Designing prospective cohort studies for assessing reproductive and developmental toxicity during sensitive windows of human reproduction and development--the LIFE Study.

The relationship between the environment and human fecundity and fertility remains virtually unstudied from a couple-based perspective in which longitudinal exposure data and biospecimens are captured across sensitive windows. In response, we completed the LIFE Study with methodology that intended to empirically evaluate a priori purported methodological challenges: implementation of population-based sampling frameworks suitable for recruiting couples planning pregnancy; obtaining environmental data across sensitive windows of reproduction and development; home-based biospecimen collection; and development of a data management system for hierarchical exposome data. We used two sampling frameworks (i.e., fish/wildlife licence registry and a direct marketing database) for 16 targeted counties with presumed environmental exposures to persistent organochlorine chemicals to recruit 501 couples planning pregnancies for prospective longitudinal follow-up while trying to conceive and throughout pregnancy. Enrolment rates varied from <1% of the targeted population (n = 424,423) to 42% of eligible couples who were successfully screened; 84% of the targeted population could not be reached, while 36% refused screening. Among enrolled couples, ∼ 85% completed daily journals while trying; 82% of pregnant women completed daily early pregnancy journals, and 80% completed monthly pregnancy journals. All couples provided baseline blood/urine samples; 94% of men provided one or more semen samples and 98% of women provided one or more saliva samples. Women successfully used urinary fertility monitors for identifying ovulation and home pregnancy test kits. Couples can be recruited for preconception cohorts and will comply with intensive data collection across sensitive windows. However, appropriately sized sampling frameworks are critical, given the small percentage of couples contacted found eligible and reportedly planning pregnancy at any point in time.

A GIS-based method for household recruitment in a prospective pesticide exposure study.

BACKGROUND: Recent advances in GIS technology and remote sensing have provided new opportunities to collect ecologic data on agricultural pesticide exposure. Many pesticide studies have used historical or records-based data on crops and their associated pesticide applications to estimate exposure by measuring residential proximity to agricultural fields. Very few of these studies collected environmental and biological samples from study participants. One of the reasons for this is the cost of identifying participants who reside near study fields and analyzing samples obtained from them. In this paper, we present a cost-effective, GIS-based method for crop field selection and household recruitment in a prospective pesticide exposure study in a remote location. For the most part, our multi-phased approach was carried out in a research facility, but involved two brief episodes of fieldwork for ground truthing purposes. This method was developed for a larger study designed to examine the validity of indirect pesticide exposure estimates by comparing measured exposures in household dust, water and urine with records-based estimates that use crop location, residential proximity and pesticide application data. The study focused on the pesticide atrazine, a broadleaf herbicide used in corn production and one of the most widely-used pesticides in the U.S. RESULTS: We successfully used a combination of remotely-sensed data, GIS-based methods and fieldwork to select study fields and recruit participants in Illinois, a state with high corn production and heavy atrazine use. Our several-step process consisted of the identification of potential study fields and residential areas using aerial photography; verification of crop patterns and land use via site visits; development of a GIS-based algorithm to define recruitment areas around crop fields; acquisition of geocoded household-level data within each recruitment area from a commercial vendor; and confirmation of final participant household locations via ground truthing. The use of these procedures resulted in a sufficient sample of participants from 14 recruitment areas in seven Illinois counties. CONCLUSION: One of the challenges in pesticide research is the identification and recruitment of study participants, which is time consuming and costly, especially when the study site is in a remote location. We have demonstrated how GIS-based processes can be used to recruit participants, increase efficiency and enhance accuracy. The method that we used ultimately made it possible to collect biological samples from a specific demographic group within strictly defined exposure areas, with little advance knowledge of the location or population.

Race, poverty, and potential exposure of middle-school students to air emissions from confined swine feeding operations.

Previous studies suggest that airborne effluent from swine confined animal feeding operations (CAFOs) may affect the health and quality of life of adults and the prevalence of asthma symptoms among children. To investigate the extent to which public school students may be exposed to airborne effluent from swine CAFOs and to evaluate the association between schools' demographic characteristics and swine CAFO exposures, we assessed the proximity of 226 schools to the nearest swine CAFO and conducted a survey of school employees to identify schools with noticeable livestock odor. We used publicly available information describing the enrollment of each school to assess the association between race and socioeconomic status (SES) and swine CAFO exposure. Odor from livestock was noticeable outside (n = 47, 21%) and inside (n = 19, 8%) school buildings. Schools with < 63% enrollment of white students and > or = 47% of students receiving subsidized lunches at school were located closer to swine CAFOs (mean = 4.9 miles) than were the remaining schools (mean = 10.8 miles) and were more likely to be located within 3 miles of an operation than were schools with high-white/high-SES enrollment (prevalence ratio = 2.63; 95% confidence interval, 1.59-4.33). The prevalence of reported livestock odor varied with SES (low SES, 25%; high SES, 17%). These analyses indicate that the potential for in-school exposure to pollution arising from swine CAFOs in North Carolina and the environmental health risks associated with such exposures vary according to the racial and economic characteristics of enrolled students.

Sociodemographic indicators and risk of brain tumours.

BACKGROUND: To better understand patterns of occurrence or diagnosis of brain tumours in different segments of the population, we evaluated associations between sociodemographic variables and the relative incidence of brain tumours as part of a multi-faceted case-control study. METHODS: The study was conducted at hospitals in three US cities between 1994 and 1998. In all, 489 glioma cases (354 high-grade, 135 low-grade), 197 meningioma cases, 96 acoustic neuroma cases, and 799 controls admitted to the same hospitals for any of a variety of non-neoplastic diseases or conditions were enrolled and interviewed. Logistic regression was used to estimate odds ratios (OR), calculate 95% CI, and test for trends. RESULTS: The OR showed significant positive associations with household income for low-grade glioma, meningioma, and acoustic neuroma, but not for high-grade glioma. Positive associations were observed with level of education for low-grade glioma and acoustic neuroma, but not for high-grade glioma or meningioma. Jewish religion was associated with a significantly elevated risk for meningioma (OR = 4.3; 95% CI: 2.0-9.0). Being single at the time of tumour diagnosis or enrolment was associated with significantly reduced risks for meningioma (OR = 0.4; 95% CI: 0.3-0.6) and low- or high-grade glioma (OR = 0.6; 95% CI: 0.5-0.8), but not for acoustic neuroma. CONCLUSIONS: Associations with sociodemographic variables varied considerably among the different subtypes of brain tumour, including between low-grade and high-grade glioma. The general pattern was for associations with indicators of affluence and education to be stronger for tumours that tend to grow more slowly and have less catastrophic effects, although the evidence was mixed for meningioma. We cannot isolate the specific factors underlying the observed associations, but intrapopulation differences in the completeness or timing of diagnosis may have played a role. There is less opportunity for such influences to operate for the rapidly progressing, high-grade gliomas than for more slowly growing tumours.

Asthma symptoms among adolescents who attend public schools that are located near confined swine feeding operations.

OBJECTIVES: Little is known about the health effects of living in close proximity to industrial swine operations. We assessed the relationship between estimated exposure to airborne effluent from confined swine feeding operations and asthma symptoms among adolescents who were aged 12 to 14 years. METHODS: During the 1999-2000 school year, 58169 adolescents in North Carolina answered questions about their respiratory symptoms, allergies, medications, socioeconomic status, and household environments. To estimate the extent to which these students may have been exposed during the school day to air pollution from confined swine feeding operations, we used publicly available data about schools (n = 265) and swine operations (n = 2343) to generate estimates of exposure for each public school. Prevalence ratios and 95% confidence intervals for wheezing within the past year were estimated using random-intercepts binary regression models, adjusting for potential confounders, including age, race, socioeconomic status, smoking, school exposures, and household exposures. RESULTS: The prevalence of wheezing during the past year was slightly higher at schools that were estimated to be exposed to airborne effluent from confined swine feeding operations. For students who reported allergies, the prevalence of wheezing within the past year was 5% higher at schools that were located within 3 miles of an operation relative to those beyond 3 miles and 24% higher at schools in which livestock odor was noticeable indoors twice per month or more relative to those with no odor. CONCLUSIONS: Estimated exposure to airborne pollution from confined swine feeding operations is associated with adolescents' wheezing symptoms.

Laterality of brain tumors.

Tumor laterality was evaluated with respect to presenting symptoms and demographic factors among 489 adults with histologically confirmed glioma (354 high-grade, 135 low-grade), 197 with meningioma, and 96 with acoustic neuroma. The ratio of left-sided to right-sided tumors did not differ significantly from 1.00 for any of the major tumor types. Low-grade glioma and meningioma occurred nonsignificantly more often on the left side, whereas high-grade glioma and acoustic neuroma occurred nonsignificantly more often on the right side. Aphasia or mental status changes were significantly more common among glioma patients with tumors on the left side than among those with tumors on the right side. Associations between tumor laterality and symptoms may influence the probability or timing of diagnosis, possibly differentially by marital status.