Abstract Reprints

1. Dog bite incidence in the city of Pittsburgh: a capture-recapture approach

Yue-Fang Chang, Joan E McMahon, Deidre L Hennon, Ronald E LaPorte, Jeffrey H Coben
Am J Public Health 1997;87(10):1703-5

Objectives. The purpose of this study was to estimate the number of dog bite injuries occurring in the city of Pittsburgh in 1993.

Methods. The capture-recapture method was used, along with log-linear modeling. Three sources were used to identify victims: hospital reports, animal control reports, and police/victim reports.

Results. In 1993, 790 dog bites were reported. The capture-recapture method estimated that there were 1388 unreported dog bites, with an estimated incidence rate of 58.9 per 10 000.

Conclusions. Dog bite is a common but preventable injury. To improve surveillance, the focus should be on educating the general public about the serious consequences of dog bite injuries.

2. Alcohol, tobacco and cannabis use among Nova Scotia adolescents: implications for prevention and harm reduction

Christiane Poulin, David Elliott
Can Med Assoc J 1997;156(10):1387-93

Objective: To characterize adolescent drug use in terms of a risk continuum and to explore the rationale for harm reduction as a potential approach for school-based drug prevention.

Design: Self-reported surveys, in 1991 and 1996, of adolescent students concerning their use of drugs, especially alcohol, tobacco and cannabis, and the harmful consequences of such use.

Setting: Nova Scotia.

Participants: A total of 3452 (in 1991) and 3790 (in 1996) junior and high school students in randomly selected classes in the public school system.

Outcome measures: Prevalence of drug use and patterns of multiple drug use and of alcohol- and drug-related problems; independent risk factors for multiple drug use. The risk continuum for the response to alcohol problems was used as a policy framework.

Results: The prevalence of cigarette smoking and the use of hallucinogens and stimulants was markedly higher in 1996 than in 1991. Over one-fifth (21.9%) of the students reported multiple drug use of alcohol and tobacco and cannabis in the 12 months before the 1996 survey. The 3 main subgroups-nonusers, users of alcohol only and users of multiple drugs-had distinct patterns of use, numbers of problems and risk factors. In all, 27.1% of the students had experienced at least 1 alcohol-related problem and 6% had experienced at least 1 drug-related problem in the 12 months before the 1996 survey.

Conclusion: There is a need for integrated school- and community-based drug prevention programs, with goals, strategies and outcome measures capturing the full spectrum of patterns of use and levels of risk among subgroups of the adolescent student population.

3. Alcohol consumption and breast cancer risk among women under age 45 years

Christine A Swanson, Ralph J Coates, Kathleen E Malone, Marilie D Gammon, Janet B Schoenberg, Donna J Brogan, Mary McAdams, Nancy Potischman, Robert N Hoover, Louise A Brinton
Epidemiology 1997;8(3):231-7

In a population-based case-control study of women younger than 45 years of age, we obtained a detailed lifetime history of alcohol use to evaluate the effects of drinking during different periods of life in relation to breast cancer risk. This analysis focused on interviews obtained from 1,645 cases and 1,497 controls. Breast cancer risk was not influenced by drinking during the teenage years or early adulthood. Contemporary drinking (that is, average intake during the recent 5-year interval) was directly associated with risk, but the adverse effect of recent drinking was restricted to women who consumed ³14 drinks per week [relative risk (RR) = 1.7; 95% confidence interval (CI) = 1.2-2.5]. The effect of alcohol was most pronounced among women with advanced disease. Compared with nondrinkers, the risk estimate associated with recent consumption of ³14 drinks per week was 2.4 (95% CI = 1.6-3.8) for women with regional/distant disease. Our data add support to the accumulating evidence that alcohol consumption is associated with increased risk of breast cancer and further indicate that alcohol acts at a late stage in breast carcinogenesis.

4. Alcohol consumption and coronary heart disease morbidity and mortality

Jürgen T Rehm, Susan J Bondy, Christopher T Sempos, Cuong V Vuong
Am J Epidemiol 1997;146(6):495-501

Alcohol consumption is associated with a reduced risk of coronary heart disease (CHD) but an increased risk of other causes of morbidity and mortality. It remains unclear whether there is an upper limit to a protective effect of alcohol intake on CHD risk. Whether there is a U- or an L-shaped relation between alcohol consumption and CHD incidence (hospitalization and mortality due to ischemic heart disease: International Classification of Diseases codes 410-414) is examined using the National Health and Nutrition Examination Survey I. Baseline data were collected in 1971-1975. Follow-up data through 1987 (14.6 years mean follow-up) were analyzed for 6,788 European-American males (n = 2,960) and females (n = 3,828) aged 40-75 years at baseline. Cox regression was used to assess the association between alcohol consumption and incidence of CHD. For females, an increased risk was found above 28 drinks per week relative to abstainers (relative risk = 2.6, 95% confidence interval 1.2-5.5), which was significant, but was based on small numbers. For males, no upturn in risk was found at higher intake. Mortality data supported these results. Sex differences should be explored further, since they are relevant to understanding causal mechanisms and public policy and prevention.

5. Marijuana use and mortality

Stephen Sidney, Jerome E Beck, Irene S Tekawa, Charles P Quesenberry, Gary D Friedman
Am J Public Health 1997;87(4):585-90

Objectives. The purpose of this study was to examine the relationship of marijuana use to mortality.

Methods. The study population comprised 65 171 Kaiser Permanente Medical Care Program enrollees, aged 15 through 49 years, who completed questionnaires about smoking habits, including marijuana use, between 1979 and 1985. Mortality follow-up was conducted through 1991.

Results. Compared with nonuse or experimentation (lifetime use six or fewer times), current marijuana use was not associated with a significant increased risk of non-acquired immunodeficiency syndrome (AIDS) mortality in men (relative risk [RR] = 1.12, 95% confidence interval [CI] = 0.89, 1.39) or of total mortality in women (RR = 1.09, 95% CI = 0.80, 1.48). Current marijuana use was associated with increased risk of AIDS mortality in men (RR = 1.90, 95% CI = 1.33, 2.73), an association that probably was not causal but most likely represented uncontrolled confounding by male homosexual behavior. This interpretation was supported by the lack of association of marijuana use with AIDS mortality in men from a Kaiser Permanente AIDS database. Relative risks for ever use of marijuana were similar.

Conclusions. Marijuana use in a prepaid health care-based study cohort had little effect on non-AIDS mortality in men and on total mortality in women.

6. Marijuana use and cancer incidence (California, United States)

Stephen Sidney, Charles P Quesenberry Jr, Gary D Friedman, Irene S Tekawa
Cancer Causes Control 1997;(8):722-8

The purpose of this retrospective cohort study was to examine the relationship of marijuana use to cancer incidence. The study population consisted of 64,855 examinees in the Kaiser Permanente multiphasic health checkup in San Francisco and Oakland (California, United States), between 1979-85, aged 15 to 49 years, who completed self-administered questionnaires about smoking habits, including marijuana use. Follow-up for cancer incidence was conducted through 1993 (mean length 8.6 years). Compared with nonusers/experimenters (lifetime use of less than seven times), ever- and current use of marijuana were not associated with increased risk of cancer of all sites (relative risk [RR] = 0.9, 95 percent confidence interval [CI] = 0.7-1.2 for ever-use in men; RR = 1.0, CI = 0.8-1.1 in women) in analyses adjusted for sociodemographic factors, cigarette smoking, and alcohol use. Marijuana use also was not associated with tobacco-related cancers or with cancer of the following sites: colorectal, lung, melanoma, prostate, breast, cervix. Among nonsmokers of tobacco cigarettes, ever having used marijuana was associated with increased risk of prostate cancer (RR = 3.1, CI = 1.0-95) and nearly significantly increased risk of cervical cancer (RR = 1.4, CI = 1.0-2.1). We conclude that, in this relatively young study cohort, marijuana use and cancer were not associated in overall analyses, but that associations in nonsmokers of tobacco cigarettes suggested that marijuana use might affect certain site-specific cancer risks.

7. Smoking in Ontario, 1991 to 1996

Susan Jane Bondy, Anca Ruxandra Ialomiteanu
Can J Public Health 1997;88(4):225-9

Surveys by the Addiction Research Foundation of Ontario have produced annual estimates on smoking prevalence since 1991. This report describes the three series of telephone surveys from which these data are drawn as well as future plans to monitor tobacco use in Ontario. In addition to provision of updated descriptive results, the methodology and limitations of the data are discussed. Prevalence data for 1996 are presented from the Ontario Drug Monitor, a telephone survey of Ontario adults (n=2721). The overall prevalence of smoking in Ontario was 27% (95% confidence interval: 25% to 29%); 23% smoked daily (95% confidence interval: 21% to 25%). There is no evidence of any decline in the prevalence of smoking since 1991, and no sex differences were found in smoking prevalence. Future reports will update trend data and provide robust regional estimates.

8. The health of Canada's elderly population: current status and future implications

Mark W Rosenberg, Eric G Moore
Can Med Assoc J 1997;157(8):1025-32

The growing size of Canada's elderly population and its use of health care services has generated much discussion in policy circles and the popular press. With data from the National Population Health Survey, undertaken in 1994-95, the authors examine the health status of Canada's elderly population using 3 sets of measures: level of activity limitations, prevalence of chronic illnesses and self-assessment of overall health. They also analyse the utilization of physician and institutional services. The profile of this population the authors develop is in many respects not much different from that of the remaining adult population, until the age of 75. People aged 75 and over are much more likely than other adults to have health problems and use health care services. Also, elderly women living alone and with low income are identified as an especially vulnerable group who need access to medical and nonmedical services if they are to remain in the community. Using Statistics Canada projection data the authors discuss some aspects of the elderly population's health status in the future. Their look into the future raises issues about the preparedness of health care providers and our health care system to meet the challenges of tomorrow's elderly population.

9. Characteristics of non-responders and the impact of non-response on prevalence estimates of dementia

Froukje Boersma, Jan A Eefsting, Wim Van Den Brink, Willem Van Tilburg
Int J Epidemiol 1997;26(5):1055-62

Background. Differential distributions of sociodemographic characteristics and cognitive impairment in responders and non-responders may result in a biased prevalence estimate of dementia based on responders only.

Methods. Responders (n = 2191) to a cross-sectional, two-stage community study were compared with regard to sociodemographic characteristics and cognition with three subgroups of non-responders: (A) subjects who refused to participate (n = 369), (B) subjects who were too ill or who had died prior to the screening (n = 72) and (C) subjects who had moved out of the study region or were not traceable (n = 23). Prevalence estimates specific for age and housing situation in responders and physicians' ratings of cognitive impairment were used to estimate the prevalence of dementia among non-responders.

Results. Group A differed from responders in age and housing situation, group B in age, housing and cognition, and group C only in age. Separate prevalence estimates of dementia based on age, housing and cognition yielded figures for group A between 4.9% and 7.2%, for group B between 13.1% and 19.1%, and for group C between 2.6% and 4.2%. Joined with the prevalence rate among responders (6.5%) the best possible point estimate of the prevalence of dementia in the target population lies between 6.4% and 6.9%, i.e. within the 95% confidence interval (CI) of the prevalence among responders (5.4-7.5%).

Conclusions. Although in this study non-response had no important influence on the overall prevalence, the findings among the distinct non-response subgroups point to the importance of describing non-response sociodemographically as well as in terms of the study objective. The authors recommend that non-responders are categorized into distinct groups based on the reason for non-response.

10. Vector diagnostics in dementia derived from Bayes' theorem

Arnold B Mitnitski, Janice E Graham, Alexander J Mogilner, Kenneth Rockwood
Am J Epidemiol 1997;146(8):665-71

This paper introduces the concept of vector diagnostics. In contrast to the conventional approach where one diagnosis takes precedence, the authors propose an alternative strategy that addresses the clinical reality of comorbidity and multiple diagnoses for an individual. Based on a Bayesian approach, the probability distribution for the etiologically heterogeneous dementia diagnoses is estimated from the Canadian Study of Health and Aging database. These data were collected between February 1991 and May 1992. This method facilitates the establishment of a probability for more than one diagnosis within a given individual. By analyzing the correspondence between diagnostic groups, it is demonstrated that some clinical diagnoses are not reliably distinguished on the basis of the considered subset of symptoms and signs. As a consequence, the conventional diagnostic categories might require revision. The resulting probabilistic algorithm allows for the mining of existing epidemiologic databases for patterns of signs and symptoms that characterize emerging diagnostic categories which might better account for the heterogeneity of the dementia subtypes and individual variability.

11. Prostate cancer screening in the midst of controversy: Canadian men's knowledge, beliefs, utilization, and future intentions

Shawna L Mercer, Vivek Goel, Isra G Levy, Fredrick D Ashbury, Donald C Iverson, Neill A Iscoe
Can J Public Health 1997;88(5):327-32

Despite controversy about prostate cancer screening, administrative data show that the use of prostate specific antigen (PSA) testing in Canada has increased. This study sought to determine awareness and knowledge of prostate cancer and screening, use to date, and future intentions to have a digital rectal examination (DRE) and PSA test among Canadian men aged 40 and over. Data were collected through a Canada-wide cross-sectional random digit dial telephone survey of 629 men. Awareness of DRE and PSA, use to date, and future intended use varied with age and education. Although only 9% of respondents had had PSA testing for screening, future intentions to undergo this test were higher than use to date. Knowledge of prostate cancer and screening controversies was low, and men received more information about PSA from the media than from doctors. Men would, therefore, benefit from age- and education-specific information regarding the factors to consider in making an informed choice about prostate cancer screening.

12. Factors important in promoting mammography screening among Canadian women

Colleen J Maxwell, Jean F Kozak, Sheril D Desjardins-Denault, Jean Parboosingh
Can J Public Health 1997;88(5):346-50

Among women aged 50 to 69 years, regular screening by mammography in combination with clinical examination, can substantially decrease the morbidity and mortality associated with breast cancer by facilitating early detection. Unfortunately, many Canadian women are not screened in accordance with current guidelines. Research to date is based primarily on large surveys conducted in the United States and less is known about the relevance of specific barriers to mammography screening among Canadian women.

Multivariate results from the 1994-95 National Population Health Survey (NPHS) indicate that younger (40-49) and older (70+) women, those who are socioeconomically disadvantaged, and minority women are least likely to report having had a mammogram. Conversely, women with positive health behaviours, high social support, and positive mental health attributes are more likely to participate in mammography screening. These findings are discussed in terms of the implications for developing successful intervention programs for Canadian women and for setting priorities for further research.

13. Effect of breast self-examination techniques on the risk of death from breast cancer

Bart J Harvey, Anthony B Miller, Cornelia J Baines, Paul N Corey
Can Med Assoc J 1997;157(9):1205-12

Objective: To measure the effect of breast self-examination (BSE) technique and frequency on the risk of death from breast cancer.

Design: Case-control study nested within the Canadian National Breast Screening Study (NBSS).

Setting: The Canadian NBSS, a multicentre randomized controlled trial of screening for breast cancer in Canadian women.

Subjects: The case subjects were 163 women who had died from breast cancer and 57 women with distant metastases. Ten control subjects matched by 5-year age group, screening centre, year of enrolment and random allocation group were randomly selected for each case subject.

Exposure measures: Self-reported BSE frequency before enrolment in the NBSS, annual self-reports of BSE frequency during the program and annual objective assessments of BSE technique.

Outcome measures: Odds ratios (ORs) associated with BSE practice were estimated by conditional multiple logistic regression modelling, which permitted control of covariates.

Results: Relative to women who, when assessed 2 years before diagnosis, examined their breasts visually, used their finger pads for palpation and examined with their 3 middle fingers, the OR for death from breast cancer or distant metastatic disease for women who omitted 1, 2 or 3 of these components was 2.20 (95% confidence interval [CI] 1.30 to 3.71, p = 0.003). The OR for women who omitted 1 of the 3 components was 1.82 (95% CI 1.00 to 3.29, p = 0.05), for those who omitted 2 of the 3 components, 2.84 (95% CI 1.44 to 5.59, p = 0.003), and for those who omitted all 3 components, 2.95 (95% CI 1.19 to 7.30, p = 0.02). The results remained unchanged after adjustment for potential confounders.

Conclusion: The results, obtained with the use of prospectively collected data, suggest that the performance of specific BSE components may reduce the risk of death from breast cancer.

14. Current and projected rates of hip fracture in Canada

Emmanuel A Papadimitropoulos, Peter C Coyte, Robert G Josse, Carol E Greenwood
Can Med Assoc J 1997;157(10):1357-63

Objective: To determine the current values and estimate the projected values (to the year 2041) for annual number of proximal femoral fractures (PFFs), age-adjusted rates of fracture, rates of death in the acute care setting, associated length of stay (LOS) in hospital, and seasonal variation by sex and age in elderly Canadians.

Design: Hospital discharge data for fiscal year 1993-94 from the Canadian Institute for Health Information were used to determine PFF incidence, and Statistics Canada population projections were used to estimate the rate and number of PFFs to 2041.

Setting: Canada.

Participants: Canadian patients 65 years of age or older who underwent hip arthroplasty.

Outcome measures: PFF rates, death rates and LOS by age, sex and province.

Results: In 1993-94 the incidence of PFF increased exponentially with increasing age. The age-adjusted rates were 479 per 100 000 for women and 187 per 100 000 for men. The number of PFFs was estimated at 23 375 (17 823 in women and 5552 in men), with a projected increase to 88 124 in 2041. The rate of death during the acute care stay increased exponentially with increasing age. The death rates for men were twice those for women. In 1993-94 an estimated 1570 deaths occurred in the acute care setting, and 7000 deaths were projected for 2041. LOS in the acute care setting increased with advancing age, as did variability in LOS, which suggests a more heterogeneous case mix with advancing age. The LOS for 1993-94 and 2041 was estimated at 465 000 and 1.8 million patient-days respectively. Seasonal variability in the incidence of PFFs by sex was not significant. Significant season-province interactions were seen (p < 0.05); however, the differences in incidence were small (on the order of 2% to 3%) and were not considered to have a large effect on resource use in the acute care setting.

Conclusions: On the assumption that current conditions contributing to hip fractures will remain constant, the number of PFFs will rise exponentially over the next 40 years. The results of this study highlight the serious implications for Canadians if incidence rates are not reduced by some form of intervention.

15. Injuries in a problematic socioeconomic context: a population-based study in Réunion, Indian Ocean, 1993-1994

Françoise Masson, Marianne Savès, L Rachid Salmi, Arnaud Bourdé, Guy Henrion, Philippe Erny
Int J Epidemiol 1997;26(5):1033-40

Background. This study was designed to estimate the incidence and describe the characteristics of injuries during a one-year period in the French island of Réunion, Indian Ocean, a defined geographic population with socioeconomic problems.

Methods. Cases were injuries from accidents (unintentional injuries), self-inflicted injuries (suicides and attempted suicides), or injuries purposely inflicted by other people, that resulted in hospital admission or death. Patients and injury characteristics were recorded prospectively, alternately every other week, in all emergency rooms on the island; all death certificates were studied.

Results. The overall annual incidence of injuries was 1578 per 100 000 residents. The three main causes of injury were (i) falls on the same level (23.6%), (ii) poisoning (23.0%) and (iii) traffic accidents (21.5%). Of the traffic accident cases, 44% were motorcyclists (mostly mopeds) and more than half of the cases were 15-25 years old. Suicides and attempted suicides accounted for 80.9% of poisonings, 35.5% of immediately fatal injuries, and 19.6% of non-fatal injuries. Homicides and assaults accounted for 8.3% of all injuries. The employment rate was lower for injured patients than in the total Réunion population (standardized ratio for males: 74; P < 0.001). Half of the injured hospitalized patients had an Injury Severity Score < 5 and 8 days after hospitalization, 83.5% of patients had returned home.

Conclusion. Injury epidemiology may be affected by different demographic, socioeconomic, cultural and geographical factors. Targeted studies are therefore necessary to guide injury prevention measures.

16. Incidence and mortality of neuroblastoma in Canada compared with other childhood cancers

Ru-Nie Gao, Isra G Levy, William G Woods, B Ann Coombs, Leslie A Gaudette, Gerry B Hill
Cancer Causes Control 1997;8:745-54

The incidence and mortality of neuroblastoma was reviewed in the general context of childhood cancer in Canada for the periods 1982-86 and 1987-91. This was done to complement the preliminary work of the Quebec Neuroblastoma Screening Project that is studying the impact of screening North American infants for the preclinical detection of neuroblastoma on population-based mortality. Annual age-standardized incidence rates for all childhood cancer in Canada appear to have declined slightly (nonsignificantly) from 155.1 to 150.8 per million, between 1982-86 and 1987-91; the rates for neuroblastoma were stable between the two five-year periods (11.8 per million in 1982-86 and 11.4 per million in 1987-91). With respect to mortality, the age-standardized rates for childhood cancer in Canada have shown a declining trend between the first and second halves of the decade, from 43.4 to 34.7 per million, while the rates for neuroblastoma have not changed (4.4 and 4.2 per million). The age-specific distributions of incident cancers indicate that neuroblastoma accounts for the greatest proportion of all cancers in children less than one year of age. Similarly, neuroblastoma is the leading cause of cancer deaths in children aged one to four years. Theoretically, infants less than one year of age could benefit most from effective preventive interventions, treatment, and research.

17. Quantifying the future impact of disease on society: life table-based measures of potential life lost

Wen-Chung Lee
Am J Public Health 1997;87(9):1456-60

Objectives. Quantifying health status in human populations by means of an index such as "years of potential life lost" has recently received attention. However, such an index, being cross-sectional in nature, only measures the current burden to society resulting from a specific cause of death.

Methods. The author proposes new indices of potential life lost to quantify future impacts on society of particular causes of death. These indices also properly reflect the effects of competing risks. The computation is simple, requiring no more than a standard life-table calculation. Real-world as well as hypothetical data are used to illustrate the method.

Results. The new indices convey valuable health status information about a population that is not revealed by traditional indices.

Conclusions. The new indices are promising alternatives as measures of future potential life lost.

18. Age and depression in a nationally representative sample of Canadians: a preliminary look at the National Population Health Survey

Terrance J Wade, John Cairney
Can J Public Health 1997;88(5):297-302

There are considerable inconsistencies in the literature concerning the relationship between age and depression. Recently, however, two independent studies in the U.S. have shown that the distribution is U-shaped with the lowest reported levels of depression at ages 45-49. Three reasons for past inconsistencies are identified and addressed using the 1994 National Population Health Survey by Statistics Canada. Using both a distress scale and a diagnostic measure, a substantially different relationship was found. The prevalence of distress decreased steadily with age until about 65, with only a slight increase afterwards for both males and females. After the introduction of several sociodemographic covariates, however, this relationship was clearly negative. These findings are discussed in terms of future research questions.

19. Predictors of dietary intake in Ontario seniors

Heather H Keller, Truls Østbye, Elizabeth Bright-See
Can J Public Health 1997;88(5):305-9

This study determined the independent association of 24 risk factors with dietary intake in community-living seniors. The study sample was 5,073 seniors for whom complete data were available from the 1990 Ontario Health Survey. Risk factors were items completed on an interviewer-administered health questionnaire. Diet Score, Mean Adequacy Ratio and energy were the diet outcomes derived from a self-administered food frequency questionnaire. The independent association of risk factors with these diet outcomes was assessed with multiple linear regression analyses. Factors that were consistently and positively associated with diet outcomes included: education, income, social support, perceived health status, belief in the nutrition/health link, dependence in walking and vision. Factors that were consistently and negatively associated with diet outcomes included: chewing status, dentition, hearing, level of happiness and body mass index. These results provide a basis for the development of a screening tool for the identification of "at risk" subgroups of seniors.

20. Self-reported cardiovascular disease and risk factors: prevalence in Ontario among women 50 and older

Corinne Hodgson, Ellen Jamieson
Can Fam Physician 1997;43:1747-52

Objective. To determine the prevalence of self-reported cardiovascular disease and risk factors among Ontario women aged 50 and older.

Design. Analysis of the 1990 Ontario Health Survey, a population-based, cross-sectional survey.

Setting. Ontario communities.

Participants. Residents of Ontario communities during 1990 who responded to the 1990 Ontario Health Survey (61 239 respondents in 35 479 households), weighted to represent the population of Ontario.

Main outcome measures. Reported heart disease, hypertension, diabetes, height and weight, physical activity, and smoking habits.

Results. Nearly 11% of women aged 50 and older report "heart disease"; 24.9% hypertension, and 5.4% diabetes. Women were less likely than men to smoke daily, to smoke 25 or more cigarettes a day, and to be overweight, but were more likely to have lower levels of physical activity.

Conclusions. The prevalence of self-reported heart disease and medical and lifestyle risk factors for heart disease is relatively high among Ontario women aged 50 and older. Physicians and public health officials must keep women in mind when designing or implementing programs or services for heart disease.