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Biomedical subjects

N S Weiss

Publications and source records attributed to N S Weiss.

At least 73 records · Page 4Linked to original sources
PubMed1999

Natural history of interstitial cystitis in 274 patients receiving sulfated polysaccharide therapy.

OBJECTIVES: To assess the natural history of interstitial cystitis in the presence of sulfated polysaccharide treatment. METHODS: This was a longitudinal study of 274 patients. Questionnaires were administered at first visit to obtain information on demographic characteristics, medical history, other risk factors, and type and severity of symptoms. Follow-up questionnaires were administered at subsequent visits to measure symptom progress. Patient status over time was measured for three symptoms: pain, urgency, and nocturia. Changes in symptom and severity were assessed at 6, 12, and 24 months on treatment. Comparisons of symptom change from baseline to 6 and 12 months were assessed for different characteristics among patients with the most severe symptoms. RESULTS: After 1 year of treatment, a decrease of two or more points in symptom score was observed for 33.5% of all patients for pain and 35.4% for urgency. Among patients with the most severe symptoms, a decrease of two or more points was observed in more than 54% for pain and urgency; 55.7% experienced remission to the moderate and mild level (49.2% and 6.5%, respectively). There was no appreciable decrease in nocturia at any severity level. With the exception of feeling heavy and experiencing dull pain at baseline, patients who did not report a specific type of pain improved more than those who did. CONCLUSIONS: The results of this study suggest that treatment with sulfated polysaccharides can help alleviate the symptoms of patients suffering from the most severe stages of interstitial cystitis.

Adult↗
PubMed1999

Screening plasma aluminum levels in relation to aluminum bone disease among asymptomatic dialysis patients.

Aluminum accumulation in plasma and tissues is a well-described complication among persons undergoing peritoneal dialysis or hemodialysis. Excess bone aluminum is associated with low bone formation rates and increased risk for fractures. Current recommendations for care of patients with end-stage renal disease include screening for aluminum toxicity with plasma aluminum levels; patients with levels below 40 microg/L are considered to be at low risk for aluminum bone disease (ABD). We examined data from the Toronto Renal Osteodystrophy Study to evaluate the performance of plasma aluminum levels in screening for ABD. Two hundred fifty-eight unselected patients undergoing peritoneal dialysis (n = 143) or hemodialysis (n = 115) underwent diagnostic bone biopsy and measurement of plasma aluminum level. Sixty-nine patients (26.7%) were identified as having ABD, defined as low or normal bone formation rates with 25% or more bone surface aluminum staining. Plasma aluminum level was strongly associated with the presence of ABD; the odds ratio was 1.4 for each increase of 10 microg/L (95%CI, 1.2, 1.6). However, only 50.1% of patients with a plasma aluminum level of 40 microg/L or greater had ABD, whereas 14.2% of patients with a level below this threshold also had ABD. Using this cutoff level of 40 microg/L, the sensitivity and specificity were 65.2% and 76.7%, respectively. We conclude that although there is a correlation between high aluminum levels and ABD, a patient's plasma aluminum level does not predict well the presence of ABD in spite of a relatively high prevalence of disease.

Adult↗
PubMed1999

The incidence of gastric carcinoma in Asian migrants to the United States and their descendants.

OBJECTIVES: We examined the incidence of gastric carcinoma in Chinese, Japanese, and Filipino residents of the United States to obtain additional information about the etiology of this disease. METHODS: The age, race, and birthplace of residents of Hawaii, San Francisco/Oakland, and northwestern Washington who were diagnosed with gastric carcinoma during the period 1973-1986 were obtained from population-based registries, and a special tabulation from the 1980 Census was used to estimate the number of person-years at risk for each category of resident. RESULTS: The incidence of gastric carcinoma in Japanese-Americans was three to six times higher than that of US-born whites, with the highest rates occurring in those persons born in Japan. The rate in US-born Chinese and Chinese men who immigrated to the US was similar to that of whites, whereas the rate in Chinese female migrants was twice that of white American women. Filipino men, regardless of birthplace, were only at 60% the risk of US-born white men, while their female counterparts had a rate very similar to that of US-born white women. The high incidence observed among Japanese-Americans and Chinese female immigrants was largely restricted to sites other than the gastric cardia. CONCLUSIONS: Our findings suggest that dietary and other lifestyle differences between the different generations of Japanese-Americans, and between Japanese residents of the US and Japan may provide clues regarding the etiologies of stomach cancers that arise beyond the gastric cardia.

Adult↗
PubMed1999

Hair product use and the risk of breast cancer in young women.

OBJECTIVES: The reported mutagenic and carcinogenic effects of some chemicals present in hair dyes have raised concern that hair dye use could increase breast cancer risk. This case-control study evaluated how detailed aspects of hair coloring and hair spray application by reproductive-age women may affect breast cancer risk. METHODS: Cases were white female residents of three counties of western Washington state 45 years of age or less, who were diagnosed with breast cancer between 1983 and 1990 (n = 844). A sample of similarly aged women residing in the same counties served as controls (n = 960). Information on hair coloring and hair spray use, as well as other exposures, was ascertained during in-person interviews. RESULTS: Breast cancer cases were slightly more likely than controls to report ever having used some type of hair coloring application, including use of rinses, semi-permanent or permanent dyes, as well as bleaching then dyeing or frosting their hair (relative risk [RR] = 1.3, 95% CI = 1.0-1.6, adjusted for age, fullterm pregnancies, family history of breast cancer, and weight). In subgroup analyses, women with exclusive use of just one of these methods of hair coloring application had no elevation in risk (similarly adjusted RR = 1.1, 95% CI = 0.9-1.3), whereas women who used two or more of these methods did have an elevated risk (RR = 1.9, 95% CI = 1.4-2.5). Hair spray use was not related to the risk of breast cancer (ever versus never users: RR = 1.0, 95% CI = 0.8- 1.3). CONCLUSION: The lack of an association between exclusive use of a single type of hair coloring application and breast cancer risk argues that hair coloring application does not influence breast cancer risk among reproductive-age women. Thus, the results of the present study, as well as negative ones from most (but not all) prior studies, are most consistent with the conclusion that neither hair coloring application nor hair spray application influences breast cancer risk.

Adult↗
PubMed1999

Hormone replacement therapy and colon cancer among members of a health maintenance organization.

We investigated the association between hormone replacement therapy (HRT), primarily conjugated estrogens with or without medroxyprogesterone acetate, and colon cancer risk in a nested case-control study among women ages 55-79 years enrolled in Group Health Cooperative, a health maintenance organization in Washington state. Cases were diagnosed between 1984 and 1993. We selected controls randomly from enrollment files. HRT use was ascertained from a computerized database containing virtually all prescriptions dispensed since 1977. Among subjects with at least 5 years of pharmacy database information before reference date (1 year before diagnosis date), there were 341 cases of incident colon cancer and 1,679 controls. Estrogen use during the 5 years before reference date was not associated with risk of colon cancer [odds ratio (OR) = 0.85 and 95% confidence interval (CI) = 0.57-1.27 for 1-749 estrogen tablets; OR = 0.97 and 95% CI = 0.68-1.40 for > or =750 estrogen tablets]. An analysis including only women with at least 10 years of pharmacy database coverage found no association with use during the 10 years before reference date [OR = 1.07 (95% CI = 0.61-1.86) for 1-749 estrogen tablets; OR = 1.11 (95% CI = 0.69-1.80) for 750 or more estrogen tablets]. These results do not support the hypothesis that recent HRT use substantially reduces risk of colon cancer.

Adenocarcinoma↗
PubMed1999

Assessment and control for confounding by indication in observational studies.

In the evaluation of pharmacologic therapies, the controlled clinical trial is the preferred design. When clinical trial results are not available, the alternative designs are observational epidemiologic studies. A traditional concern about the validity of findings from epidemiologic studies is the possibility of bias from uncontrolled confounding. In studies of pharmacologic therapies, confounding by indication may arise when a drug treatment serves as a marker for a clinical characteristic or medical condition that triggers the use of the treatment and that, at the same time, increases the risk of the outcome under study. Confounding by indication is not conceptually different from confounding by other factors, and the approaches to detect and control for confounding--matching, stratification, restriction, and multivariate adjustment--are the same. Even after adjustment for known risk factors, residual confounding may occur because of measurement error or unmeasured or unknown risk factors. Although residual confounding is difficult to exclude in observational studies, there are limits to what this "unknown" confounding can explain. The degree of confounding depends on the prevalence of the putative confounding factor, the level of its association with the disease, and the level of its association with the exposure. For example, a confounding factor with a prevalence of 20% would have to increase the relative odds of both outcome and exposure by factors of 4 to 5 before the relative risk of 1.57 would be reduced to 1.00. Observational studies have provided important scientific evidence about the risks associated with several risk factors, including drug therapies, and they are often the only option for assessing safety. Understanding the methods to detect and control for confounding makes it possible to assess the plausibility of claims that confounding is an alternative explanation for the findings of particular studies.

Antihypertensive Agents↗
PubMed1999

Incidence of adenocarcinoma of the prostate in Asian immigrants to the United States and their descendants.

PURPOSE: We characterize the incidence of adenocarcinoma of the prostate among Chinese, Japanese and Filipino immigrants to the United States and their descendants. MATERIALS AND METHODS: Subjects included 1,511 Asian and 16,000 white residents of Hawaii, San Francisco/Oakland and western Washington diagnosed with primary adenocarcinoma of the prostate during 1973 through 1986, and identified from the Surveillance, Epidemiology and End Results program. The size and composition of the population at risk were provided by a special tabulation of the 1980 United States Census. RESULTS: Among Asian-Americans 45 to 69 years old the annual rate per 100,000 for Chinese (24.0), Japanese (29.6) and Filipino (56.8) men born in China, Japan and the Philippines, respectively, was approximately half that of United States born Chinese, Japanese and Filipino men (44.4, 42.2 and 111.3, respectively). For Japanese Americans 70 to 84 years old at diagnosis differences in incidence persisted between those born in Japan (238.0) and the United States (446.4), while for older Chinese Americans incidence rates were nearly the same for those born in China (428.3) and the United States (425.0). In contrast, older Filipino men born in the Philippines had a higher rate (400.1) than their United States born counterparts (264.9) but the latter rate was based on a small number of men. Among United States residents the annual incidence for all generations of Asian-Americans was roughly half that of white men born in the United States (215.9). CONCLUSIONS: These results suggest that, irrespective of birthplace or age, Asian-American men retain 1 or more genetic or lifestyle characteristics that make their risk of prostate cancer less than that of white residents of the United States.

Adenocarcinoma↗
PubMed1999

Body mass index and risk of renal cell carcinoma.

To examine the association between body mass index and renal cell carcinoma risk, we analyzed data from a case-control study of members of a health maintenance organization in western Washington State. We identified cases diagnosed between 1980 and 1995 through a population-based cancer registry. We selected controls from membership files. We collected adult weight and height from medical records. Increased body mass index was associated with increases in risk for both men and women (for the top quartile relative to the bottom quartile of maximum body mass index: in women, OR = 3.3, 95% CI = 1.2-8.7; in men, OR = 2.3, 95% CI = 1.2-4.5).

Adult↗
PubMed1999

CYP2D6 genotype and the incidence of anal and vulvar cancer.

The risks of anal and vulvar cancer are strongly related to cigarette smoking. Smokers are exposed to a substantial quantity of tobacco-specific nitrosamines, including 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNK is present in the mucus of the female genital tract. The enzyme debrisoquine 4-hydroxylase (CYP2D6) activates NNK and is present in foreskin kerotinocytes and cervical epithelial cells. A polymorphism for the gene CYP2D6 exists, and persons who possess alleles that are associated with reduced levels of CYP2D6 activity might be expected to be at a relatively lower risk of cancers arising from NNK exposure. To test this hypothesis, we conducted a case-control study to examine the association of CYP2D6 genotype and the incidence of anal and vulvar cancer among cigarette smokers in western Washington State. We tested for 14 alleles (*1-*12, *14, and *17) among cases (25 men and 43 women with anal cancer, 64 women with vulvar cancer) and controls (30 men and 110 women). Contrary to the hypothesis, cases were not less likely than controls to have one (43.9 versus 40.7%) or two (6.8 versus 4.3%) inactivating alleles (*3, *4, *5, *6, *7, *8, *11, or *12). There was a suggestion that, if anything, the combined anal and vulvar cancer risk increased (rather than decreased) with an increasing number of CYP2D6 inactivation alleles: odds ratio = 1.2, 95% confidence interval = 0.7-2.0 with one inactivating allele; odds ratio = 1.8, 95% confidence interval = 0.6-5.4 with two inactivating alleles. These results provide no support for the hypothesis that cigarette smokers who carry the CYP2D6 alleles that result in a low activity phenotype have a decreased risk of anogenital cancer.

Adolescent↗
PubMed1999

The additional risk of endometrial cancer associated with unopposed estrogen use in women with other risk factors.

We analyzed data from a population-based case-control study of endometrial cancer. Our goal was to identify a subgroup of women in whom the additional cancer risk associated with unopposed estrogen use was sufficiently small so as to not be a deterrent to taking a hormone preparation of this type. Researchers interviewed women with endometrial cancer (N = 553) and controls (N = 752) regarding hormone use. The additional risk of endometrial cancer associated with unopposed estrogen use did not vary substantially in the presence or absence of hypertension, parity, oral contraceptive use, or smoking. The results suggest that, although heavier women may experience a greater risk of endometrial cancer associated with unopposed estrogen use (8.2 per 1,000 per year) than lighter women (4.2 per 1,000 per year), long-term users in the latter group nonetheless face a substantial absolute increase in risk. We conclude that subdividing women on the basis of the presence or absence of other known risk factors for endometrial cancer fails to delineate a subgroup that is exempt from the increased risk of this cancer associated with use of unopposed estrogens. 83.6% of estrogen users reported taking conjugated estrogens.

Body Mass Index↗
PubMed1999

Reproductive risk factors for mucinous and non-mucinous epithelial ovarian cancer.

We evaluated reproductive risk factors for mucinous and non-mucinous tumors in a population-based case-control study of epithelial ovarian cancer among women ages 20-79 years. We observed a reduction in risk of tumors of both types in association with one or more full-term pregnancies and with use of oral contraceptives for 5 or more years. While findings of some previous studies support the hypothesis that certain aspects of a woman's reproductive life have a different impact on the risk of these subtypes of ovarian epithelial cancer, our data suggest that this issue is not yet resolved.

Adult↗
PubMed1999

Prostate cancer in relation to the use of electric blanket or heated water bed.

Using data from a case-control study conducted in Group Health Cooperative (GHC) of Puget Sound, we examined the relation between the use of electric blankets or heated water beds and the risk of prostate cancer. Cases were 175 prostate cancer patients ages 40-69 years. Controls were 258 male GHC members frequency matched to cases. The odds ratio (OR) for prostate cancer associated with the use of an electric blanket or heated water bed was 1.4 (95% confidence interval (CI) 0.9-2.2). The risk, however, did not tend to be higher with increasing months per year or years of use. This study did not provide clear evidence on the hypothesized association.

Adult↗
PubMed1998

Analysis of case-control studies of screening: impact of misspecifying the duration of detectable preclinical pathologic changes.

In case-control studies of screening to prevent cancer mortality, exposure is ideally defined as screening that takes place within that period prior to diagnosis during which the cancer is potentially detectable using the screening modality under study. This interval has been called the detectable preclinical period (DPP). Misspecifying the duration of the DPP can bias the results of such studies. This article quantifies the impact of incorrectly estimating the duration of the DPP or using the correct average DPP but failing to consider its variability. The authors developed a computer simulation model of disease incidence and mortality with and without screening. The authors then selected cases and controls from the generated population and compared their screening histories. The results indicate that underestimation of the duration of the DPP generally leads to greater bias than does overestimation, but in both instances the extent of the bias is modified by the relative length of the DPP and the average interscreening interval. In practice, the authors recommend that to prevent a falsely low estimate of the effectiveness of a screening test in reducing mortality, a high percentile of the DPP distribution be used when analyzing the results of case-control studies of screening.

Aged↗