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Abstract Reprints:
1. Predictors of mortality and institutionalization after hip fracture: the New Haven EPESE cohort
Richard A Marottoli, Lisa F Berkman, Linda Leo-Summers, Leo M Cooney Jr Am J Public Health 1994;84(11):1807-12 Objectives. Hip fractures can have devastating effects on the lives of older individuals. We determined the frequency of occurrence of hip fracture and the baseline factors predicting death and institutionalization at 6 months after hip fracture. Methods. A representative cohort of 2812 individuals aged 65 years and older was followed prospectively for 6 years. Hip fractures were identified, and the occurrence of death and institutionalization within 6 months of the fracture was determined. Prefracture information on physical and mental function, social support, and demographic features and in-hospital data on comorbid diagnoses, fracture site, and complications were analyzed to determine predictors of death and institutionalization after hip fracture. Results. Of 120 individuals suffering a hip fracture, 22 (18%) died within 6 months and 35 (29%) were institutionalized at 6 months. The predictors of death in multiple logistic regression included fracture site, a high number of comorbid conditions, a high number of complications, and poor baseline mental status. The primary predictor of institutionalization was poor baseline mental status. Conclusions. The frequency of death, institutionalization, and loss of function after hip fracture should prompt a reevaluation of the current approach to this problem.
2. The health burden of diabetes for the elderly in four communities
Deborah J Moritz, Adrian M Ostfeld, Dan Blazer, David Curb, James O Taylor, Robert B Wallace Public Health Rep 1994;109(6):782-90 Although diabetes is a common health problem of the elderly, the impact of diabetes on health and functioning in older persons is not well established. The purpose of this analysis was to identify health conditions accompanying diabetes in four samples of community dwelling elderly people. The study samples consisted of 13,601 persons ages 65 or older who participated in the Established Populations for Epidemiologic Studies in the Elderly (EPESE). Extensive interviews were conducted in respondents' homes to obtain information on diabetes and other health conditions, health behaviors, use of health services, and demographic characteristics. A lifetime history of diabetes was reported by 14 percent of respondents. The prevalence of the disease was higher in blacks than whites, especially among women. Persons with diabetes were more likely to report myocardial infarction, stroke, vision problems, physical disability, incontinence, and nursing home stays than persons without diabetes, but the diabetics were less likely to consume alcohol or tobacco. Those with diabetes were only slightly heavier than those without diabetes at the time of the interview. However, body mass at age 50 was substantially greater among persons with diabetes. Associations between diabetes and other health conditions and behaviors were similar for whites and blacks. These results show that aged persons with diabetes experience substantial comorbidity, which has important ramifications for functioning and survival.
3. Acute care hospital morbidity in the Blood Indian Band
Sherri Kashuba, Gordon Flowerdew, Patrick A Hessel, L Duncan Saunders, George Jarvis, Lory Laing, Clarke B Hazlett, Richard Musto Can J Public Health 1994;85(5):317-21 Acute care hospital morbidity of the Blood Indian Band was compared with that of all Albertans between April 1, 1984 and March 31, 1987. The Blood Indians had over 2.5 times as many hospital separations and 2.2 times as many patient days as the Albertans. The highest separation rate ratios by ICD-9-CM chapter for both Blood males and females were for endocrine, metabolic and nutritional disorders. Blood females had higher rate ratios for hospitalizations for all chapters except neoplasms and Blood males had higher rate ratios for all except congenital anomalies and neoplasms. For individual conditions, Blood males had the highest separation rate ratios for alcohol dependence syndrome, gastritis/duodenitis and diabetes mellitus. Bronchitis/emphysema and diabetes mellitus had the highest rate ratios for Blood females. The results are consistent with those reported in other studies of North American Indians. Their health status is more consistent with a developing country than that expected in Canada and does not appear to be improving.
4. Mortality in relation to smoking: 40 years' observations on male British doctors Richard Doll, Richard Peto, Keith Wheatley, Richard Gray, Isabelle Sutherland Br Med J 1994;309(6959):901-11 Objective-To assess the hazards associated with long term use of tobacco. Design-Prospective study of mortality in relation to smoking habits assessed in 1951 and again from time to time thereafter, with causes sought of deaths over 40 years (to 1991). Continuation of a study that was last reported after 20 years' follow up (1951-71). Subjects-34 439 British male doctors who replied to a postal questionnaire in 1951, of whom 10 000 had died during the first 20 years and another 10 000 have died during the second 20 years. Results-Excess mortality associated with smoking was about twice as extreme during the second half of the study as it had been during the first half. The death rate ratios during 1971-91 (comparing continuing cigarette smokers with lifelong non-smokers) were approximately threefold at ages 45-64 and twofold at ages 65-84. The excess mortality was chiefly from diseases that can be caused by smoking. Positive associations with smoking were confirmed for death from cancers of the mouth, oesophagus, pharynx, larynx, lung, pancreas, and bladder; from chronic obstructive pulmonary disease and other respiratory diseases; from vascular diseases; from peptic ulcer; and (perhaps because of confounding by personality and alcohol use) from cirrhosis, suicide, and poisoning. A negative association was confirmed with death from Parkinson's disease. Those who stopped smoking before middle age subsequently avoided almost all of the excess risk that they would otherwise have suffered, but even those who stopped smoking in middle age were subsequently at substantially less risk than those who continued to smoke. Conclusion-Results from the first 20 years of this study, and of other studies at that time, substantially underestimated the hazards of long term use of tobacco. It now seems that about half of all regular cigarette smokers will eventually be killed by their habit.
5. Prevalence of smoking among pregnant women in Nova Scotia from 1988 to 1992 Linda Dodds Objective: To determine the prevalence of smoking during pregnancy in Nova Scotia and to identify women at high risk of smoking during pregnancy. Design: Population-based descriptive study. Setting: All hospitals providing obstetric services in Nova Scotia. Patients: All 60 754 women residing in Nova Scotia who had a baby in hospital between 1988 and 1992; smoking data were available for 57 750 (95.1%) of them. Outcome measures: Proportion of women who smoked during pregnancy and the maternal smoking rates by age, marital status, parity, attendance at prenatal classes and residence. Results: Overall, 32.4% of the women smoked at some point during their pregnancy. The rate was highest among the women less than 20 years of age (47.0%) and decreased with each increasing 5-year age interval. Overall, the unmarried women were 2.1 times as likely to smoke as the married women. The smoking rates were highest among the women who were para 3 or greater regardless of age (women less than 20 were excluded here, since very few had such a parity). Of the nulliparous women, those who attended prenatal classes were less likely to smoke during pregnancy than those who did not attend. There was no relation between urban or rural residence and smoking rates. The smoking rates decreased little between 1988 and 1992 and in fact increased among the women 35 and over and among those who were para 3 or greater. Conclusions: The smoking rates among pregnant women in Nova Scotia changed little between 1988 and 1992. Therefore, it seems that current strategies for smoking cessation have not been successful. Since prenatal classes are more likely to attract nonsmokers than smokers, other avenues for education and cessation are necessary.
6. Trends in cigarette smoking among US adolescents, 1974 through 1991
David E Nelson, Gary A Giovino, Donald R Shopland, Paul D Mowery, Sherry L Mills, Michael P Eriksen Am J Public Health 1995;85(1):34-40 Objectives. The purpose of this study was to determine national trends in adolescent cigarette smoking prevalence. Methods. We conducted trend analyses based on 1974 through 1991 current smoking prevalence data among persons aged 12 through 19 years from the National Household Surveys on Drug Abuse, High School Seniors Surveys, and National Health Interview Surveys. Results. Overall smoking prevalence declined much more rapidly from 1974 through 1980 (1.9 percentage points annually among younger adolescents; the range among surveys of older adolescents was 0.2 to 2.0 percentage points annually) than from 1985 through 1991 (0 to 0.5 percentage points annually among all adolescents). Since 1980, smoking has generally declined at a slightly faster rate among older female adolescents than among male adolescents. Smoking among Black adolescents of all ages declined in nearly every survey population during each study period (range among surveys: 1974-1985 = 1.0 to 2.9 percentage points; 1985-1991 = 0.7 to 1.5 percentage points annually); for White adolescents, only minimal declines in smoking have occurred since 1985. Conclusions. Since 1974, major changes in adolescent smoking patterns have occurred, especially among Blacks. The overall slowing rate of decline in smoking prevalence since 1985 may indicate success of increased tobacco advertising and promotional activities targeted at adolescents or inadequate antitobacco education efforts.
7. Cigarette smoking by socioeconomic group, sex, and age: effects of price, income, and health publicity Joy Townsend, Paul Roderick, Jacqueline Cooper Br Med J 1994;309(6959):923-7 Objective-To assess effects of price, income, and health publicity on cigarette smoking by age, sex, and socioeconomic group. Design-Econometric multiple regression analysis of data on cigarette smoking from the British general household survey. Subjects-Random sample of adult population in Britain interviewed for biennial general household surveys 1972-90. Main outcome measures-Changes in cigarette consumption and prevalence of smoking. Results-Price elasticities of demand for cigarettes (percentage change in cigarette consumption for a 1% change in price) were significant at -0.5 (95% confidence interval -0.8 to -0.1) for men and -0.6 (-0.9 to -0.3) for women, were highest in socioeconomic group V (-1.0 for men and -0.9 for women), and lowest (not significantly different from zero) in socioeconomic groups I and II. The gradient in price elasticities by socioeconomic group was significant for men (F = 5.6, P = 0.02) and for women (F = 6.1, P = 0.02). Price was a significant factor in cigarette consumption by age for women in every age group and for men aged 25-34. Cigarette consumption by young men aged 16-34 increased with income. There was a significant decrease in smoking over time by women in socioeconomic groups I and II and by men in all age and social groups except socioeconomic group V attributable to health publicity. Price significantly affected smoking prevalence in socioeconomic group V (-0.6 for men and -0.5 for women) and for all women (-0.2). Conclusions-Men and women in lower socioeconomic groups are more responsive than are those in higher socioeconomic groups to changes in the price of cigarettes and less to health publicity. Women of all ages, including teenagers, appear to have been less responsive to health publicity than have men but more responsive to price. Response to health publicity decreased linearly with age. Real price increases in cigarettes could narrow differences between socioeconomic groups in smoking and the related inequalities in health, but specific measures would be necessary to ameliorate effects on the most deprived families that may include members who continue to smoke. The use of a policy to steadily increase cigarette tax is likely to help achieve the government's targets for smoking and smoking related diseases.
David Whiteman, Adèle Green Cancer Causes Control 1994;5:564-72 A computer-aided search identified 16 case-control studies which specifically assessed sunburn as a risk factor for cutaneous malignant melanoma. Using unadjusted estimates, a history of sunburn was associated with significantly increased risk of melanoma in all but one study. Four studies were defined as core studies after assessment of study quality; however, only two of these had sufficiently similar definitions of sunburn to allow pooling of results. Using pooled data, the risk of melanoma in those ever sunburned was 2.0 (95 percent confidence interval [CI] = 1.6-2.6), while the highest category of sunburn exposure had a risk of 3.7 (CI = 2.5-5.4). The suggestion that sunburns in childhood carry greater risk of melanoma cannot be supported by pooled analysis. This review demonstrated considerable variation in design and method among the studies, and identified sources of bias which prevented a pooled analysis using all available data. The need for strong epidemiologic evidence relating sunburn to melanoma, particularly in childhood, is of prime importance, since avoidance of sunburn is one of the few potential means of primary prevention of melanoma.
9. Neurodevelopment of adopted children exposed in utero to cocaine
Irena Nulman, Joanne Rovet, Deborah Altmann, Carole Bradley, Tom Einarson, Gideon Koren Can Med Assoc J 1994;151(11):1591-7 Objective: To assess the neurodevelopment of adopted children who had been exposed in utero to cocaine. Design: A case-control observational study. Participants: Twenty-three children aged 14 months to 6.5 years exposed in utero to cocaine and their adoptive mothers, and 23 age-matched control children not exposed to cocaine and their mothers, matched with the adoptive mothers for IQ and socioeconomic status. Setting: The Motherisk Programme at The Hospital for Sick Children, Toronto, a consultation service for chemical exposure during pregnancy. Main outcome measures: Height, weight and head circumference at birth and at follow-up, and achievement on standard tests of cognitive and language development. Results: Compared with the control group, children exposed in utero to cocaine had an 8-fold increased risk for microcephaly (95% confidence interval 1.5 to 42.3); they also had a lower mean birth weight (p = 0.005) and a lower gestational age (p = 0.002). In follow-up the cocaine-exposed children caught up with the control subjects in weight and stature but not in head circumference (mean 31st percentile v. 63rd percentile) (p = 0.001). Although there were no significant differences between the two groups in global IQ, the cocaine-exposed children had significantly lower scores than the control subjects on the Reynell language test for both verbal comprehension (p = 0.003) and expressive language (p = 0.001). Conclusions: This is the first study to document that intrauterine exposure to cocaine is associated with measurable and clinically significant toxic neurologic effects, independent of postnatal home and environmental confounders. Because women who use cocaine during pregnancy almost invariably smoke cigarettes and often use alcohol, it is impossible to attribute the measured toxic effects to cocaine alone.
10. First-trimester anesthesia exposure and the risk of central nervous system defects: a population-based case-control study
Gregg C Sylvester, Muin J Khoury, Xinpei Lu, J David Erickson Am J Public Health 1994;84(11):1757-60 Objectives. Although up to 2% of women undergo surgery during pregnancy, teratogenic effects of general anesthesia have not been adequately studied. Recently, an association between first-trimester operations and central nervous system defects has been described. This issue was explored in a population-based case-control study. Methods. Case patients included live-born and stillborn infants with central nervous system defects born to residents of metropolitan Atlanta, Ga, between 1968 and 1980. Control patients included normal babies frequency matched to case patients by race, birth hospital, and period of birth. Conditional logistic regression analysis was used to adjust for potential confounding factors. Results. Of 694 mothers of infants with central nervous system defects, 12 reported first-trimester anesthesia exposure; 34 of 2984 control mothers reported such exposure (odds ratio [OR] =1.7, 95% confidence interval [CI] = 0.8, 3.3). A striking association was observed between reported anesthesia exposure and hydrocephalus with another major defect (OR = 9.6, 95% CI = 3.8, 24.6). The strongest association was that of anesthesia exposure with hydrocephalus and eye defects (OR = 39.6, 95% CI = 7.5, 209.2). Conclusions. An increased risk of hydrocephalus with other defects was found among offspring of mothers with reported first-trimester anesthesia. Further studies are needed to explore the possible teratogenic effects of general anesthesia.
11. Physical activity and the risk of prostate and testicular cancer: a cohort study of 53,000 Norwegian men Inger Thune, Eiliv Lund Cancer Causes Control 1994;5:549-56 The associations between recreational and occupational physical activity and the subsequent risk of prostate and testicular cancer were examined in a population-based cohort study of 53,242 men in Norway. Age at study entry was 19 to 50 years. Information on physical activity was based on questionnaire responses and a brief clinical examination. A total of 220 prostate and 47 testicular cancer cases were recorded in the Cancer Registry of Norway during a mean follow-up time of 16.3 years. We found a nonsignificant, reduced, adjusted relative risk (RR) of prostate cancer with increased level of physical activity at work and among those men with the greatest recreational physical activity. When occupational and recreational physical activity were combined, a reduced adjusted risk of prostate cancer was observed among men who walked during occupational hours and performed either moderate recreational activity (RR = 0.61, 95 percent confidence interval [CI] = 0.36 to 1.01) or regular recreational training (RR = 0.45, CI = 0.20 to 1.01) relative to sedentary men (test for trend, P = 0.03). Physically active men who were older than 60 years of age at diagnosis showed a reduced adjusted RR of borderline significance, while no association was observed for younger men. No evidence was found for any association between physical activity and testicular cancer regardless of physical activity at work and recreation.
12. Bicyclist and environmental factors associated with fatal bicycle-related trauma in Ontario
Brian H Rowe, Alison M Rowe, Gary W Bota Can Med Assoc J 1995;152(1):45-51 Objective: To identify bicyclist and environmental factors associated with fatal bicycle-related trauma in Ontario. Design: Retrospective study. Setting: Ontario. Participants: Information was extracted from the provincial coroner's reports on 212 people who had died of bicycle-related injuries on Ontario between 1986 and 1991. Outcome measures: Age, sex and helmet use of the bicyclist, time and place of the event, type of bicyclist or motorist error(s) and use of alcohol by bicyclist or motorist. Results: Only 32% of the deaths involved bicyclists under 15 years of age. The male-female ratio was 3.5. Over 75% of the cases involved head injury; however, only 8 (4%) of the bicyclists had been wearing a helmet. In 91% of the cases death occurred as the result of a bicycle-motor vehicle collision. Most (65%) of the deaths for which the time was known occurred between 4 pm and 8 am. Bicyclist error was the main cause of crash for 26 (79%) of the children less than 10 years old; it was also the main cause of crash among the bicyclists aged 10 to 19 years (43 [55%]) and those aged 45 years or more (15 [44%]). However, motorist error was the most common cause of collision in the group of cyclists 20 to 44 years of age (42 [63%]). Alcohol was detected in the blood of 7% of the bicyclists killed; alcohol had been consumed by 30% of the motorists who claimed not to have seen the cyclist. Conclusions: Bicycle-related deaths result from factors that are generally avoidable. Identifiable risk factors other than lack of helmet use suggest that additional research is required to determine the benefits of preventive interventions aimed at reducing the number of such deaths. Age-specific strategies appear warranted.
13. Comparison of dietary habits, physical activity and body size among Chinese in North America and China
Marion M Lee, Anna Wu-Williams, Alice S Whittemore, Shu Zheng, Richard Gallagher, Chong-Ze Teh, Lun Zhou, Xianghui Wang, Kun Chen, Chengde Ling, Deng-Ao Jiao, Dexter Jung, Ralph S Paffenbarger Jr Int J Epidemiol 1994;23(5):984-90 Background. Chinese in North America have higher rates of many chronic diseases than do Chinese in Asia. However, there is a lack of data among comparisons of the environmental and lifestyle factors for Chinese in China and Chinese residing in North America. Methods. We examined self-reported dietary nutrient intakes, physical activity patterns and body mass index of 2488 healthy Chinese men and women residing in North America (US and Canada) and in the People's Republic of China. Results. On average, Chinese in China consumed more calories (males 2904 kcal in China, versus 2201 kcal in North America; females 2317 Kcal in China, versus 1795 Kcal in North America) and more carbohydrate, but less fat (males 72.2 g in China versus 84.5 g in North America, females 56.6 g in China versus 70.8 g in North America), protein, vitamin A, beta-carotene and vitamin C than did Chinese in North America. Per cent calories from fat was 35% for Chinese in North America and 22% for Chinese in China. In contrast, the per cent of calories from carbohydrates was 62-68% in China and 48% in North America. Chinese in China reported spending more time in vigorous activity, sleeping and walking but less hours in sitting than Chinese in North America. Chinese in China weighed less and were leaner than North American Chinese. Conclusions. These differences in nutrient intakes, physical activity and body size of Chinese living on two different continents suggest possible explanations for observed differences in chronic disease rates in the two populations.
14.Recent cancer trends in the United States
Susan S Devesa, William J Blot, BJ Stone, Barry A Miller, Robert E Tarone, Joseph F Fraumeni Jr J Natl Cancer Inst 1995;87(3):175-82 Background: Cancer incidence rates have been reported to be increasing in the United States, although trends vary according to form of cancer. Purpose: We identify the cancers accounting for the rising incidence, quantify the changes that have occurred from the mid-1970s to the early 1990s, and contrast incidence and mortality trends to provide clues to the determinants of the temporal patterns. Methods: Sex-, race-, and age-specific and age-adjusted incidence rates for the 5-year periods 1987-1991 versus 1975-1979 were calculated for 28 cancers among men and 30 cancers among women using data from the Surveillance, Epidemiology and End Results (SEER) Program of cancer registration covering about 10% of the U.S. population. Similar rates were computed using national mortality data. Cancers were ranked according to the change in incidence rates over the two periods. Results: Age-adjusted incidence rates for all cancers combined increased by 18.6% among males and 12.4% among females from 1975-1979 to 1987-1991, due largely to rising rates for prostate cancer among men and for breast and lung cancers among women. National mortality rates for all cancers combined rose less steeply, 3% and 6% among men and women, respectively, driven mostly by continuing increases in lung cancer mortality, while death rates for the majority of the cancers were steady or declining. Total cancer incidence rose at all ages, but with different tumors responsible for the increases at different ages: leukemia and brain/nervous system cancer among children; testicular cancer, nonmelanoma skin cancer (largely Kaposi's sarcoma), non-Hodgkin's lymphoma, and melanoma among young and middle-aged adults; and prostate, breast, and lung cancers among older individuals. In contrast, mortality rates for all cancers combined declined among both males and females under age 55 years, increasing only among older persons. Conclusions: Trends in cancer incidence and mortality differ. For most cancers, incidence rates are rising, while mortality rates are generally stable or declining. Implications: Much of the recent increase in cancer incidence can be explained by known factors. Improved detection appears to account for most of the increases in breast cancer among women and prostate cancer among men. On the other hand, cigarette smoking is the major determinant of the rise in lung cancer among women, acquired immunodeficiency syndrome has led to increases in non-Hodgkin's lymphoma and Kaposi's sarcoma among young and middle-aged men, and sunlight exposure patterns have affected the trends in melanoma. Some trends remain unexplained, however, and may reflect changing exposures to carcinogens yet to be identified and clarified.
15. Bayesian estimation of disease prevalence and the parameters of diagnostic tests in the absence of a gold standard
Lawrence Joseph, Theresa W Gyorkos, Louis Coupal Am J Epidemiol 1995;141(3):263-72 It is common in population screening surveys or in the investigation of new diagnostic tests to have results from one or more tests investigating the same condition or disease, none of which can be considered a gold standard. For example, two methods often used in population-based surveys for estimating the prevalence of a parasitic or other infection are stool examinations and serologic testing. However, it is known that results from stool examinations generally underestimate the prevalence, while serology generally results in overestimation. Using a Bayesian approach, simultaneous inferences about the population prevalence and the sensitivity, specificity, and positive and negative predictive values of each diagnostic test are possible. The methods presented here can be applied to each test separately or to two or more tests combined. Marginal posterior densities of all parameters are estimated using the Gibbs sampler. The techniques are applied to the estimation of the prevalence of Strongyloides infection and to the investigation of the diagnostic test properties of stool examinations and serologic testing, using data from a survey of all Cambodian refugees who arrived in Montreal, Canada, during an 8-month period.
16. Dietary fat intake and risk of epithelial ovarian cancer Harvey A Risch, Meera Jain, Loraine D Marrett, Geoffrey R Howe J Natl Cancer Inst 1994;86(18):1409-15 Background: Evidence exists that dietary fat may be a contributory factor in the development of hormone-related cancers such as ovarian cancer. Previous studies have demonstrated significantly higher circulating-estrogen levels among nonvegetarian women than among vegetarian women; the increase correlated directly with consumption of saturated fat. However, the contribution that dietary fat plays in the development of hormone-related cancers remains unresolved. Purpose: Our purpose was to evaluate whether saturated fat intake increases the risk of ovarian cancer development. Methods: Population-based sampling was used to acquire cases and controls over a 3-year period from the study area, which included the highly populated region surrounding the western end of Lake Ontario, Canada. From the Ontario Cancer Registry, all histologically confirmed, primary malignant or borderline malignant epithelial ovarian tumors first diagnosed from November 1989 through October 1992 among study-area residents aged 35-79 years were determined. In total, 631 eligible case subjects were identified, of whom 450 (71.3%) were interviewed concerning reproduction and diet; 564 randomly selected population control subjects were similarly interviewed. From the quantitative diet-history information, average daily intakes of macronutrients and micronutrients were calculated. Unconditional continuous logistic regression methods were used for analysis, with adjustment for age at interview, number of full-term pregnancies, years of oral contraceptive use, and total daily caloric intake. Results: Saturated fat consumption was associated with increasing risk of ovarian cancer (odds ratio [OR] = 1.20 for each 10 g/day of intake; 95% confidence interval [CI] = 1.03-1.40; one-sided P = .0082). No relationship was seen with intake of unsaturated fats. Egg consumption also appeared related to increased risk (OR = 1.42 for each 100 mg of egg cholesterol per day; 95% CI = 1.18-1.72; two-sided P = .0002), though this association may have resulted from disease-related changes in the dietary practices of case subjects prior to diagnosis. Consumption of vegetable fiber (but not fruit or cereal fiber) was associated with decreased risk (OR = 0.63 for each 10 g/day; 95% CI = 0.49-0.80; two-sided P = .0001). All three nutrients (saturated fat, egg cholesterol, and vegetable fiber) remained statistically significant when included in the same regression model. Conclusion: Diet may contribute to risk of ovarian cancer development. Implication: If confirmed in further studies, this association may allow women to appreciably lower their risk of ovarian cancer through dietary modifications: reducing the intake of saturated fats and eating more vegetables.
17.Periodic health examination, 1995 update: 1. Screening for human papillomavirus infection in asymptomatic women
Ken Johnson, with the Canadian Task Force on the Periodic Health Examination Can Med Assoc J 1995;152(4):483-93 Objective: To develop recommendations for practising physicians on the advisability of screening for human papillomavirus (HPV) infection in asymptomatic women. Options: Visual inspection, Papanicolaou testing, colposcopy or cervicography, use of HPV group-specific antigen, DNA hybridization, dot blot technique, Southern blot technique or polymerase chain reaction followed by physical or chemical therapeutic intervention. Outcomes: Evidence for a link between HPV infection and cervical cancer, sensitivity and specificity of HPV screening techniques, effectiveness of treatments for HPV infection, and the social and economic costs incurred by screening. Evidence: MEDLINE was searched for articles published between January 1966 to June 1993 with the use of the key words "papillomavirus," "cervix neoplasms," "mass screening," "prospective studies," "prevalence," "sensitivity," "specificity," "human" and "female." Values: Proven cost-effective screening techniques that could lead to decreased morbidity or mortality were given a high value. The evidence-based methods and values of the Canadian Task Force on the Periodic Health Examination were used. Benefits, harms and costs: Potential benefits are to prevent cervical cancer and eliminate HPV infection. Potential harmful effects include the creation of an unnecessary burden on the health care system and the labelling of otherwise healthy people as patients with a sexually transmitted disease for which therapy is generally ineffective. Potential costs would include expense of testing, increased use of colposcopy and treatment. Recommendations: There is fair evidence to exclude HPV screening (beyond Papanicolaou testing for cervical cancer) in asymptomatic women (grade D recommendation). Validation: The report was reviewed by members of the task force and three external reviewers who were selected to represent different areas of expertise. Sponsors: These guidelines were developed and endorsed by the task force, which is funded by Health Canada and the National Health Research and Development Program. The principal author (K.J.) was supported in part by the National Health Research and Development Program through a National Health Fellowship (AIDS).
18. Cohort study of silicon carbide production workers Claire Infante-Rivard, André Dufresne, Ben Armstrong, Paul Bouchard, Gilles Thériault Am J Epidemiol 1994;140(11):1009-15 Silicon carbide is produced by a chemical reaction at high temperature between free crystalline silica and petroleum coke. The process generates airborne fibers and fibrogenic dusts such as a-quartz and cristobalite, which are also potentially carcinogenic. The authors report that this is the first cohort study in this industry. The study was carried out among 585 Québec silicon carbide production workers who had worked at any time from 1950 to 1980. Follow-up was to December 31, 1989, and 167 deaths were observed. The standardized mortality ratio (SMR) for all causes of death was 1.05 (95% confidence interval (CI) 0.90-1.23); for nonmalignant respiratory diseases it was 2.03 (95% CI 1.21-3.22); and for lung cancer it was 1.69 (95% CI 1.09-2.52). Controlling for smoking status using a Cox regression analysis, the risk for nonmalignant respiratory diseases and for lung cancer increased with exposure to total dust; in the highest exposure category, rate ratios (RR) were 4.08 (95% CI 1.11-14.96) for nonmalignant respiratory diseases and 1.67 (95% CI 0.57-4.83) for lung cancer. Results were in the expected direction, but the power of the study was low, because of small sample size and use of cumulative total dust as the exposure variable, which may be a poor indicator of lung irritants and other potential carcinogens in this industry, notably silicon carbide ceramic fibers.
19.Occupational risk factors for bladder cancer: results from a case-control study in Montreal, Quebec, Canada Jack Siemiatycki, Ronald Dewar, Louise Nadon, Michel Gérin Am J Epidemiol 1994;140(12):1061-80 A population-based case-control study of the associations between various cancers and occupational exposures was carried out in Montreal, Quebec, Canada. Between 1979 and 1986, 484 persons with pathologically confirmed cases of bladder cancer and 1,879 controls with cancers at other sites were interviewed, as was a series of 533 population controls. The job histories of these subjects were evaluated by a team of chemist/hygienists for evidence of exposure to a list of 294 workplace chemicals, and information on relevant non-occupational confounders was obtained. On the basis of results of preliminary analyses and literature review, 19 occupations, 11 industries, and 23 substances were selected for in-depth multivariate analysis. Logistic regression analyses were carried out to estimate the odds ratio between each of these occupational circumstances and bladder cancer. There was weak evidence that the following substances may be risk factors for bladder cancer: natural gas combustion products, aromatic amines, cadmium compounds, photographic products, acrylic fibers, polyethylene, titanium dioxide, and chlorine. Among the substances evaluated which showed no evidence of an association were benzo(a)pyrene, leather dust, and formaldehyde. Several occupations and industries were associated with bladder cancer, including motor vehicle drivers and textile dyers.
20. Radiographic abnormalities and the risk of lung cancer among workers exposed to silica dust in Ontario
Murray M Finkelstein Can Med Assoc J 1995;152(1):37-43 Objective: To determine whether workers in Ontario who had been exposed to silica dust and who have radiographic abnormalities are at increased risk of lung cancer. Design: Cohort and case-control studies of rates of death from lung cancer and cancer incidence rates; data were obtained from the Ontario Silicosis Surveillance Registry. Follow-up was through linkage to the Ontario mortality and cancer registries. Setting: Ontario. Participants: A total of 523 workers with radiographic abnormalities and 1568 control subjects with normal radiographic findings who had been exposed to silica dust. Matching criteria were year of birth and the requirement that the control subject have a normal radiographic finding either later than or in the same year that the radiographic abnormality was identified in the silicosis subject. Outcome measures: Standardized mortality ratios (SMRs), standardized incidence ratios (SIRs) and odds ratios for lung cancer. Results: In the cohort analysis, with the Ontario population rates as reference, the all-cause SMR was 0.96 among the workers with radiographic abnormalities and 0.51 among the control subjects. The corresponding SIRs for lung cancer were 2.49 and 0.87 (p < 0.001). In the case-control analysis the workers with silicosis were more likely than the control subjects to have been smokers, but this difference likely accounted for only a small part of the difference in the incidence of lung cancer. The relative risk of lung cancer was elevated among the workers with silicosis from the foundry, mining and nonmetallic-minerals industries; however, the number of subjects was too small for a significant difference to be detected. Among the miners exposure to radon daughters did not affect the risk of lung cancer attributable to radiographic abnormalities. Conclusions: Radiographic abnormalities suggestive of exposure to silica dust are markers for increased risk of lung cancer. Physicians might thus wish to warn their patients with silica-associated radiographic abnormalities about the increased risk and to counsel those who smoke to stop.
21. Net economic costs of dementia in Canada Truls Østbye, Evelyn Crosse Can Med Assoc J 1994;151(10):1457-64 Objective: To estimate the net economic costs of dementia in Canada in 1991 by comparing costs related to elderly patients with dementia with those related to elderly people without dementia. Design: Cost-of-illness study. Data sources: Most of the data analysed in this study were from the Canadian Study of Health and Aging (CSHA), in which 10 263 Canadians aged 65 years and over were randomly selected, surveyed and, when appropriate, given clinical examinations. Data on patients with dementia and on people without cognitive impairment (control subjects) were used for this analysis. Data on activities of daily living (ADLs) were taken from a separate study under the CSHA, in which the principal caregivers of the subjects in the prevalence study were interviewed. Setting: Community and institutional settings in Canada, excluding those in the territories. Patients: All patients with dementia 65 years and older as determined from the CSHA. Patients with dementia under 65 were also considered. Outcome measures: Costs of paid and unpaid services in the community, care in long-term care institutions, drugs, hospitalization, diagnosis and research. Results: The total annual net cost of dementia was estimated to be over $3.9 billion. Costs associated with elderly patients in the community were estimated to be $1.25 billion ($615 million for paid services, $636 million for unpaid services), whereas costs for patients in long-term care institutions were $2.18 billion. Costs were about $74 million for drugs, hospitalization and diagnosis, $10 million for research and $389 million related to patients under age 65. Conclusion: The annual net economic cost of dementia in Canada is at least $3.9 billion. The most significant component of the total cost was for care in long-term care institutions and for assistance with ADLs by professionals, family and friends in the community. The economic burden of dementia is significant not only for patients, their families and friends, but also for society.
Many thanks to our 1994 peer reviewers!
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