ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

This population-based case-control study examined the risk of multiple myeloma in relation to socioeconomic status. Subjects included 689 cases with newly diagnosed multiple myeloma during 1977–1981 from tour U.S. populations and 1,680 controls selected from residents of these same populations. We collected lifetime occupational histories and coded them according to the 1970 Duncan Socioeconomic Index and Nam-Powers Socioeconomic Status scores. We classified scores for the occupations held the longest, highest ever held, and held most recently into quartiles based on the distribution among controls. After adjusting for age group, race, and study site, risk of multiple myeloma was inversely associated with socioeconomic status scores in both men and women. Risk among persons in the lowest quartile of scores was 63% higher (95% confidence interval 21%-119%) than that among those in the highest quartile when the highest Nam-Powers score was used. Similar trends were evident for all three methods of classifying occupational history and for both Duncan and Nam-Power scores. These results changed little after removing from analyses occupations previously associated with increased risk. The occupation-based scores were stronger predictors of risk than years of education. As a proxy measure of occupational, environmental, or life-style factors, socioeconomic status may be a clue to etiologic factors for multiple myeloma.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Tamoxifen, a synthetic antiestrogen, has been shown to he effective in reducing mortality from breast cancer and the occurrence of contralateral breast cancer. Tamoxifen is now being studied as a preventive of breast cancer among healthy women considered to the at high risk; preventive trials are now under way both in the USA and in Europe. We undertook a case-control study in Lyon and Dijon, France, to assess the effect of tamoxifen and other treatments for breast cancer on subsequent endometrial cancer. Through the use of clinicians' surveys in Lyon and a population-based cancer registry in Dijon, we identified 43 cases of endometrial cancer diagnosed at least 1 year after the diagnosis of breast cancer. We matched 177 controls to the cases for age, region, year of diagnosis of breast cancer, and survival from breast cancer. Tamoxifen had been used in 67% of cases and 60% of controls [odds ratio (OR) = 1.4; 95% confidence interval (CI) = 0.60–3.5]. Relative risk of endometrial cancer increased with duration of tamoxifen use: less than 2 years, 1.5; 95% CI = 0.44–4.9; 2–5 years, 1.5; 95% CI = 0.42–5.6; more than 5 years, 3.5; 95% CI = 0.94–12.7. Radiotherapeutic castration increased the risk for endometrial cancer more than tamoxifen (OR = 7.7; 95% CI = 1.8–32.8).

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

In a cohort of Danish boys characterized by (1) being born between 1941 and 1957, (2) having attended schools in a defined area of Denmark, and (3) having a school health record available, 183 were registered in the Danish Cancer Registry with testicular cancer diagnosed before January I, 1985. We selected 366 age- and sex-matched controls from the same cohort. Using information recorded by school physicians, we performed logistic regression analyses to estimate the relative risks (RR) associated with various genital anomalies.We found the risk for testicular cancer to be raised for men with a history of cryptorchidism [RR = 5.2; 95% confidence interval (CI) = 2.1–13.0], inguinal hernia (RR = 1.8; 95% CI = 0.9–3.7), hypospadias (RR = 4.2; 95% CI = 0.4–42.7), and hydrocele (RR = 2.4; 95% CI = 0.6–9.0). We observed no decrease in the risk associated with cryptorchidism after correction of the maldescent in early childhood. The RR of testicular cancer in the contralateral, normally descended testis in unilateral cryptorchid men was increased to 3.6. The results add to the growing evidence for a common causal factor for both testicular cancer and cryptorchidism and support the findings from other studies of associations between other genital anomalies involving the closure of the processus vaginalis and the risk of testicular cancer.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Several recent studies have reported associations between short term changes in air pollution and respiratory hospital admissions. Most of those studies analyzed locations where there was a high correlation between airborne particles and sulfur dioxide (SO2), and between all air pollutants and temperature. Here, I seek to replicate the previous findings in a location where SO2, concentrations were trivial, and the correlation between both airborne particles and ozone with temperature was considerably lower than in previous studies. I constructed daily counts of admissions to all hospitals in Spokane, WA, for respiratory disease (International Classification of Diseases, 9th revision, codes 460–519) for persons age 65 years and older. I computed average daily concentrations of airborne particles whose diameter is 10 μm or less (PM10) and ozone (SO3, from all monitors in each city, and I obtained daily average temperature and humidity from the U.S. weather service. SO, concentrations in Spokane were so low that monitoring was discontinued. I regressed daily respiratory admission counts on temperature, humidity, day of the week indicators, and air pollution. I used a Poisson regression analysis and removed long wavelength patterns using a nonparametric smooth function of day of study. I dealt with a possible Ushaped dependence of admissions on temperature and/or humidity by using nonparametric smooth functions of weather variables as well. I then examined sensitivity analyses to control for weather.Both PM10, and ozone were associated with increased risk of respiratory hospital admissions [ relative risk (RR) = 1.085; 95% confidence interval (CI) = 1.036–1.136 for a 50-μg per m3increase in and RR = 1.244; 95% CI = 1.002–1.544 for a 50-μgper m3increase in peak-hour ozone]. The PM10association was insensitive to alternative methods of control for weather, including exclusion of extreme temperature days and control for temperature on multiple days. The ozone results were more sensitive to the approach for weather control. The magnitude of the PM10, effect in this location, where SO2, was essentially not present, and where the correlation between PM10, and temperature was close to zero, was similar to that reported in other locations in the eastern United States and Europe, where confounding by weather and SO2, is a more substantial concern.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The incidence rate ratio is a basic measure of association in epidemiology. We present a simple and efficient method for computing exact confidence limits for the common rate ratio in a series of 2 X2 tables with person-time denominators. The method uses a polynomial multiplication (convolution) algorithm previously described for an odds ratio. We also present two tests, one asymptotic, the other exact, for evaluating rate ratio homogeneity. We extend these homogeneity tests to apply to data where strata have been partitioned into subgroups in which the rate ratio is assumed homogeneous within subgroups, but not necessarily between them. We conclude with a brief description of a microcomputer program that computes exact and asymptotic estimates for both a rate ratio and an odds ratio.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

A high level of endogenous estrogen inuterohas been hypothesized to he a possible risk factor for breast cancer. We used information from two population-hosed case-control studies to investigate the relation between perinatal factors and risk of invasive breast cancer among women age 21–45 years (746 cases, 960 controls) and women age 50–64 years (401 cases, 439 controls). Breast cancer cases were ascertained through a population-based cancer registry, and controls were selected by random digit dialing. After adjustment for age, menopausal status, and maternal smoking, the birthweight-breast cancer association in women age 21–45 years followed aJ-shaped curve, with women whose birthweight was less than 2,500 gm [odds ratio (OR) = 1.3; 95.4, confidence interval (CI) = 09–2.01 and 4,000 gm or more (OR = 1.7; 95% CI = 1.1–2.5) at increased risk. Women age 50–64 years who were 4,000 gm or more at birth appeared to be at slightly reduced risk of breast cancer (OR = 0.6; 95% CI = 0.3–1.1). With the exception of maternal smirking, there was little effect of other perinatal factors on breast cancer risk in either group. These results support the hypothesized association between intrauterine estrogen exposure and subsequent risk of breast cancer.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We investigated the association of epithelial ovarian cancer with physical activity, waist-to-hip ratio, reproductive factors, and family history of cancer in a prospective cohort study of 31,396 postmenopausal women. Ninety-seven women developed incident epithelial ovarian cancer over 7 years. The number of livebirths was associated with lower risk (multivariate-adjusted relative risks for 1–2, 3–4, and ≤4 livebirths compared with nulliparity were 0.64, 0.47, and 0.43, respectively). A family history of ovarian cancer in a first-degree relative was associated with a 2.5 times greater risk (95% confidence interval = 0.90–6.7). Multivariate-adjusted relative risks for the upper three quartiles of waist-to-hip ratio compared with the lowest quartile were 2.0, 1.6, and 2.3, respectively. Women with “moderate” and “high” levels of physical activity compared with those with “low” physical activity had relative risks of 1.4 and 2.1, respectively. Positive associations of physical activity and waist-to-hip ratio with ovarian cancer seem inconsistent with existing theories of ovarian cancer pathogenesis.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

A key assumption underlying the use of model-based estimates in epidemiology is that the structural-model form is an adequate mathematical description of the dependence of disease occurrence on exposures and covariates (that is, the model form is correctly specified). If this assumption is violated, model-based point estimators and variance estimators may he biased, standard confidence intervals may be invalid, and inferences derived from these estimators may he incorrect. In practice, the true structural-model form is usually unknown, and investigators frequently use their data to help select a model form. We conducted a simulation study to examine the impact of model-form selection on the accuracy of rate estimation in cohort-study situations resembling those found in environmental and occupational epidemiology. For the situations we examined, the increase in variance produced by using model-form selection was often more than offset by the corresponding reduction in bias, sometimes resulting in a dramatic increase in accuracy. Model-form selection was observed to be most beneficial relative to no selection when effects were stronger, the sample size was larger, and the candidate model forms included the true model form or allowed the model to more closely approximate the true model form. It was least beneficial when effects were weak and the sample size was small, even if the candidate model forms included the true model form.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We conducted a case-control study in the western United States to determine the relation between occupations or chemical exposures and increased risk of uveal melanoma. Among men (221 patients, 447 controls), we found increased risks for occupational groups who had intense exposure to ultraviolet light [odds ratio (OR) = 3.0; 95% confidence interval (CI) = 1.2–7.8], welding exposure (OR = 2.2; 95% CI = 1.3–3.5), and asbestos exposure (OR = 2.4; 95% CI = 1.5–3.9 for most likely exposed). The highest odds ratio was for the small number of men (nine cases, three controls) who were chemists, chemical engineers, and chemical technicians (OR = 5.9; 95% CI = 1.6–22.7). Odds ratios also were elevated for exposures to antifreeze, formaldehyde, pesticides, and carbon tetrachloride, but these findings, based on recall of specific chemical exposures, are more subject to recall bias than the findings based on occupational groups.

ISSN:1044-3983    

出版商:OVID    

年代:1996

数据来源: OVID