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oai:open-archive.highwire.org:amjepid:133/7/6352015-05-11HighWireOUPamjepid:133:7
What is a Cause and How Do We Know One? A Grammar for Pragmatic Epidemiology
Susser, Mervyn
REVIEWS AND COMMENTARY
In this paper, criteria used by many epidemiologists as aids in causal inference are reviewed and revised. The revised scheme emphasizes the distinction between essential properties of a cause and criteria useful for deciding on the presence of these properties in a given case. A systematic procedure for causal inference tests each essential causal property in turn against appropriate criteria. For a pragmatic epidemiology in which all determinants serve as causes, their essential properties are held to be association, time order, and direction, in an ascending hierarchy. Criteria for association are probabilistic and can be enhanced by strength and consistency. Given association, criteria for time order of the relevant variables follow from access to observation, which is dependent on design. Given association and time order, causal direction (or consequential change) calls on an array of criteria, namely, consistency and survivability, strength, specilicity in cause and in effect, predictive performance, and coherence in all its forms (e.g., theoretical, factual, biologic, and statistical). The evolution of such criteria is traced through the epidemiologic literature in the light of historical context. Although Popper's philosophy cannot directly serve an inherently inductive judgmental process, his notion of survivability has here been added, alongside replicability, as a subclass of consistency. This criterion is proposed to bridge the gap between the particularity of designs and the generality required of causal relations. Designs are ordered and described in the framework of testing survivability. Finally, definitions are offered for the list of criteria deployed.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/635
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/6492015-05-11HighWireOUPamjepid:133:7
A Prospective Study of Bone Mineral Content and Fracture in Communities with Differential Fluoride Exposure
Sowers, MaryFran R.
Clerk, Kathleen M.
Jannausch, Mary L.
Wallace, Robert B.
ORIGINAL CONTRIBUTIONS
In 1983/1984, a study of bone mass and fractures was begun in 827 women aged 20–80 years in three rural Iowa communities selected for the fluoride and calcium content of their community water supplies. The control community's water had a calcium content of 67 mg/liter and a fluoride content of 1 mg/liter. The higher-calcium community had water with a calcium content of 375 mg/liter and a fluoride content of 1 mg/liter. The higher-fluoride community's water had 15 mg/liter of calcium and 4 mg/liter of fluoride naturally occurring. In 1988/1989, a follow-up study characterized the 684 women still living and available for study. Residence in the higher-fluoride community was associated with a significantly lower radial bone mass in premenopausal and postmenopausal women, an increased rate of radial bone mass loss in premenopausal women, and significantly more fractures among postmenopausal women. There was no difference in the 5-year relative risk of any fracture in the higher-calcium community versus the control community; however, the relative risk was 2.1 (95% confidence interval (Cl) 1.0–4.4) in women in the higher-fluoride community compared with women in the control community. There was no difference in the 5-year risk of wrist, spine, or hip fracture in the higher-calcium community versus the control community; however, the 5-year relative risk for women in the higher-fluoride community, compared with women in the control community, was 2.2 (95% Cl 1.1–4.7). Estimates of risk were adjusted for age and body size.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/649
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/6612015-05-11HighWireOUPamjepid:133:7
Serum Beta-Carotene in Persons with Cancer and Their Immediate Families
Smith, Allan H.
Waller, Kim D.
ORIGINAL CONTRIBUTIONS
A unique case-control study design including family members of cases and controls was used to assess the association between serum beta-carotene and cancer. The cases (<it>n</it> = 389) were incident cancer cases diagnosed between 1981 and 1984 in Wellington, New Zealand, and the controls (<it>n</it> = 391) were hospital patients without cancer. Both cases and controls were on a home diet at the time beta-carotene levels were measured. Since findings concerning patients who have already been diagnosed with cancer may reflect changes that occurred subsequent to development of cancer, family members of cancer patients (n = 618) and control patients (<it>n</it> = 675) were included, giving a total of 2,073 study participants. Low levels of beta-carotene were observed for individuals with a number of cancers, including cancers of the lung, stomach, esophagus, small intestine, cervix, and uterus. Low levels of beta-carotene were also found in the relatives of these cancer patients. These differences persisted after stratification by current cigarette smoking. The strongest findings were those for lung cancer. Excluding adenocarcinoma, lung cancer patients had average serum beta-carotene levels of 40.2μ/dl, 25.9 μ/dl lower than those of controls, adjusted for age, sex, and length of sample storage (p < 0.01). Family members of the lung cancer patients also had lower values than family members of control patients, with an adjusted difference of 10.8 μ/dl (<it>p</it> < 0.01). Odds ratio estimates for lung cancer by quartiles of beta-carotene residuals ranged from 3.6 (90% confidence interval (Cl) 1.1–12.2) for the second-highest quartile to 6.6 (90% Cl 1 .9–23.0) for the lowest quartile (test for trend, <it>p</it> < 0.001). Patients with cancers of the breast, colon, prostate, and skin did not have lower levels of serum beta-carotene than expected. Family members of individuals with these cancers also did not have lower levels of serum beta-carotene. The cancer sites that were associated with serum beta-carotene are, in general, sites for which smoking is a strong risk factor, and the sites that were not associated with beta-carotene do not have smoking as a risk factor.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/661
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/6722015-05-11HighWireOUPamjepid:133:7
Black-White Differences in Stage-Specific Cancer Survival: Analysis of Seven Selected Sites
Regland, Kathleen E.
Selvin, Steve
Merrill, Deane W.
ORIGINAL CONTRIBUTIONS
A number of reserachers have noted that the black population in the United States generally has less favorable cancer survival than does the white population. It is not clear, however, whether this difference is fully explained by differences in stage of disease at diagnosis. This study uses Surveillance, Epidemiology, and End Results program data from the San Francisco-Oakland (California) Metropolitan Statistical Area for the years 1974–1985 to study survival differences between blacks and whites while controlling for both stage and age at diagnosis. The cancer sites examined are those for which mortality is considered avoidable by early detection and treatment, namely the colon, rectum, bladder, breast, cervix, uterine corpus, and prostate. Stage-specific (local, regional, and remote) survival curves are examined for each cancer site. The site- and stage-specific curves for colon, male rectal, and prostate cancer, supplemented by proportional hazards analyses, indicate no significant stage-specific racial differentials. Stage-specific survival differentials persist for male bladder, female rectal, and breast cancer. The relation between race and stage is more complex for female bladder, cervical, and uterine corpus cancer; for these sites, there is a racial difference at some stages but not all. The consequences for secondary intervention programs are considered for the seven sites in light of these findings.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/672
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/6832015-05-11HighWireOUPamjepid:133:7
Diet and Lung Cancer in California Seventh-day Adventists
Fraser, Gary E.
Beeson, W. Lowrence
Phillips, Ronald L.
ORIGINAL CONTRIBUTIONS
The Adventist Health Study, a cohort study of 34,198 California Seventh-day Adventists, identified 61 cases of new primary lung cancer over 6 years of follow-up (1977–1982). The population studied was unique in that only 4% admitted to current cigarette smoking and about half were lacto-ovovegetarlans. A total of 36% of the lung tumors were adenocarcinomas, and 19% were squamous cell carcinomas. The expected associations with cigarette smoking were noted for Kreyberg group I tumors (squamous cell, large cell, and small cell carcinoma; relative risk (AR) = 53.2 for current smokers and 7.07 for past smokers), but much lesser associations were noted for Kreyberg group II tumors (adenocarcinorna and bronchoalveolar carcinoma; AR = 1.99 for current smokers and 1.59 for past smokers). In this study, fruit consumption was the dietary constituent that showed a strong, statistically significant protective association with lung cancer that was independent of smoking (fruit consumption <3 times/week, RR = 1.0; 3–7 times/week, RR = 0.30; ≥ times/day, RR = 0.26). This association was somewhat stronger for Kreyberg group II tumors, but similar trends were also noted for Kreyberg group I tumors. Confounding with smoking seems unlikely in a population with very few current smokers and where both stratification and Cox modeling methods of analysis led to similar conclusions.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/683
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/6942015-05-11HighWireOUPamjepid:133:7
Body Conformation, Diet, and Risk of Breast Cancer in Pet Dogs: A Case-Control Study
Sonnenschein, Elizabeth G.
Glickman, Lowrence T.
Goldschmidt, Michael H.
McKee, Linda J.
ORIGINAL CONTRIBUTIONS
Canine and human breast cancer share several important clinical and histologic features. A case-control study of nutritional factors and canine breast cancer was conducted at the Veterinary Hospital of the University of Pennsylvania in 1984–1987 by interviewing owners of 150 pet dogs diagnosed with breast cancer, owners of 147 cancer control dogs, and owners of 131 noncancer control dogs. The risk of breast cancer was significantly reduced in dogs spayed at or before 2.5 years of age. Neither a high-fat diet nor obesity 1 year before diagnosis increased the risk of breast cancer according to multiple logistic regression analysis. However, the risk of breast cancer among spayed dogs was significantly reduced in dogs that had been thin at 9–12 months of age (odds ratio (OR) = 0.04 (95% confidence interval (Cl) 0.004–0.4) and OR = 0.04 (95% Cl 0.004–0.5) for cases vs. cancer controls and cases vs. noncancer controls, respectively, after adjustment for age at spay). Among intact dogs, the risk associated with being thin at 9–12 months of age was reduced, but not significantly so (OR = 0.60 (95% Cl 0.2–1.9) and OR = 0.51 (95% Cl 0.2–1.4) for the two comparisons, respectively). Results of this study suggest that nutritional factors operating early in life may be of etiologic importance in canine breast cancer.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/694
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7042015-05-11HighWireOUPamjepid:133:7
Cardiovascular Risk Factors in Hispanic, White, and Black Children: The Brooks County and Bogalusa Heart Studies
Webber, Larry S.
Harsha, David W.
Phillips, George T.
Srinivasan, Sathanur R.
Simpson, James W.
Berenson, Gerold S.
ORIGINAL CONTRIBUTIONS
Cardiovascular disease risk factors were studied in Hispanic children in Brooks County, Texas, and in white and black children in Bogalusa, Louisiana, in 1984–1985. The same protocols were used at both sites; examiners in Brooks County were trained by Bogalusa Heart Study staff. Pdl blood samples were analyzed in a single laboratory standardized by the Centers for Disease Control. Hispanic children were about 4 cm shorter and were about the same weight as white and black children. Subscapular skinfolds were thickest in Hispanic children. Utile difference was noted for blood pressure levels in the three ethnic groups. Total cholesterol levels were highest in black children, with a drop during puberty being noted in all of the ethnic groups. This drop with puberty appeared somewhat earlier in the Hispanic children. Lipoprotein levels for Hispanic children were, in general, similar to those noted for white children. Some of the Hispanic-black differences in lipid and lipoprotein levels could be explained by differences in body size. Because Hispanics are at increased risk for specific diseases, such as diabetes, increased study of this population is warranted. Intervention and education programs aimed at altering this risk must address the unique cultural heritage of this population.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/704
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7152015-05-11HighWireOUPamjepid:133:7
A Preliminary Study of Excess Risk of Cardiovascular Disease in the Mothers of Patients with Rheumatoid Arthritis
Kaplan, David
Feldman, Joseph
ORIGINAL CONTRIBUTIONS
Family histories were obtained from 123 patients with rheumatoid arthritis and 152 patients with other musculoskeletal complaints. The subjects were female patients aged 40 years or more seen at the Arthritis Clinic of the State University of New York Health Science Center at Brooklyn between October 1985 and February 1986. It was found that death due to heart disease or stroke was more common (adjusted <it>p</it> < 0.02) in the mothers of patients with rheumatoid arthritis than in the mothers of control patients, and that heart disease was also reported to be more common in these mothers (adjusted <it>p</it> < 0.005). Thus, it is possible that cardiovascular disease at least partially accounts for the previously noted (<it>J Rheumatol</it> 1986;13:903–6) shorter life expectancy of the mothers of patients with rheumatoid arthritis.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/715
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7212015-05-11HighWireOUPamjepid:133:7
Epidemiologic Aspects of Coronary Heart Disease in Malmö, Sweden, 1935-1988
Hansen, Ole
Johansson, Bengt W.
ORIGINAL CONTRIBUTIONS
Mortality from coronary heart disease has declined for more than 20 years in several industrialized countries. Partly because of a lack of morbidity data, the reasons for the decline are not satisfactorily established. This community-wide survey of coronary heart disease morbidity and mortality in Malm�, Sweden, showed declining mortality rates beginning in the mid-1970s. Between the 3-year intervals 1975–1977 and 1984–1986, coronary heart disease mortality declined by 17% (2,610/100,000 inhabitants in 1984–1986) in men aged ≥70 years and by 8% (938/100,000 inhabitants in 1984–1986) in men aged 60–69 years, while coronary heart disease mortality in men aged 50–59 years increased by 7% (355/100,000 inhabitants in 1984–1986). In women aged ≥70 years, coronary heart disease mortality decreased by 12% between 1975–1977 and 1984–1986 (1,609/100,000 inhabitants in 1984–1986), while the decrease in women aged 60–69 years was 5% (242/100,000 inhabitants in 1984–1986). The decline in mortality was associated with a decline in both incidence rates and in-hospital case fatality rates for myocardial infarction. The authors suggest that the declining coronary heart disease mortality In Malm� was due partly to prevention of coronary heart disease but that improved medical care for acute and chronic coronary heart disease may also have contributed.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/721
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7342015-05-11HighWireOUPamjepid:133:7
Cigarette Smoking, Tea and Coffee Drinking, and Subfecundity
Olsen, Jørn
ORIGINAL CONTRIBUTIONS
A population-based survey of life-style factors and subfecundity (prolonged time to pregnancy) was conducted between 1984 and 1987 in two cities in Denmark. Altogether, 11,888 women filled out a questionnaire in the last trimester of pregnancy (an 86 percent response rate). After exclusion of women who had been treated for infertility or who did not respond to the question on infertility, 10,886 subjects remained. Among nonsmokers, no association was found between subfecundity (defined as a waiting time of 1 year or more from cessation of contraception to achievement of pregnancy) and consumption of hot caffeinated beverages. For women who smoked and also consumed at least 8 cups of coffee per day (or an equivalent amount of tea), a statistically significant association was seen (odds ratio = 1.35, 95% confidence interval 1.02–1.48) for a wait of 1 year or more. Consumption of coffee was closely related to smoking habits and to a number of social factors, such as education and peer group acceptance, which may play a role in subfecundlty.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/734
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7402015-05-11HighWireOUPamjepid:133:7
Chagas' Disease: Risk Factors for House Infestation by Triatoma dimidiata, the Major Vector of Trypanosoma cruzi in Costa Rica
Starr, Mark D.
Rojas, Julio C.
Zeledón, Rodrigo
Hird, David W.
Carpenter, Tim E.
ORIGINAL CONTRIBUTIONS
The reduction of domiciliary infestation by insect vectors, the key to controlling Chagas' disease, depends on identification of housing features associated with infestation. In this study, log-linear modeling was used to reanalyze data collected in 1964–1968 from 371 houses on characteristics potentially associated with infestation by the vector <it>Triatoma dimidiata</it> in a Costa Rican town with endemic Chagas' disease. A possible increased risk of infestation was observed for houses with a dirt floor (as compared with houses with another floor type) and for houses in poor sanitary condition (as compared with houses in good sanitary condition). A new risk factor for house infestation, the presence of roof tiles, was identified; the odds of infestation for houses with a tile roof were 2.4 times greater than the odds for houses with a galvanized metal roof. This significantly increased risk is probably due to the harboring of <it>T. dimidiata</it> in stacks of spare tiles next to house walls rather than to the tile roofs themselves.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/740
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7482015-05-11HighWireOUPamjepid:133:7
Use of the Case-Control Method in Outbreak Investigations
Fonseca, Maria Goretti Pereira
Armenian, Haroutune K.
ORIGINAL CONTRIBUTIONS
The authors carried out a critical assessment of the literature to learn about the extent of use of the case-control method in outbreak investigations, and to identify problems observed in the use of this method to investigate outbreaks. The literature search comprised reports of outbreak investigations from the MEDUNEθ system, <it>Morbidity and Mortality Weekly Report</it>, and six epidemiologic and medical journals. The proportion of these reports that used the case-control method increased from one artide out of 519 in the 1960–1965 period to 144 out of 845 reported outbreaks in the 1980–1985 period. A comparison of the case-control studies of outbreak investigations in the 1970–1975 period with those in the 1980–1985 period revealed relatively more sophisticated methods of analysis in the latter period.
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/748
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7532015-05-11HighWireOUPamjepid:133:7
RE: "PRECURSORS OF ESSENTIAL HYPERTENSION: PULMONARY FUNCTION, HEART RATE, URIC ACID, SERUM CHOLESTEROL, AND OTHER SERUM CHEMISTRIES"
Richards, Stephen M.
Clark, Michael G.
Colquhoun, Eric Q.
Rattigan, Stephen
LETTERS TO THE EDITOR
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/753
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7542015-05-11HighWireOUPamjepid:133:7
RE: "LYME DISEASE IN OUTDOOR WORKERS: RISK FACTORS, PREVENTIVE MEASURES, AND TICK REMOVAL METHODS"
Oteo, Josése
Casas, Juan Manuel
de Artola, Victor Martínez
LETTERS TO THE EDITOR
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/754
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Copyright (C) 1991, Oxford University Press
oai:open-archive.highwire.org:amjepid:133/7/7552015-05-11HighWireOUPamjepid:133:7
THE FIRST AUTHOR REPLIES
Schwartz, Brian S.
LETTERS TO THE EDITOR
Oxford University Press
1991-04-01 00:00:00.0
TEXT
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http://aje.oxfordjournals.org/cgi/content/short/133/7/755
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Copyright (C) 1991, Oxford University Press