Biomedical subjects

L Fenster

Publications and source records attributed to L Fenster.

43 records · Page 3Linked to original sources

PubMed1991

Pregnancy outcomes in women potentially exposed to occupational solvents and women working in the electronics industry.

Associations of occupational solvent exposure and/or work in electronics production with adverse pregnancy outcomes were examined in a large cross-sectional community-based reproductive health study of 1038 California women pregnant between 1980 and 1985. Occupational solvent exposure was determined by two different methods: Bureau of Census codes judged by experts to probably include solvent exposure and self-reported exposure. First trimester solvent exposure classified by either method (n = 52) was significantly associated with spontaneous abortion, adjusted odds ratio 3.34 (95% confidence interval 1.42, 7.81). Among 29 women reporting regular and daily solvent exposure, the adjusted odds ratio increased to 4.44 (95% confidence interval 1.86, 10.58). Work in electronics assembly was significantly associated with delivering a low birth weight infant (adjusted odds ratio 5.38; 95% confidence interval 1.42, 20.46) but was not associated with spontaneous abortions. Further research using biologic monitoring and/or other objective measures of exposure is needed to validate these findings.

Abortion, Spontaneous↗

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↗

PubMed1990

Pregnancy outcomes in women potentially exposed to solvent-contaminated drinking water in San Jose, California.

During 1980-1981, solvents leaked from an underground storage tank of a semiconductor firm in southern Santa Clara County, California, contaminating local drinking water. The contaminated well was closed in December 1981. An epidemiologic study conducted in 1983 confirmed statistically significant excesses of adverse pregnancy outcomes in an exposed community compared with an unexposed community, but could not establish a causal connection between the leak and the adverse outcomes. This study expanded the first study; adverse pregnancy outcomes occurring in 1980-1985 were studied in two communities exposed to the contaminated drinking water and in two demographically comparable but unexposed communities. The period 1980-1981 was the time period in which the well was considered to have been contaminated and 1982-1985 was considered the postcontamination time period. Both exposed and unexposed communities were considered unexposed during the latter period (1982-1985). Out of 10,055 households surveyed, interviews were conducted with 1,105 women who reported one or more eligible pregnancies. Miscarriages and birth defects were validated by medical record review or physician reports. Although the authors again observed statistically significant excesses of spontaneous abortions and birth defects in the originally studied exposed area in 1980-1981, they observed deficits of these outcomes in the second exposed study area. Adjustment for potential confounders did not alter these findings. Analyses of pregnancy outcomes during 1981 in relation to exposure estimates based on hydrogeologic modeling of water and contaminant distribution within the exposed areas also indicated that the leak was not likely to have caused the observed excesses of adverse pregnancy outcomes in the originally studied area.

Abnormalities, Drug-Induced↗

PubMedDate not supplied

Assessment of reproductive disorders and birth defects in communities near hazardous chemical sites. III. Guidelines for field studies of male reproductive disorders.

Exposures to environmental toxicants can have detrimental effects on several aspects of human male reproduction: fertility, sexual function, hormone status, and pregnancy/birth outcomes. However, no simple prescreening methods are available for reliably identifying potential hazards; questionnaires alone are relatively imprecise and inefficient in the absence of field data. Multidisciplinary field studies are required that include detailed exposure information, health and reproductive histories, physical examinations, semen analyses, and possibly, hormone analyses. Semen analysis is a critical component of field studies for evaluating two aspects of male reproduction: 1) changes in sperm or seminal content, which may be indicative of adverse effects on the male reproductive system with possible implications for fertility potential; and 2) defects in sperm DNA or chromosomes, which may be associated with subsequent changes in viability during embryonic development and health risks to the offspring. Semen analyses may be tiered: 1) initially, each semen study may include conventional semen assays (concentration, motility, and morphology) as well as specific biomarkers indicated by the health effect of concern in the study cohort: and 2) archived samples (i.e., frozen, videotaped, or smeared) may be utilized in later second-tier analyses to further characterize specific findings. Before initiating any field study, it is cost effective to critically evaluate the suitability of the cohort by confirming exposure and determining that there are adequate numbers of male participants in each exposure category. Such evaluations must be based on the statistical sensitivities of the specific tissue biomarkers and health endpoints for detecting changes. This article summarizes the components of the ideal field study and identifies research needs for improving field studies of male effects and for understanding the mechanisms of male reproductive toxicity. Several promising semen methods currently under development are also discussed.

Adult↗

PubMedDate not supplied

Influence of exposure assessment methods on risk estimates in an epidemiologic study of total trihalomethane exposure and spontaneous abortion.

Trihalomethanes are common contaminants of chlorinated drinking water. Studies of their health effects have been hampered by exposure misclassification, due in part to limitations inherent in using utility sampling records. We used two exposure assessment methods, one based on utility-wide sampling averages, and one based on measurements from the utility sampling site closest to the subject's residence, to reestimate total trihalomethane (TTHM) exposure for 4212 participants in a preexisting study of risk factors for spontaneous abortion (SAB). For both approaches we performed unweighted, weighted, and subset analyses. The weighted and subset analyses were intended to reduce exposure misclassification, and were based on within-utility variance in TTHM measurements for the utility-wide average approach, and the distance between the subject's residence and sampling site for the closest-site approach. In general, the utility-wide average methods produced odds ratios equivalent to or slightly higher than the closest-site methods. Odds ratios obtained using the utility-wide average, but not the closest-site, approach also became progressively stronger in the weighted and subset analyses. A dose-response was seen between SAB and an exposure metric incorporating both TTHM concentration (utility-wide average approach) and personal ingestion, with SAB rates ranging from 8.3% to 13.7% (unweighted), 7.9% to 16.6% (variance weighted), and 6.6% to 23.1% (low-variance subset). Utility-wide average TTHM exposure assessment methods together with variance-based weights and subsets are relatively simple exposure assessment techniques, which may increase the epidemiologic usefulness of utility sampling records.

Abortion, Spontaneous↗

PubMedDate not supplied

Birthweight of infants born to Hispanic women employed in agriculture.

A prospective study examined the effects of maternal occupation on the birthweight of infants of Hispanic women. The study population consisted of 1,040 pregnant women enrolled for prenatal care in two rural health care centers in California between 1982 and 1984. Birthweights of infants were examined after classifying these women into three groups: (1) 255 mothers who did agricultural work, (2) 134 mothers who worked in nonagricultural jobs, and (3) 651 mothers who did not work during pregnancy. Prenatal interviews and medical records revealed medical, social, and occupational histories of the mothers. Stepwise linear regression analyses, using the backward elimination method, were conducted for some exposure models to determine whether work category influenced birthweight after controlling for confounders. The incidence of low birthweight and mean birthweights did not vary significantly with work status.

Agriculture↗

PubMedDate not supplied

Effects of psychological stress on human semen quality.

We investigated the relationship between psychological stress and sperm concentration, motility, and morphometry in a prospective study of 157 volunteers who were enrolled in a prepaid health plan. We measured psychological job stress and life-event stress by telephone interview. Sperm-kinematic and nuclear-morphometric variables were measured using computer-assisted image analyses. Sperm concentration, percent motility, and semen volume were determined by objective visual methods. We performed multiple linear regression for each semen variable to examine its relationship to stress, controlling for potential confounders. Stress at work and total number of life events were not related to differences in semen quality. However, the recent death of a close family member was associated with a reduction in straight-line velocity (P = 0.002) and percent of progressively motile sperm (P = 0.02); it was also marginally associated with an increase in the fraction of sperm with larger and more tapered nuclei. These findings suggest that the fecundity of men experiencing the stress of a family member's death might be temporarily diminished.

Adult↗