Quarterly Digest
Volume 12 - Number 2 December 2002

• Preface
  
  
• Map: B.C. Local Health Areas

• Local Health Areas(LHA) within Health Service Delivery Area (HSDA) and Health Authority

• Vital Event Statistics - April 1, 2002 - June 30, 2002 and Year-to-date
  (Population, Livebirth, Death, Marriage, Stillbirth, Infant Deaths)

• Selected Birth Statistics - April 1, 2002 - June 30, 2002 and Year-to-date
  (Low Birthweight, Preterm, Teenage Mother, Elderly Gravida, Cesarean Section)

• External Causes of Death - April 1, 2002 - June 30, 2002 and Year-to-date
  (Accidents - [Motor Vehicle Accidents, Poisoning, Falls, Burns/Fire, Drowning, Other], Suicide, Homicide, Other External Causes)

• Neoplasm Deaths - April 1, 2002 - June 30, 2002 and Year-to-date
  (Lung, Female Breast, Colorectal, Other G.I., Female Reproductive, Prostate, Blood/Lymph, Other Malignancy, Nonmalignant and Unspecified)

• Heart Disease Deaths - April 1, 2002 - June 30, 2002 and Year-to-date
  (Rheumatic/Valvular, Hypertension, Ischemic, Conductive & Dysrhythmic, Heart Failure, Congenital, Other)

• Respiratory Disease Death Statistics - April 1, 2002 - June 30, 2002 and Year-End
  (Emphysema, COPD, Pneumonia, Influenza, Asthma, Lung Disease from External Agents, Pulmonary Fibrosis, Other Respiratory)

• Other Selected Death Statistics - April 1, 2002 - June 30, 2002 and Year-to-date
  (Diabetes, Alcohol-Related, AIDS, Other Infectious Disease, Cerebral and Other Vascular, Liver Disease, Amyotrophic Lateral Sclerosis and Multiple Sclerosis, Alzheimer's Disease, Parkinson's Disease)

• Summary Article:
  Leukemia Mortality in British Columbia, 1986-2000
  by R. Pelletier, & Z. Kashaninia

• Glossary

• Contributors' Note

• Readers' Note

Preface

This Quarterly Digest features a report on leukemia mortality within British Columbia for the years 1986 - 2000. Leukemia is the name given to a group of malignancies that originate in the blood-forming cells of bone marrow and which can spread to other tissues such as the spleen, liver and lymph nodes. During the time period under scrutiny, 3,284 B.C. residents died due to this group of diseases. This study examines incidence and mortality of leukemia nationally and provincially and focuses more specifically on the B.C. situation in terms of age, gender and geographical distribution.

This edition of the Quarterly Digest marks the last one in which a "Feature Article" will be included as a matter of course. While we hope, in the future, to be able to produce the occasional article and/or "Special Report", structural changes within the Ministry of Health Planning preclude the regular production of these research articles. We will however, continue to publish vital event data on a quarterly basis. These data are also posted on the Vital Statistics web site.

We encourage submission of vital event related papers from elsewhere within the government, or from members of the public for inclusion in future issues of this publication. And, as always, we welcome any comments or questions about the data presented here, as well as requests for information not supplied in our regular publications. Contact information is included at the back of this report.

R.J. Danderfer	Terry Tuk
CEO/Director	Manager
British Columbia	Information and Resource
Vital Statistics Agency	Management Branch
	Vital Statistics Agency

[Return to Table of Contents]

Local Health Areas within
Health Service Delivery Area & Health Authority

Leukemia Mortality in British Columbia, 1986-2000

Introduction

Leukemia is cancer that originates in a cell in the marrow and is characterized by the uncontrolled growth of developing marrow cells. There are two major classifications of leukemia: myelogenous and lymphocytic, which can each be acute or chronic. Acute leukemia is a rapidly progressive disease that results in the accumulation of immature, functionless cells in the marrow and blood. The marrow often can no longer produce enough normal red and white blood cells and platelets. Anemia, a deficiency of red cells, develops in virtually all leukemia patients. The lack of normal white cells impairs the body's ability to fight infections. A shortage of platelets results in bruising and easy bleeding. Chronic leukemia progresses more slowly and permits greater numbers of more mature, functional cells to be made. Other, more rare, types of leukemia include plasma cell leukemia, hairy cell leukemia and monocytic leukemia. (Leukemia & Lymphoma Society, 2001)

While leukemia is neither contagious nor hereditary, certain genetic disorders such as Down syndrome, exposure to certain chemicals and radiation may increase susceptibility. All cancers, including leukemias, appear to arise because of gene mutations. Pathways that may lead to cancer include factors such as genetics, environment, diet, infections, immunosuppression, chemicals, radiation and unknown factors. (Mughal, T. & Goldman, J., 1999)

Methodology

It should be noted that the information submitted on death certificates does not always provide complete or precise diagnostic descriptions. If it were possible to assign the events included in the "unspecified leukemia" category to more precise codes, obviously this would alter the mortality count distribution among the various types of leukemia.

Age standardized mortality rates (ASMRs) are a summary of age adjusted death rates by gender that are standardized to a specific population to compare different time periods or geographical locations. The Vital Statistics data that are used in this report are standardized to 1991 Canada Census population.

Standardized mortality ratios (SMRs) are the ratio of the actual number of deaths in a Local Health Area (LHA) to the expected number of deaths in that area that are based on provincial age-specific mortality rates (SMRs are used for comparing each LHA's observed leukemia mortality to that of the Province as a whole).

• There were 1,973 deaths due to leukemias in Canada in 1997 (Statistics Canada's, Mortality-Summary List of Causes, 1997).

• In 1997 in Canada, the total rate for deaths due to leukemia was 6.6 per 100,000 standard population.

• Overall, British Columbia had the third lowest rate of leukemia (6.2)

• Of all the provinces, Saskatchewan had the highest rate (8.4) followed by Manitoba (7.7).

• Alberta had the lowest total rate in the country (5.7) followed by Newfoundland (6.0).

• In addition to having the highest overall rate in Canada, Saskatchewan also had the highest rate (9.8) of deaths for males due to leukemia, followed by Manitoba (8.2).

• Newfoundland had the lowest rate for males (5.1) followed by Alberta (6.5).

• Manitoba had the highest rate for females (7.7) followed by Saskatchewan (7.0).

• Alberta had the lowest rate for females (4.9) followed by Quebec (5.5).

Incidence in British Columbia

• Acute Lymphatic leukemia has shown a slight decrease in the male population of British Columbia from 1986-1998 with an ASIR of 1.9 (per 100,000 standard population) in 1986 to 1.4 in 1998.

• The British Columbian female population from 1986-1998 experienced stable incidence rates for Acute Lymphatic leukemia with an ASIR of 1.2. The highest rate was in 1992 (1.7) and the lowest rate was in 1987 (0.9).

• In British Columbia, from 1986 to 1998, Chronic Lymphatic leukemia has generally increased in the male population rising from an ASIR of 3.7 in 1986 to 4.2 in 1998. The lowest rate was in 1990 (1.8) and the highest rate was in 1998 (4.2).

• Female incidence rates of Chronic Lymphatic leukemia have shown a slight decrease from 2.2 to 1.7 over the thirteen-year span.

• Acute Myelocytic leukemia has shown an overall increase in the male population of British Columbia from 1986-1998 with an ASIR ranging from a low of 1.2 to a high of 2.5.

• Acute Myelocytic leukemia has shown a steady rise in incidence in the British Columbia female population with an ASIR of 0.9 in 1986 to 2.1 in 1998.

• Chronic Myelocytic leukemia has increased in the male population in British Columbia with an ASIR of 1.5 in 1986 to 1.7 in 1998. The lowest rates were in 1987 and 1991 (1.3) and the highest rate was in 1995 (2.5).

• The female population's incidence rates of Chronic Myelocytic leukemia have remained relatively stable, showing a slightly increased overall trend, with an AISR of 0.8 in 1986 to 1.0 in 1998.

• Other and Unspecified leukemias (including Hairy Cell, Monocytic, Other Specified and Unspecified for the purposes of this paper) have remained relatively stable for the male population of BC over the thirteen year period with an ASIR of 1.8.

• Other and Unspecified leukemias (including Hairy Cell, Monocytic, Other Specified and Unspecified for the purposes of this paper) have decreased slightly in the female population of BC since 1986 with a peak ASIR of 1.8 in 1986 decreasing to 1.1 in 1998.

• From 1986 to 2000, there was an average of 219 leukemia deaths per year in British Columbia. There were 3284 (1857 male and 1427 female) deaths in British Columbia in the 15-year time period.

• Over the 15-year period, Myeloid and Lymphoid leukemia were the most prominent causes of death in the leukemia group, with 1259 (38.34 percent) and 1004 (30.57 percent) deaths respectively.

• The number of leukemia deaths increased from 1986 to 2000 for both males and females.

• Overall, during the 15-year time period, more males than females died from leukemias in every year with the exception of 1992 (101 females compared to 96 males).

• In all categories, except for plasma cell leukemia, there were more male than female deaths.

Age Specific Mortality Rates

• In 1658 (72.2%) of the 2296 leukemia deaths between 1991 and 1998, the type of leukemia was identified on the death record. Among the type-identified group, myeloid was the most frequent (53.7%) followed by lymphoid (42.8%). Other specified types of leukemia were apparently relatively rare.

• Leukemia deaths occur across all age groups.

• In British Columbia, the risk of dying from leukemias increased with age.

• From infancy, the risk of dying from leukemias was relatively stable until age 45. The increase in the late 40s continued with age peaking at 6.65 (per 10,000 population) for age 85 and over. The risk nearly doubled from a rate of 0.12 in the 40-44 age group to 0.22 in the 45-49 age group.

• The age groups with the lowest risk of dying from leukemias were those under one year of age, those from 5-9 years of age and those from 20-24 years of age, all tied at a rate of 0.07.

• The age group with the greatest risk of death from leukemias was 85+, with a rate of 6.65.

• Females with the lowest risk (nearly zero) of death from leukemias were those under one year of age followed by females in the 20-24 age group (0.05).

• Women aged 85 and over were at greatest risk of death from leukemias (5.60) followed by those in the 80-84 age group (4.34).

• Males with the lowest risk of death from leukemia were those in the 1-4 age group (0.06) followed by the 5-9 and 30-34 age groups (both 0.07).

• Males 85 and over were also at greatest risk of death from leukemias (8.77) followed by the 80-84 age group (8.73).

• The only age groups where females had a greater rate of death from leukemias was in the one to four years (0.06 for males and 0.11 for females) and 30-34 years (0.07 for males and 0.09 for females).

• During the time period, 1991-2000, there were deaths due to lymphoid leukemia in every age group except for those under one year of age.

• During the time period, 1991-2000, there were 710 British Columbians who died of lymphoid leukemia (422 male and 288 female).

• Overall, those in 85 and over age group had the greatest risk of death due to lymphoid leukemia (2.62 per 10,000 population).

• The overall crude rate was 1.5 times greater for males than for females (0.22 vs. 0.15).

• Males in the 80-84 age group had the greatest risk of dying from lymphoid leukemia (2.99). Risk for males increased greatly at age 60-64 when the age specific rate was 3 times higher than the rate for 55-59 age group.

• Among females, the 85+ age group had the greatest risk of dying from lymphoid leukemia (2.48). This was nearly double the rate for those 80-84 (1.47).

• There were 888 deaths in British Columbia due to myeloid leukemia (484 male and 404 female) between 1991 and 2000.

• From 1991 to 2000, there were deaths due to myeloid leukemia in every age group.

• Overall, those in 80-84 age group had the greatest risk of dying from myeloid leukemia (1.80 per 10,000 population).

• The overall crude rate was slightly greater for males dying from myeloid leukemia than females (0.26 and 0.21 respectively).

• Males in the 80-84 age group had the greatest risk of dying from myeloid leukemia (2.38).

• Among females, those 80-84 had the greatest risk of dying from myeloid leukemia (1.42 per 10,000 population). In the one to four year age group, the females' risk of dying from myeloid leukemia was more than three times that of males (0.10 vs. 0.03 respectively).

Age Standardized Mortality Rates

• Over the last 15 years, there has been a slight decline in age standardized mortality rates (ASMR) for leukemias in British Columbia.

• ASMRs for males increased slightly over the 15-year period.

• For males, the highest rate was in 1996 with an ASMR of 0.82 per 10,000 standard population. The lowest rate was in 1992 with an ASMR of 0.59.

• The highest ASMR for females was in 1993 (0.51) while the lowest was in 2000 with an ASMR of 0.34.

• ASMRs for males exceeded females in every year. The average male ASMR was 1.7 times greater than the ASMR for females.

Standardized Mortality Ratios

• Local Health Areas (LHAs) with statistically significantly high SMRs for leukemias were Castlegar (1.77), Kootenay Lake/Nelson (1.49), Prince George (1.37) and Nanaimo (1.24).

• Kamloops was the only LHA that showed statistically significantly fewer deaths than expected with an SMR of 0.77.

Summary

Although the overall age standardized mortality rates for leukemia showed a slight downward trend over the study period, the rates for men showed a slight increase. The non-standardized annual mortality counts for B.C. showed a general upward trend from 1986 (175 deaths) through 2000 (249 deaths).

The risk of dying from leukemia increased with age for both genders. The age specific mortality rates for leukemia mortality were relatively stable for individuals under 45 years of age, ranging from 0.07 to 0.12. A sharp increase was seen beginning at ages 45-49 (0.22), with a consistent upward trend peaking at age 85 and over (6.65).

Between 1991 and 2000, there were 61 deaths due to leukemia among children aged 14 and younger. 36 (59 percent) of those deaths were in children 9 and younger (a 10-year age span). The remaining 25 deaths (41 percent) were concentrated in children aged 10-14 (a 5-year age span).

Over the study period, leukemia deaths in males were more numerous than in females for every year except 1992. Overall, deaths due to leukemia were 1.3 times more likely to involve a male.

The local health areas (LHAs) of Kootenay Lake/Nelson (6/7), Castlegar (9), Prince George (57), and Nanaimo (68) showed a statistically significant higher-than-expected number of deaths. Kamloops (24) was the only local health area that showed statistically significant fewer-than-expected number of deaths.

References

Glossary

Alcohol-Related:
This category includes all deaths considered as being directly or indirectly related to alcohol as indicated by inclusion by the certifier of selected alcohol identifying conditions anywhere on the death record (including "lifestyle" field). It should be noted that where alcohol is an indirect cause of death (i.e. not UCOD) and the direct underlying cause of death falls within one of our selected causes (e.g. motor vehicle accidents), then this death may be counted in both columns. That is, not all of "alcohol-related" are exclusive. This category includes ICD-10 codes: F100-F109, K700-K709, O993, P043, O354, Q860, G312, G621, G721, I426, K292, K860, X45, X65, Y14, T510-T512, T519. Note: now excludes acute pancreatitis, and cirrhosis not specifically identified as alcohol induced.

Assignment of Health Region:
Cases are assigned to Health Regions by the aggregation of appropriate LHAs.

Assignment of Local Health Area (LHA):
Allocation of LHA, in the case of births and deaths is based upon the usual residence (by postal code) of the mother and deceased respectively. Marriages are assigned to LHAs according to the place of event. Community name, is used in the absence of postal code.

Elderly Gravida:
Any mother who was 35 years of age or older at the time of delivery of a live born infant.

External Causes of Death:
Deaths due to environmental events, circumstances and conditions as the cause of injury, poisoning, and other adverse effects. Broad categories include accidents, suicide, medical or abnormal reactions (considered accidents), homicide, legal intervention, misadventures (counted as accident) and injury from war operations. Standard "Quarterly" tables under this heading include deaths due to accidents, suicide, homicide, and other. Accidents are subdivided by the following categories; motor vehicle accidents (MVA) (ICD-10 V020-V049, V090-V092, V093, V120-V149, V190-V196, V200-V249, V260-V349, V360-V449, V460-V549, V560-V649, V660-V749, V760-V799, V803-V805, V820-V821, V823-V839, V840-V875, V877-V8999, Y850), poisoning (X40-X49), falls (W00-W19), burns/fire (X00-X19), drowning (V900-V909, V920-V929, W65-W74), other accidents (V010-V019, V050-V069, V091, V099, V100-V119, V150-V189, V198-V199, V250-V259, V350-V359, V450-V459, V550-V559, V650-V659, V750-V759, V800-V802, V806-V819, V822, V876, V910-V919, V930-V949, V950-V978, V98-V99, W20-W64, W75-W99, X20-X39, X50-X59, Y40-Y849, Y859, Y86, Y880-Y883). Suicide ICD-10 codes are X60-X84, Y870; homicide (X85-Y09, Y871); "other [external]" consists of events of undetermined intent, legal interventions, and operations of war (Y10-Y369, Y890-Y899).

Note: the late effects of accidental poisoning, falls, and burns/fire are no longer identified separately for inclusion in these categories and are now part of "other accidents"). Trains are now considered motor vehicles in ICD-10 but for consistency, have been excluded from MVA counts to still be considered as "other transport".

Heart Disease:
Tables under this heading include deaths due to:

• rheumatic/valvular: (I050-I099, I340-I38)
  
• hypertension/hypertensive: (I10-I159)
  
• ischemic: (I200-I259) (Note: now includes cardiomyopathy specified as ischemic)
  
• conductive & dysrythmic: (I440-I499)
  
• heart failure: (I500-I509)
  
• congenital: (Q200-Q249)
  
• other: pulmonary (I260-I289), inflammatory (I300-I311, I319-I339, I400-I409, I514); cardiomyopathy (I420-I429) (Note: now excludes ischemic); other ill-defined and unspecified heart disease (I312-I318, I510-I513, I515-I519) (includes myocardial degeneration)

ICD-9:
The ninth revision of International Classification of Diseases, World Health Organization, Geneva, 1977. An internationally used system of approximately 12,000 four (and some three) digit numbers representing a system of categories to which morbid entities are assigned according to an established criteria. ICD provides a common basis of disease and injury classification that facilitates storage, retrieval, and tabulation of statistical data.

ICD-10:
The tenth revision of International Classification of Diseases and Related Health Problems, World Health Organization, 1992. In use beginning with year 2000, update of ICD-9 revised with alpha-numeric system and increased code detail (approximately 18,000). The BC Vital Statistics Agency and all their provincial counterparts utilize an ICD-10 that has been modified by the National Center for Health Statistics (NCHS) for use in the classification and analysis of medical mortality data in the United States (October, 1998).

Infant Deaths:
Deaths of children under one year of age.

Live birth:
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:

• breathing;
  
• beating of the heart;
  
• pulsation of the umbilical cord; or
  
• unmistakable movement of voluntary muscle, whether or not the umbilical cord has been cut or the placenta attached.

Low Birth Weight:
Any liveborn infant weighing less than 2500 grams.

Neoplasms (ICD-10 C000-D489):
Although the vast majority of deaths in this category are due to malignant cancer, also included are benign, in-situ, and unspecified "tumours". Detailed ICD-10 breakdown used in "Neoplasm Deaths" tables are;

• lung: includes trachea, bronchus, lung and pleura (C33, C340-C349, C384, C450). Note: now excludes mesothelioma of lung and trachea.
  
• female breast: (C500-C509)
  
• colorectal: (C180-C218)
  
• other G.I.: includes esophagus, stomach, small intestine and duodenum, liver & intrahepatic bile ducts, gallbladder and extrahepatic ducts, pancreas, peritoneum, other and ill-defined within digestive organs (C150-C179, C220-C269)
  
• female reproductive: includes uterus, cervix, placenta, ovary and adnexa, vagina & external genitalia (C510-C58)
  
• prostate: C61
  
• blood lymph: includes lymphatic and haematopoietic tissue (C810-C969, C463).
  
• other malignancy: includes malignant neoplasms of other (e.g. lip, oral cavity, pharynx, nose, ear, larynx, heart, bone and connective tissue, urinary tract, eye, brain, endocrine glands)and ill-defined or unspecified sites (C000-C148, C300-C449, C451-C462, C467-C499, C600-C609, C620-C768, C5099*, C80*). Note: * codes used exclusively by BC Vital Statistics Agency for male breast cancer and for unknown primary site cancer.
  
• non-malignant & unspecified: includes benign, in-situ, and neoplasms of uncertain or unknown behaviour (D000-D489).
  Note: This neoplasm group now includes myeloproliferative disease, thrombocythemia, monoclonal gammopathy, and lymphoproliferative disease which were not previously considered neoplastic in ICD-9 and were counted in other ICD chapters.

Other Selected Death Statistics:
Tables under this heading include deaths due to:

• diabetes (E100-E149).
  
• alcohol related - see above.
  
• AIDS/HIV: (B200-B24).
  
• other infectious and parasitic disease: (A000-B199, B250-B999) Note: Now includes obstetrical and neonatal tetanus.
  
• cerebro and other vascular disease: (I600-I698, I700-I879, I950-I959, I880-I899, I970-I979, I99). Includes cerebrovascular disease, disease of arteries and veins, hypotension, and other circulatory system disease. Note: "Other circulatory system disease" now includes post procedural disorders of the circulatory system (I970-I979) which are never selected as the UCOD. However they are confirmed by editing and either recoded to the more specific disease (embolism, stroke, M.I.) or double coded if the complication is confirmed.
  
• liver disease: (K700-K7699). Note: Now includes toxic liver disease with cholestasis.
  
• ALS/MS: Amyotrophic lateral sclerosis and multiple sclerosis: (G122, G1221, G35). Note: In order to maintain continuity with ICD-9, unspecified motor neuron disease (G122) is included in this category as it was previously not distinguishable from ALS.

Premature/Pre-term:
Any live born infant less than 37 weeks gestation at delivery.

Respiratory Disease Death Statistics:
Tables under this heading include deaths due to the following:

• emphysema: (J430-J439) Note: Now excludes when described as or resulting in obstructive disease -see note at COPD.
  
• COPD: (J440-J449). Note: Now includes specific code within the group for COPD when accompanied with acute lower respiratory infection, or with acute exacerbation. This inclusion has no statistical impact on UCOD. Also, this category now includes asthma and emphysema described as obstructive not previously included in ICD-9.
  
• pneumonia: (J120-J181, J188-J189) Note: ICD-10 has a new code for chlamydial pneumonia (J160). It is uncertain if this condition would have previously been coded to "pneumonia due to other specified bacteria" (ICD-9 4828) or to "other diseases due to viruses and chlamydia" (0788), or to both. This disease is very rare on death records so if not coded to 4828, the impact to comparison of historical data would still be minimal. Daily VS edits have been implemented to unsure consistent selection of pneumonia.
  
• influenza: (J100-J118)
  
• asthma: (J450-J459, J46) Note: Now excludes when described as obstructive - see note at COPD.
  
• lung disease due to external agents: (J60-J709)
  
• pulmonary fibrosis: (J841)
  
• other respiratory diseases: (J00-J069, J182, J200-J42, J47, J80-J840, J848-J9899) Note: Now includes post procedural respiratory disorders (J950-J959) which formerly used to be injury codes. These codes are never selected as the UCOD so their impact would only effect multiple code analyses. The Vital Statistics Agency includes these in daily data edits to confirm them as post procedural and to double code for the specific respiratory condition (e.g. pneumonia). As a result, respiratory disease statistics in BC are more consistent with historical data.

Standardized Mortality Ratio (SMR):
The ratio of the number of deaths occurring to residents of a geographical area (e.g. LHA) to the expected number of deaths in that area based on provincial age specific mortality rates.

Stillbirth:
The complete expulsion or extraction from its mother after at least twenty weeks of pregnancy or after attaining a weight of at least 500 grams, of a product of conception in which, after expulsion or extraction, there is no breathing, beating of the heart, pulsation of the umbilical cord or unmistakable movement of voluntary muscle.

Teenage Mother:
Any mother who was age 19 or less at the time of delivery.

UCOD:
Underlying cause of death - based upon application of standard international coding rules for determining sequential relationships of conditions and diseases from immediate cause backwards to underlying cause.

[Return to Table of Contents]

Contributors' Note:

The editorial staff would like to invite any researchers of health-related topics who wish to contribute an article or paper summary for publication in this Quarterly Digest to contact the Information and Resource Management Branch of the British Columbia Vital Statistics Agency. Articles should focus on health status issues in British Columbia. It is preferable that submissions be in "electronic media" format (e.g. Word, Word Perfect, Excel, Power Point, Corel, Pagemaker, etc.). Article presentation will be subject to space allowances and publishing deadlines.

Readers' Note:

Re: "Letters to the Editor", or mailing and distribution.

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