
30-345174568.5
35-391269017.4
40-4425813.4
TOTAL2043,552374.2

For the Local Health Area:

  1. the age-specific fertility rate (ASFR) for age group 15-19 years is:

    ASFRi=bi/wi x 1,000 = 19/598 x 1,000=31.8

    Where:
    bi = number of live births for age group i; and
    wi = number of female population for age group i.

  2. the total fertility rate (TFR)is:

    Image


    Where:
    ASFRi = age specific fertility rate for age group i; and
    a = number of years in each age group i.

LHABritish Columbia
Low Birth WeightLow Birth Weight
Live BirthsTotalLive BirthsTotal
YearObservedExpectedLive BirthsObservedLive Births
(i)(Oi)(Ei)(Li ) (bi)(Bi)
19959282.91,7012,09642,989
19966974.61,5881,96541,846
199710280.21,5822,11341,655
19988574.71,4952,14542,913
19999178.11,5012,26743,586
TOTAL439390.67,86710,586212,989


For the Local Health Area:

  1. the expected low birth weight live births for year i = 1995 were:

    Image

    Where:
    bi = number of LBW live births for the province in year i;
    Bi = number of live births for the province in year i; and
    Li = number of live births for the LHA.
  2. the ratio of observed over the expected LBW live births for the five-year peroid was:

    Image

    Where:
    Oi = observed LBW live births for year i; and
    Ei = expected LBW live births for year i.
  3. Chi-Square (X2):
Image


LHA
AgeAgeStandardEstimatedDeathObservedObserved
GroupFactorPopulationPopulation Rate/1,000DeathPYLL
(i)(75-Yi)Image(pi)(mi)(di)(di(75-Yi))
< 174.5403,0611,3392.23223.5
1-472.01,550,2855,4830.2172.0
5-967.51,953,0456,5530.2167.5
.......
.......
.......
65-697.51,084,5883,53818.766495.0
70-742.5834,0242,77928.880200.0
TOTAL-28,120,06579,1402393,183.0

For the Local Health Area:

Image


Image


Image


  • Potential Years of Life Lost Index (PYLLI):


Image

For the Local Health Area:

Image


Where:
O = observed PYLL;
E = expected PYLL;
di = observed deaths in age group i;
ei = expected deaths in age group i;
Yi = age at midpoint of age group i;
pi = LHA population for age group i;
Pi = provincial population for age group i;
Di = provincial deaths for age group i.

1) Observed PYLL (O)

The number of potential years of life lost (PYLL) based on the number and age at death of deaths that occurred in the LHA. For example, for age group under one year of age, the observed PYLL are:

Observed PYLL=deaths x age factor= di(75-Yi)= 3 x 74.5 = 223.52

2) Expected PYLL (E)

The number of potential years of life lost (PYLL) expected for residents of the LHA based on the PYLL from the expected deaths in the age group. For example, for age group under one year of age, the expected PYLL are:

Expected PYLL = expected deaths x age factor = ei(75-Yi) = Di/Pi x pi x (75-Yi)
= 328/42,700 x 1,339 x 74.5 = 766.3

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LHABritish Columbia
AgeEstimatedDeathObservedExpectedEstimatedDeathObserved
GroupPopulationRate/1,000DeathsDeathsPopulationRate/1,000Deaths
(i)(pi)(mi)(di)(ei)(Pi)(Mi)(Di)
< 11,3392.2310.342,7007.7328
1-45,4830.211.9172,5000.461
........
........
........
80-841,19870.18487.248,10072.83,502
85+908159.7145138.834,500152.85,272
TOTAL81,016561595.13,131,70023,389


For the Local Health Area:

Image


Where:
    di = observed deaths in age group i; and
    ei = expected deaths in age group i
1) Observed Deaths (d)
The actual number of deaths that occurred in the LHA. For example, for age group under one year of age, the observed deaths are three.

2) Expected Deaths (e)
The number of deaths expected for residents of the LHA based on the age specific mortality rates for the province as a whole and the population age structure of the LHA. For age group under one year, the expected deaths are:

Image


Where:
    pi = LHA population for age group i;
    Di = provincial death for age group i; and
    Pi = provincial population for age group i.

STATISTICAL TEST

  • P-VALUE
The p-value is the probability of rejecting the null hypothesis when a specified test procedure is used on a given data set. This probability is the smallest level of significance at which the null hypothesis would be rejected. Once the p-value has been determined, the conclusion at any particular level a results from comparing the p-value to a (e.g., 0.05):

(a) p-value less than or equal to a reject null hypothesis at level a,

(b) p-value >  a do not reject the null hypothesis at level a,

and we call the data statistically significant when the null hypothesis is rejected and not significant otherwise.

  • For rates, such as ASMRs, the test employed to determine statistical significance is a confidence interval. The 95% confidence interval for the difference (D) between a LHA and a provincial rate is defined by the upper and lower limits of the interval as follows:
Image


Image


Where:
    Rl = Rate for LHA l;
    Rp = Rate for the province;
    Ol = Observed number for LHA l; and
    Op = Observed number for the province.
If the Lower Limit > 0, then Rl is statistically significantly higher than Rp;
if the Upper Limit < 0, then Rl is statistically significantly lower than Rp; otherwise,
there is no statistically significant difference.

  • For ratios, such as SMRs, a Chi-square (X 2) test is applied to determine whether the observed number of cases is statistically significantly different from the expected number. For LHA l:
Image

Where:

    Ol = Observed number for LHA l;and
    El = Expected number for LHA l;

If X21>3.84, the ratio is statistically significant at 5% significance level.

  • For SMR values, the Chi-square statistic that is applied is:
Image

Where:
    Ôl = Ol if Ol>  El; otherwise
    Ôl = Ol + 1

STILLBIRTH

The Vital Statistics Act defines a stillbirth as "The complete expulsion or extraction from its mother after at least 20 weeks of pregnancy, or after attaining a weight of at least 500 grams, of a product of conception in which, after the expulsion or extraction, there is no breathing, beating of the heart, pulsation of the umbilical cord, or unmistakable movement of voluntary muscle."

The definition of a stillbirth has changed over the years. From July 1, 1962 until January 1, 1986, the definition of a stillbirth did not include the phrase "or after attaining a weight of at least 500 grams. " From 1950 until July 1, 1962, the definition of a stillbirth was: the birth of a viable fetus after at least 28 weeks pregnancy in which pulmonary respiration does not occur, whether death occurs before, during, or after birth.


STILLBIRTH RATE

(See Crude Rates.)


TEENAGE MOTHERS

Mothers less than 20 years of age.


TERM

(See Gestational Age.)


TFR

(See Total Fertility Rate.)


TOTAL BIRTHS

The number of live births plus stillbirths.


TOTAL FERTILITY RATE (TFR)

The rate is calculated by summing all of the age-specific birth rates multiplied by the number of years by which the age-specific birth rates are grouped (this assumes the same number of women in each age group). "The total fertility rate indicates the number of births that a group of 1,000 women would have if they experienced, during their childbearing years (i.e., age 15 to 44 years), the age-specific birth rates observed in a given calendar year. It is a hypothetical measure that shows the implications of current levels of fertility by age for completed family size." (National Center for Health Statistics. Supplements to the monthly vital statistics report: advance reports, 1987. National Center for Health Statistics. Vital Health Stat 24 (4) p. 5. 1990.)
(See Statistical Computation for an example.)


TOTAL PYLL

The total number of potential years of life lost prior to an established cut-off point of 75 years.


VERY LOW BIRTH WEIGHT

A birth weight of less than 1,500 grams.


UCOD

(See Underlying Cause of Death)


UNDERLYING CAUSE OF DEATH (UCOD)

The World Health Organization defines the underlying cause of death as "(a) the disease of injury which initiated the train of events leading directly to death, or (b) the circumstances of the accident or violence which produced the fatal injury."


VACUUM

(See Mode of Delivery.)


VERTEX

(See Mode of Delivery.)

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