ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The effects of barrier and spermicidal methods of contraception on cervical cancer risk were examined by studying 479 cases of histologically confirmed invasive cervical cancer cases and 788 random digit dialing controls. In addition to a detailed history of contraceptive practices, information was available on numerous potential confounders, including demographic characteristics, sexual behavior, reproductive factors, Pap smear screening history, and smoking. After adjustment for relevant confounders, diaphragm and condom use were found not to be significantly associated with risk of cervical cancer. Although there was a small reduction in risk (OR = 0.8) associated with long-term use (5+ years) of the diaphragm, the effect appeared to relate to concomitant spermicide use, since there was evidence of further decreases in risk for women using spermicides alone for extended periods (OR = 0.7 for 5+ years). Effects were only seen among subjects of higher income and education levels, suggesting that patterns of usage may be important. The potential ability of spermicides to reduce cervical cancer risk by neutralizing viral agents warrants further attention. (Epidemiology 1990; 1:266–272)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

An unbiased estimate of the rate ratio can be obtained using a case-control design in which each case is matched to one or more controls randomly selected from population members at risk and in the same stratum as the case at the time of disease onset. However, the nonrandom assignment of controls to cases is quite frequent in case-control research. It occurs, for example, in matched case-control studies using either friend controls or neighborhood controls. Many valid random designs, in contrast to most nonrandom designs, require enumeration of a substantial fraction of the study base. Therefore, there may be important cost and logistic advantages to using valid nonrandom designs. In this paper we determine those nonrandom case-control designs that can produce unbiased estimates of the rate ratio and discuss the implications of our findings for the design of case-control studies. We conclude, as did Flanders and Austin, that friend-case-control studies should generally be avoided. On the other hand, in a typical neighborhood-matched, case-control study, any bias attributable to nonrandom control selection is usually too small to affect substantive conclusions. (Epidemiology 1990;1:273–284)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Risk factors for rheumatoid arthritis were examined in a cohort of 121,700 female nurses aged 30–55, followed in the Nurses' Health Study. Baseline information on reproductive variables, cigarette smoking, obesity, and other variables was obtained in 1976 and updated every 2 years. Cases of rheumatoid arthritis were defined by standardized questionnaire and review of medical records. During 883, 187 person-years of follow-up, 217 new cases of rheumatoid arthritis were identified (115 had definite rheumatoid arthritis and 102 had “undifferentiated polyarthritis”). When compared with women who experienced menarche at age 13 years, the age-adjusted relative risk of rheumatoid arthritis among women with early menarche was 1.9 (95% confidence interval, 0.9–2.4). There were, however, no significant associations between parity, age at birth of the first child, menopause, or obesity and the incidence of rheumatoid arthritis.Cigarette smokers had a slight apparent increase in the risk of rheumatoid arthritis. Among current smokers, the age-adjusted relative risk for RA rheumatoid arthritis was 1.3 (0.9–2.1); among former smokers, the relative risk was 1.5 (0.9–2.3). (Epidemiology 1990;l:285–291)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We conducted a validity study to assess whether information bias from differential misclassification of occupational exposures occurred in a case-referent study on mental retardation and parental occupation. The colleagues of 42 case parents and 38 referent parents were traced and interviewed with a questionnaire similar to that used for the parents. Within each parent-colleague pair, Cohen's kappa coefficient was calculated as a measure of agreement between the reported occupational exposures. Averaged across pairs, the mean kappa coefficient was 0.48 (95% CI = 0.40–0.56) for case pairs and 0.46 (95% CI = 0.38–0.54) for referent pairs, indicating little evidence for differential reporting of exposures between cases and referents. Our results also indicate that colleagues are eligible substitute respondents for information on occupational exposures. (Epidemiology 1990; 1:292–297)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We used a unique data base containing medical family history information from representative Utah families to investigate interactions between diabetes and family history of coronary heart disease and other risk factors for coronary heart disease. We compared nonrelated individuals reported to have had diabetes mellitus diagnosed over the age of 19 (948) with 2150 nondiabetic individuals. Among both men and women, diabetes and family history of early coronary heart disease magnified the risk for coronary heart disease, so that in diabetic individuals with a positive family history of coronary heart disease, about 74% of the coronary heart disease could be attributed to interaction. Relative to nondiabetics without a family history of early coronary heart disease, nondiabetics with family history had a relative risk of 4.5 (2.3–8.7), diabetics without a family history had a relative risk of 2.8 (1.6–4.9), and diabetics with a family history had a relative risk of 21.3 (9.1–50.0). Smoking also interacted with diabetes; among smoking diabetics, 47% of early heart disease may be attributable to interaction between smoking and diabetes. Smoking entailed the highest risk for diabetic women. Hypertension and diabetes appeared to act additively, with little interaction. Among women, family history of diabetes was a risk factor for coronary heart disease with a relative risk of 2.5 (1.0–6.4), whereas for men the relative risk was estimated to be 0.4 (0.2–1.1). (Epidemiology 1990; 1:298–304)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

To investigate the relationship between the reproducihility of measurements of exposure from a frequency questionnaire and inferences from a case-control study, 229 patients were reinterviewed on the telephone an average of 6 weeks after the original interview. Several indices of agreement were computed. Information on smoking and use of alcohol and coffee was quite reproducible, as reflected by most measures of agreement, using grouped or continuous data. Frequency of meat, vegetable, and fruit intake had low reproducibility. For all variables, reproducibility was similar for cases and controls. Reproducibility of the exposure variables was a good predictor of the reproducibility of the relative odds (RO) obtained with the first and the repeat interviews. Lack of reliability of the exposure variable appeared to produce fluctuations in the ROs in either direction, even though the same degree of agreement was observed for cases and controls. This situation may partially explain discrepant findings between case-control studies of diet and chronic diseases. (Epidemiology 1990; 1:305–310)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Hazardous roadway locations can be identified by monitoring the distribution of collisions on roads or by community concern following spectacular collisions. An in-depth investigation of collisions at a suspected high-risk site can allow engineers to conclude about causative factors. Expensive roadway investigations and modifications, however, should be undertaken only after an excess risk is demonstrated. We suggest using standard analytic cohort study methods for assessing suspected high-risk locations. The proposed approach complements the traditional approach of engineers, but differs from other epidemiologic studies of roadway hazards. This new application of standard techniques could help optimize the allocation of resources. (Epidemiology 1990;1:311–314)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Mathematical modeling of risk of lung cancer upon smoking cessation suggests increasing risk, whereas the facts show decreasing mortality. This discordance is resolved by taking into account the mechanistically distinct steps in chemical carcinogenesis: (1) neoplastic conversion hygenotoxic carcinogens and (2) neoplastic growth and development by agents with epigenetic and promoting effects. Tobacco smoke contains relatively small amounts of several types of genotoxic carcinogens, the effect of which is considerably and vitally enhanced by nongenotoxic promoting factors. Upon smoking cessation, the effect of the second type of agent is abruptly eliminated. Therefore, any preneoplastic lesions remain static or regress, whereas in the continuing smoker they progress. These sequences also apply, with different chemicals involved, in nutritional carcinogenesis. (Epidemiology 1990;1:314–317)

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID