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:

Epidemiologic studies have focused on the association between diet and breast cancer with conflicting results. Whereas a majority of case-control studies indicate a role for the intake of total fat and saturated fat, most prospective cohort studies either are negative or indicate very modest associations. Only a few authors have examined the role of meat intake in relation to breast cancer risk. The aim of this study was to examine the relation between risk of breast cancer and dietary intake of meat, animal products, fat, and protein. Between 1985 and 1991, we recruited 14,291 New York City women in a prospective cohort study of endogenous hormones, diet, and cancer in which they reported on their recent diet using a food frequency questionnaire self-administered at enrollment. From the cohort, 180 invasive breast cancer cases diagnosed before December 1990 and five times as many controls, individually matched by age, calendar time at enrollment, menopausal status, and, if premenopausal, phase of menstrual cycle, were included in a nested case-control study. There was an evident increase in the relative risk (RR) of breast cancer for increasing consumption of meat. Women in the upper quintile of meat consumption, as compared with the lowest quintile, had an energy-adjusted RR of 1.87 (95% confidence interval = 1.09–3.21). There was a modest RR increase in the upper quintile of total and saturated fat and no apparent association for other types of fat, protein, dairy products, poultry, or fish. The study indicates that the elevated consumption of certain foods of animal origin, such as red meat, may be a factor in explaining the postulated role of diet in breast cancer etiology.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We examined the relation between recent cocaine use and heterosexual exposure to human immunodeficiency virus (HIV). Five hundred nineteen heterosexually active participants in the New England Behavioral Health Study, an HIV testing and counseling program, provided information for this study. The outcome measure included behaviors that increased the risk for exposure to HIV via contact with infected genital secretions. Nearly one-third (31.8%) of participants reported use of cocaine during the year before study entry. These individuals were 1.3 times [90% confidence interval (CI) = 1.1–1.7] more likely to risk HIV exposure than people not using cocaine during this period, with evidence of a dose-dependent relation among HIV-positive cocaine users. HIV-positive crack users were at 1.9 times greater risk (90% CI = 1.2–2.9) for HIV risk-taking behavior than those who did not use crack. The effect of cocaine was present even among those individuals without other injection drug use.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The toxic oil syndrome (TOS), which affected over 20,000 persons in Spain in 1981, has been linked to the consumption of aniline-denatured rapeseed oil, but the precise etiologic agent is still unknown. We attempted to validate the use of high concentrations of oleyl anilide as a marker for oils that contain (or contained) the causal agent. We compared the chemical compositions of oils obtained from ill (N = 59) and unaffected (N = 70) families in 1981. Case oils had higher concentrations of fatty acids and sterols in which rapeseed oil is particularly rich. In addition, case oils had more frequent and extensive contamination with oleyl anilide and other fatty acid anilides. We observed a dose-response effect; risk increased sharply with increasing concentrations of oleyl anilide, and no control oil had more than about 825 μg per liter of that compound. We conclude that high concentrations of oleyl anilide specifically mark oils that contain (or used to contain) the TOS etiologic agent.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Estimating and monitoring the total number of people infected with human immunodeficiency virus type 1 (HIV-1) is a critical public health objective. No single epidemiologic methodology yields completely reliable estimates. We used techniques originally designed to estimate the size of wildlife populations to complement estimates of the size of the population with HIV-1 infection in Lazio, Italy, during 1990 obtained from surveillance, surveys, and dynamic mathematical models. We used reports from four large testing sites to generate incomplete, partially overlapping lists of HIV-positive subjects. Log-linear models yielded estimated prevalences of 5.65 per 1,000 among males (95% confidence interval = 4.52–6.78) and 1.84 per 1,000 (95% confidence interval = 1.34–2.33) among females in the population age 15–64 years. This method provides a simple and inexpensive means of obtaining accurate estimates of the total number of HIV seropositives. It could be applied easily in all situations in which data from multiple sources are available.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Recent meta-analyses of studies of the risk of breast cancer associated with hormone replacement therapy agree that little risk is associated with ever-use or short-term use of estrogen replacement. These analyses disagree, however, about the effect of long-duration estrogen use. To understand differences in the findings among the meta-analyses of the effect of long-term use, we investigated the source of heterogeneity among the included studies. We analyzed subgroups by source of controls (community vs hospital), study design (case-control vs follow-up), and types of estrogen. We also examined the effect of modeling assumptions: that before women began estrogen use, those who chose to use estrogen replacement (1) were, or (2) were not, at substantially different risk from those who chose not to use estrogen. We found a small increase in risk in all subgroups of studies except those that used hospital controls. From a homogeneous group of case-control studies using community controls that analyzed the effect of conjugated equine estrogens, we estimated that the risk of breast cancer after 10 years of estrogen use increased by at least 15% and up to 29%.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

This analysis tests the hypothesis that women who conceive within 3 months after stopping oral contraceptives (“the pill”) have an intrinsically lower risk of chromosomally normal loss. About 30% of women show evidence of endocrine dysfunction, including anovulation, for 1–3 months after stopping the pill. In women who recover rapidly, and therefore are at risk of pregnancy, a common endocrinologic factor may account for both the quick return to normal functioning and improved intrauterine survival of the chromosomally normal conceptus. The hypothesis was tested in women with chromosomally normal (N = 334) and chromosomally aberrant (N = 239) spontaneous abortions. Women were classified according to the number of months between last pill use and last menstrual period. The adjusted odds ratios relating conception in months 0 and 1 after stopping the pill to chromosomally normal (vs chromosomally aberrant) loss were each 0.4, with upper 95% confidence limits of 1.0 and 0.9, respectively. The odds ratios for conception at longer intervals after stopping were 1.1 [95% confidence interval (CI) = 0.4–3.1], 0.7 (95% CI = 0.3–1.2), and 0.9 (95% CI = 0.5–1.5) for 2, 3–11, and ≥12 months, respectively. Rates of spontaneous abortion in previous pregnancies were lowest in women who conceived quickly after stopping the pill. Further support for an endocrinologic explanation requires direct measures of endocrine functioning in the post-pill period among women with varying reproductive histories.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

In view of recent advances in molecular and biochemical epidemiology, there is growing interest in the creation of biological banks of blood, urine, tissue, or other biological specimens collected from participants in prospective cohort studies. The existence of biological banks may make it possible to study a multitude of etiologic hypotheses, by comparing biochemical parameters measured in the biological specimens of subjects who will eventually develop the disease of interest (“cases”) and of control subjects, using a nested case-control or a case-cohort design. In practice, however, the amount of biological material available per subject (in particular, that of cases) will limit the number of hypotheses that can be tested. The present paper discusses the use of a sequential t-test which, compared with an analogous fixed sample procedure, will on average require fewer biological specimens before a given study hypothesis can be accepted or rejected. The sequential test should thus facilitate an early decision on whether a new hypothesis is worth further investigation, while avoiding wasting too much biological material on testing hypotheses that may eventually prove unfruitful. If the test reveals an exposure difference of interest, the study may be extended so that relevant epidemiologic effect measures can be estimated more accurately.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

In this article, I describe a simple relation between stratum-specific risk ratios and the distribution of strata in disease-exposure categories. The relation does not seem well known, but it presents an alternative way to view how to make adjustments to biased stratum-specific relative risk estimates when bias is due to either a misclassified or missing confounding variable. For instance, it demonstrates that there would be no misclassification bias if categories of a confounder surrogate have the same prevalence as those of the true confounder, in each disease-exposure category, regardless of whether the surrogate is a good or bad approximation to the true confounder. It also provides an insight into the conditions required to ensure uniformity of stratum-specific relative risks.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID