ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Previous analyses of prenatal screening for neural tube defects have generally found benefits to exceed costs. The usual screening battery follows an elevated maternal serum alpha-fetoprotein level with high-resolution ultrasound and/or amniocentesis. Current thinking focuses on weighing the risk of a false-negative (an abnormality missed) against the risk of an amniocentesis-induced fetal loss. This thinking neglects the risk of a false-positive (an unaffected fetus labeled abnormal) and individual parents' preferences concerning a false-negative vs a fetal loss. With these risks included, we find that high-resolution ultrasound is appropriate for all women with elevated serum alpha-fetoprotein. Women with moderately elevated serum alpha-fetoprotein who have negative ultrasound scans need no further testing, nor do women with highly elevated serum alpha-fetoprotein and positive ultrasound scans. Further testing using amniocentesis to confirm the ultrasound result is appropriate for women with moderately elevated serum alpha-fetoprotein and positive ultrasound scans, and for women with highly elevated serum alpha-fetoprotein and negative ultrasound scans. The actual cutoffs defining normal, moderately elevated, and highly elevated serum alpha-fetoprotein depend on several parameters, particularly the underlying prevalence of neural tube defects and the parents' preferences.

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

We studied whether paternal exposure to Agent Orange and its dioxin contaminant (2,3,7,8-tetrachlorodibenzo-p-dioxin) during the Vietnam War is related to adverse reproductive outcomes after service in Southeast Asia. The index cohort comprises conceptions and children of veterans of Operation Ranch Hand, the unit responsible for aerial spraying of herbicides in Vietnam from 1962 to 1971. The comparison cohort comprises conceptions and children of Air Force veterans who served in Southeast Asia during the same period but who were not involved with spraying herbicides. We found no meaningful elevation in risk for spontaneous abortion or stillbirth. In analyses of birth defects, we found elevations in risk in some organ system categories, which, after review of the clinical descriptions, were found to be not biologically meaningful. There was an increase in nervous system defects in Ranch Hand children with increased paternal dioxin, but it was based on sparse data. We found no indication of increased birth defect severity, delays in development, or hyperkinetic syndrome with paternal dioxin. These data provide little or no support for the theory that paternal exposure to Agent Orange and its dioxin contaminant is associated with adverse reproductive outcomes.

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

We studied the relation between birth defects and maternal agricultural work in a nationwide time- and area-matched case-referent series of 1,306 pairs of infants (581 orofacial clefts, 365 central nervous system defects, 360 skeletal defects) obtained through the Finnish Register of Congenital Malformations. We supplemented the Register data, including the mothers' latest and previous pregnancies, diseases, consumption of drugs and alcohol, smoking habits, and the like, with detailed interviews on the mothers' work conditions. When all of the birth defects were pooled and agricultural work was compared with nonagricultural work in the first trimester of pregnancy, the adjusted odds ratio was 1.4 [95% confidence interval (CI) = 0.9–2.0]. For orofacial clefts, the corresponding odds ratio was 1.9 (95% CI = 1.1–3.5). An industrial hygienist's blinded assessment indicated that seven mothers of infants with orofacial clefts and three reference mothers had been exposed to pesticides in agricultural work; the adjusted odds ratio for work with pesticide exposure, when compared with unexposed agricultural work, was 1.9 (95% CI = 0.4–8.3). Exposure to solvents did not explain the observed association.

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Several case-control studies have reported positive associations between childhood cancer and proximity to high-current residential power lines as defined by the Wertheimer-Leeper code. We conducted a study to evaluate whether or not differential nonparticipation of controls as a function of socio-economic status is likely to account for the observed associations. We assessed the relation of annual family income to the Wertheimer-Leeper code in a sample of 392 households in western Washington state, and we evaluated the magnitude of bias that could occur from differential participation of low- and high-income eligible controls. Very-high-current configurations were most frequently located among households with self-reported family income of less than $15,000 per year, and very-low-current configurations were most frequently located among those with self-reported family income of more than $45,000 per year. In a hypothetical case-control study in which: (1) it was assumed that there is no true etiologic relation between power line configurations and cancer occurrence, and (2) controls with very low income were less likely to participate than others, observed (biased) odds ratios ranged from 1.03 to 1.24. If these results are applicable to other areas where case-control studies of cancer in relation to power lines have been conducted, they suggest that relatively lower participation among exposed controls (as a function of very low income) is not likely to account for the elevated risks of 1.5− to 3-fold that have been observed in these previous studies.

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

We investigated risk factors for primary liver cancer among a cohort of 36,133 residents in Hiroshima and Nagasaki, Japan, originally established to examine the association between exposure to atomic bomb radiation and disease. A mail survey to study the late effects of atomic bomb radiation was conducted among the cohort between 1978 and 1981. During the subsequent follow-up period (average 8.61 years), 242 cases of primary liver cancer were identified through population-based tumor registries in the two cities. The relative risk (RR) of liver cancer was 2.23 [95% confidence interval (CI) = 1.53–3.23] for tobacco smokers compared with those who had never smoked. Alcohol use was slightly positively associated with the risk of liver cancer, and men who had quit drinking had an RR of 2.33 (95% CI = 1.34–4.07) compared with those who never drank. Among alcohol drinkers, an inverse relation between years of abstinence and the rate of liver cancer was found, possibly attributable to a confounding effect of preclinical disease. The use of female hormone preparations was modestly associated with the risk of liver cancer (RR = 1.29; 95% CI = 0.59–2.84). Other risk factors included a self-reported history of radiation therapy (RR = 1.79; 95% CI = 1.34–2.40) and a history of diabetes mellitus (RR = 1.79; 95% CI = 1.31–2.43).

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Capture-recapture techniques are employed increasingly to correct for underascertainment of cases in epidemiologic surveillance. A key assumption of the basic two-source capture-recapture method is the independence of sources, which is often violated in practice. This paper provides a quantitative comparison of the performance of the capture-recapture method and the traditional registration approach in disease monitoring with two dependent sources. If sources are negatively dependent, underascertainment of cases by the traditional registration approach is transformed into overestimation of case numbers with the capture-recapture method. This over-estimation can be extreme under certain conditions. Application of the capture-recapture method is therefore discouraged if negative source dependence is of concern. In other situations, the capture-recapture method can be a valuable tool to correct for underascertainment of cases. Although the correction remains imperfect if notifications from both sources are positively dependent, underestimation of case numbers is typically much less severe than with the traditional registration approach. I illustrate the findings for a broad range of registration scenarios and provide empirical examples from population-based cancer registration. I also discuss strategies that may minimize the degree of source dependence in the design and analysis of capture-recapture studies.

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Although the etiologic relation between nonsteroidal antiinflammatory drug (NSAID) use and gastrointestinal lesions is well documented, newly introduced NSAIDs deserve a fresh examination for their risk/benefit ratio. To estimate the association between consumption of ketorolac and the occurrence of gastroduodenal lesions, we conducted a case-control study. The study population comprised 600 outpatients with a confirmed endoscopic diagnosis of ulcer and erosion in 1991 and 1992 and 6,000 community controls matched by age and sex. We retrieved the prescription history through a computerized prescription monitoring system. We defined exposure to each study drug as “current” (month of endoscopy and preceding month), “recent” (second or third month preceding endoscopy), and “past” (fourth to sixth month preceding endoscopy). Current users of NSAIDs showed a 30% increase in the incidence of gastroduodenal lesions [odds ratio (OR) = 1.3; 95% confidence interval (CI) = 0.98–1.8] after adjustment for recent or past use of any NSAID, recent or past gastrotoxic therapy, recent or past use of gastroprotective drugs, and recent or past use of any other drug. Among NSAIDs, ketorolac was the only one showing a distinctly elevated risk of gastroduodenal lesions (OR = 4.2; 95% CI = 1.9–9.4). Current use of any NSAID was associated with almost a doubling of risk for ulcer alone (OR = 1.9; 95% CI = 1.3–3.0); no elevation in risk was found for erosions. The adjusted relative risk for ulcer associated with current use of ketorolac was 9.8 (95% CI = 3.4–28.1). Recent and past use of NSAIDs does not increase the risk of ulcer. The use of ketorolac appears to carry a greater gastrotoxicity than other NSAIDs.

ISSN:1044-3983    

出版商:OVID    

年代:1995

数据来源: OVID