BACKGROUND: Since the introduction of copper based, lead-free frangible (LFF) ammunition to Air Force small arms firing ranges, instructors have reported symptoms including chest tightness, respiratory irritation, and metallic taste. These symptoms have been reported despite measurements determining that instructor exposure does not exceed established occupational exposure limits (OELs). The disconnect between reported symptoms and exposure limits may be due to a limited understanding of LFF firing byproducts and subsequent health effects. A comprehensive characterization of exposure to instructors was completed, including ventilation system evaluation, personal monitoring, symptom tracking, and biomarker analysis, at both a partially enclosed and fully enclosed range. RESULTS: Instructors reported symptoms more frequently after M4 rifle classes compared to classes firing only the M9 pistol. Ventilation measurements demonstrated that airflow velocities at the firing line were highly variable and often outside established standards at both ranges. Personal breathing zone air monitoring showed exposure to carbon monoxide, ultrafine particulate, and metals. In general, exposure to instructors was higher at the partially enclosed range compared to the fully enclosed range. Copper measured in the breathing zone of instructors, on rare occasions, approached OELs for copper fume (0.1 mg/m(3)). Peak carbon monoxide concentrations were 4-5 times higher at the partially enclosed range compared to the enclosed range and occasionally exceeded the ceiling limit (125 ppm). Biological monitoring showed that lung function was maintained in instructors despite respiratory symptoms. However, urinary oxidative stress biomarkers and urinary copper measurements were increased in instructors compared to control groups. CONCLUSIONS: Consistent with prior work, this study demonstrates that symptoms still occurred despite exposures below OELs. Routine monitoring of symptoms, urinary metals, and oxidative stress biomarkers can help identify instructors who are particularly affected by exposures. These results can assist in guiding protective measures to reduce exposure and protect instructor health. Further, a longitudinal study is needed to determine the long-term health consequences of LFF firing emissions exposure.

Social determinants contribute to health disparities. Previous research has indicated that community trauma is associated with negative health outcomes. This study examined the impact of community trauma on sexual risk, marijuana use and mental health among African-American female adolescents in a juvenile detention center. One hundred and eighty-eight African-American female adolescents, aged 13–17 years, were recruited from a short-term detention facility and completed assessments on community trauma, sexual risk behavior, marijuana use, symptoms of posttraumatic stress disorder and psychosocial HIV/STD risk factors. Findings indicate that community trauma was associated with unprotected sex, having a sex partner with a correctional/juvenile justice history, sexual sensation seeking, marijuana use, affiliation with deviant peers and posttraumatic stress disorder symptoms at baseline and longitudinally. Findings reinforce the impact of community-level factors and co-occurring health issues, particularly in high-risk environments and among vulnerable populations. Structural and community-level interventions and policy-level changes may help improve access to resources and improve adolescents’ overall health and standard of living in at-risk communities.

U.S. Air Force small arms firing ranges began using copper-based, lead-free frangible ammunition in the early 2000s due to environmental and health concerns related to the use of lead-based ammunition. Exposure assessments at these firing ranges have routinely detected chemicals and metals in amounts much lower than their mass-based occupational exposure limits, yet, instructors report work-related health concerns including respiratory distress, nausea, and headache. The objective of this study at one firing range was to characterize the aerosol emissions produced by weapons during firing events and evaluate the ventilation system's effectiveness in controlling instructor exposure to these emissions. The ventilation system was assessed by measuring the range static air pressure differential and the air velocity at the firing line. Air flow patterns were observed near the firing line. Instructor exposure was sampled using a filter-based air sampling method for metals and a wearable, real-time ultrafine particle counter. Area air sampling was simultaneously performed to characterize the particle size distribution, morphology and composition. In the instructor's breathing zone, the airborne mass concentration of copper was low (range = <1-microg/m3 to 16-microg/m3), yet the ultrafine (nanoscale) particle number concentration increased substantially during each firing event. Ultrafine particles contained some copper and were complex in morphology and composition. The ventilation assessment found that the average velocity across all shooting lanes was acceptable compared to the recommended guideline (20% of the ideal 0.38-m/s (75-ft/min). However, uniform, downrange airflow pattern requirements were not met. These results suggest that the mass-based occupational exposure limits, as applied to this environment, may not be protective enough to eliminate health complaints reported by instructors whose full-time job involves training personnel on weapons that fire lead free frangible ammunition. Using an ultrafine particle counter appears to be an alternative method of assessing ventilation effectiveness in removing ultrafine particulate produced during firing events.

The prevalence of trisomy 21 has been reported to differ by race-ethnicity, however, the results are inconsistent and the cause of the differences is unknown. Using data from 1996 to 2005 from the Metropolitan Atlanta Congenital Defects Program (MACDP), we analyzed the use of prenatal cytogenetic testing and the subsequent use of elective termination among pregnancies affected with any MACDP-eligible birth defect and trisomy 21, by maternal race-ethnicity. We then examined whether these factors could explain the observed differences in the prevalence of trisomy 21 among race-ethnicity groups. Among all pregnancies with birth defects, prenatal cytogenetic testing as well as elective terminations after an abnormal prenatal cytogenetic test result were observed less frequently among Hispanic women than among non-Hispanic white women (odds ratio [OR] 0.66, 95% confidence interval [CI] 0.56-0.78, respectively). In pregnancies affected by trisomy 21, both the Hispanic and the non-Hispanic black populations had more live births (89.5% and 77.8%, respectively) and fewer elective terminations (5.7% and 15.2%, respectively) compared to the non-Hispanic white population (63.0% live births, 32.3% elective terminations). After adjusting for elective terminations, non-Hispanic white mothers had a higher live birth prevalence of trisomy 21 compared to non-Hispanic black (OR 0.64, 95% CI 0.54-0.76) or Hispanic mothers (OR 0.69, 95% CI 0.55-0.86). Overall, our data suggest that factors associated with decisions made about the use of prenatal testing, and about pregnancy management after testing, might play a large role in the race-ethnicity differences observed in the live birth prevalence of trisomy 21.

The annual National Birth Defects Prevention Network (NBDPN) Congenital Malformations Surveillance Report includes state-level data on major birth defects (i.e., conditions present at birth that cause adverse structural changes in one or more parts of the body) and a directory of population-based birth defects surveillance systems in the United States. Beginning in 2012, these annually updated data and directory information are available in an electronic format accompanied by a data brief. This year’s report includes data from 41 population-based birth defects surveillance programs and a data brief highlighting the more common trisomy conditions (i.e., disorders characterized by an additional chromosome): trisomy 21 (commonly referred to as Down syndrome), trisomy 18, and trisomy 13.

For decades, classical cytogenetic techniques that yielded a karyotype were the mainstay for identifying and characterizing the causes of certain genetic syndromes and birth defects. The capacity to identify chromosome anomalies expanded in the late 1980s and the 1990s with the development and maturation of fluorescent in situ hybridization (FISH) techniques to interrogate submicroscopic regions of the chromosomes for deletions or duplications. Beyond karyotypes and FISH, new technologies—chromosomal microarrays and next generation DNA sequencing—have markedly increased the number of birth defects and genetic syndromes that now have a known cause. These new testing techniques that can unambiguously confirm a diagnosis—as occurred previously, for example, with FISH for 22q11.2 deletions—will increase the specificity and sensitivity for classifying birth defects and improve prevalence estimates. Although these testing techniques improve the resolution of analysis of smaller and more complex chromosome and DNA anomalies, their interpretation can be problematic, particularly when the test results are of unknown significance. Broader usage of new prenatal screening technologies, such as testing for chromosome and DNA anomalies in cell-free fetal DNA, will likely impact prevalence estimates of certain birth defects included in surveillance systems. These new advancements in genetic testing can create challenges for birth defects surveillance and research programs in learning how to abstract, interpret, classify, store, and incorporate new findings into surveillance systems, as well as categorizing the data in epidemiological studies. Birth defects research and surveillance programs must be mindful of these new challenges and thoughtful in addressing them.

The purpose of this study was to examine changes in the use of cytogenetic testing and identification of chromosomal abnormalities among pregnancies and children with birth defects. Utilizing data from 1968 to 2005 from the Metropolitan Atlanta Congenital Defects Program, we analyzed trends in the frequency and timing (prenatal or postnatal) of cytogenetic testing and the prevalence of recognized chromosome abnormalities among pregnancies and children with birth defects (n = 51,424). Cytogenetic testing of pregnancies and children with birth defects increased from 7.2% in 1968 to 25.0% in 2005, as did the identification of chromosomal abnormalities (2.2% in 1968 to 6.8% in 2005). The use of prenatal cytogenetic testing decreased from 1996 to 2005 among women aged ≥35 years. Identification of chromosomal abnormalities in pregnancies and children with birth defects increased from 1968 to 2005, possibly due to increased testing, improved diagnostic techniques, or increasing maternal age. The decline in prenatal cytogenetic testing observed among mothers aged ≥35 years may be related to the availability of improved prenatal screening techniques, resulting in a reduction in the utilization of invasive diagnostic tests. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

Chromosome rearrangements are a significant cause of intellectual disability and birth defects. Subtelomeric rearrangements, including deletions, duplications and translocations of chromosome ends, were first discovered over 40 years ago and are now recognized as being responsible for several genetic syndromes. Unlike the deletions and duplications that cause some genomic disorders, subtelomeric rearrangements do not typically have recurrent breakpoints and involve many different chromosome ends. To capture the molecular mechanisms responsible for this heterogeneous class of chromosome abnormality, we coupled high-resolution array CGH with breakpoint junction sequencing of a diverse collection of subtelomeric rearrangements. We analyzed 102 breakpoints corresponding to 78 rearrangements involving 28 chromosome ends. Sequencing 21 breakpoint junctions revealed signatures of non-homologous end-joining, non-allelic homologous recombination between interspersed repeats and DNA replication processes. Thus, subtelomeric rearrangements arise from diverse mutational mechanisms. In addition, we find hotspots of subtelomeric breakage at the end of chromosomes 9q and 22q; these sites may correspond to genomic regions that are particularly susceptible to double-strand breaks. Finally, fine-mapping the smallest subtelomeric rearrangements has narrowed the critical regions for some chromosomal disorders.

Worldwide, an estimated 7.9 million children are affected by congenital and inherited disorders. Some disorders are relatively common, affecting tens of thousands of newborns annually; others are rare, involving disorders that, in extreme cases, can affect less than 30 infants per year. However, this infrequency does not reduce the impact or burden on individuals and their families. Congenital defects can cause long-term disability, have a lifelong impact on health, and cost billions of dollars in care. Collection of population-based surveillance data ideally enables the discovery of etiologies for rare congenital disorders of unknown cause, allows for examining outcomes, and evaluating treatments and interventions for children with all types of congenital and inherited disorders. Many challenges are associated with performing population-based surveillance, such as difficulty in ascertaining appropriate diagnoses and frequent unavailability of necessary resources. This chapter focuses on the importance of population-based data and uses national and international surveillance systems as models for how these rare disorders can be better understood.