Along the Texas–Mexico border, the prevalence of neural tube defects (NTDs) among Mexican-American women doubled during 1990–1991. The human outbreak began during the same crop year as epizootics attributed to exposure to fumonisin, a mycotoxin that often contaminates corn. Because Mexican Americans in Texas consume large quantities of corn, primarily in the form of tortillas, they may be exposed to high levels of fumonisins. We examined whether or not maternal exposure to fumonisins increases the risk of NTDs in offspring using a population-based case–control study. We estimated fumonisin exposure from a postpartum sphinganine:sphingosine (sa:so) ratio, a biomarker for fumonisin exposure measured in maternal serum, and from maternal recall of periconceptional corn tortilla intake. After adjusting for confounders, moderate (301–400) compared with low (≤ 100) consumption of tortillas during the first trimester was associated with increased odds ratios (ORs) of having an NTD-affected pregnancy (OR = 2.4; 95% confidence interval, 1.1–5.3). No increased risks were observed at intakes higher than 400 tortillas (OR = 0.8 for 401–800, OR = 1.0 for > 800). Based on the postpartum sa:so ratio, increasing levels of fumonisin exposure were associated with increasing ORs for NTD occurrences, except for the highest exposure category (sa:so > 0.35). Our findings suggest that fumonisin exposure increases the risk of NTD, proportionate to dose, up to a threshold level, at which point fetal death may be more likely to occur. These results also call for population studies that can more directly measure individual fumonisin intakes and assess effects on the developing embryo.

Older, US-born, and more-educated respondents were less likely to be current smokers. Respondents of Puerto Rican and Cuban origin were more likely to smoke. Acculturation has divergent effects on smoking behavior by sex.

Factors related to mammography and Pap smear screening vary among the different Hispanic populations. Limitations include the cross-sectional nature of the study, self-reported measures of screening, and the limited assessment of attitudes. The data and diversity of Hispanic groups reinforce the position that ethno-regional characteristics should be clarified and addressed in cancer screening promotion efforts. The practical relationships among knowledge, attitudes, and cancer screening are not altogether clear and require further research.

Although both maternal obesity and diabetes mellitus increase the risk for neural tube defects, it is unknown whether they are independent risk factors or manifestations of an underlying prediabetic state such as hyperinsulinemia. We investigated whether hyperinsulinemia was a risk factor for neural tube defects independent of obesity and hyperglycemia in Mexican-American women. We identified case and control women from residents delivering or terminating pregnancies in hospitals or birthing centers in any of the 14 Texas-Mexico border counties during 1995-2000. Case women had a pregnancy affected by anencephaly, spina bifida, or encephalocele; randomly selected control women had normal births, frequency matched by year and birth facility. Questionnaire and laboratory values obtained 5-6 weeks postpartum were available for 149 case and 178 control women. Both hyperinsulinemia and obesity were related to increased neural tube defect risk [odds ratio (OR) = 1.91, 95% confidence interval (CI) = 1.21-3.01 and OR = 1.73, 95% CI = 1.03-2.92, respectively]. Adjustment for obesity only slightly reduced the effect of hyperinsulinemia (OR = 1.75, 95% CI = 1.09-2.82). Alternatively, a modest effect remained for obesity after adjustment for hyperinsulinemia (OR = 1.45, 95% CI = 0.84-2.51). Hyperinsulinemia is a strong risk factor for neural tube defects and may be the driving force for the observed risk in obese women.

Findings suggest that effects of nitrosatable drug exposure on risk for neural tube defects in offspring could depend on the amounts of dietary nitrite and total nitrite intake.