Drinking water disinfection byproducts and risk of orofacial clefts in the National Birth Defects Prevention Study

BACKGROUND

Maternal exposure to drinking water disinfection byproducts (DBP)s may contribute to orofacial cleft (OFC) development, but studies are sparse and beset with limitations.

METHODS

Population-based, maternal interview reports of drinking water filtration and consumption for 680 OFC cases (535 isolated) and 1826 controls were linked with DBP concentration data using maternal residential addresses and public water system monitoring data. Maternal individual-level exposures to trihalomethanes (THM)s and haloacetic acids (HAA)s (µg/L of water consumed) were estimated from reported consumption at home, work, and school. Compared to no exposure, associations with multisource maternal exposure <1/2 or ≥1/2 the Maximum Contaminant Levels (MCL)s for total THMs (TTHM)s and HAAs (HAA5) or Maximum Contaminant Level Goals (MCLG)s for individual THMs and HAAs (if non-zero) were estimated for all OFCs and isolated OFCs, cleft palate (CP), and cleft lip ± cleft palate (CL/P) using logistic regression analyses.

RESULTS

Compared to controls, associations were near or below unity for maternal TTHM, HAA5, and individual THM exposures with all OFCs and isolated OFCs, CP, and CL/P. Associations also were near or below unity for individual HAAs with statistically significant, inverse associations observed with each OFC outcome group except CL/P.

CONCLUSIONS

This study examined associations for maternal reports of drinking water filtration and consumption and maternal DBP exposure from drinking water with OFCs in offspring. Associations observed were near or below unity and mostly nonsignificant. Continued, improved research using maternal individual-level exposure data will be useful in better characterizing these associations.

Prevalence of Duchenne and Becker muscular dystrophies in the United States

OBJECTIVE

To estimate prevalence of childhood-onset Duchenne and Becker muscular dystrophies (DBMD) in 6 sites in the United States by race/ethnicity and phenotype (Duchenne muscular dystrophy [DMD] or Becker muscular dystrophy [BMD]).

METHODS

In 2002, the Centers for Disease Control and Prevention established the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) to conduct longitudinal, population-based surveillance and research of DBMD in the United States. Six sites conducted active, multiple-source case finding and record abstraction to identify MD STARnet cases born January 1982 to December 2011. We used cross-sectional analyses to estimate prevalence of DBMD per 10 000 boys, ages 5 to 9 years, for 4 quinquennia (1991-1995, 1996-2000, 2001-2005, and 2006-2010) and prevalence per 10 000 male individuals, ages 5 to 24 years, in 2010. Prevalence was also estimated by race/ethnicity and phenotype.

RESULTS

Overall, 649 cases resided in an MD STARnet site during ≥1 quinquennia. Prevalence estimates per 10 000 boys, ages 5 to 9 years, were 1.93, 2.05, 2.04, and 1.51, respectively, for 1991-1995, 1996-2000, 2001-2005, and 2006-2010. Prevalence tended to be higher for Hispanic individuals than non-Hispanic white or black individuals, and higher for DMD than BMD. In 2010, prevalence of DBMD was 1.38 per 10 000 male individuals, ages 5 to 24 years.

CONCLUSIONS

We present population-based prevalence estimates for DBMD in 6 US sites. Prevalence differed by race/ethnicity, suggesting potential cultural and socioeconomic influences in the diagnosis of DBMD. Prevalence also was higher for DMD than BMD. Continued longitudinal surveillance will permit us to examine racial/ethnic and socioeconomic differences in treatment and outcomes for MD STARnet cases.

Cancer risk in children and adolescents with birth defects: a population-based cohort study

Objective

Birth defects are an increasing health priority worldwide, and the subject of a major 2010 World Health Assembly Resolution. Excess cancer risk may be an added burden in this vulnerable group of children, but studies to date have provided inconsistent findings. This study assessed the risk for cancer in children and young adolescents with major birth defects.

Methods and Findings

This retrospective, statewide, population-based, cohort study was conducted in three US states (Utah, Arizona, Iowa). A cohort of 44,151 children and young adolescents (0 through 14 years of age) with selected major, non-chromosomal birth defects or chromosomal anomalies was compared to a reference cohort of 147,940 children without birth defects randomly sampled from each state’s births and frequency matched by year of birth. The primary outcome was rate of cancer prior to age 15 years, by type of cancer and type of birth defect. The incidence of cancer was increased 2.9-fold (95% CI, 2.3 to 3.7) in children with birth defects (123 cases of cancer) compared to the reference cohort; the incidence rates were 33.8 and 11.7 per 100,000 person-years, respectively. However, the excess risk varied markedly by type of birth defect. Increased risks were seen in children with microcephaly, cleft palate, and selected eye, cardiac, and renal defects. Cancer risk was not increased with many common birth defects, including hypospadias, cleft lip with or without cleft palate, or hydrocephalus.

Conclusion

Children with some structural, non-chromosomal birth defects, but not others, have a moderately increased risk for childhood cancer. Information on such selective risk can promote more effective clinical evaluation, counseling, and research.

Reproductive patterns among mothers of males diagnosed with Duchenne or Becker muscular dystrophy

Diagnosis of a child with Duchenne or Becker muscular dystrophy (DBMD) may impact future maternal reproductive choice; however, little is known about the reproductive patterns of mothers with a male child diagnosed with DBMD. Using population-based surveillance data collected by the muscular dystrophy surveillance, tracking, and research network, the proportion of mothers who conceived and delivered a live birth following the diagnosis of DBMD in an affected male child and factors associated with such reproductive choice were identified. To accomplish this, maternal demographic data were linked to birth certificate data to construct the reproductive history for 239 mothers. Univariable and bivariable analyses were conducted to determine the proportion of mothers delivering a live birth and associated factors. By the time of the current study, 96 (40.2%) of the 239 mothers had at least one live birth following delivery of their oldest affected male child; 53 (22.2%) of these mothers had a live birth before and 43 (18.0%) had a live birth after DBMD diagnosis of a male child. Mothers with a live birth after diagnosis were significantly younger at diagnosis of the oldest affected male child (26.2 ± 4.2 years vs. 31.5 ± 5.5 years), and were less likely to be white non-Hispanic compared to those with no live birth after diagnosis. These results suggest that about one in five mothers deliver a live birth subsequent to DBMD diagnosis in a male child. Maternal age and race/ethnicity were associated with this reproductive choice.

Use of complementary and alternative medicine by males with Duchenne or Becker muscular dystrophy

Use of complementary and alternative medicine by males with Duchenne or Becker muscular dystrophy was examined using interview reports from caregivers enrolled in the population-based Muscular Dystrophy Surveillance, Tracking, and Research Network. Of the 200 caregivers interviewed, 160 (80%) reported "ever" using complementary and alternative medicine for their affected children. Mind-body medicine (61.5%) was most frequently used, followed by biologically based practices (48.0%), manipulative and body-based practices (29.0%), and whole medical systems (8.5%). Caregivers reporting use of whole medical systems had higher education and income levels compared with nonusers; affected males had shorter disease duration. Caregivers reporting use of mind-body medicine, excluding aquatherapy, had higher education level compared with nonusers. Overall, complementary and alternative medicine use was high; disease duration, education, and income levels influenced use. These findings have implications for developing clinical care protocols and monitoring possible interactions between complementary and alternative medicine and conventional medical therapies.

Use of active surveillance methodologies to examine over-reporting of stillbirths on fetal death certificates

BACKGROUND

Data from Iowa fetal death certificates (FDCs) suggest that reportable stillbirths (unintended fetal deaths ≥ 20 weeks gestation and/or weighing ≥ 350 grams) occur in about 1 in 200 deliveries. In 2005, the Iowa Department of Public Health and the Iowa Registry for Congenital and Inherited Disorders (IRCID) collaborated with other state stakeholders to establish the Iowa Stillbirth Surveillance Project. The goal of this project was to use population-based, active surveillance methodologies to identify reportable stillbirths delivered by Iowa residents since January 1, 2000.

METHODS

To conduct stillbirth surveillance, the IRCID expanded its existing public health authority and electronic abstract application for birth defects surveillance. The expanded application was piloted using a random sample (n = 250 of 989) of FDCs reported from January 2000 through December 2004.

RESULTS

IRCID procedures for active case finding and medical record abstraction verified 192 (76.8%) as reportable stillbirths. Stillbirths not verified as reportable were due to findings of elective terminations (n = 30), live births (n = 3), induced deliveries (n = 2), and FDC entries for gestational age and/or delivery weight that were either inaccurately recorded (n = 13) or accurately recorded but did not meet Iowa FDC reporting criteria (n = 9); medical records for one FDC were unavailable. Infant malformations were more common among unverified stillbirths, whereas the cause of death due to maternal-related conditions was higher among verified stillbirths.

CONCLUSIONS

These results suggest that over-reporting limits the use of FDCs as a primary ascertainment source for stillbirth surveillance in Iowa. Continued expansion of the IRCID active surveillance methodologies to monitor stillbirths in Iowa is recommended.

Identification of Iowa live births in the Agricultural Health Study

In the Agricultural Health Study, information on participant live births was largely provided by female partners of male private applicators. At the Iowa site, such information was available for 13,599 (42.9%) of 31,707 applicators. To improve identification of live births among Iowa participants, we used a probabilistic and deterministic approach to link available demographic data from 31,707 households and information on live births from 13,599 households with 1,014,916 Iowa birth certificates. Record linkage identified 16,611 (93.7%) of 17,719 reported live births and 17,883 additional live births, most (14,411 or 80.6%) not reported due to nonresponse by female partners. This record linkage produced an expanded cohort of live-born children among Iowa participants, which will facilitate improved study of the effects of agricultural exposures, including pesticides, on selected birth outcomes and childhood disease.

Epidemiology of congenital idiopathic talipes equinovarus in Iowa, 1997-2005

Congenital idiopathic talipes equinovarus (ITEV), also known as clubfoot, is a well-recognized foot deformity. To date, prevalence estimates and descriptive data reported for ITEV have varied due to differences in study methodology. Using population-based surveillance data collected by the Iowa Registry for Congenital and Inherited Disorders, we examined isolated ITEV births delivered from 1997 through 2005 and compared to live births in Iowa during the same time period. An overall prevalence was calculated for live, singleton full-term births only. Prevalence odds ratios (POR)s and 95% confidence intervals (CI)s were examined for selected infant and parental characteristics. The prevalence of isolated ITEV was 11.4 per 10,000 live, singleton full-term births (95% CI = 10.3, 12.6), with no significant variation in prevalence during the study period. Increased PORs were found for males (POR 1.8; 95% CI = 1.5, 2.3) and maternal smoking during pregnancy (POR = 1.5, 95% CI = 1.2, 1.9); low birth weight (<2,500 g) showed an increase among females (POR = 3.2, 95% CI = 1.5, 6.9) but not males (POR = 0.9, 95% CI = 0.3, 2.8). Elevated, but non-significant, PORs were found for season of birth, maternal education, and trimester prenatal care was initiated; decreased PORs were found for fetal presentation, maternal race/ethnicity, parity, area of residence, and parental age at delivery. Our study of a well-defined, homogenous sample suggested that prevalence of isolated ITEV in Iowa was similar to that reported in other population-based studies and provided support for some, but not all, previously reported associations with infant and parental characteristics. More detailed, longitudinal studies of isolated ITEV are recommended.

Delayed diagnosis in duchenne muscular dystrophy: data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet)

OBJECTIVE

To identify key factors for the delay in diagnosis of Duchenne muscular dystrophy (DMD) without known family history.

STUDY DESIGN

The cohort comes from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet), a multistate, multiple-source, population-based surveillance system that identifies and gathers information on all cases of Duchenne and Becker muscular dystrophy born since 1982. We analyzed medical records of 453 Duchenne and Becker muscular dystrophy boys to document the time course and steps taken to reach a definitive diagnosis.

RESULTS

Among 156 boys without known family history of DMD prior to birth, first signs or symptoms were noted at a mean age of 2.5 years. Concerns resulted in primary care provider evaluation of the child at a mean age of 3.6 years. Mean age at time of initial creatine kinase was 4.7 years. Mean age at definitive diagnosis of DMD was 4.9 years.

CONCLUSIONS

There is a delay of about 2.5 years between onset of DMD symptoms and the time of definitive diagnosis, unchanged over the previous 2 decades. This delay results in lost opportunities for timely genetic counseling and initiation of corticosteroid treatment. We recommend checking creatine kinase early in the evaluation of boys with unexplained developmental delay.