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N S Weiss

Publications and source records attributed to N S Weiss.

At least 55 records · Page 3Linked to original sources
PubMed2000

Recommendations for the design of epidemiologic studies of endometriosis.

This paper proposes a standard definition of endometriotic disease for epidemiologic studies and suggests subject-selection strategies to increase the validity of clinic- or population-based studies of the disease. Although endometriosis can be defined simply as the presence of ectopic endometrial tissue, emerging evidence indicates that to be pathologic, such tissue must persist and progress. The proposed disease definition incorporates the concepts of persistence and progression, and its use may increase the likelihood of observing true associations in etiologic studies. Potential threats to validity of substantial magnitude exist in both clinic- and population-based epidemiologic studies of endometriosis. In clinic-based studies, control subjects (infertility clinic patients, women delivering infants, or women undergoing tubal ligation) often are not representative of the population from which the cases arose, and bias can be considerable for behavioral and hormone-related exposures. In population-based studies, substantial case underascertainment may exist, and diagnosed cases may be a biased sample of all potential cases in the population. Although neither the ideal design nor the ideal case and control groups are likely to be achievable in epidemiologic studies of endometriosis, the subject-selection strategies suggested may improve the validity of studies that are obliged to depart from the ideal.

Adolescent↗
PubMed2000

Outcome of children who require mechanical ventilatory support after bone marrow transplantation.

OBJECTIVE: To identify clinically measurable factors that could predict outcome for pediatric patients undergoing mechanical ventilatory support after bone marrow transplant. DESIGN: Cohort study. SETTING: A referral center for bone marrow transplant patients in Seattle, Washington. PATIENTS: Children <17 yrs old who received a bone marrow transplant and subsequently required mechanical ventilatory support for > or =24 hrs between 1983 and 1996. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data were abstracted from the charts of 121 pediatric patients who received a bone marrow transplant and subsequently required mechanical ventilatory support. A total of 19 patients (16%) survived to be extubated and survived for > or =30 days postextubation. Major risk factors for death included respiratory failure as the reason for endotracheal intubation (4% survival), the presence of pulmonary infection (6% survival), and impairment of more than one organ system (2% survival if more than one organ system was dysfunctional on day 7 postintubation). CONCLUSIONS: Although the prognosis generally is poor among pediatric bone marrow transplant recipients who subsequently require mechanical ventilatory support, there appear to be some groups within this population in whom the likelihood of survival is close to 0. Because the chance of survival was so small for children with dysfunction of more than one organ system on day 7 after intubation, a recommendation to limit medical support for these children could be considered pending the results of other studies.

Adolescent↗
PubMed2000

Risk factors for hip fracture among patients with end-stage renal disease.

BACKGROUND: Although bone disease is well described among end-stage renal disease (ESRD) patients, little attention has been paid to the occurrence of fracture. We sought to identify factors that are associated with hip fracture among ESRD patients. METHODS: Data from patients who participated in the United States Renal Data System Dialysis Morbidity and Mortality Study Wave 1 were used for this study. Hip fractures occurring among these patients between 1993 and 1996 were identified from Medicare claims data available from the United States Renal Data System. Cox proportional hazards models were used to estimate the risk of hip fracture associated with demographic and medical variables. RESULTS: Of the 4952 patients included in this analysis, 103 sustained a hip fracture. In the multivariate analysis, age (per increasing decade, RR = 1.40, 95% CI 1.20, 1.64), female gender (RR = 2.26, 95% CI 1.48, 3.44), race (blacks compared with whites, RR = 0.58, 95% CI 0.37, 0.91), body mass index (per 1 unit increase, RR 0.89, 95% CI 0.86, 0.93), and the presence of peripheral vascular disease (RR 1.94, 95% CI 1.29, 2.92) were independently associated with hip fracture. Serum intact parathyroid hormone (iPTH), aluminum, diabetes, and bicarbonate levels did not appreciably influence the risk of hip fracture. CONCLUSIONS: Demographic and other characteristics that predict risk of hip fracture in the population at large also do so in ESRD patients. However, we could identify no characteristics of ESRD or its treatment that were independently related to hip fracture incidence.

Adult↗
PubMed2000

Glutathione S-transferase theta 1 gene deletion and risk of acute myeloid leukemia.

Individuals with a homozygous deletion of the glutathione S-transferase theta 1 (GSTT1) gene lack GSTT1 enzymatic detoxification of environmental carcinogens by conjugation with glutathione. The GSTT1 gene deletion has been associated with carcinogen-induced chromosomal changes in lymphocytes, and some but not all epidemiological evidence has suggested that the GSTT1 gene deletion may increase susceptibility to myelodysplasia. We conducted a case-control study to test whether individuals with an inherited homozygous deletion of the GSTT1 gene are at increased risk of acute myeloid leukemia (AML). The GSTT1 and GST mu 1 (GSTM1) genotypes were determined by PCR using lymphocyte or bone marrow DNA from 297 AML patients and 152 controls. AML patients were selected from Southwest Oncology Group clinical studies, and controls were identified by random digit dialing in Washington state. No association was observed between the GSTT1 gene deletion and AML [race-adjusted odds ratio (OR), 0.94; 95% confidence interval (CI), 0.55-1.60] or between the GSTM1 gene deletion and AML (race-adjusted OR, 1.26; 95% CI, 0.85-1.88). Patients with secondary AML had a slightly higher prevalence of the GSTT1 and GSTM1 gene deletions compared with de novo AML patients or controls, but this was consistent with chance. Exploratory analyses of AML cytogenetics suggested a few associations, i.e., between the GSTT1 gene deletion and trisomy 8, and between the GSTM1 gene deletion and non-8 trisomies or inv(16). These results do not support the hypothesis that the GSTT1 gene deletion is related to the incidence of AML.

Acute Disease↗
PubMed2000

Oral contraceptives and epithelial ovarian cancer. Does dose matter?

OBJECTIVE: To determine the risk of ovarian cancer among women who use low-estrogen-dose oral contraceptives. STUDY DESIGN: The study used data on white women under 70 years of age who had been enrolled in a population-based case-control study conducted between 1986 and 1988 in three western Washington counties. Women with ovarian cancer (n = 276) were ascertained through a population-based cancer registry, and controls (n = 391) were selected by random digit dialing. Unconditional logistic regression was used to estimate the risk of ovarian cancer associated with oral contraceptive use. RESULTS: After adjustment for age and parity, women who took oral contraceptives for at least three months were at decreased risk of ovarian cancer (odds ratio [OR] 0.8, 95% confidence interval [CI] 0.5-1.1) relative to women who never used this form of contraception. The reduced risk of ovarian cancer was present among women whose only preparation contained a low (< 50 micrograms ethinyl estradiol or < 80 micrograms mestranol) (OR 0.6, 95% CI 0.3-1.1) and high (OR 0.8, 95% CI 0.5-1.2) estrogen dose. CONCLUSION: While our results are limited in their statistical precision and by the inability of many subjects to recall the brands of oral contraceptives that they took, they suggest that the newer, low-estrogen-dose oral contraceptives confer a benefit regarding ovarian cancer risk similar to that conferred by earlier, high-estrogen-dose formulations.

Adult↗
PubMed1999

Glutathione S-transferase M1 genotypes and the risk of squamous carcinoma of the cervix: a population-based case-control study.

The authors determined the GSTM1 genotype of 190 Caucasian women with invasive squamous cell cervical cancer in western Washington State between January 1986 and June 1994 and of 206 controls. It was found that 53% of cases and 57% of controls had the GSTM1 null genotype. The age-adjusted odds ratio associated with GSTM1 null genotype was 0.8 (95% confidence interval 0.6, 1.3). The lack of association between cervical cancer risk and GSTM1 genotype was true both for smokers and nonsmokers of cigarettes and for heavy and light smokers. These data suggest that women with the GSTM1 null genotype are not at increased risk of cervical cancer.

Adult↗
PubMed1999

Glutathione S-transferase M1 genotypes and the risk of vulvar cancer: a population-based case-control study.

Glutathione S-transferases (GSTs) facilitate the excretion of a variety of potential carcinogens. Some 50-60% of Caucasians are homozygous for the null allele of GSTM1, a gene responsible for the presence of one of these enzymes. The authors examined whether women with the GSTM1 null genotype are at altered risk of vulvar cancer. They obtained peripheral blood specimens from 18- to 79-year-old residents of King, Pierce, and Snohomish counties of western Washington who were diagnosed with vulvar cancer between April 1991 and June 1994. Blood specimens were also obtained from controls identified via random digit telephone dialing of western Washington households. The authors determined the GSTM1 genotype of 137 cases (120 in situ and 17 invasive cases) and 248 controls. The frequency of the GSTM1 null genotype was 46.7% among cases and 57.3% among controls. The age-adjusted odds ratio associated with the GSTM1 null genotype was 0.7 (95% confidence interval: 0.4, 1.0). Among current smokers of cigarettes, the age-adjusted odds ratio associated with the GSTM1 null genotype was 0.5 (95% confidence interval: 0.2, 0.9), differing little between heavy and light smokers. Our data suggest that women with the GSTM1 null genotype are not at increased risk of vulvar cancer.

Adult↗
PubMed1999

Incidence of testicular cancer in the United States: has the epidemic begun to abate?

In response to a report that testicular cancer incidence in non-Hispanic White males in Los Angeles county had fallen in the 1990s, particularly in young men, the authors analyzed data collected by the Surveillance, Epidemiology, and End Results (SEER) program from 1973 to 1995. While the incidence rate of testicular cancer in US White males ages 15-64 years did stabilize in the first half of the 1990s, after a number of years of a steady increase, there was no indication of an actual decline.

Adolescent↗
PubMed1999

Pregnancy after breast carcinoma: outcomes and influence on mortality.

BACKGROUND: To the authors' knowledge, no previous studies have identified an adverse effect of pregnancy on patient survival after breast carcinoma. However, results are difficult to interpret because of failure to control for stage of disease at the time the pregnancy occurred. METHODS: Study participants were women diagnosed with invasive breast carcinoma between 1983-1992 who previously had participated in a population-based case-control study or, if deceased, proxy respondents. Information regarding subsequent pregnancies was obtained by self-administered questionnaire or telephone interview. Information regarding breast carcinoma recurrences was obtained by questionnaire and from cancer registry abstracts. Women who became pregnant after a diagnosis of breast carcinoma (n = 53) were matched with women without subsequent pregnancies based on stage of disease at diagnosis and a recurrence free survival time in the comparison women greater than or equal to the interval between breast carcinoma diagnosis and onset of pregnancy in the women with a subsequent pregnancy. RESULTS: Sixty-eight percent of women who became pregnant after being diagnosed with breast carcinoma delivered one or more live-born infants. Miscarriages occurred in 24% of the patients who became pregnant compared with 18% of the controls (women without breast carcinoma) of similar ages from the case-control study. Five of the 53 women who had been pregnant after breast carcinoma died of the disease. The age-adjusted relative risk (RR) of death associated with any subsequent pregnancy was 0.8 (95% confidence interval [95% CI], 0.3-2.3). All five deaths occurred among the 36 women who had a live birth (age-adjusted RR = 1.1; 95% CI, 0.4-3.7). CONCLUSIONS: The findings of the current study are based on a small number of deaths but do not suggest that pregnancy after a diagnosis of breast carcinoma has an adverse effect on survival.

Adult↗
PubMed1999

Logistic regression analysis for more than one characteristic of exposure.

When more than one characteristic of an exposure is under study, it is easy to misinterpret the results of a logistic regression analysis that incorporates terms for each characteristic. For example, in a study of the risk of endometrial cancer in relation to the duration and the recency of use of estrogen replacement therapy (ERT), simultaneously including terms for duration and recency of exposure to ERT in a logistic model may leave the mistaken impression that it is possible to adjust for recency when a given duration of ERT use is compared with no use. In this article, the authors show why such an adjusted comparison is impossible, and they discuss several pitfalls in the interpretation of logistic regression coefficients when two or more characteristics of exposure are under study. They also suggest a method for avoiding these pitfalls.

Confounding Factors, Epidemiologic↗
PubMed1999

Hypertension, antihypertensive medication use, and risk of renal cell carcinoma.

To investigate whether diuretic medication use increases risk of renal cell carcinoma (RCC), the authors conducted a case-control study of health maintenance organization members in western Washington State. Cases (n = 238) diagnosed between January 1980 and June 1995 were compared with controls (n = 616) selected from health maintenance organization membership files. The computerized health maintenance organization pharmacy database provided information on medications prescribed after March 1977. Additional exposure information was collected from medical records. For women, use of diuretics was associated with increased risk of RCC (odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.0-3.1), but the association was not independent of a diagnosis of hypertension (adjusted for hypertension, OR = 1.1, 95% CI 0.5-2.1). Similarly, nondiuretic antihypertensive use was associated with increased risk, but only when unadjusted for hypertension. For men, neither diuretic nor nondiuretic antihypertensive use was associated with risk of RCC. A diagnosis of hypertension was clearly associated with RCC risk for women (OR = 2.5, 95% CI 1.2-5.1), but not men (OR = 1.3, 95% CI 0.7-2.5). High systolic and diastolic blood pressures were associated with increased risk in both sexes. These results do not support the hypothesis that use of diuretic medication increases RCC risk; they are more consistent with an association between RCC and high blood pressure.

Adolescent↗
PubMed1999

Syringe exchange and risk of infection with hepatitis B and C viruses.

The authors utilized a cohort study among Seattle injection drug users (IDUs) to assess whether participation in a syringe exchange program was associated with incidence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. Susceptible IDU subjects (187 seronegative for antibody to HCV, and 460 seronegative for core antibody to HBV) were identified in drug treatment, corrections, and social service agencies from June 1994 to January 1996, and followed for seroconversion one year later. The subjects included in the analysis were Seattle-King County (Washington State) area IDUs enrolled in a larger multipurpose cohort study, the Risk Activity Variables, Epidemiology, and Network Study (RAVEN Study). There were 39 HCV infections (20.9/100/year) and 46 HBV infections (10.0/100/year). There was no apparent protective effect of syringe exchange against HBV (former exchange users, relative risk (RR) = 0.68, 95% confidence interval (CI) 0.2-2.5; sporadic exchange users, RR = 2.4, 95% CI 0.9-6.5; regular users, RR = 1.81, 95% CI 0.7-4.8; vs. RR = 1.0 for nonusers of the exchange; adjusted for daily drug injection). Neither did the exchange protect against HCV infection (sporadic users, RR = 2.6, 95% CI 0.8-8.5; regular users, RR = 1.3, 95% CI 0.8-2.2; vs. RR = 1.0 for nonusers; adjusted for recent onset of injection and syringe sharing prior to enrollment). While it is possible that uncontrolled confounding or other bias obscured a true beneficial impact of exchange use, these data suggest that no such benefit occurred during the period of the study.

Adult↗