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:

We studied whether moderate alcohol drinkers have a lower total and coronary heart disease (CHD) mortality than nondrinkers. Among 276,802 U.S. men aged 40–59 enrolled in 1959 in an American Cancer Society prospective study, 42,756 deaths, 18,771 from CHD, occurred during the following 12 years (3% of the cohort was lost to follow-up). Using nondrinkers (55.3% of the cohort) as a reference category, age- and smoking-stratified relative risks (RR) of total mortality were 0.88 for occasional drinkers, 0.84 for those drinking_1_drink per day, 0.93, 1.02, 1.08, 1.22, and 1.38 for those drinking 2, 3, 4, 5, and 6 or more drinks per day, respectively. RRs of CHD mortality were 0.86, 0.79, 0.80, 0.83, 0.74 0.85, and 0.92, respectively. Multivariate analysis failed to identify other confounders. No changes in RRs were introduced by excluding subjects with poor health or history of chronic disease at enrollment (32.8% of the cohort) or excluding subjects who died during the first 6 years of follow-up. These data indicate an apparent protective effect of moderate alcohol intake on CHD mortality that cannot be attributed to the inclusion of subjects with CHD or related diseases into the nondrinker category

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

To evaluate the role of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in the development of non-Hodgkin's lymphoma (NHL), we conducted a population-based, case-control study in 66 counties in eastern Nebraska. Telephone interviews were conducted with 201 white men diagnosed with NHL between July 1, 1983, and June 30, 1986, and with 725 controls. There was a 50% excess of NHL among men who mixed or applied 2,4-D (odds ratio [OR] = 1.5; 95% confidence interval = 0.9, 2.5). The risk of NHL increased with the average frequency of use to over threefold for those exposed 20 or more days per year (p for trend = 0.051). Adjusting for use of organophosphate insecticides lowered the risk estimate for frequent users (OR = 1.8), but adjustment for fungicide use increased the risk estimate (OR = 4.5). Simultaneous adjustment for organophosphates and fungicides yielded an OR of 3.1 for farmers who mixed or applied 2,4-D more than 20 days per year. Risk also increased with degree of exposure, as indicated by application method and time spent in contaminated clothing, but not with the number of years of 2,4-D use or failure to use protective equipment. Although other pesticides, especially organophosphate insecticides, may be related to NHL, the risk associated with 2,4-D does not appear to be explained completely by these other exposures

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

This paper explores the relation between reliability and validity (or binary variables. An equation is first derived for expressing the kappa coefficient of reliability as a function of true prevalence, sensitivity, specificity, and the degree of correlation of errors within true positives and within true negatives. It is then shown that under certain circumstances kappa is closely related to an index of the validity of the odds ratio as a means for quantifying an association between an imperfectly classified binary factor and membership in two subpopulations. This index is defined as the ratio of the observed odds ratio minus one to the true odds ratio minus one. Numerical results indicate that, when error rates are high, kappa can be of smaller magnitude than this index of validity. When the value of kappa reflects substantial correlation of errors, however, the value of kappa typically exceeds that of the index of validity. Correlated errors among the true negatives are found to affect the correspondence between kappa and the index of validity rather differently than do correlated errors among the true positives. Although kappa often exceeds the index of validity, use of kappa to correct the odds ratio for attenuation owing to nondifferential misclassification generally leads to undercorrection rather than overcorrection. Consequently, the relation between kappa and the index of the validity of the odds ratio may have practical value for reducing bias in the estimation of exposure—disease associations in epidemiologic research

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Stressful life events may adversely affect health, but these effects may be mitigated by a strong social support network. The elderly should be a focus for investigation in this area, but epidemiologic studies in the elderly are often complicated by the need to rely upon information collected from surrogates. We assessed the degree to which 622 elderly cancer patients and surrogates agreed in their answers to questions about life events, social network, and health and functional status. We compared spouses, friends, and children as surrogates by evaluating (1) their agreement with index subjects and (2) the proportion of surrogates of each type who could not answer one or more questions. Agreement for most items on health and functional status was at least moderately good, but agreement was more inconsistent for questions about social network and major life events. Agreement was higher when factual information was solicited than when the question regarded more personal information or attitudes. For questions about health status, social network, and life events, spouses agreed more closely with index subjects than did children or friends. For questions about functional status, however, agreement did not vary consistently by respondent type. We found no consistent effects of the index subject's age or cognitive status on levels of agreement, nor did we find evidence of bias in the surrogates' responses

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Age at menarche shows a downward secular trend and differs according to socioeconomic conditions, presumably the result of dietary variations. We report two studies conducted in Quebec City in which the relation between diet and menarche was evaluated. In 1978–1980, baseline information for these studies was obtained on girls aged 9 through 15 and included body weight, height, fatfold thickness at six sites, percent of body fat (derived from underwater weighing), and a 3-day dietary record. In a cross-sectional study of 207 girls aged 11 through 15, we compared dietary patterns between premenarcheal and menarcheal girls using logistic regression. In a 6-year follow-up study of 109 girls who had not experienced menarche at the baseline data collection, the relation between time of occurrence of menarche and dietary patterns was assessed using proportional hazards models. The results confirm the association between body weight and age at menarche. Body fat, however, was not strongly related to the onset of menstruation. In both studies, a higher dietary energy intake was associated with an earlier age at menarche. Dietary composition, and dietary fat in particular, was not related to menarche

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We looked at risk of early pregnancy loss among 171 women who conceived while participating in a prospective study. Twenty-five percent of biochemically detected pregnancies ended within six weeks of the last menstrual period; all but two of these losses were clinically unrecognized. While our sample is small, it is the first to allow description of possible associations between risk of early pregnancy loss and maternal characteristics or exposures. We looked at risk in relation to a woman's age, pregnancy history, weight, education, prenatal DES exposure, cigarette smoking, use of caffeinated and alcoholic beverages, marijuana, cigarette smoking by baby's father, and other variables. None of these factors was definitely associated with early pregnancy loss. Still, the possibility of real effects cannot be excluded and deserves further study

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

This study investigated how well people can recall their food habits of years ago and identified factors that predict recall ability. We examined the self-reported dietary intakes of 623 people, about one-third of whom were vegetarians. Subjects included cancer cases and controls who were selected as a representative sample of the Adventist Health Study population. We compared the initial (1976) dietary data with data recalled retrospectively in 1984. The initial and retrospective assessments made use of the same food frequency questionnaire for the same 35 food items. Recall ability was measured in two ways: exact recall and recall error. Persons with a stable diet had by far the best recall. Vegetarian status and level of education also were determinants of exact recall, whereas diet stability and education were the most significant determinants of recall error. These results indicate that some individuals, particularly those with a stable diet, those with a vegetarian diet, and those with more education, are able to recall their past dietary practices with reasonable reliability

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We addressed three questions concerning diet recall in a population of 181 incident cancer cases diagnosed between 1976 and 1984 in the Adventist Health Study, and 225 controls randomly selected from the same population after removing cancer cases: (1) Are recalls of past dietary habits reliable? (2) Does recall ability differ between cancer cases and controls? and (3) Are current or retrospectively recalled reports the best estimator of past dietary practices? Three sets of dietary data were compared using a 35-item nonquantitative food frequency questionnaire: initial reports in 1976, recalled reports obtained retrospectively in 1984, and current reports for 1984. Recall ability was evaluated for individual foods and for all foods combined by comparing recall error scores summing the absolute differences between initial and recalled frequencies. Means and medians for all three food groups were similar for cases and controls. The Spearman rank-order correlations between pairs of reports (initial/recalled, initial/current, and recalled/cunent) averaged 0.48, 0.41, and 0.62, respectively. A crude difference of 2.0 between cases and controls (p < 0.05) in the recall error score indicated that cases on the average recalled two foods one frequency category closer to the initial estimate compared with controls. The case-control difference decreased to a nonsignificant 0.4 (p = 0.7) in multivariate analysis that conditioned on dietary changes. On the average, recalled reports estimated initial reports one frequency category closer than did current reports for three foods (p < 0.001), primarily because of changes in dietary habits

ISSN:1044-3983    

出版商:OVID    

年代:1990

数据来源: OVID