Birth cohort and calendar period trends in breast cancer mortality in the United States and Canada.

BACKGROUND: Previous studies of regional and temporal variation in U.S. breast cancer mortality rates have been confined largely to analyses of rates for white women. PURPOSE: Breast cancer mortality rates from 1969 through 1992 for white women and black women in four regions of the United States and for all women throughout Canada were compared to identify racial, regional, and temporal differences. Differences and trends in the rates were evaluated in view of breast cancer risk factors and relevant medical interventions. METHODS: Age-period-cohort models were fit to the data, and changes in birth cohort trends (suggesting a change in a breast cancer risk factor or protective factor) and calendar period trends (suggesting, in part, the impact of new or improved medical interventions) were examined. RESULTS: Breast cancer mortality rates for white women were significantly higher in the Northeast than in any other region of the United States (two-sided t tests; P<.005); the rates for black women were not. Birth cohort trends for all women were similar until about 1940, with a moderation of mortality risk beginning around 1924. A marked moderation of risk by 4-year birth cohorts was observed for U.S. white women born after 1950, whereas stable or slightly decreasing trends were observed for U.S. black women and Canadian women. For women born from 1924 to around 1938, fertility rates increased for all three groups; after 1950, they declined uniformly. Looking at temporal effects, we found that the slope of the mortality calendar period trend increased in the 1980s compared with the 1970s for all women. In the last calendar period, 1991-1992, a trend of decreasing mortality rates was found for white women in the United States and for Canadian women. IMPLICATIONS: Widespread environmental exposures are unlikely to explain the higher relative breast cancer mortality rates observed for U.S. white women in the Northeast, since the rates for black women in this region were not higher than in other regions. The moderation of breast cancer mortality rates for women born between 1924 and 1938 coincides with increased fertility rates following World War II. Stable or decreasing mortality rates for U.S. women and Canadian women born after 1950 were not expected in view of declining fertility rates, suggesting a change in a breast cancer risk factor or protective factor. The increase in calendar period trend slope in the 1980s likely reflects the coincident rise in breast cancer diagnosis via mammography. The recent decline in calendar period trend for white women in the United States and for Canadian women may be the result of earlier detection and increased use of adjuvant therapy.

Cancer incidence in a religious isolate of Alberta, Canada, 1953-74.

Members of a religious isolate who live in approximately 240 farming colonies in the Canadian prairie provinces and the United States border states were studied. The sect's 6,700 members living in the province of Alberta, Canada, comprise more than 30% of this sect's population of North America. The numbers of their cancer cases ascertained from 1953 to 1974 in Alberta were compared to those expected from Alberta Cancer Registry rates. The overall incidence of registered cases of cancer among the religious isolate's females was significantly less than expected (48 observed, 74.2 expected), and in the males the overall incidence of cancer did not differ from that expected (52 observed, 56.5 expected). Significantly fewer cases of lung cancer than expected were found in males, and significantly fewer cases of carcinoma in situ of the cervix uteri were found in females. Finally, significantly higher incidence of stomach cancer was found in the sect's males. Data on a family with two cases of stomach cancer contributed to this observed excess of stomach cancer.

Cytodiagnostic urinalysis. Three years experience with a new laboratory test.

Cytodiagnostic urinalysis is performed by examining Papanicolaou-stained cytocentrifuge preparations of urine sediment. Nonrenal transplant patient results (N = 1,602) were reviewed. Renal hematuria was found in 37.7% of specimens, white blood cell casts in 11%, and renal tubule cell injury in 53%. The technique demonstrates significantly improved sensitivity to detect urine sediment abnormalities indicative of renal parenchymal disease. The technical requirements are readily available and easy to implement in the laboratory. Skills required for identification and quantitation can be acquired in a few weeks.

Status Report--Retracing the history of the early development of national chronic disease surveillance in Canada and the major role of the Laboratory Centre for Disease Control (LCDC) from 1972 to 2000.

TITRE: Rapport d'étape - Historique des débuts de la surveillance nationale des maladies chroniques au Canada et rôle majeur du Laboratoire de lutte contre la maladie (LLCM) de 1972 à 2000. INTRODUCTION: La surveillance de la santé consiste en l'utilisation systématique et continue de données sur la santé recueillies régulièrement en vue d'orienter les mesures de santé publique en temps opportun. Ce document décrit la création et l'essor des systèmes nationaux de surveillance au Canada et les répercussions de ces systèmes sur la prévention des maladies chroniques et des blessures. En 2008, les auteurs ont commencé à retracer l'historique des débuts de la surveillance nationale des maladies chroniques au Canada, en commençant à 1960, et ils ont poursuivi leur examen jusqu'en 2000. Une publication de 1967 a retracé l'historique de la création du Laboratoire d'hygiène de 1921 à 1967. Notre étude fait suite à cette publication et décrit l'historique de l'établissement de la surveillance nationale des maladies chroniques au Canada, à la fois avant et après la création du Laboratoire de lutte contre la maladie (LCDC).

Tuberculosis in Canada 1987.

In 1987, 1,957 new or reactivated cases of tuberculosis were reported in Canada, an 8.8% drop from 1986. This corresponds to an overall decline of almost 50% in Canada's tuberculosis rates over the past decade. This article examines tuberculosis rates by sex, age and province, and identifies four high risk groups. The first group, comprising North American Indians and Inuit, has a rate five to ten times higher than the Canadian population. Poor inner city residents have rates up to four times higher, and foreign-born Canadians up to three times higher. For all Canadians, risk increases with age, and thus the elderly comprise the fourth risk group. A fifth group, males aged 25 to 44 infected with Human Immunodeficiency Virus (HIV) and who later develop Acquired Immune Deficiency Syndrome (AIDS), has emerged in the United States although no increased risk is at yet seen in Canada.

Cancer in Canada 1984.

This article provides an overview of cancer in Canada in 1984, including an analysis of geographic patterns by province. Trends for selected sites of cancer incidence from 1970 to 1984 and cancer mortality from 1970 to 1987 are also examined. Finally, trends since 1970 in cancer incidence and mortality are examined in the context of strategies for cancer control. Because of the need to assemble cancer information from a variety of sources within each province and territory, several years elapse between cancer diagnosis and the compilation of national figures. Still, the year-to-year analysis of incidence data in this article provides valuable information of cancer trends. In recent years, considerable improvements in Canada's system of cancer registration have led to improved consistency among provinces for both age-standardized rates and mortality/incidence ratios.

Changing trends in melanoma incidence and mortality.

OBJECTIVES: This article analyzes trends in melanoma incidence and mortality rates. Information on sun exposure supplements these statistics. DATA SOURCES: Melanoma incidence data were obtained from the National Cancer Incidence Reporting System and from the Canadian Cancer Registry. Cancer mortality data were extracted from the Canadian Vital Statistics Data Base. Information on sun exposure is from the 1996 Sun Exposure Survey. ANALYTICAL TECHNIQUES: Incidence and mortality rates were age-standardized to the 1991 Canadian population to account for changes in the age structure of the population over time. The average annual percentage changes in age-specific rates were calculated for selected time periods. MAIN RESULTS: After years of steady increases, melanoma incidence and mortality rates have levelled off as a result of declining rates in younger age groups, and for melanoma of the trunk among men and of the leg among women. Incidence rates for men are now higher than those for women; mortality rates for men are twice as high as for women.

Breast cancer in Circumpolar Inuit 1969-1988.

Breast cancer was studied over a 20-year period in Inuit populations in the Circumpolar region. A total of 193 breast cancers were observed in women. The incidence increased from 28.2 per 100 000 in 1969-1973 to 34.3 per 100 000 in 1984-1988. However, the incidence is low, about half what could be expected based on the rates in Denmark, Canada and Connecticut (USA). The low incidence could be explained by the Inuit diet and other lifestyle factors. These benefits should be preserved, in particular in the young, to maintain a low breast cancer incidence.

Cancer of the respiratory system in Circumpolar Inuit.

Cancer incidence of the nasal cavities in Inuit men are high (ASR=3.0 1984-1988), and higher than seen in Denmark, Connecticut (USA) and Canada. Lung cancer incidence is among the highest in the world, for both men and women, and larynx cancer among the lowest. The smoking pattern among Inuit, possibly combined with co-factors related to environment and diet, are believed to be the relevant causal factors.

Cancers of skin, bone, connective tissues, brain, eye, thyroid and other specified and unspecified sites in Inuit.

Low rates of skin cancer, both melanoma and non-melanoma, were observed in Inuit after 20 years of observation. Tumours of the brain and central nervous system, of the thyroid, bone and connective tissues and other specified sites occurred with rates similar to those in comparison populations in Denmark, Connecticut and Canada. These findings support that neither UV and ionizing radiation from nuclear fall-out, nor pollution of herbicides and pesticides in the Arctic area have yet had any noticeable impact on cancer risk. However, unspecified and secondary neoplasms constitute 7-8% of the total Circumpolar cancer incidence and the pattern of rare cancers must be interpreted with caution. Increased diagnostic efforts with a higher precision in the future are warranted.

Canadian cancer statistics 1990.

In 1990, an estimated 104,000 new cases of cancer (excluding non-melanoma skin cancer) will be diagnosed in Canada. The estimated number of deaths due to cancer in that same year will total 54,500. Just over one in three Canadians can expect to develop some form of cancer during their lifetime, and one in four men and one in five women will die from this disease. Almost 10% of women will develop breast cancer, while close to 8% of men will develop lung cancer. In 1990, lung cancer alone is expected to account for 17,300 newly diagnosed cancers (16.6% of the total), and 14,200 cancer deaths (26% of the total). Cancer will also take its toll as the fourth leading cause of death in children. This article explores additional statistics, trends in cancer incidence and mortality since 1970, cancer survival rates, and cancer mortality by income level. This article is based on material prepared by Statistics Canada for inclusion in Canadian Cancer Statistics 1990 (1), and developed in collaboration with the Canadian Cancer Society, Health and Welfare Canada, and provincial and territorial cancer registries.

Tuberculosis in Canada: a focal disease requiring distinct control strategies for different risk groups.

Cases of new or reactivated tuberculosis (TB) reported in Canadian residents during 1985-1987 (1984-1988 in the province of Quebec) were analyzed by geographic region relative to the geographic distribution of groups known to be at high risk. The crude incidence rate (per 100,000 population) of TB was calculated by census division (or Région socio-sanitaire in Quebec). Rates of TB by census division ranged from 0 to over 200 per 100,000 population; the average rate for Canada was 8.3 per 100,000. Census divisions with very high rates (over 20 per 100,000) were concentrated in the northern regions, with 80% or more of TB cases occurring among aboriginal persons. Census divisions with moderately high TB rates of 10-19 per 100,000 were located either in northerly regions or in major metropolitan areas; reported TB cases in these areas occurred disproportionately in the aboriginal or immigrant populations. Tuberculosis continues to become more geographically focused and limited to aboriginal Canadians, immigrants and the urban poor. Priority must be given to full implementation of effective prevention and control methods in geographic areas with higher incidence rates. Different methods will be required for different areas depending upon the risk groups present.

Canadian Cancer Statistics 1991.

During 1991, an estimated 109,000 new cases of cancer will be diagnosed in Canada (excluding non-melanoma skin cancer). Estimated cancer deaths in 1991 will total 56,700. Excluding non- melanoma skin cancer, over one in three Canadians will develop some form of cancer during their lifetime, while one in four men and one in five women will die from this disease. These statistics are discussed, as well as cancer risk factors, cancer in children, age and sex distribution of cancer, cancer survival rates, trends in cancer incidence and mortality since 1970, smoking and lung cancer, and cancer among the Inuit and Indians.

The increasing incidence of breast cancer in Alberta 1953-1973.

The incidence of female breast cancer in Alberta increased steadily by one case per 100,000 per year from 1953 to 1973 to a current rate of 68.6 per year when adjusted to the 1950 U.S. population. Incidence rates of breast cancer in Alberta and Saskatchewan were identical after population adjustment. The incidence increased in women over 40, implicating an increase in the postmenopausal type of breast cancer. Birth cohort analysis showed increased age-specific incidence rates in middle-aged women occurring in successive cohorts from 1903 to 1918, a result similar to that found in Saskatchewan, Connecticut, and Finland. The menopausal hook is disappearing in Alberta data, apparently due to cohort-specific increases in incidence. Possible etiological factors involved in these incidence changes are discussed; a detailed analysis of specific etiological factors is currently underway on over 3,000 patients with malignant or benign breast disease who were examined at the Dr. W. W. Cross Cancer Institute in Edmonton from 1971 to 1974.

Which workers smoke?

OBJECTIVES: This article examines differences by occupation in daily cigarette smoking prevalence and intensity among full-time workers, and how these differences are associated with smoking restrictions at work. DATA SOURCES: Most of the data are from a Health Canada-sponsored Supplement to the 1994/95 National Population Health Survey (NPHS). The analysis is based on 5,674 respondents aged 15 to 64 who were full-time workers at the time of their interview. Comparable information is presented from the 1978/79 Canada Health Survey and the 1986 Labour Force Survey Smoking Supplement. MAIN RESULTS: In 1994/95, 28% of full-time workers were daily smokers, and about a third of them smoked 25 or more cigarettes a day. Smoking prevalence and intensity were lowest among white-collar workers and highest among blue-collar workers. Since 1978/79, there has been an overall decline in smoking prevalence, and since 1986, a decline in smoking intensity among all workers except those in outdoor blue-collar occupations. About 6 in 10 full-time workers who smoked daily encountered restrictions at work.

Cancer incidence by ethnic group in the Northwest Territories (NWT) 1969-1988.

Clear differences occurred in the cancer patterns among the population sub-groups in the NWT. When compared to those for the total Canadian population, rates for all cancers tended to be higher than expected among Inuit, lower than expected among Status Indians, and at expected levels for the Other NWT population. Among Inuit, traditional patterns still persist. Cancers of the lung, cervix, nasopharynx and salivary gland, and choriocarcinoma, occurred more often, and cancers of the breast, prostate, uterus and colon less often than in the total Canadian population. Among Status Indians, small numbers precluded definitive conclusions. However, several cancer sites occurred less often than expected, including colon, bladder and prostate among males, and uterus in females. While no cancer was significantly elevated in either males or females, SIRs for cervix and lung were above 1.0 for females, and kidney cancer was significantly higher when data for both sexes were combined (SIR = 2.0). For the Other NWT group--comprising about 50% of the population--most types of cancers occurred at about the expected rate, except that lung cancer was significantly elevated in females. Nevertheless, the generally high rates for lung and cervical cancer, which were particularly evident among the Inuit, are clearly targets for prevention programmes. It is hoped the cancer registry data now available for twenty years for the NWT, as well as for the overall Canadian Inuit population, can be used by researchers for studies to further determine the etiology of cancers, especially where distinctive patterns occur in these populations.

Cancer patterns in the Inuit population of Canada 1970-1984.

1. Rates for lung cancer in Canadian Inuit are high and increasing for both men and women; in fact they are the highest reported rates for lung cancer among any Inuit population. 2. Cervical cancer in Canadian Inuit are high but rates appear to be stable, unlike the rapidly increasing trend reported in both Alaska and Greenland. 3. Rates for traditional Inuit cancers such as those of the nasopharynx and salivary gland do not appear to be declining in Canadian Inuit. 4. Rates for colorectal cancer in Canadian Inuit are similar to those expected for the Canadian population as a whole and do not appear to be increasing. 5. Finally, cancers traditionally reported to be rare in Inuit are still rare in the Canadian Inuit population; these include breast, prostate, bladder, and endometrial cancer. Cancer is a disease which can be controlled through prevention, early detection or treatment. The following future directions arising from this work reflect this paradigm. First, the Inuit cancer registry developed for this analysis will be used as a base for further research into environmental and genetic factors influencing cancer rates in the Inuit. Second, given that at least 40% of cancers in Canadian Inuit are cancers of the lung and cervix, health promotion programs should be developed to encourage tobacco-free environments to halt the epidemic of lung cancer, and also to make available Pap smear programs for early detection of cervical cancer. Third, health care services and programs, including diagnosis and treatment, should be culturally accessible to the Inuit population (6).(ABSTRACT TRUNCATED AT 250 WORDS)

Cancer incidence and mortality across Canada.

OBJECTIVES: This article analyses provincial and territorial patterns in incidence and mortality rates for selected cancer sites. DATA SOURCES: Cancer incidence data were obtained from the National Cancer incidence Reporting System and from the Canadian Cancer Registry. Mortality data are from the Canadian Vital Statistics Data Base. ANALYTICAL TECHNIQUES: Age-standardized incidence and mortality rates were calculated for Canada and each province/territory for men and women for major cancer sites for the 1991-1993 period. MAIN RESULTS: Geographic variations in cancer incidence and mortality rates are strongly influenced by trends in the four leading cancers: lung, colorectal, prostate and breast. Cancer rates tended to be significantly high in Quebec and Nova Scotia and significantly low in the three westernmost provinces. These patterns generally reflect provincial/territorial variations in smoking prevalence, dietary habits, and the extent of cancer control programs, such as screening.

Cancer in Circumpolar Inuit. Background information for cancer patterns in Canadian Inuit.

The cancer pattern among Inuit in the Circumpolar area is remarkably different from those of other populations in the world. The current paper summarizes the most important risk factors in Canadian Inuit residing in the Northwest Territories, northern Quebec (Nunavik) and Labrador, particularly during the time period 1969-1988 covered by the study. Factors considered include: the geographic area and physical environment; population and human environment, including fertility and life expectancy; lifestyle and diet, including tobacco and alcohol use; other lifestyle factors, and health conditions; and health services and cultural accessibility. Development of the cancer registry and population databases supporting the analysis of cancer rates is described. The information in the present paper is needed to interpret cancer incidence patterns and differences among the Circumpolar Inuit of Canada, Alaska and Greenland.