摘要:

To evaluate the quality of exposure data provided by proxy respondents, we used a dual interview protocol in a case-control study of subarachnoid hemorrhage. All control subjects and their proxy respondents were interviewed (N = 283 control-proxy pairs), as were the cases who were able to provide their own information and their proxy respondents (N = 68 case-proxy pairs). The reliability of proxy-derived data was excellent for demographic and body habitus measures (kappa or intraclass correlation range = 0.86–0.99), and all aspects of cigarette smoking history (range = 0.79–0.93). Proxy reliability was somewhat lower for questions regarding medications and hormone preparations (range = 0.55–0.88), alcohol consumption (range = 0.52–0.82), and recreational physical activity (range = 0.55–0.67). Proxy reliability varied according to the relationship of the proxy to the index subject. Relative to the index subjects, proxy respondents tended to underreport the presence or level of exposure. For most exposures, odds ratios computed with proxy-derived data were similar in magnitude to odds ratios obtained with index subject data; important bias due to differential nonre-sponse or differential misclassification was suggested only for questions regarding hormone replacement therapy. Epide-miologic studies that rely on proxy respondents may require more subjects to offset the effect of nondifferential nonre-sponse and misclassification on the precision of effect estimates.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Using data on 1,860 bladder cancer cases and 3,934 population-based controls from the National Bladder Cancer Study, we examined associations between suspected bladder cancer risk factors and tumor stage and grade. Employment in a high-risk occupation was associated with the entire clinical spectrum of bladder cancer rather than a particular tumor stage or grade. For example, relative risks (RR) were similar for noninvasive and invasive disease (1.5 and 1.6, respectively). Cigarette smoking also increased risk of the entire clinical spectrum of bladder cancer, but the more advanced the stage, the stronger the effect. For example, relative risks of noninvasive and invasive bladder cancer for current heavy smokers were 3.0 and 5.2, respectively. Cigarette smoking was associated with higher risk of low-grade than high-grade tumors, once stage of disease was taken into account. Compared with whites, nonwhites were at a lower risk of noninvasive bladder cancer (RR = 0.4) but at similar risk of invasive bladder cancer (RR = 1.1), a pattern indicating racial differences in health practices related to bladder cancer detection. History of urinary tract infections and bladder stones was associated with increasing relative risks for advanced tumor stage. Heavy artificial sweetener use was associated with higher-grade, poorly differentiated tumors. Coffee consumption and family history of bladder cancer were not consistently associated with tumor stage or grade. Overall, different clinical presentations of bladder cancer share most suspected bladder cancer risk factors, including employment in a high-risk occupation and cigarette smoking.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We assessed seasonal reporting bias in a 59-item food frequency questionnaire (FFQ) administered throughout 1 year using data from the 1987 National Health Interview Survey (N = 20,143 adults). Few meaningful differences were found in the proportion of individuals reporting rarely or never consuming a food by season of questionnaire administration. Seasonal reporting bias is evident in FFQs, however, and appears to be due to reporting most recent consumption. Using gender-specific median servings per week, an analysis using logistic regression showed that the estimated proportion of individuals reporting food intake at greater than the yearly median differed between any two seasons by at least 5% of the population for 22 foods. We compared gender-specific quintiles of selected nutrients/food groups for the whole year and each season; these showed that quintile assignment never varied by more than one adjacent quintile. The most frequent shift in quintile assignment, involving as many as 18.5% of women in the summer, occurred for citrus fruits. The intake biases are small and do not greatly affect population estimates if the FFQ is administered in all seasons, but they may somewhat affect classification of individuals into quantiles for some foods/nutrients.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The epidemiologic study of pelvic inflammatory disease (PID) is hindered by symptoms that differ substantially from case to case, and by a substantial number of “silent” cases with few or no symptoms. Demographic data indicate that PID is primarily a disease of the young. Race also appears to be a determinant, but whether for biologic or sociologic reasons is not known. Women who are not married face a greater risk for PID than married women. The majority of PID cases are associated with sexually transmitted diseases. Consistent with this finding is the pattern of risk factors related to sexual behavior: young age at first intercourse, high frequency of intercourse, and a large number of sexual partners all increase the risk of PID. On the other hand, barrier methods of contraception appear to reduce the risk of PID, as does oral contraception. Perhaps the best publicized risk factor for PID is another contraceptive, the intrauterine device (IUD). The increased risk of PID in IUD users appears to be confined to new users and women at high risk of sexually transmitted disease infection. Douching and cigarette smoking may also be associated with the development of PID, but the evidence is weak.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We assessed the relation of serum iron, dietary iron, and the use of iron supplements to the risk of fatal acute myocardial infarction in the Nutrition Canada Survey cohort. We found an association between serum iron and risk of fatal acute myocardial infarction, with rate ratios for males and females in the highest category of serum iron (≥175 μg per dl) of 2.18 [95% confidence intervals (CI) = 1.01–4.74] and 5.53 (95% CI = 1.69–18.12), respectively. We found no important association between risk of fatal acute myocardial infarction and either dietary iron or iron supplement use among the 9,920 participants included in this study.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Several studies have examined the association between body mass index and infertility. We compared body mass index in 597 women diagnosed with ovulatory infertility at seven infertility clinics in the United States and Canada with 1,695 primiparous controls who recently gave birth. The obese women (body mass index ≥27) had a relative risk of ovulatory infertility of 3.1 (95% confidence interval (CI) = 2.2–4.4], compared with women of lower body weight (body mass index 20–24.9). We found a small effect in women with a body mass index of 25–26.9 or less than 17 [relative risk (RR) = 1.2, 95% CI = 0.8–1.9; and RR = 1.6, 95% CI = 0.7–3.9, respectively). We conclude that the risk of ovulatory infertility is highest in obese women but is also slightly increased in moderately overweight and underweight women.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We evaluated the performance of two reduced dietary questionnaires (RDQ). They were derived from a more complex questionnaire used to investigate the relation between diet and gastric cancer in a case-control study recently concluded in Italy. The full dietary questionnaire (FDQ) used in that study included 181 questions on the frequency/portion size of consumption of 146 different foods and drinks. Two different RDQs were defined, including subgroups of the original food items able to reproduce at least 90% (RDQ90) or 75% (RDQ75), respectively, of the total variability captured by the FDQ on the nutrient intake of controls. Each RDQ provided estimates of nutrients highly correlated with the estimates produced by the FDQ. For different quintiles of nutrient intake, we compared the estimated relative risk obtained by means of the RDQs and the FDQ. For various nutrients, the differences in relative risks were relatively minor, below 20%, but were larger for protein and beta-carotene. These analyses indicate that a RDQ is able to quantify adequately various aspects of the Italian diet for the purpose of epidemiologic inference.

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

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID