A blood lead benchmark for assessing risks from childhood lead exposure.

Lead exposure is an insidious problem, causing subtle effects in children at low exposure levels where clinical signs are not apparent. Although a target blood lead concentration (Pb(B)) of ten micrograms per deciliter (10 microg/dL) has been used as the basis for environmental decision-making in California for nearly two decades, recent epidemiologic evidence suggests a relationship between cognitive deficits and Pb(B) at concentrations < 10 microg/dL. Based on a published meta-analysis of children's IQ scores and their blood lead concentrations, we developed a new blood lead benchmark: an incremental increase in blood lead concentration (DeltaPb(B)) of 1 microg/dL, an increase that we estimate could decrease the IQ score in an average school child in California by up to one point. Although there is no evidence to date for a threshold for the neurobehavioral effects of lead, a one-point IQ decrement was chosen to represent a de minimus change. To safeguard the intellectual potential of all children, additional efforts to reduce or eliminate multiple-source exposures to lead are warranted.

Improved participation for blood lead screening with in-home phlebotomy.

Both nationally and within the State of California, it is unlikely that those children most susceptible to lead exposure are adequately screened for blood lead levels. New and creative approaches are necessary to reach these individuals. In-home phlebotomy was employed to test blood lead levels of 128 San Diego households containing Latino children aged 12-71 months. As part of a lead exposure study, these households were randomly selected from 12 census tracts in the downtown area during February-July, 2006. By employing a bicultural/bilingual phlebotomist, the participation rate for in-home phlebotomy was 89% among enrolled study participants. This rate is substantially higher than estimates for customary testing of similar underserved groups through physicians, has the advantage of reaching individuals without medical insurance, and contrasts favorably ($45 per individual test) with typical office visit costs. Culturally appropriate in-home phlebotomy may be a useful method for medical screening to meet the needs of underserved communities. Editors' Strategic Implications: The authors provide an excellent example of the importance of bringing prevention services to clients, literally in terms of the home visitation format but also with respect to the comfort level that may come from interacting with a bicultural and bilingual professional.

The geography of COPD hospitalization in California.

Exposure to tobacco smoke is an important risk factor for chronic obstructive pulmonary disease. We investigated the relationship between chronic obstructive pulmonary disease hospitalization counts (and hospitalization-related charges) in California and sociodemographic and smoking measures, employing geospatial techniques that permit more sensitive scrutiny at the zip code level while controlling for spatial confounding. We analyzed 1,707 zip code tabulation areas in California for chronic obstructive pulmonary disease hospitalization rates and related hospitalization charges (using 1999 hospital discharge data). After controlling for spatial auto-correlation, positive relationships were found for age, percentage Hispanics, number of tobacco outlets and level of smoking. Inverse relationships were found for percentage with undergraduate degrees and income level. When examining "hotspot" zip code tabulation areas (those with higher than expected model-based chronic obstructive pulmonary disease hospitalization counts), minority/immigrant status, depressed socioeconomic measures, and elevated tobacco use were clearly associated, suggesting the need for increased intervention among the poor and persons of color. Although limited by the availability of air pollution monitoring data, a preliminary descriptive analysis indicated that the numbers of particulate matter exceedances mirrored both the hotspots of the Los Angelesair basin and coldspots in the San Francisco Bay Area.

Chiari I malformation: potential role for intraoperative electrophysiologic monitoring.

Intraoperative electrophysiologic monitoring can diminish the risk of neurologic injury by enabling the detection of injury at a time when it can be reversed or minimized. Although it is clear that in patients with cervical spine disease monitoring during surgery reduces the incidence of neurologic injury, almost no data are available regarding its utility in patients undergoing suboccipital decompression for Chiari I malformation. Patients with Chiari I malformation have caudal displacement of the cerebellar tonsils below the skull base, thereby creating a tight foramen magnum and cervical canal. Although the majority of pediatric neurosurgeons perform a bony decompression with duraplasty for symptomatic patients, there is much controversy regarding the amount of bony decompression required for clinical improvement and whether a duraplasty is essential. The authors therefore conducted a prospective, observational study using intraoperative brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials in pediatric patients undergoing suboccipital decompressions for Chiari I malformations to determine whether there were consistent changes in intraoperative BAEPs that could help the operating surgeon decide how extensive a decompression was needed in these patients, and whether changes in BAEPs or somatosensory evoked potentials occurred during operative positioning that could be modified to reduce the risk of neurologic injury.

Improvement in brainstem auditory evoked potentials after suboccipital decompression in patients with chiari I malformations.

OBJECT: The optimal treatment for patients with symptoms related to Chiari I malformation remains controversial. Although a suboccipital decompression with duraplasty is most commonly performed, there may be a subset of patients who improve in response to bone decompression alone. In an initial attempt to identify such patients, we performed a continuous study of intraoperative brainstem auditory evoked potentials (BAEPs) in patients undergoing a standard decompression with duraplasty and compared conduction times at three different time points: 1) baseline while the patient is supine (before positioning); 2) immediately after opening of the bone and release of the atlantooccipital membrane (that is, the dural band); and 3) after opening of the dura mater. METHODS: Eleven children and young adults (mean age 9.8 years) with symptoms related to Chiari I malformation underwent suboccipital decompression and duraplasty with intraoperative monitoring of BAEPs and somatosensory evoked potentials (SSEPs). Six patients (55%) had associated syringomyelia. At baseline, the I to V interpeak latency (IPL) for both sides (total 21 BAEPs) was 4.19 +/- 0.22 msec (mean +/- standard deviation). After complete bone decompression and before the dura mater was opened, the I to V IPL decreased to 4.03 +/- 0.25 msec (p = 0.0005). When the dura was opened, however, no further decrease in the I to V IPL was detected (4.03 +/- 0.25 msec; p = 0.6). The SSEPs remained stable throughout the procedure. CONCLUSIONS: In children and young adults undergoing suboccipital decompression with duraplasty for Chiari I malformation, the vast majority of improvement in conduction through the brainstem occurs after bone decompressionand division of the atlantooccipital membrane, rather than after opening of the dura. Additional studies are needed to establish whether the improvement seen with BAEP monitoring during bone decompression will predict long-term clinical improvement in these patients.

Importance of respiratory exposure to pesticides among agricultural populations.

In the majority of cases, respiratory exposure accounts for a small fraction of total body exposure to pesticides; however, higher volatility pesticides pose a greater risk for exposure, particularly in enclosed spaces and near application sites. In 2000, nearly 22 million pounds of active ingredients designated as toxic air contaminants (TACs) were applied as pesticides in California (combined agricultural and reportable non-agricultural uses; California Department of Pesticide Regulation, 2001a, Summary of Pesticide Use Report Data, 2000, Sacramento, CA: author). Agricultural workers and agricultural community residents are at particular risk for exposure to these compounds. The TAC program in California, and more recently the federal Clean Air Act amendments, have begun to address the exposures of these groups and have promulgated exposure guidelines that are, in general, much more stringent than the Occupational Safety and Health Administration (OSHA) and American Conference of Governmental Industrial Hygienists (ACGIH) worker exposure guidelines. Choosing lower volatility pesticides, lower concentrations of active ingredients, and handling equipment designed to minimize exposure can often reduce worker respiratory exposures significantly. The use of personal protective equipment, which would be facilitated by the development of more ergonomic alternatives, is important in these higher respiratory exposure situations. Finally, in the case of community residents, measures taken to protect workers often translate to lower ambient air concentrations, but further study and development of buffer zones and application controls in a given area are necessary to assure community protection.