Judy P. Henry

Maternal pesticide exposure and neural tube defects in Mexican Americans.

PURPOSE The relation between maternal pesticide exposures and neural tube defects (NTDs) in offspring was evaluated in 184 Mexican American case-women and 225 comparison women. METHODS In-person interviews solicited information about environmental and occupational exposures to pesticides during the periconceptional period. RESULTS With adjustment for maternal education, smoking, and folate intake, women who reported using pesticides in their homes or yards were two times more likely (95% confidence interval [CI], 1.2-3.1) to have NTD-affected pregnancies than women without these reported exposures. Case-women were also more likely to report living within 0.25 mile of cultivated fields than control-women (odds ratio [OR] 3.6; 95% CI, 1.7-7.6). As sources of pesticide exposure opportunities increased, risk of NTDs also increased. The adjusted ORs and 95% CIs for one, two, and three or more exposure sources were 1.2 (0.69-1.9), 2.3 (1.3-4.1) and 2.8 (1.2-6.3) respectively, and this positive trend was stronger for risk of anencephaly than for spina bifida. CONCLUSIONS Self-reported pesticide exposures were associated with NTD risk in this study population, especially use of pesticides within the home and a periconceptional residence within 0.25 mile of cultivated fields.

Challenges in Addressing Community Concerns Regarding Clusters of Multiple Sclerosis and Potential Environmental Exposures

Citizens living around hazardous waste sites in the USA have expressed concern to public health officials at the local, state and federal level about a perceived high prevalence of multiple sclerosis (MS) in their communities. Many believe the occurrence of the disease is directly linked to exposure to chemical agents from the nearby hazardous waste site. Although the public’s concern regarding these clusters should be addressed, epidemiologists have long known that evaluating perceived clusters is rarely fruitful for identifying an etiologic agent. In order to adequately address concerns regarding clusters of MS, as well as examining the role of environmental exposures and genetic susceptibility in the causal mechanism of disease, several activities need to be conducted including characterizing the occurrence of disease, developing a standardized case definition and establishing partnerships to develop innovative research techniques. Only with collaboration across disciplines and lessons learned from past research will we be able to effectively guide research efforts directed at determining the etiology of this disease.

Exposure to polychlorinated biphenyls and risk of neural-tube defects in a Mexican American population.

Abstract The authors examined the association between maternal polychlorinated biphenyl (PCB) levels and risk of neural tube defects (NTDs) in Mexican American women with NTD-affected pregnancies who resided in the 14 Texas-Mexico border counties during 1995–2000 (cases). Controls were randomly selected from study area women delivering normal live births. For PCB congeners with sufficient numbers of detectab values (PCB 99, 101, 110, 118, 138, 153, 180), there was little association between the proportions with detectable PCB levels in cases and controls. Odds ratios were <1 or compatible with the null, but power was low for some congeners. All index of seven PCB congeners (105, 118, 138,153, 170, 180, 194) was also not associated with NTD risk. The maternal serum PCB levels in this study population (median PCB 153 level: 18 ng/g) were comparable to those with background exposure and do not appear to have contributed to the high prevalence of NTDs in this population.