ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Whereas case-control studies have been very consistent in suggesting a positive association between intake of dietary fat, especially animal fat, and prostate cancer, the results from past cohort studies have been mostly inconclusive. In this study, we evaluated consumption of high-fat animal products, raw vegetables, and fresh fruits, as well as obesity, smoking, and drinking, in relation to subsequent occurrence of prostate cancer. We studied a cohort of 20,316 men of various ethnicities interviewed between 1975 and 1980 in Hawaii. As of December 1989, 198 incident cases with invasive prostate cancer were identified by computer-assisted linkage of this cohort to the statewide Surveillance, Epidemiology, and End Results registry. Relative risks (RRs) for prostate cancer computed by proportional hazards regression were elevated for intake of beef [RR for highest to lowest tertile of intake = 1.6; 95% confidence interval (CI) = 1.1–2.4] and milk (RR = 1.4; 95% CI = 1.0–2.1), and for a summary variable for intake of high-fat animal products (RR = 1.6; 95% CI = 1.0–2.4). Weight was not consistently associated with prostate cancer, but there was an association with height (>167 cm) (RR = 1.8; 95% CI = 1.0–3.2 for the third and fourth quartiles relative to the lowest quartile in height). These associations were stronger in men diagnosed before age 72.5 years. The risk estimates for raw vegetable and fresh fruit intakes were close to 1.0. Smoking and alcohol drinking appeared to be unrelated to risk. This study provides further evidence for a role of animal fat in the etiology of prostate cancer and indicates that it may act by shortening the latency period of the disease.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

An international study to validate the Ten Questions screen for serious childhood disability was undertaken in communities in Bangladesh, Jamaica, and Pakistan, where community workers screened more than 22,000 children ages 2–9 years. All children who screened positive, as well as random samples of those who screened negative, were referred for clinical evaluations. Applying comparable diagnostic criteria, the sensitivity of the screen for serious cognitive, motor, and seizure disabilities is acceptable (80–100%) in all three populations, whereas the positive predictive values range from 3 to 15%. These results confirm the usefulness of the Ten Questions as a low-cost and rapid screen for these disabilities, although not for vision and hearing disabilities, in populations where few affected children have previously been identified and treated. They also show that the value of the Ten Questions for identifying disability in underserved populations is limited to that of a screen; more thorough evaluations of children screened positive are necessary to distinguish true- from false-positive results and to identify the nature of the disability if present.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Previous estimates of the lifetime risk of developing breast cancer have used cross-sectional estimates of incidence. Cross-sectional rates, however, yield a biased picture of cohort risks when rates are unstable, as breast cancer trends have been. We developed cohort life tables for Connecticut women born from 1888–1892 to 1948–1952 to generate more specific estimates of breast cancer risk to age 85. Multiple decrement life tables were produced for each birth cohort. We included as cases only the first reports of breast cancer in women with no earlier malignancy. Our results indicate that widely circulated lifetime risks of 1 in 9 may be inflated slightly owing to changing incidence. We estimate that of those women 40–44 years old in 1992, 1 woman in 10 will develop breast cancer by age 85. For women born between 1928 and 1932, 1 in 13 will be diagnosed with breast cancer by age 85. The results are insensitive to mortality trends in the past. Errors in the estimates are more likely to arise from changes in incidence and mortality in the future.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

There have been many advances in the mapping of disease mortality and morbidity rates in recent years. An increasingly common approach is to calculate “stabilized” rates for individual geographic areas by incorporating information from the entire set of data. One such method, adopted by the National Cancer Institute for its mortality maps, is described and applied to national end-stage renal disease data. Some possible difficulties in interpretation are noted, resulting from: (1) insufficient shrinkage, (2) highly skewed rate distributions, (3) different denominator distributions, and (4) variations in population density.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Using patient data obtained from the International Cooperative Aneurysm Study that evaluated clinical records from 68 neurosurgical centers in 14 countries, we evaluated the data as to the monthly occurrence of cerebral vasospasm and subarachnoid hemorrhage relative to the latitude of the medical center where the data were gathered. Using the Edwards analysis for cyclic patterns, we examined peak to trough ratios and months of peak to assess the strength and nature of the cyclic variations between December 1980 and July 1983. Of the 3,521 subarachnoid hemorrhage patient records examined, 685 developed some grade of vasospasm as defined symptomatically, angiographically, and by the Fisher Grading Scale. Cyclic analysis demonstrated a strong seasonal occurrence for the incidence of subarachnoid hemorrhage, with a peak in February, in the northern hemisphere. Cerebral vasospasm incidence, after controlling for subarachnoid hemorrhage occurrence, exhibited only a small peak to trough ratio (1.15) relative to the larger ratio (1.74) seen with unadjusted vasospasm data. Age was related to both incidence and location. In populations at high risk for cerebrovascular diseases, climatic conditions may act as synchronizers of pathologic vascular events.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Misclassification of a binary exposure in case-control studies is usually assessed by sensitivity and specificity of the measured exposure. Sensitivity and specificity do not adequately measure the degree of misclassification because they assess only the proportion of truly exposed (or unexposed) subjects who are misclassified by the defective measurement. They do not account for the proportion of subjects, categorized by the defective measurement as either exposed or unexposed, who are misclassified, in other words, the predictive value of the measurement. A more appropriate way of measuring misclassification is by “quality indices” that take both of these criteria into account and that are essentially rescaled sensitivity and specificity, or predictive value, measures. I present the relation between measured and actual odds ratios in terms of quality indices. If quality indices are nondifferential or proportional, there is no misclassification bias to the odds ratio. The relation offers a new approach to correcting measured odds ratios.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Apparent relative sensitivity, based on an investigator's external standard, is the ratio of observed case to control exposure sensitivity. An apparent relative sensitivity different from 1.0 is usually interpreted as evidence for differential misclassification of exposure status. We undertook this investigation to determine the conditions under which an apparent relative sensitivity exceeding 1.0 is actually due to differential misclassification. We also consider whether apparent relative sensitivity correctly quantifies the degree of differential misclassification. To achieve these goals, we de-rived an algebraic relation involving apparent relative sensitivity, true sensitivities and specificities, true odds ratio, an index of how well the external standard classifies true expo-sure, and the incidence of the disease among the nonexposed. We found that an apparent relative sensitivity greater than 1.0 correctly indicates differential misclassification when either (1) the investigator's external standard classifies true exposure perfectly, or (2) the investigator's external standard is imperfect, but the true odds ratio equals 1.0, true relative sensitivity is greater than 1.0, and true relative specificity is less than 1.0. We also found that apparent relative sensitivity greater than 1.0 falsely suggests differential misclassification when true relative sensitivity equals 1.0, the investigator's external standard is imperfect, and the true odds ratio is greater than 1.0. Furthermore, even when apparent relative sensitivity correctly detects the presence of differential misclassification, it may misrepresent the degree.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID