Lucina Suarez

Exposure to Fumonisins and the Occurrence of Neural Tube Defects Along the Texas–Mexico Border

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.

Cigarette Smoking Behavior Among US Latino Men and Women From Different Countries of Origin

OBJECTIVES This study sought to compare smoking behavior among Latino men and women from different countries of origin. METHODS A telephone-administered survey was conducted in 8 cities with Latino men and women of different national origin living in census tracts with at least 70% Latino individuals. RESULTS A total of 8882 participants completed the survey; 53% were women. The average age of respondents was 44 years; 63% were foreign-born, and 59% preferred Spanish for the interview. Current smoking was more prevalent among men (25.0%, 95% confidence interval [CI] = 23.7, 26.3) than among women (12.1%, 95% CI = 11.1, 13.0). Smoking rates were not significantly different by national origin among men, but Puerto Rican women had higher rates of smoking than other women. Central American men and women had the lowest smoking rates. Foreign-born respondents were less likely to be smokers (odds ratio [OR] = 0.77, 95% CI = 0.66, 0.90) than US-born respondents, and respondents with 12 years or less of education had an increased odds of smoking (OR = 1.17, 95% CI = 1.01, 1.35). High ac culturation was associated with more smoking in women (OR = 1.12, 95% CI = 1.00-1.25) and less smoking in men (OR = 0.86, 95% CI = 0.78-0.95). Puerto Rican and Cuban respondents were more likely to be current smokers and to smoke more than 20 cigarettes per day. CONCLUSIONS 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.

Pap smear and mammogram screening in Mexican-American women: the effects of acculturation.

OBJECTIVES For Mexican Americans, acculturation is a multidimensional process of adopting attitudes, values, and behavior from the non-Hispanic White culture. This study examines the effects of different dimensions of acculturation on the cancer screening behavior of Mexican-American women. METHODS Subjects were 450 randomly selected Mexican-American women age 40 years and older living in El Paso, Texas. Personal interviews solicited information on age, income, education, health insurance, Pap smear and mammogram use, and acculturation. Acculturation was measured with five scales that assessed English proficiency, English use, value placed on culture, traditional family attitudes, and social interaction. RESULTS The 2-year prevalence of Pap smear and mammogram screening increased with each gain in acculturation on English proficiency and use. These associations disappeared when adjusted for age, income, insurance, and education. After adjusting for sociodemographic factors and other acculturation dimensions, a strong traditional Mexican attitude toward family was positively related to mammography use. CONCLUSIONS Taking advantage of the positive influence of Hispanic familism on cancer screening behavior may increase the effectiveness of cancer control interventions in Mexican Americans.

Hispanic women's breast and cervical cancer knowledge, attitudes, and screening behaviors

Purpose. This study examined breast and cervical cancer knowledge, attitudes, and screening behaviors among different Hispanic populations in the United States. Design. Data were collected from a random digit dial telephone survey of 8903 Hispanic adults from eight U.S. sites. Across sites, the average response rate was 83%. Setting. Data were collected as part of the baseline assessment in a national Hispanic cancer control and prevention intervention study. Subjects. Analysis was restricted to 2239 Hispanic women age 40 and older who were self-identified as either Central American (n = 174), Cuban (n = 279), Mexican American (n = 1550), or Puerto Rican (n = 236). Measures. A bilingual survey instrument was used to solicit information on age, education, income, health insurance coverage, language use, U.S.-born status, knowledge of screening guidelines, attitudes toward cancer, and screening participation. Differences in knowledge and attitudes across Hispanic groups were assessed by either chi-square tests or analysis of variance. Logistic regression models assessed the influence of knowledge and attitudes on screening participation. Results. The level of knowledge of guidelines ranged from 58.3% (Mexican Americans) to 71.8% (Cubans) for mammography, and from 41.1% (Puerto Ricans) to 55.6% (Cubans) for Pap smear among the different Hispanic populations. Attitudes also varied, with Mexican Americans and Puerto Ricans having more negative or fatalistic views of cancer than Cuban or Central Americans. Knowledge was significantly related to age, education, income, language preference, and recent screening history. Overall, attitudes were not predictive of mammography and Pap smear behavior. Conclusions. 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.

Effects of hyperinsulinemia and obesity on risk of neural tube defects among Mexican Americans.

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.

Social networks and cancer screening in four U.S. Hispanic groups

BACKGROUND Evidence shows that social relationships play an important role in health and health behavior. We examined the relationship between social networks and cancer screening among four U.S. Hispanic groups. METHODS We used telephone surveys to collect data in eight U.S. regions that have concentrations of diverse Hispanic-origin populations. We interviewed 8903 Hispanic adults, for a response rate of 83%; analysis was restricted to the 2383 women aged > or =40. As a measure of social integration, we formed a social network index from items on the number of close relatives and friends, frequency of contact, and church membership. We used logistic regression to estimate the effects of social integration on screening, adjusting for sociodemographic factors. RESULTS Among Mexican, Cuban, and Central-American women, the effect of social integration on mammography screening was slight. The odds ratios (OR) per unit change in social integration category ranged from 1.16 to 1.22 with confidence intervals (CI) that overlapped with the null. For Pap smear screening, the effect was strongest among Mexican-American women (OR=1.44, 95% CI=1.21 to 1.72), but also evident among Central-American women (OR=1.22, 95% CI=0.72 to 2.06) and Cuban women (OR = 1.25, 95% CI = 0.81 to 1.93). Among Puerto Rican women, social integration had no effect on either mammography (OR=1.03) or Pap smear screening (OR=1.08). CONCLUSIONS Independent of socioeconomic factors, social integration appears to influence cancer screening participation of Hispanic women. The modest effect is not universal across Hispanic groups and was stronger for Pap smear than for mammography screening behavior. Researchers should recognize Hispanic group differences in social network characteristics and the potential of social networks to change screening behavior.

Maternal Serum B12 Levels and Risk for Neural Tube Defects in a Texas-Mexico Border Population

PURPOSE Neural tube defects (NTDs) are common birth defects that can be prevented with folate fortification and supplementation. Studies suggest that other nutrients may also be essential to neural tube closure and have a potential role in risk reduction, with vitamin B(12) mentioned most often. We determined the effect of maternal serum B(12) levels, measured postpartum, on the risk of NTDs among a high risk Mexican American population. METHODS The case-control study included 157 Mexican American women with NTD-affected pregnancies and 186 Mexican American women with normal pregnancies, who were residents of Texas-Mexico border counties and delivered during 1995 to 2000. RESULTS Compared with women in the highest vitamin B(12) quintile, women in the lowest quintile showed a strong risk effect (odds ratio (OR) = 3.0, confidence interval (CI): 1.4, 6.3); while those in the 2nd and 3rd quintiles showed moderate risk effects (OR = 1.6, CI = 0.7, 3.6 and OR = 1.7, CI = 0.8, 3.8, respectively). Adjusting for obesity, vitamin supplements, dietary folate, dietary B(12), red blood cell folate, and other covariates did not materially change these estimates. CONCLUSIONS Insufficient levels of serum B(12), which are not normally indicative of a classical vitamin B(12) deficiency nor stem from an inadequate diet, may be an important etiologic factor for NTDs in this population.

Dietary nitrites and nitrates, nitrosatable drugs, and neural tube defects.

Background: Amine-containing (nitrosatable) drugs can react with nitrite to form N-nitroso compounds, some of which are teratogenic. Data are lacking on whether dietary intake of nitrates and nitrites modifies the association between maternal nitrosatable drug exposure and neural tube defects (NTDs) in offspring. Methods: We examined nitrosatable drug exposure and NTD-affected pregnancies in relation to dietary nitrite and total nitrite intake in a case-control study of Mexican American women. We interviewed 184 women with NTD-affected pregnancies and 225 women with normal live births, including questions on periconceptional drug exposures and dietary intake. For 110 study participants, nitrate was also measured in the usual source of drinking water. Results: Women who reported taking drugs classified as nitrosatable were 2.7 times more likely to have an NTD-affected pregnancy than women without this exposure (95% confidence interval [CI] = 1.4–5.3). The effect of nitrosatable drugs was observed only in women with higher intakes of dietary nitrite and total nitrite (dietary nitrite + 5% dietary nitrate). Women within the highest tertile (greater than 10.5 mg/day) of total nitrite were 7.5 times more likely to have an NTD-affected pregnancy if they took nitrosatable drugs (95% CI = 1.8–45.4). The association between nitrosatable drug exposure and NTDs was also stronger in women whose water nitrate levels were higher. Conclusions: 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.

Parental occupation and neural tube defect-affected pregnancies among Mexican Americans.

In a case–control study, we examined whether parental occupational exposures were related to neural tube defect (NTD)–affected pregnancies among Mexican Americans living along the Texas–Mexico border. Case women were 184 Mexican-American women with NTD-affected pregnancies; control women were 225 study-area residents who delivered normal babies during the same period as the case women. The women were interviewed in person about maternal and paternal occupations and work exposures during the periconceptional period. Compared with control women, case women were more likely to have had occupational exposures to solvents (odds ratio [OR], ∞; 95% confidence interval [CI], 2.4−∞) and also were more likely to have worked in cleaning (OR 9.5; 95% CI, 1.1 to 82.2) or health care occupations (OR 3.0; 95% CI, 1.0 to 9.0) than control women. No compelling associations were found between paternal work exposures or occupations and NTDs in offspring in this population.

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.