Pesticides and inner-city children: exposures, risks, and prevention

Six million children live in poverty in America's inner cities. These children are at high risk of exposure to pesticides that are used extensively in urban schools, homes, and day-care centers for control of roaches, rats, and other vermin. The organophosphate insecticide chlorpyrifos and certain pyrethroids are the registered pesticides most heavily applied in cities. Illegal street pesticides are also in use, including tres pasitos (a carbamate), tiza china, and methyl parathion. In New York State in 1997, the heaviest use of pesticides in all counties statewide was in the urban boroughs of Manhattan and Brooklyn. Children are highly vulnerable to pesticides. Because of their play close to the ground, their hand-to-mouth behavior, and their unique dietary patterns, children absorb more pesticides from their environment than adults. The long persistence of semivolatile pesticides such as chlorpyrifos on rugs, furniture, stuffed toys, and other absorbent surfaces within closed apartments further enhances urban children's exposures. Compounding these risks of heavy exposures are children's decreased ability to detoxify and excrete pesticides and the rapid growth, development, and differentiation of their vital organ systems. These developmental immaturities create early windows of great vulnerability. Recent experimental data suggest, for example, that chlorpyrifos may be a developmental neurotoxicant and that exposure in utero may cause biochemical and functional aberrations in fetal neurons as well as deficits in the number of neurons. Certain pyrethroids exert hormonal activity that may alter early neurologic and reproductive development. Assays currently used for assessment of the toxicity of pesticides are insensitive and cannot accurately predict effects to children exposed in utero or in early postnatal life. Protection of American children, and particularly of inner-city children, against the developmental hazards of pesticides requires a comprehensive strategy that monitors patterns of pesticide use on a continuing basis, assesses children's actual exposures to pesticides, uses state-of-the-art developmental toxicity testing, and establishes societal targets for reduction of pesticide use.

Risk factors for preterm birth subtypes

To assess epidemiologic risk factors for preterm birth subcategories in an urban population, we undertook a study of 31,107 singleton livebirths that took place at Mount Sinai Hospital in New York City between 1986 and 1994. We subdivided the preterm births into preterm premature rupture of the membranes, preterm labor, and medically induced births. We obtained information regarding the preterm subtypes and their epidemiologic risk factors from a computerized perinatal database. Adjusted odds ratios showed an increased risk for all three preterm birth subtypes in women who were black (1.9 for preterm premature rupture of membranes, 2.1 for preterm labor, and 1.7 for medically induced births) or Hispanic (1.7 for preterm premature rupture of membranes, 1.9 for preterm labor, and 1.6 for medically induced births), those who had had a previous preterm birth (3.2 for preterm premature rupture of membranes, 4.5 for preterm labor, and 3.3 for medically induced births), those who began prenatal care after the first trimester ( 1.4 for preterm premature rupture of membranes, 1.3 for preterm labor, and 1.3 for medically induced births), women who had been exposed to diethylstilbestrol in utero (3.1 for preterm premature rupture of membranes, 4.1 for preterm labor, and 3.7 for medically induced births), patients with preexisting diabetes mellitus (2.2 for preterm premature rupture of membranes, 2.4 for preterm labor, and 9.5 for medically induced births), and those with antepartum bleeding (2.8 for preterm premature rupture of membranes, 3.6 for preterm labor, and 3.7 for medically induced births). Other sociodemographic, constitutional, life-style, and obstetrical characteristics differed across the groups. Variation in some of the risk factors among the preterm subtypes implies that epidemiologic assessment of the more specific outcomes would be advisable.

p53 haplotype determination in breast cancer

Inheritance of certain germ line haplotypes consisting of three biallelic polymorphisms of p53 has been proposed as a risk factor for breast cancer and colorectal cancer [A. Själander et al., Carcinogenesis (Lond.), 17: 1313-1316, 1996, and Carcinogenesis (Lond.), 16: 1461-1464, 1995]. In their studies, pairwise haplotypes of these three polymorphisms were estimated. Extended haplotypes were further projected from the pairwise combinations. To overcome the necessity to estimate pairwise and extended haplotype frequencies, a PCR method has been developed to determine the absolute extended p53 haplotypes in diploid genomes. The method requires allele-specific PCR, confirmed by restriction analysis, and successive amplicon analysis. It has been applied to a nested case-control study of breast cancer (284 subjects; 99 cases and 185 controls; 182 Caucasians, 56 Hispanics, and 46 African-Americans). Evidence is presented that minor variants of the intron 3, codon 72, and intron 6 polymorphisms were moderately elevated in Caucasian breast cancer cases (intron 3, P = 0.03 for genotype and P = 0.01 for allelic frequency; codon 72, P = 0.07 for genotype and P = 0.054 for allelic frequency; and intron 6, P = 0.02 for genotype and P = 0.02 for allele frequency). Accordingly, analysis of haplotype distributions suggested an association of minor p53 haplotypes with breast cancer risk in Caucasians (P = 0.07). The relative allelic frequencies in breast cancer cases compared with controls also differed by age and menopausal status; the 1-2-1 haplotype was overrepresented in postmenopausal cases (P = 0.02) and cases older than 50 years (P = 0.02), whereas the other minor haplotypes (1-1-2 and rare variants) were overrepresented in premenopausal cases (P = 0.003) and cases 50 years of age and younger (P = 0.02). Genotype distributions at each locus and for all control groups were consistent with Hardy-Weinberg equilibria. Differences in haplotype distribution were associated with ethnicity (Caucasians versus African-Americans and Caucasians versus Hispanics, P < 0.001). The new haplotyping method may be useful in the study of gene-environment interactions.

Corticotropin-releasing factor and its binding protein: maternal serum levels in term and preterm deliveries

OBJECTIVE

The primary objective of this investigation was to evaluate whether maternal serum corticotropin-releasing factor levels during pregnancy were predictive of spontaneous preterm delivery.

STUDY DESIGN

Maternal serum levels of corticotropin-releasing factor and its binding protein were measured from 20 weeks of gestation in a cross-sectional study of 396 asymptomatic women at high risk for preterm delivery.

RESULTS

Gestational age-specific corticotropin-releasing factor levels were not consistently or substantially increased for preterm compared with term deliveries, whether preterm delivery was due to preterm labor or preterm premature rupture of membranes. The binding protein for corticotropin-releasing factor did not vary according to gestational age until term, when it dropped substantially.

CONCLUSION

Serum corticotropin-releasing factor levels do not appear to be an important predictor of preterm birth in asymptomatic patients who subsequently have either preterm labor or preterm premature rupture of membranes. Nevertheless, the drop in the corticotropin-releasing factor binding protein level at term suggests that the bioavailability of corticotropin-releasing factor increases as parturition approaches.

The role of DDE and polychlorinated biphenyl levels in preterm birth

Maternal serum levels of DDE and polychlorinated biphenyls (PCB) and their congeners were compared for 20 women who had a spontaneous preterm delivery and 20 matched women who had delivered at term at Mount Sinai Medical Center in New York between October 1990 and August 1993. Since no substantial case-control differences were evident, these findings do not indicate that increased DDE or PCB levels are associated with spontaneous preterm birth.

Risk factors for cryptorchidism: a nested case-control study

A nested case-control study of cryptorchidism (i.e. undescended testicles) was undertaken as part of a hospital-based cohort study of 6699 singleton male neonates in New York City. Since some of the cryptorchid infants experienced spontaneous descent of their testes, separate analysis was performed for this third group of 'late descenders' (n=140). Cases (n=63) represented infants whose testes remained undescended at the one year assessment. Controls (n=219) represented the next male infant who was delivered immediately after an infant who was cryptorchid at birth. The only independent risk factors for cryptorchidism were Asian ethnic group (adjusted odds ratio (OR) = 3.90, 95% confidence interval (CI) = 1.22-12.41), swollen legs or feet during pregnancy (adjusted OR = 2.16, 95% CI = 1.15-4.04), a family history of cryptorchidism (adjusted OR = 4.32, 95% CI = 1.91-9.80), low birthweight (adjusted OR = 4.10, 95% CI = 1.39-12.08), and use of analgesics during pregnancy (adjusted OR = 1.93, 95% CI = 1.03-3.62). Multiple logistic regression analysis was also performed to identify those factors that were associated with late testicular descent. In this analysis the independent risk factors were black or Hispanic ethnicity (adjusted OR = 2.05, 95% CI = 1.09-3.83), a family history of cryptorchidism (adjusted OR = 4.25, 95% CI = 1.84-9.78), consumption of cola-containing drinks during the pregnancy (adjusted OR = 2.09, 95% CI = 1.10-3.99), a low birthweight delivery (adjusted OR = 9.78, 95% CI = 3.39-28.20), and preterm birth (adjusted OR = 4.01, 95% CI = 1.66-9.70).

Corticotropin-releasing hormone and related pituitary-adrenal axis hormones in fetal and maternal blood during the second half of pregnancy

There is little information available concerning the ontologic development of the human hypothalamic-pituitary-adrenal (HPA) axis nor of the potential interactions among fetal, maternal and placental-derived HPA axis hormones. This study evaluated levels of these hormones in matched maternal and fetal pairs during the second half of uncomplicated pregnancies. Immunoassays were used to measure serum concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropin (ACTH) and cortisol in 104 matched fetal and maternal blood samples. Fetal specimens were obtained by percutaneous umbilical blood sampling (PUBS) between 18 and 40 weeks in patients whose pregnancies resulted in healthy, term infants. Correlations among these hormones, and the effect of gestational age were assessed. Maternal CRH concentrations [median (range)] [1.10 ng/ml (0.15 to 23.69)] were significantly greater than fetal values [0.35 ng/ml (0.07 to 1.0)]. Levels of maternal CRH (r = 0.73; p < 0.001) but not fetal CRH (r = 0.01; p = 0.98) correlated with gestational age. Maternal ACTH decreased (r = -0.21; p = 0.04) while fetal ACTH increased (r = 0.35; p < 0.003) with gestational age. Both maternal (r = 0.45; p < 0.001) and fetal (r = 0.57; p < 0.001) cortisol levels increased with gestational age. Maternal serum CRH values correlated best with fetal cortisol (r = 0.40; p = 0.0002) and correlated modestly with maternal cortisol (r = 0.28; p = 0.01), fetal ACTH (r = 0.24; p = 0.03) and fetal CRH (r = 0.23; p = 0.04); but not with maternal ACTH (r = -0.12; p = 0.3). Maternal CRH concentrations increase in the third trimester and correlate with rising fetal cortisol levels.

Employment-related physical activity and pregnancy outcome

Concern about possible adverse reproductive effects of employment reflects the increasing participation of pregnant women in the labor force. Although the literature on the effect of employment-related physical activity on pregnancy outcome is substantial, no general consensus has been reached. A growing number of studies, however, suggests that prolonged standing and long working hours may pose a risk to pregnancy. The provision of maternity benefits varies greatly between the United States and European countries. Current modifications of working conditions for both pregnant and non-pregnant women differ even among European countries.

Working conditions, maternity legislation, and preterm birth

The review of the scientific literature on the role of employment-related physical activity suggests that prolonged standing and long working hours may increase the risk of preterm delivery. Although maternity legislation in many European countries has regulated work schedules and working conditions for pregnant women, none of the European countries except for France seems to have experienced a reduction in preterm rates. France has had both a comprehensive maternity legislation and a national program specifically aimed to reduce preterm birth. Despite the lack of reduction in preterm rates, paid maternity leave, guaranteed job protection, and regulation of hazardous working conditions remain a desirable societal goal for any industrialized nation.

Maternal and neonatal risk factors for cryptorchidism

We assessed risk factors for cryptorchidism in a prospective hospital-based cohort study at Mount Sinai Hospital in New York City. We examined at birth 6,699 singleton male neonates who were delivered between October 1987 and October 1990. Follow-up examinations were undertaken at 3 months and 1 year for those diagnosed as cryptorchid at birth. We calculated prevalence ratios and adjusted odds ratios according to selected maternal and neonatal characteristics for those who remained cryptorchid at the 1-year assessment. We found elevated risks for maternal obesity [prevalence ratio = 2.42; 95% confidence interval (CI) = 1.11-5.27], for infants delivered by cesarean section (adjusted odds ratio = 2.17; 95% CI = 1.29-3.65), for low birthweight (adjusted odds ratio = 2.29; 95% CI = 1.12-4.70), for preterm birth (adjusted odds ratio = 2.25; 95% CI = 1.16-4.35), and for infants with congenital malformations (prevalence ratio = 13.97; 95% CI = 1.27-26.67). We observed a seasonal effect, with a peak in births of cryptorchid infants during September through November and a smaller peak during the months of March through May. We found no evidence that young women, white women, or primiparas were at increased risk.

An estrogen receptor genetic polymorphism and the risk of primary and secondary recurrent spontaneous abortion

OBJECTIVE

A case-control study was undertaken to assess the association between an estrogen receptor gene variant and the risk of recurrent spontaneous abortions.

STUDY DESIGN

The frequency of the estrogen receptor gene variant in blood lymphocyte deoxyribonucleic acid and other selected maternal characteristics was compared among 60 primary recurrent aborters, 61 secondary recurrent aborters, and 43 women who had had at least two live births but no spontaneous abortions.

RESULTS

No association was evident between the estrogen receptor gene variant and the risk of either primary or secondary recurrent abortion. There were data suggesting that primary recurrent aborters in particular were more likely to report a family history of recurrent abortion and a family history of breast cancer.

CONCLUSIONS

These findings indicate that the estrogen receptor polymorphism is not a genetic marker for recurrent spontaneous abortions. Therefore, as suggested by previous investigations, this polymorphism appears to be a marker for breast cancer risk only among the subgroups who have had a history of repeated abortions.

Association of an estrogen receptor variant with increased height in women

There is an association between a B region allele (here called the B' allele) of the estrogen receptor (ER) and a history of spontaneous abortion in women with ER positive breast cancer, but no such association for women with ER negative tumors or women without breast cancer. In this study we compared the heights of women carrying the B and B' alleles. The B' allele was identified by polymerase chain reaction to amplify genomic DNA around the polymorphic region of the ER gene, followed by allele specific oligonucleotide hybridization. This analysis used DNA obtained from blood lymphocytes. Women carrying the B' allele were significantly taller than those carrying the wild type allele (B allele). Multiple linear regression also demonstrated that this association remained (p = 0.017), controlling for the effects of age and race. Since the B' ER allele results from a silent mutation, a second mutation, segregating with it, no doubt plays a role in producing the high incidence of spontaneous abortion we reported previously and the height difference we report here. This second mutation might lie within the estrogen receptor itself or within one of the genes nearby.

Fractured clavicle in the neonate: a retrospective three-year review

A hospital-based case-controlled study was undertaken to determine maternal and neonatal characteristics associated with fractured clavicle. A total of 11,604 consecutive vaginal deliveries of liveborn infants in vertex presentation at the Mount Sinai Hospital from 1988 to 1990 were reviewed. Maternal and neonatal characteristics were compared for the neonates with and without a diagnosis of a fractured clavicle. Compared to controls, mothers of neonates with a fractured clavicle were more likely to be nulliparas or primiparas, to have had an operative vaginal delivery, and to have been delivered by an attending as opposed to a resident physician. The fractured clavicle group also had a longer gestational age, greater birthweight, and higher frequency of macrosomic infants. After controlling for maternal parity, type of delivery and infant birthweight, experience of the delivering physician, and gestational age at delivery were not significantly different. Fracture of the clavicle in the neonate is related to maternal parity, mode of delivery, and infant birthweight but not to the level of experience of the delivering physician.

Risk factors for severe preeclampsia

OBJECTIVE

To identify risk factors associated with severe preeclampsia and to determine whether these factors are similar in nulliparous and multiparous patients.

METHODS

Patients whose pregnancies were complicated by severe preeclampsia (n = 70) were compared retrospectively to 18,964 non-preeclamptic controls. Information on maternal demographic factors; medical, obstetric, and family histories; and neonatal outcome was retrieved and analyzed by univariate and multivariate analysis.

RESULTS

By logistic regression, the only risk factors associated with the development of severe preeclampsia were severe obesity in all patients (adjusted odds ratio 3.5, 95% confidence interval [CI] 1.68-7.46) and a history of preeclampsia in multiparous patients (adjusted odds ratio 7.2, 95% CI 2.74-18.74).

CONCLUSION

Severe obesity and a history of preeclampsia are the only maternal risk factors identified for the development of severe preeclampsia.

Prevalence and natural history of cryptorchidism

OBJECTIVE

A prospective hospital-based cohort study was conducted to determine the prevalence rates of cryptorchidism at birth, 3 months, and 1 year of age.

DESIGN

A total of 6935 consecutive male neonates delivered at Mount Sinai Hospital in New York City between October 1987 and October 1990 were examined at birth for cryptorchidism. Standardized examination and classification criteria were used. Infants classified as cryptorchid at birth were reexamined at 3 months and 1 year after the expected date of delivery.

RESULTS

Of 6935 neonates assessed at birth, 255 (3.7%) were found to be cryptorchid at birth. The rates were significantly elevated for low birth weight, preterm, small-for-gestational age, and twin neonates. The overall rate had declined to 1.0% by the 3-month assessment and 1.1% at the 1-year assessment. Although the rates at the 1-year assessment tended to be higher for low birth weight and preterm infants, no significant group differences were observed.

CONCLUSIONS

Since the prevalence rates in this study are similar to those reported several decades ago, these data provide no evidence that the rate of cryptorchidism has increased either at birth or by 1 year of age. Furthermore, most testes that descend spontaneously do so within the first 3 months after the expected date of delivery.

Association between pregnancy-induced hypertension and asthma during pregnancy

OBJECTIVE

Pregnancy-induced hypertension is an important cause of maternal mortality, intrauterine growth retardation, and perinatal mortality. We examined the relationship between pregnancy-induced hypertension and asthma.

STUDY DESIGN

The study population consisted of 24,115 women without a history of chronic systemic hypertension who were delivered of live born and stillborn infants at Mount Sinai Medical Center between January 1987 and December 1991. Pregnancy-induced hypertension was defined as blood pressure of at least 140/90 mm Hg or an increase of > or = 30 mm Hg in systolic pressure or > or = 15 mm Hg in diastolic pressure.

RESULTS

There was a significant association between pregnancy-induced hypertension and asthma during pregnancy (chi 2 = 17.86, p < 0.001). In addition, there was a significant upward trend in the incidence of asthma during pregnancy in women without, with moderate, and with severe pregnancy-induced hypertension (Mantel-Haenszel chi 2 = 11.8, p = 0.001). Logistic regression analysis demonstrated that the association between pregnancy-induced hypertension and asthma during pregnancy persisted after adjustment for the confounding factors of race or ethnicity, maternal age, parity, and prepregnancy weight (adjusted odds ratio 2.52, 95% confidence interval 1.47 to 4.35, p = 0.0008). An association between pregnancy-induced hypertension and a history of asthma was also found (chi 2 = 11.2, p = 0.001). However, after adjustment for potential confounders, this association failed to achieve statistical significance (adjusted odds ratio 1.2, 95% confidence interval 0.97 to 1.53, p = 0.083).

CONCLUSION

Both pregnancy-induced hypertension and asthma might be caused by a third factor affecting smooth muscle reactivity.

Morbidity of failed labor in patients with prior cesarean section

OBJECTIVE

The aim of our study was to determine whether the reported increased morbidity associated with failed attempted vaginal birth after cesarean section is attributable to the presence of a uterine scar alone or to labor preceding a cesarean section.

STUDY DESIGN

Primiparous women (N = 237) who underwent repeat cesarean section after a failed trial of vaginal birth after cesarean section were retrospectively compared with 1582 nulliparous women who underwent a primary cesarean section after a failed trial of labor.

RESULTS

There were no significant differences in maternal or neonatal morbidity between the two groups except for an increase in the prevalence of thin meconium in patients undergoing primary cesarean section.

CONCLUSION

Our results suggest that the presence of a previous cesarean section scar does not increase the overall baseline morbidity associated with cesarean section after labor.

Maternal characteristics, neonatal outcome, and the time of diagnosis of gestational diabetes

OBJECTIVE

A study was undertaken to evaluate the yield of early, routine screening for gestational diabetes and to determine whether maternal characteristics and neonatal outcome differ according to the time of diagnosis.

STUDY DESIGN

A total of 2776 women were screened before 24 weeks of gestation, and each was delivered of a singleton infant on the clinic service of Mount Sinai Hospital in New York City between January 1986 and January 1991.

RESULTS

An abnormal glucose tolerance test was diagnosed in 102 women < 24 weeks and in 252 patients at > or = 24 weeks of gestation. Logistic regression analysis showed that the group diagnosed early was significantly older and more likely to have hypertensive disorders and low maternal weight gain and to require insulin treatment, compared with the group diagnosed late. No significant differences were evident in neonatal outcome.

CONCLUSIONS

These data indicate that a sizable proportion of patients with gestational diabetes can be diagnosed early in pregnancy. The differences in maternal characteristics and insulin requirements between the early- and late-diagnosis groups also suggest heterogeneity of gestational diabetes or the possibility of preexisting impaired glucose intolerance in the early-diagnosis group.

Race/ethnicity and other risk factors for gestational diabetes

Although gestational diabetes is estimated to complicate between 1% and 5% of pregnancies, there are only limited data on the role of race/ethnicity as well as other risk factors in the development of this disorder. Epidemiologic characteristics of gestational diabetes were assessed in an ethnically diverse cohort of 10,187 women who had undergone standardized screening for glucose intolerance and who delivered a singleton infant at the Mount Sinai Medical Center in New York City between January 1987 and December 1989. The overall prevalence of gestational diabetes was 3.2%. Multiple logistic regression analysis showed excess risks for Oriental women, Hispanics born in Puerto Rico or elsewhere outside the United States, women from the Indian subcontinent and the Middle East, older mothers, heavier women, those with a positive family history of diabetes, women with a history of infertility, and those who delivered on the clinic service. These data suggest that, after controlling for traditional risk factors (maternal age, prepregnancy weight, and a family history of diabetes), Orientals, first generation Hispanics, women from the Indian subcontinent and the Middle East, those with a history of infertility, and low socioeconomic status women are at an increased risk for gestational diabetes.

Clinical significance and sonographic diagnosis of velamentous umbilical cord insertion

In order to evaluate the clinical significance of velamentous cord insertion (VCI) and the role of ultrasound in its diagnosis, all 82 cases of VCI during January 1985 to January 1989 at the Mount Sinai Medical Center were reviewed. The overall rate of VCI in our study (0.5%) was similar to that of previous reports. Pregnancy outcomes in VCI patients with 77 singleton gestations were compared with a control group of 15,865 patients. In contrast to the existing literature, multiparity and prior cesarean section deliveries were not increased in pregnancies with VCI. The VCI group had more intrapartum complications and a lower birthweight than the controls. Routine nontargeted obstetric ultrasound failed to detect any cases of VCI, including three cases of vasa previa. Since VCI was not identified prenatally and many of its sequelae are readily identifiable only during the intrapartum period, the potential for preemptive obstetric intervention appears to be limited. In addition, failure to diagnose apparent VCI during a routine ultrasound does not appear to be a departure from the standard of care.