Abstract Reprints

1. The use of outpatient mental health services in the United States and Ontario: the impact of mental morbidity and perceived need for care

Steven J Katz, Ronald C Kessler, Richard G Frank, Philip Leaf, Elizabeth Lin, Mark Edlund
Am J Public Health 1997;87(7):1136-43

Objectives. This study compared the associations of individual mental health disorders, self-rated mental health, disability, and perceived need for care with the use of outpatient mental health services in the United States and the Canadian province of Ontario.

Methods. A cross-sectional study design was employed. Data came from the 1990 US National Comorbidity Survey and the 1990 Mental Health Supplement to the Ontario Health Survey.

Results. The odds of receiving any medical or psychiatric specialty services were as follows: for persons with any affective disorder, 3.1 in the United States vs 11.0 in Ontario; for persons with fair or poor self-rated mental health, 2.7 in the United States vs 5.0 in Ontario; for persons with mental health-related disability, 3.0 in the United States vs 1.5 in Ontario. When perceived need was controlled for, most of the between-country differences in use disappeared.

Conclusions. The higher use of mental health services in the United States than in Ontario is mostly explained by the combination of a higher prevalence of mental morbidity and a higher prevalence of perceived need for care among persons with low mental morbidity in the United States.

Patricia P Chang, Daniel E Ford, Lucy A Mead, Lisa Cooper-Patrick, Michael J Klag
Am J Epidemiol 1997:146(2):105-14

The Johns Hopkins Precursors Study, a long-term prospective study, was used to study the relation between self-reported sleep disturbances and subsequent clinical depression and psychiatric distress. A total of 1,053 men provided information on sleep habits during medical school at The Johns Hopkins University (classes of 1948-1964) and have been followed since graduation. During a median follow-up period of 34 years (range 1-45), 101 men developed clinical depression (cumulative incidence at 40 years, 12.2%), including 13 suicides. In Cox proportional hazards analysis adjusted for age at graduation, class year, parental history of clinical depression, coffee drinking, and measures of temperament, the relative risk of clinical depression was greater in those who reported insomnia in medical school (relative risk (RR) 2.0, 95% confidence interval (CI) 1.2-3.3) compared with those who did not and greater in those with difficulty sleeping under stress in medical school (RR 1.8, 95% CI 1.2-2.7) compared with those who did not report difficulty. There were weaker associations for those who reported poor quality of sleep (RR 1.6, 95% CI 0.9-2.9) and sleep duration of 7 hours or less (RR 1.5, 95% CI 0.9-2.3) with development of clinical depression. Similar associations were observed between reports of sleep disturbances in medical school and psychiatric distress assessed in 1988 by the General Health Questionnaire. These findings suggest that insomnia in young men is indicative of a greater risk for subsequent clinical depression and psychiatric distress that persists for at least 30 years.

KS Joseph, Michael S Kramer
Can Med Assoc J 1997;157(5):535-41

Objective: To identify spatial patterns of changes in infant mortality rates and proportions of low-birth-weight live births observed in 1994.

Setting: Canada.

Subjects: Live births and infant deaths in Canada between 1987 and 1994. Data for Newfoundland were unavailable for 1987 through 1990.

Outcome measures: Annual infant mortality rates (crude and after excluding live newborns weighing less than 500 g); proportion of live births by low-birth-weight category (500-2499 g).

Results: Nova Scotia, New Brunswick, Quebec and Manitoba had lower crude and adjusted infant mortality rates in 1994 than in 1993. Newfoundland, Saskatchewan, Alberta and British Columbia had higher rates in 1994 than in 1993. The crude rate in Ontario was lower, and the adjusted rate higher, in 1994 than in 1993. A downward trend in the proportion of low-birth-weight live births was observed in Quebec (c² for trend = 29.2, p < 0.01). Conversely, an upward trend was observed in Ontario (c2 for trend = 241.3, p < 0.01). However, the increase may have been due to data errors, especially in 1993 and 1994, involving truncation of ounces in 2 digits to 1 digit (e.g., 5 pounds 10 ounces became 5 pounds 1 ounce).

Conclusions: Although the marginal increases in infant mortality observed in several provinces could be the result of random variation, future trends should be closely monitored. The proportion of low-birth-weight live births in Canada (excluding Ontario) appears to be stable, with Quebec showing significant reductions. The errors in data for Ontario need to be corrected before trends can be estimated for that province and for Canada as a whole.

Kenneth C Johnson, Jocelyn Rouleau
Can J Public Health 1997;88(3):169-76

The Canadian Congenital Anomalies Surveillance System monitors birth defects reported for stillborns, newborns and infants during the first year of life. Data are available through the 1980s and early 1990s for Ontario, Manitoba and Alberta, and since 1984 for an additional four provinces. Fifty-seven routine monitoring categories and 15 summary categories were examined for temporal trends. Comparing the period 1979-1981 with 1991-1993, the reported birth defect case birth prevalence increased by 0.2% and the total birth defects birth prevalences by 2.5%. The birth prevalence of central nervous system defects decreased by 8.2%; the reported birth prevalence increased for congenital heart defects by 41%, urinary defects by 127%, Down syndrome by 13% and other chromosomal defects by 47%. Further investigation of individual defects would be required to evaluate the degree to which changes in reported birth prevalence reflect changes including the availability and use of specific diagnostic procedures. The work highlights the need to expand the surveillance system to include all affected pregnancies where an anomaly has been detected antenatally.

5. Screening for adolescent smoking among primary care physicians in California

Merula Franzgrote, Jonathan M Ellen, Susan G Millstein, Charles E Irwin Jr
Am J Public Health 1997;87(8):1341-5

Objectives. This study determined how often primary care physicians ask adolescents about smoking.

Methods. We surveyed a stratified random sample of community-based, board-certified California physicians, using a mailed questionnaire.

Results. Overall, physicians (n = 343: 77% response rate) screened younger adolescents for regular smoking during 71.4% (95% confidence interval [CI] = 67.9, 74.9) of routine physical exams and older adolescents during 84.8% (95% CI = 82.3, 87.4) of such visits. For acute-care visits, the screening rates were 24.4% (95% CI = 20.6, 28.1) for younger and 40.2% (95% CI = 36.4, 44.0) for older adolescents. Physicians asked 18.2% (95% CI = 15.2, 21.3) of younger and 35.6% (95% CI = 32.0, 39.1) of older adolescents about experimental smoking. Screening varied by specialty.

Conclusions. These data imply that physicians are missing opportunities to screen adolescents for smoking.

Sharon K Buehler, Wanda L Parsons
Can Med Assoc J 1997;157(5):521-6

Objective: To determine the effectiveness of a simple call/recall system in improving compliance with cervical cancer screening among women not screened in the previous 3 years.

Design: Prospective randomized controlled study.

Setting: Two family medicine clinics (1 urban, 1 rural) affiliated with Memorial University of Newfoundland, St. John's.

Participants: A sample of women aged 18-69 years who were listed as patients of the clinics but who had not had a Papanicolaou test (Pap test) within the 3 years before the start of the study. Of 9071 women listed as patients 1360 (15.0%) had not undergone screening in the previous 3 years. A random sample of 650 were selected, 209 of whom were excluded because they had had a hysterectomy, had had a recent Pap test, had moved or had records containing clerical errors. This left 441 women for the study.

Intervention: The 221 women in the intervention group were sent a letter asking them to seek a Pap test and a reminder letter 4 weeks later. The 220 in the control group were sent no letters.

Main outcome measures: Number of women who had a Pap test within 2 months and 6 months after the first letter was sent.

Results: Within 2 months, more women in the intervention group than in the control group had been screened (2.8% [5/178] and 1.9% [4/208] respectively). There was also a difference between the overall proportions at 6 months (10.7% (19/178] and 6.3% (13/208] respectively). None of the differences was statistically significant.

Conclusion: A letter of invitation is not sufficient to encourage women who have never or have infrequently undergone a Pap test to come in for cervical cancer screening. The effectiveness of added recruitment methods such as opportunistic screening by physicians, follow-up by telephone and the offer of a specific appointment should be evaluated.

Gavin CE Stuart, S Elizabeth McGregor, Maire A Duggan, Jill G Nation
Can Med Assoc J 1997;157(5):513-9

Objective: To conduct a failure analysis of cervical cancer screening among women with invasive cervical cancer in Alberta.

Design: Descriptive study. Review of demographic, staging and treatment information from cancer registry records; generation of documented screening history from Alberta Health billing records and self-reported history from subjects who agreed to be interviewed; and comparison of findings in initial cytology reports with those from subsequent review by at least 2 pathologists of all cytology slides for each patient for the 5 years before diagnosis. Cases were assigned to 1 of 6 categories of identified screening failure.

Setting: Alberta.

Subjects: All women with diagnosis of invasive cervical cancer reported to a population-based provincial cancer registry from January 1990 to December 1991.

Outcome measures: Demographic, staging and treatment information; documented and self-reported screening histories; correlation of test results in initial cytology report with those generated from slide review; category of identified screening failure.

Results: Of the 246 women identified with invasive cancer of the cervix, 37 (15.0%) had stage IA disease; 195 (79.3%) had squamous-cell carcinoma, and 35 (14.2%) had adenocarcinoma. According to the categories of screening failure, 74 women (30.1%) had never been screened, 38 (15.4%) had not been screened within 3 years before diagnosis, 42 (17.1%) had had a false-negative cytology result, and 20 (8.1%) had been managed outside of conventional protocols. Of the 23 women (9.3%) who had been screened appropriately and had true-negative results, 19 had smears that were considered technically limited. It was not possible to classify 49 (19.9%) of the cases. Agreement between the documented and the self-reported screening histories was exact for only 39 (36.1%) of the 108 women interviewed.

Conclusions: Despite widespread use of opportunistic cervical screening, many women in Alberta are still not being screened adequately. In most cases women are being screened too infrequently or not at all. Self-reported screening histories are unreliable because many women may overestimate the number of smears. An organized approach to screening, as recommended by the National Workshop on Cervical Cancer Screening, may assist in reducing the incidence of invasive cervical cancer.

Nancy Kreiger, Margaret Sloan, Michelle Cotterchio, Phil Parsons
Int J Epidemiol 1997;26(4):710-5

Background. This historical cohort study was conducted to examine the relationship between gynaecological surgery and ovarian cancer risk.

Methods. Women were included if they had had tubal ligation, hysterectomy, or unilateral ovariectomy in Ontario between March 1979 and April 1993. The cohort was linked to the Ontario Cancer Registry and the Ontario mortality file. Person-years in the cohort were accumulated until death, the removal of both ovaries, a diagnosis of ovarian cancer, or the end of the study period 31 December 1993. Observed cancers were compared to expected based on Ontario age- and calendar period-specific incidence rates.

Results. For tubal ligation and hysterectomy, fewer ovarian cancers were observed than were expected by age, calendar year of procedure, and length of follow-up; the observed/expected ratios were generally statistically significant. In contrast, no protective effect was evident for unilateral ovariectomy; in fact statistically significant excess cancers were seen in early follow-up periods. Observed/expected ratios were nearly identical and somewhat protective for the two strata defined by whether or not the ovaries were visualized. Disruption of the ovarian pathway conferred a protective effect, while no disruption significantly increased risk.

Conclusions. The data do not support screening bias although short-term follow-up data indicate the possibility of detection bias. The long-term follow-up data, as well as the data on pathway disruption, are consistent with the hypothesis that the surgical procedures themselves may produce a protective effect against ovarian cancer, through alteration of the hormonal environment and/or by physical destruction of a carcinogen's route to the ovary.

Kathryn M Curtis, David A Savitz, Tye E Arbuckle
Am J Epidemiol 1997;146(1):32-41

Data from the Ontario Farm Family Health Study were analyzed to determine whether smoking, caffeine, or alcohol use among men and women affect fecundability (the monthly probability of conception). In this retrospective cohort study of farm couples in Ontario, Canada, the farm operator, husband, and wife completed questionnaires during 1991-1992, yielding information on 2,607 planned pregnancies that had occurred over the previous 30 years. Fecundability ratios were calculated using an analog of the Cox proportional hazards model. Cigarette smoking among women and men was associated with decreased fecundability (fecundability ratio = 0.90, 95% confidence interval (CI) 0.82-0.98 and fecundability ratio = 0.88, 95% CI 0.81-0.95, respectively). Caffeine consumption of 100 mg or less versus more than 100 mg in women and men was not associated with fecundability (fecundability ratio = 0.98, 95% CI 0.91-1.07 and fecundability ratio = 1.05, 95% CI 0.97-1.14, respectively). Decreases were observed among women who were coffee drinkers (fecundability ratio = 0.92, 95% CI 0.84-1.00) and men who were heavy tea drinkers (fecundability ratio = 0.85, 95% CI 0.69-1.05), regardless of caffeine content. Alcohol use among women and men was not associated with fecundability. These data are consistent with previous studies of the adverse effect of tobacco on fecundability in female smokers and suggest an effect of smoking among males. Continued evaluation of coffee and tea is warranted to address constituents other than caffeine.

Marian F MacDorman, Sven Cnattingius, Howard J Hoffman, Michael S Kramer, Bengt Haglund
Am J Epidemiol 1997;146(3):249-57

The association between sudden infant death syndrome (SIDS) and maternal smoking was compared between the United States and Sweden-two countries with different health care and social support programs and degrees of sociocultural heterogeneity. For 1991-1991 among the five US race/ethnic groups studied, SIDS rates ranged from a high of 3.0 infant deaths per 1,000 live births for American Indians to a low of 0.8 for Hispanics and Asian and Pacific Islanders. The SIDS rate for Sweden (using 1983-1992 data) was 0.9. The strong association between maternal smoking and SIDS persisted after controlling for maternal age and live birth order. Adjusted odds ratios ranged from 1.6 to 2.5 for mothers who smoked 1-9 cigarettes per day during pregnancy (compared with nonsmokers) and from 2.3 to 3.8 for mothers who smoked 10 or more cigarettes per day during pregnancy. Although birth weight had a strong independent effect on SIDS, the addition of birth weight to the models lowered the odds ratios for maternal smoking only slightly, suggesting that the effect of smoking on SIDS is not mediated through birth weight. SIDS rates increased with the amount smoked for all US race/ethnic groups and for Sweden. Smoking is one of the most important preventable risk factors for SIDS, and smoking prevention/intervention programs have the potential to substantially lower SIDS rates in the United States and Sweden and presumably elsewhere as well.

Kevin M Gorey, Eric J Holowaty, Gordon Fehringer, Ethan Laukkanen, Agnes Moskowitz, David J Webster, Nancy L Richter
Am J Public Health 1997;87(7):1156-63

Objectives. This study examined whether socioeconomic status has a differential effect on the survival of adults diagnosed with cancer in Canada and the United States.

Methods. The Ontario Cancer Registry and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program provided a total of 58 202 and 76 055 population-based primary malignant cancer cases for Toronto, Ontario, and Detroit, Mich, respectively. Socioeconomic data for each person's residence at time of diagnosis were taken from population censuses.

Results. In the US cohort, there was a significant association between socioeconomic status and survival for 12 of the 15 most common cancer sites; in the Canadian cohort, there was no such association for 12 of the 15 sites. Among residents of low-income areas, persons in Toronto experienced a survival advantage for 13 of 15 cancer sites at 1- and 5-year follow-up. No such between-country differentials were observed in the middle- or high-income groups.

Conclusions. The consistent pattern of a survival advantage in Canada observed across various cancer sites and follow-up periods suggests that Canada's more equitable access to preventive and therapeutic health care services is responsible for the difference.

Donald M Keller, Eric A Peterson, George Silberman
Am J Public Health 1997;87(7):1164-7

Objectives. In this study, cancer survival rates for patients diagnosed in Ontario and selected areas within the United States were compared.

Methods. Relative survival rates were computed for patients aged 15 through 84 years diagnosed with any of four forms of cancer (breast, colon, lung, and Hodgkin's disease). The cohorts represented those diagnosed over the years 1978 through 1986 in the Canadian province of Ontario and in nine regions covered by the US National Cancer Institute's Surveillance Epidemiology and End Results program. Patients were followed through the end of 1990.

Results. The cumulative relative survival rates were similar for American and Canadian patients. The largest difference was observed for breast cancer, where patients in the United States enjoyed a survival advantage throughout the follow-up period.

Conclusions. Patients in the United States and Ontario with the diseases studied, except for breast cancer, experience very similar survival. The greater use of mammographic screening in the United States could account for that country's higher breast cancer survival rate by promoting earlier and therefore more efficacious treatment, by introducing bias, or by a combination of both treatment and bias factors.

Pierre R Band, Nhu D Le, Raymond Fang, William J Threlfall, George Astrakianakis, Judith TL Anderson, Anya Keefe, Daniel Krewski
Am J Epidemiol 1997;146:(2)186-94

The authors studied a cohort of 30,157 male pulp and paper workers in British Columbia, Canada. Of these, 20,373 worked in kraft mills only, 5,249 in sulfite mills only, and 4,535 in both kraft and sulfite mills. All workers with at least 1 year of employment on January 1, 1950, or thereafter until December 31, 1992, were studied. Standardized mortality ratios (SMRs) were used to compare the mortality rates of the cohort with those of the Canadian male population. Ninety percent confidence intervals (CIs) for the SMRs were obtained. Cancer risks significantly associated with work duration and time from first employment of 15 years or more were observed: 1) total cohort: pleura (SMR = 3.61, 90% CI 1.42-7.58); kidney (SMR = 1.69, 90% CI 1.13-2.43); brain (SMR = 1.51, 90% CI 1.03-2.16); 2) workers in kraft mills only: kidney (SMR = 1.92, 90% CI 1.04-3.26); 3) workers in sulfite mills only: Hodgkin's disease (SMR = 4.79, 90% CI 1.29-12.37); 4) workers ever employed in both kraft and sulfite mills: esophagus (SMR = 1.91, 90% CI 1.00-3.33). These malignancies have been associated with the following known or suspected carcinogens to which pulp and paper workers may have been exposed: asbestos (pleura), biocides (kidney), formaldehyde (kidney, brain, Hodgkin's disease), hypochlorite (esophagus). A nested case-control study with detailed exposure assessment is under way to help determine whether excess risks for specific cancers reflect exposure among subsets of workers.

Kay Teschke, Michael S Morgan, Harvey Checkoway, Gary Franklin, John J Spinelli, Gerald van Belle, Noel S Weiss
Can J Public Health 1997;88(3):163-8

To determine whether there were previously unrecognized sources of asbestos exposure in British Columbia, incident mesothelioma cases (n = 51) and population-based controls (n = 154) were interviewed about their occupational histories and asbestos exposures. The following occupations were at elevated risk: sheet metal workers (OR = 9.6, 95% CI: 1.5-106), plumbers and pipefitters (OR = 8.3, 95% CI: 1.5-86), shipbuilding workers (OR = 5.0, 95% CI: 1.2-23), painters (OR = 4.5, 95% CI: 1.0-24), welders (OR = 3.9, 95% CI: 0.8-22), gardeners (OR = 3.9, 95% CI: 0.8-22), bricklayers (OR = 3.5, 95% CI: 0.9-14), miners (OR = 3.4, 95% CI 0.9-13), machinists (OR = 3.2, 95% CI: 1.0-11), construction foremen (OR = 3.1, 95% CI: 0.9-11), and electricians (OR = 3.0, 95% CI: 0.8-12). In a reanalysis excluding subjects who worked in occupations or processes considered strongly a priori at risk, three groups remained of interest: non-asbestos miners (OR = 9.6, 95% CI: 1.8-53), bricklayers (OR = 5.4, 95% CI: 1.0-28), and construction labourers (OR = 2.8, 95% CI 0.7-10.6).