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R R Neutra

Publications and source records attributed to R R Neutra.

At least 19 recordsLinked to original sources
PubMed1992

An evaluation of the role of epidemiology in assessing current and future disinfection technologies for drinking water.

Six members of the International Society for Environmental Epidemiology provide a discussion of the presentations of the authors of six studies dealing with the potential chronic disease side effects of water disinfection. This symposium, which was jointly sponsored by the Society and the United States Environmental Protection Agency (EPA) also involved state epidemiologists and engineers from state drinking water programs. This article summarizes the results of the studies and the comments about them. There was a general consensus that the recent EPA sponsored studies of cancer endpoints have strengthened the evidence linking bladder cancer with long term exposure to chlorinated drinking water. The evidence for links with colon cancer is not convincing and that for serum lipid changes is quite weak. Any risks, if real, are low when compared to the risk of infection from not disinfecting water. This is particularly true for small water systems where chlorination may be the only practical option.

Chloramines↗
PubMed1992

Is drinking water related to spontaneous abortion? Reviewing the evidence from the California Department of Health Services Studies.

Because preliminary data suggested a relation between risk of spontaneous abortion and tapwater consumption during pregnancy, the California Department of Health Services included questions on prenatal water consumption in all reproductive studies conducted between 1982 and 1988. Results from four of these five retrospective data bases suggest that women abstaining from tapwater or drinking bottled water during the first trimester of pregnancy may be at reduced risk of spontaneous abortion. Fetal resorption frequencies seen in an accompanying toxicology study were consistent with these epidemiologic findings, although not conclusive. Tap and bottled water samples from these study areas were analyzed for agents that might account for these findings. Differences in trace element composition and biological activity were observed, but the reproductive significance of these differences is unknown. This paper presents an overview of these studies, which are presented in detail separately. Three alternative explanations for these findings--bias, chance, and causality--are reviewed.

Abortion, Spontaneous↗
PubMed1992

Adverse pregnancy outcomes in relation to water consumption: a re-analysis of data from the original Santa Clara County Study, California, 1980-1981.

Residents of a census tract that received drinking water from a well contaminated with solvents were previously shown to experience a spontaneous abortion rate over twice that occurring in an unexposed census tract. In addition, the rate of birth defects in the exposed tract was three times that in the unexposed tract. Surprisingly, increased tapwater consumption was associated with higher rates of spontaneous abortions in both the exposed and the unexposed tracts. Subsequent studies in this area have investigated the relation between spontaneous abortions and consumption of tapwater in more detail. In this report, data from the original study have been re-analyzed using methods comparable with those used in more recent studies. These results confirm the association between spontaneous abortions and reported cold tapwater consumption that was seen in the original study. The observed effect was not due to maternal risk factors, nor was it a function of consumption of bottled water. After controlling for bottled water, the odds ratio for consumption of tapwater was 3.4 (95% confidence interval = 0.6-19.4).

Abortion, Spontaneous↗
PubMed1992

Spontaneous abortions and birth defects related to tap and bottled water use, San Jose, California, 1980-1985.

We recently studied pregnancies occurring during 1980-1985 in four study areas in Santa Clara County, California. Two of the areas were exposed to solvent-contaminated drinking water during 1980 and 1981, and two were unexposed. There was an overall excess of spontaneous abortions among women who reported any tapwater consumption during the first trimester of pregnancy compared with those who reported no tapwater consumption [odds ratio (OR) = 4.0; 95% confidence interval (CI) = 1.8-9.1)], regardless of exposure to the contaminated water. The odds ratio for spontaneous abortion for women reporting any vs no tapwater was 6.9 (95% CI = 2.7-17.7) after adjustment for numerous potential confounders using multiple logistic regression analyses. The elevated odds ratio of spontaneous abortion was seen among tapwater drinkers who used no filters or softener-type filters but not among women who reported use of active filters. Spontaneous abortion rates were reduced in women who reported any vs no bottled water consumption (OR = 0.26; 95% CI = 0.16-0.43). Among women who reported no tapwater consumption, no birth defects occurred among 263 live births; in comparison, among women who reported tapwater consumption, 4% of 908 live births had defects (P = 0.0001). We observed no relation between birth defects and bottled water use.

Abortion, Spontaneous↗
PubMed1992

Reporting bias and mode of interview in a study of adverse pregnancy outcomes and water consumption.

In an earlier publication, it was shown that consumption of tapwater during the first trimester of pregnancy was associated with a risk of spontaneous abortion among women who attended three prenatal clinics located in northern California between September 1981 and June 1982. Evidence for biased recall was presented. This report demonstrates that the association is limited to women interviewed by telephone and is not observed among those who completed a mail questionnaire. The possibility that the association among women interviewed by telephone is causal and that the lack of association among mail respondents is due to bias, confounding, or apparently chance fluctuations is shown to be unlikely. For instance, the probability is low that, among mail respondents, cases underreported exposure as compared with controls or that random errors were common enough to camouflage a true effect. Demographic differences between mail and telephone respondents also do not explain the results. Interviewers were, however, aware of the outcome of the pregnancy, suggesting that differential reporting of exposure may have been stimulated in the nonblind telephone interview. The pattern of heterogeneity between mail and telephone respondents was also observed for reportable anomalies and tapwater consumption. The data on heterogeneity support the previously published conclusion that differential reporting (biased recall) of this common exposure, tapwater consumption, is the likely explanation for its observed association with the risk of spontaneous abortion. That this association is limited to telephone respondents elucidates the mechanism that apparently produced the bias: that is, the medium of nonblind telephone interviews.

Abortion, Spontaneous↗
PubMed1992

Tap or bottled water consumption and spontaneous abortion: a 1986 case-control study in California.

To investigate whether drinking tap or bottled water during pregnancy affects the risk of spontaneous abortion, we asked questions about water consumption in a large case-control study (626 cases, 1,300 controls). The study ascertained cases from hospital pathology laboratory reports of pregnancies that began in 1986 and obtained controls from birth certificates. The crude odds ratio for consumption of any vs no cold tapwater at home during the first trimester was 1.2 (95% confidence interval = 1.0-1.5), with no dose-response effect. The crude odds ratio for any bottled water consumption was 0.79 (95% confidence interval = 0.65-0.96), with a downward trend by amount consumed. Adjusting for many potential confounders did not alter these associations appreciably, although some variables appeared to be effect modifiers. The point estimates were stronger among women who were more difficult to contact, suggesting the possibility of bias.

Abortion, Spontaneous↗
PubMed1992

Tap or bottled water consumption and spontaneous abortion in a case-control study of reporting consistency.

A recent case-control study of 1,926 women found a slightly increased risk of spontaneous abortion associated with reported consumption of tapwater and a decreased risk with reported consumption of bottled water. In a case-control study of spontaneous abortion designed to examine the consistency of prenatal exposure reporting, the association of spontaneous abortion with tap or bottled water consumption was also examined. Cases of spontaneous abortion (N = 100) were ascertained from hospital pathology reports, and pregnant controls (N = 200) were obtained from obstetrical appointment logs. Subjects were first interviewed approximately 24 weeks after their last menstrual period and again approximately 48 weeks after their last menstrual period. Neither an increased risk for spontaneous abortion associated with consumption of tapwater nor a protective effect for consumption of bottled water was observed. Changes in reporting of tapwater consumption from the first to the second interview suggest the possibility of differential reporting in cases and controls. There was no evidence suggesting biased reporting of bottled water consumption.

Abortion, Spontaneous↗
PubMed1992

The effects of water source on reproductive outcome in Fischer-344 rats.

To investigate the relation between maternal water consumption and pregnancy loss, we conducted a reproductive toxicology study using Fischer rats. On day 0 of gestation, dams were assigned to tapwater, commercial bottled water, or purchased high pressure liquid chromatography grade water. On day 20 of gestation, we killed the dams and removed their litters for examination. There were no marked effects of dietary water source on maternal body weight, number of implantation sites, number of live fetuses, sex of offspring or number of resorptions per litter. Fetal length and weight, placenta weight, and soft tissue and skeletal malformations were also similar among groups. The tapwater group had somewhat higher resorption frequency (5.3%) and frequency of affected fetuses (6.5%) than those fed bottled water (3.8% and 4.5%, respectively).

Animals↗
PubMed1992

Potential sources of bias and confounding in environmental epidemiologic studies of pregnancy outcomes.

Biases familiar to all epidemiologists take on new importance when studying spontaneous abortion because of the significance of the timing of exposure during gestation, and because the gestational age at which the pregnancy is recognized may be related to risk factors under study. In this paper, we systematically review the principal biases that might affect epidemiologic studies of pregnancy loss, in the context of a series of studies that found associations between adverse reproductive outcomes and prenatal use of tap or bottled water. These biases relate to availability of subjects for study, exposure opportunity, recall of exposure, recall of disease, and confounding. In one of the studies, the rate of bottled water use changed dramatically over the course of the study period, providing an opportunity to test indirectly for biased recall of exposure. We conclude that a less complete recall of water intake among women with normal pregnancies, as compared with those with spontaneous abortions, may have produced, or increased the magnitude of, the associations seen in these studies.

Bias↗
PubMed1991

Assessment of reporting consistency in a case-control study of spontaneous abortions.

Reporting consistency was examined in a case-control study of spontaneous abortion in Santa Clara County, California. Each case (n = 100) and two pregnant controls (n = 200), frequency-matched by last menstrual period, were interviewed twice: first after the case's spontaneous abortion (on average, 24 weeks after the last menstrual period) and again after completion of the controls' pregnancies (on average, 48 weeks after the last menstrual period). Because of concern about differential reporting of water consumption in regions with publicized water contamination, interviews included detailed questions about consumption of tap water and bottled water during pregnancy, as well as other exposures. Most factors such as caffeine consumption, cigarette smoking, employment, and pregnancy history were consistently reported between interviews and did not appear to be subject to differential reporting between cases and controls. When variables were examined by univariate analysis, controls deleted reports of tap water consumption (any vs. more) more often than did cases. There was also a suggestion of differential reporting of up to two glasses per day for tap water and bottle water consumption when they were examined as continuous variables. However, the degree of differential reporting was not sufficient to appreciably alter the measures of association between water consumption during pregnancy and spontaneous abortion.

Abortion, Spontaneous↗
PubMed1991

A follow-up study of the community near the McColl waste disposal site.

To assess the effect of interim clean-up measures on the current health of a community, we conducted a follow-up survey of 193 residents living near the McColl waste disposal site and a comparison area located approximately 5 miles from the site. Results from this survey were compared with results from a similar survey conducted 7 years earlier. Odors were detected at least once per week by 32.7% of "high-exposed" respondents in 1988 compared with 68.5% in 1981, but prevalence odds ratios (PORs) comparing symptom reporting between "high-exposed" and comparison-area respondents were greater than that of the 1981 survey for 89% of symptoms. PORs comparing symptom reporting between these two areas were greater than 2.0 for 64% of symptoms assessed in the current survey. Symptoms reported in excess did not represent a single organ system or suggest a mechanism of response. PORs comparing respondents who were very worried about the environment and those reporting no worry were greater than 2.0 for 86% of symptoms. These finding, along with environmental data from the area, suggest that living near the waste disposal site and being very worried about the environment, rather than a toxicologic effect of chemical from the site, explain excess symptom reporting found in this follow-up study.

Adult↗
PubMed1990

Use of video display terminals during pregnancy and the risk of spontaneous abortion, low birthweight, or intrauterine growth retardation.

Use of video display terminals (VDTs) during pregnancy among working women was examined using data from a large case-control study of spontaneous abortions (SAB) occurring in 1986-1987. The crude odds ratio for SAB and VDT use was 1.2 for use of less than 20 hours per week (95% CI = 0.88, 1.6) as well as for 20 hours or more (CI = 0.87, 1.5), with little change after adjustment for a variety of confounders. The effects of VDT use may vary by the gestational age at SAB, with stronger associations seen in earlier (less than or equal to 12 weeks) compared to later SABs. Use of VDTs within specific occupational categories was examined, yielding adjusted odds ratios varying from 0.5 to 1.7. The risk for low birthweight (LBW) among the control group also was not greatly elevated at either VDT use level, with adjusted ORs of 1.1 (0.52, 2.1) and 1.4 (0.75, 2.5), respectively. However, the risk for intrauterine growth retardation was somewhat elevated among women with greater VDT use (OR = 1.6, CI = 0.92, 2.9).

Abortion, Spontaneous↗
PubMed1989

Congenital cardiac anomalies in relation to water contamination, Santa Clara County, California, 1981-1983.

In November 1981, a leak of solvents from an underground storage tank was detected at an electronics manufacturing plant in Santa Clara County, California. Solvents (predominantly 1,1,1-trichloroethene, or methyl chloroform) were found in a nearby well which supplied drinking water to the surrounding community. Residents were concerned about a possible relation between adverse reproductive outcomes and consumption of contaminated water. To address this concern, the California Department of Health Services conducted two epidemiologic studies: one of these, reported here, is a county-wide study of cardiac anomalies. This study, which looked at major cardiac anomalies among births throughout Santa Clara County in 1981-1983, found an increased prevalence in the service area of the water company which operated the contaminated well. During the potentially exposed time period (January 1981 through August 1982), 12 babies with major cardiac anomalies were born to residents of this area. This represents an excess of six cases over the number expected based on the prevalence in the remainder of the county (relative risk = 2.2, 95 per cent confidence interval 1.2-4.0). No excess was observed in the unexposed time period (September 1982 through December 1983). However, the temporal distribution of major cardiac cases born during the exposed time period suggests that the solvent leak is an unlikely explanation for this excess.

California↗
PubMed1989

Adverse pregnancy outcomes in relation to water contamination, Santa Clara County, California, 1980-1981.

An epidemiologic study was conducted to investigate a suspected cluster of adverse outcomes of pregnancies conceived in 1980-1981 among women who resided in a census tract in Santa Clara County, California that was thought to be exposed to drinking water from a well contaminated by an organic solvent, trichloroethane. A comparison census tract that received water from a different source was selected on the basis of demographic comparability. The cluster was confirmed; the odds ratio for spontaneous abortion was 2.3 (95% confidence interval (Cl) 1.3-4.2) after adjustment by multiple logistic regression for maternal risk factors, including maternal age, alcohol consumption, smoking, and prior fetal loss. The relative risk for congenital malformations was 3.1 (95% Cl 1.1-10.4). Because of the lack of precise information on the timing and extent of contamination, the pattern of spontaneous abortion rates throughout the study period cannot be used to either support or refute a causal inference.

Abnormalities, Drug-Induced↗
PubMed1989

Spontaneous abortions in relation to consumption of tap water: an application of methods from survival analysis to a pregnancy follow-up study.

A previous study of pregnant women whose water supply was potentially contaminated revealed a significant increase in spontaneous abortions among those drinking tap as opposed to bottled water, regardless of exposure to the contamination. The relation between reported prenatal water consumption and risk of spontaneous abortion was therefore analyzed in an independent cohort of pregnancies seen in 1981-1982 at a health maintenance organization in three counties in northern California. The study used a nested case-control design. Since early miscarriages are left-truncated, gestational age at which a pregnancy comes to medical attention may confound results of pregnancy outcome studies. Risk set analyses were therefore conducted in two stages: 1) the life of table-adjusted risk for those drinking mainly bottled water was 8.4%; the risk for those drinking mainly tap water was 12.5%, and 2) the Cox proportional hazards model was used to control for multiple confounders, yielding a hazard ratio for spontaneous abortion of 1.5 (95% confidence interval 1.1-2.0) for consumers of tap water compared with bottled water. Tap water drinkers whose home source of water included ground water had the greatest risk (13.8) and, after controlling for confounders, their hazard ratio was 1.7. Based on external data from comparable studies, bottled water drinkers appeared to have had unusually low risks, and tap water drinkers who received ground water may have had slightly high risks. Inconsistencies in the reporting of tap water consumption suggest recall bias. Causal factors could not be ruled out, however, although no reproductive toxins, either biological or chemical, have yet been identified in the tap water in this area.

Abortion, Spontaneous↗
PubMed1988

Selenium and human health implications in California's San Joaquin Valley.

An evaluation was conducted on the human health impacts of elevated levels of selenium in the Kesterson National Wildlife Refuge and its surroundings in Merced County, California. Investigative activities of various agencies were summarized and assessed. Agricultural waste water not intended for human use showed elevated selenium concentrations of up to 1400 ppb. Levels of selenium in fish (up to 96 ppm, wet weight), aquatic birds (up to 130 ppm in liver, dry weight), and waterfowl (up to 5.3 ppm flesh, wet weight) were unsafe for unrestricted human consumption. Data on selenium in drinking water (less than 10 ppb), animals (mean values: beef liver 0.3-0.35 ppm, wet weight; milk, 0.01-0.02 ppm), and air (particulate, 14.8 ng/m3; gaseous, less than 1080 ng/m3) did not suggest a high level of exposure. Selenium concentrations in soil were highly variable and suggested a potential source of high exposure. Selenium values in blood and urine of workers were within normal range. A community health survey did not show any trend of adverse health effects in the local population.

Animals↗
PubMed1979

Determinants of dropout rate among hypertensive patients in an urban clinic.

Noncompliance with follow-up is a serious problem in the management of hypertension. A retrospective cohort study examined dropout rates and their determinants among 249 randomly selected outpatients with essential hypertension from the medical clinic of an urban teaching hospital. Data were abstracted from hospital records and a subset of dropouts was interviewed. A lifetable analysis revealed that patients who were initiating therapy or who had been under therapy for less than six months had a 50% chance of remaining in care two years later, while 70% of patients who had been under therapy for more than six months at entry were still in care after this period. Patients who were less severely ill by several indicators were the most likely to drop out. It is hypothesized that the low perceived severity of illness, coupled with the costs and inconvenience of care and the lack of physician enthusiasm for the treatment of mild hypertension leads to non-compliance with follow-up.

Adult↗