Cohort profile: The Assessing Imperial Valley Respiratory Health and the Environment (AIRE) study

BACKGROUND

The Children's Assessing Imperial Valley Respiratory Health and the Environment (AIRE) study is a prospective cohort study of environmental influences on respiratory health in a rural, southeastern region of California (CA), which aims to longitudinally examine the contribution of a drying saline lake to adverse health impacts in children.

OBJECTIVES

This cohort was established through a community-academic partnership with the goal of assessing the health effects of childhood exposures to wind-blown particulate matter (PM) and inform public health action. We hypothesize that local PM sources are related to poorer children's respiratory health.

POPULATION

Elementary school children in Imperial Valley, CA.

DESIGN

Prospective cohort study.

METHODS

Between 2017 and 2019, we collected baseline information on 731 children, then follow-up assessments yearly or twice-yearly since 2019. Data have been collected on children's respiratory health, demographics, household characteristics, physical activity and lifestyle, via questionnaires completed by parents or primary caregivers. In-person measurements, conducted since 2019, repeatedly assessed lung function, height, weight and blood pressure. Exposure to air pollutants has been assessed by multiple methods and individually assigned to participants using residential and school addresses. Health data will be linked to ambient and local sources of PM, during and preceding the study period to understand how spatiotemporal trends in these environmental exposures may relate to respiratory health.

PRELIMINARY RESULTS

Analyses of respiratory symptoms indicate a high prevalence of allergies, bronchitic symptoms and wheezing. Asthma diagnosis was reported in 24% of children at enrolment, which exceeds both CA state and US national prevalence estimates for children.

CONCLUSIONS

The Children's AIRE cohort, while focused on the health impacts of the drying Salton Sea and air quality in Imperial Valley, is poised to elucidate the growing threat of drying saline lakes and wind-blown dust sources to respiratory health worldwide, as sources of wind-blown dust emerge in our changing climate.

Fire and Water: Assessing Drinking Water Contamination After a Major Wildfire

We investigated patterns of volatile organic compound (VOC) contamination in drinking water systems affected by the California 2018 Camp Fire. We performed spatial analysis of over 5000 water samples collected over a 17 month period by a local water utility, sampled tap water for VOCs in approximately 10% (N = 136) of standing homes, and conducted additional nontargeted chemical analysis of 10 samples. Benzene contamination was present in 29% of service connections to destroyed structures and 2% of service connections to standing homes. A spatial pattern was apparent. Tap water in standing homes 11 months after the fire contained low concentrations of benzene in 1% of samples, but methylene chloride was present in 19% of samples, including several above regulatory limits. Elevated methylene chloride was associated with greater distance from the water meter to the tap, longer stagnation time, and the presence of a destroyed structure on the service connection; it was inversely associated with certain trihalomethanes. Nontargeted analysis identified multiple combustion byproducts in the water at 2/10 homes. Our findings support the hypothesis that pyrolysis and smoke intrusion from depressurization contributed to the benzene contamination. Further research is needed to test the hypothesis that methylene chloride may be generated from the dehalogenation of disinfection byproducts stagnating in galvanized iron pipes.

Performance of a Low-Cost Sensor Community Air Monitoring Network in Imperial County, CA

Air monitoring networks developed by communities have potential to reduce exposures and affect environmental health policy, yet there have been few performance evaluations of networks of these sensors in the field. We developed a network of over 40 air sensors in Imperial County, CA, which is delivering real-time data to local communities on levels of particulate matter. We report here on the performance of the Network to date by comparing the low-cost sensor readings to regulatory monitors for 4 years of operation (2015-2018) on a network-wide basis. Annual mean levels of PM10 did not differ statistically from regulatory annual means, but did for PM2.5 for two out of the 4 years. R2s from ordinary least square regression results ranged from 0.16 to 0.67 for PM10, and increased each year of operation. Sensor variability was higher among the Network monitors than the regulatory monitors. The Network identified a larger number of pollution episodes and identified under-reporting by the regulatory monitors. The participatory approach of the project resulted in increased engagement from local and state agencies and increased local knowledge about air quality, data interpretation, and health impacts. Community air monitoring networks have the potential to provide real-time reliable data to local populations.

Next-Generation Community Air Quality Sensors for Identifying Air Pollution Episodes

Conventional regulatory air quality monitoring sites tend to be sparsely located. The availability of lower-cost air pollution sensors, however, allows for their use in spatially dense community monitoring networks, which can be operated by various stakeholders, including concerned residents, organizations, academics, or government agencies. Networks of many community monitors have the potential to fill the spatial gaps between existing government-operated monitoring sites. One potential benefit of finer scale monitoring might be the ability to discern elevated air pollution episodes in locations that have not been identified by government-operated monitoring sites, which might improve public health warnings for populations sensitive to high levels of air pollution. In the Imperial Air study, a large network of low-cost particle monitors was deployed in the Imperial Valley in Southeastern California. Data from the new monitors is validated against regulatory air monitoring. Neighborhood-level air pollution episodes, which are defined as periods in which the PM2.5 (airborne particles with sizes less than 2.5 μm in diameter) hourly average concentration is equal to or greater than 35 μg m-3, are identified and corroborate with other sites in the network and against the small number of government monitors in the region. During the period from October 2016 to February 2017, a total of 116 episodes were identified among six government monitors in the study region; however, more than 10 times as many episodes are identified among the 38 community air monitors. Of the 1426 episodes identified by the community sensors, 723 (51%) were not observed by the government monitors. These findings suggest that the dense network of community air monitors could be useful for addressing current limitations in the spatial coverage of government air monitoring to provide real-time warnings of high pollution episodes to vulnerable populations.

Correction to: Adipokines and the insulin resistance syndrome in familial partial lipodystrophy caused by a mutation in lamin A/C

The authors regret that Alexandra Bargiota's name was spelt incorrectly in the author list. The details given in this correction are correct.

Is in utero exposure to maternal socioeconomic disadvantage related to offspring ovarian reserve in adulthood?

BACKGROUND

Because the ovarian follicle pool is established in utero, adverse exposures during this period may be especially impactful on the size and health of the initial follicle endowment, potentially shaping trajectories of ovarian follicle loss and the eventual onset of menopause. Building on a robust literature linking socioeconomic status (SES) and menopausal timing, the current study examined adverse prenatal exposures related to maternal SES, hypothesizing that greater maternal socioeconomic disadvantage would be associated with lower ovarian reserve in the adult offspring.

METHODS

In a healthy, community-based sub-sample (n = 350) of reproductive age participants in the OVA Study (2006-2011), prenatal maternal SES was examined in relation to two biomarkers of ovarian reserve, antimullerian hormone (AMH) and antral follicle count (AFC). Prenatal maternal SES was assessed indirectly using maternal addresses abstracted from participant birth certificates, geocoded, and linked to US Census-derived variables, including neighborhood-level characteristics: education (% of individuals with a HS diploma); poverty (% of families below the poverty line); unemployment (% of individuals > 16 years who are unemployed); and income (median family income).

RESULTS

In separate covariate-adjusted linear regression models (following the backward elimination of main effects with P > .10), greater maternal neighborhood education was related to higher ovarian reserve as marked by higher levels of offspring AMH (beta = .142, P < .001) and AFC (beta = .092, P < .10) with models accounting for 19.6% and 21.5% of the variance in AMH and AFC, respectively. In addition, greater maternal neighborhood poverty was related to lower ovarian reserve as marked by lower offspring AMH (beta = -.144, P < .01), with the model accounting for 19.5% of the variance in AMH.

CONCLUSIONS

Maternal socioeconomic disadvantage measured indirectly at the neighborhood level was associated with lower ovarian reserve among the adult offspring, independently of offspring SES and other potential confounding factors. This suggests SES-related adversity exposures may have a detrimental impact on the size or health of the initial follicle endowment, leading to accelerated follicle loss over time.

Evaluating the Use of Electronic Health Records for Type 2 Diabetes Surveillance in 2 California Counties, 2010-2014

OBJECTIVES

Electronic health records (EHRs) and electronic laboratory records (ELRs) are increasingly seen as a rich source of data for performing public health surveillance activities and monitoring community health status. Their potential for surveillance of chronic illness, however, may be underused. Our objectives were to (1) evaluate the use of EHRs and ELRs for diabetes surveillance in 2 California counties and (2) examine disparities in diabetes prevalence by geography, income, and race/ethnicity.

METHODS

We obtained data on a clinical diagnosis of diabetes and hemoglobin A1c (HbA1c) test results for adult members of Kaiser Permanente Northern California living in Contra Costa County or Solano County at any time during 2010-2014. We evaluated the validity of using HbA1c test results to determine diabetes prevalence, using clinical diagnoses as a gold standard. We estimated disparities in diabetes prevalence by combining HbA1c test results with US Census data on income, race, and ethnicity.

RESULTS

When compared with a clinical diagnosis of diabetes, data on a patient's 5-year maximum HbA1c value ≥6.5% yielded the best combination of sensitivity (87.4%) and specificity (99.2%). The prevalence of 5-year maximum HbA1c ≥6.5% decreased with increasing median family income and increased with greater proportions of residents who were either non-Hispanic black or Hispanic.

CONCLUSIONS

Timely diabetes surveillance data from ELRs can be used to document disparities, target interventions, and evaluate changes in population health. ELR data may be easier to access than a patient's entire EHR, but outcome metric validation with diabetes diagnoses would need to be ongoing. Future research should validate ELR and EHR data across multiple providers.

Estimating the Proportion of Childhood Cancer Cases and Costs Attributable to the Environment in California

OBJECTIVES

To estimate the proportion of cases and costs of the most common cancers among children aged 0 to 14 years (leukemia, lymphoma, and brain or central nervous system tumors) that were attributable to preventable environmental pollution in California in 2013.

METHODS

We conducted a literature review to identify preventable environmental hazards associated with childhood cancer. We combined risk estimates with California-specific exposure prevalence estimates to calculate hazard-specific environmental attributable fractions (EAFs). We combined hazard-specific EAFs to estimate EAFs for each cancer and calculated an overall EAF. Estimated economic costs included annual (indirect and direct medical) and lifetime costs.

RESULTS

Hazards associated with childhood cancer risks included tobacco smoke, residential exposures, and parental occupational exposures. Estimated EAFs for leukemia, lymphoma, and brain or central nervous system cancer were 21.3% (range = 11.7%-30.9%), 16.1% (range = 15.0%-17.2%), and 2.0% (range = 1.7%-2.2%), respectively. The combined EAF was 15.1% (range = 9.4%-20.7%), representing $18.6 million (range = $11.6 to $25.5 million) in annual costs and $31 million in lifetime costs.

CONCLUSIONS

Reducing environmental hazards and exposures in California could substantially reduce the human burden of childhood cancer and result in significant annual and lifetime savings.

Heat Death Associations with the built environment, social vulnerability and their interactions with rising temperature

In an extreme heat event, people can go to air-conditioned public facilities if residential air-conditioning is not available. Residences that heat slowly may also mitigate health effects, particularly in neighborhoods with social vulnerability. We explored the contributions of social vulnerability and these infrastructures to heat mortality in Maricopa County and whether these relationships are sensitive to temperature. Using Poisson regression modeling with heat-related mortality as the outcome, we assessed the interaction of increasing temperature with social vulnerability, access to publicly available air conditioned space, home air conditioning and the thermal properties of residences. As temperatures increase, mortality from heat-related illness increases less in census tracts with more publicly accessible cooled spaces. Mortality from all internal causes of death did not have this association. Building thermal protection was not associated with mortality. Social vulnerability was still associated with mortality after adjusting for the infrastructure variables. To reduce heat-related mortality, the use of public cooled spaces might be expanded to target the most vulnerable.

Joint effects of genetic variants and residential proximity to pesticide applications on hypospadias risk

BACKGROUND

We examined risks associated with joint exposure of gene variants and pesticides.

METHODS

Analyses included 189 cases and 390 male controls born from 1991 to 2003 in California's San Joaquin Valley. We used logistic regression to examine risks associated with joint exposures of gene variants and pesticides that our previous work identified as associated with hypospadias. Genetic variables were based on variants in DGKK, genes involved in sex steroid synthesis/metabolism, and genes involved in genital tubercle development. Pesticide exposure was based on residential proximity to commercial agricultural pesticide applications.

RESULTS

Odds ratios (ORs) were highest among babies with joint exposures, who had two- to fourfold increased risks; for example, the OR was 3.7 (95% confidence interval [CI], 0.8-16.5) among subjects with the risk-associated DGKK haplotype and pesticide exposure; OR, 1.5 (95% CI, 0.7-3.1) among subjects with the haplotype and no pesticide exposure; and OR, 0.9 (95% CI, 0.5-1.6) among subjects without the haplotype but with pesticide exposure, relative to subjects with neither. However, results did not provide statistical evidence that these risks were significantly greater than expected on an additive scale, relative to risks associated with one exposure at a time.

CONCLUSION

We observed elevated risks associated with joint exposures to selected pesticides and genetic variants but no statistical evidence for interaction. Birth Defects Research (Part A) 106:653-658, 2016. © 2016 Wiley Periodicals, Inc.

Epidemiology and surveillance of amyotrophic lateral sclerosis in two large metropolitan areas in California

Our objective was to provide demographic profiles and incidence estimates of amyotrophic lateral sclerosis (ALS) in two diverse California metropolitan areas: Los Angeles County (LA) and the San Francisco Bay Area (SFBA). Data were retrospectively collected from multiple sources. Case eligibility criteria included residency in SFBA or LA, and treatment for or diagnosis of ALS between 1 January 2009 and 31 December 2011. Overall incidence rates as well as age-, gender-, race- and ethnicity-specific rates were calculated. We identified 539 ALS cases in SFBA and 545 in LA; 618 were incident cases. Cases were more likely to be male and white. There were considerably more cases (p < 0.05) in LA who were foreign-born (LA, 22%; SFBA, 15%), black (LA, 10%; SFBA, 6%) or Hispanic (LA, 19%; SFBA, 10%). Conversely, the age adjusted incidence rates (per 100,000) were higher in SFBA for whites (LA, 1.40; SFBA, 2.49) and Hispanics (LA, 0.66; SFBA, 1.57) compared with LA. General case demographics and incidence rates in these two areas were similar to published studies. However, the differences between the two areas raise questions about how factors such as geography, access to care, and referral patterns may affect case ascertainment and diagnosis.

Hypospadias and residential proximity to pesticide applications

BACKGROUND

Experimental evidence suggests pesticides may be associated with hypospadias.

OBJECTIVE

Examine the association of hypospadias with residential proximity to commercial agricultural pesticide applications.

METHODS

The study population included male infants born from 1991 to 2004 to mothers residing in 8 California counties. Cases (n = 690) were ascertained by the California Birth Defects Monitoring Program; controls were selected randomly from the birth population (n = 2195). We determined early pregnancy exposure to pesticide applications within a 500-m radius of mother's residential address, using detailed data on applications and land use. Associations with exposures to physicochemical groups of pesticides and specific chemicals were assessed using logistic regression adjusted for maternal race or ethnicity and age and infant birth year.

RESULTS

Forty-one percent of cases and controls were classified as exposed to 57 chemical groups and 292 chemicals. Despite >500 statistical comparisons, there were few elevated odds ratios with confidence intervals that excluded 1 for chemical groups or specific chemicals. Those that did were for monochlorophenoxy acid or ester herbicides; the insecticides aldicarb, dimethoate, phorate, and petroleum oils; and adjuvant polyoxyethylene sorbitol among all cases; 2,6-dinitroaniline herbicides, the herbicide oxyfluorfen, and the fungicide copper sulfate among mild cases; and chloroacetanilide herbicides, polyalkyloxy compounds used as adjuvants, the insecticides aldicarb and acephate, and the adjuvant nonyl-phenoxy-poly(ethylene oxy)ethanol among moderate and severe cases. Odds ratios ranged from 1.9 to 2.9.

CONCLUSIONS

Most pesticides were not associated with elevated hypospadias risk. For the few that were associated, results should be interpreted with caution until replicated in other study populations.

A health impact assessment of California's proposed cap-and-trade regulations

OBJECTIVES

To identify unintended health effects of California's controversial cap-and-trade regulations and establish health-promoting policy recommendations, we performed a health impact assessment.

METHODS

We used literature reviews, public data, and local health surveys to qualitatively assess potential health risks and benefits related to changes in employment and income, energy costs, effects of emission offset projects, and cobenefits from the allocation of program revenue. We examined case studies from various communities to find existing social, economic, and environmental health conditions.

RESULTS

We found that policy implementation will minimally impact job creation (< 0.1% change) and that health effects from job sector shifts are unlikely. Fuel prices may increase (0%-11%), and minor negative health effects could accrue for some low-income households.

CONCLUSIONS

Offset projects would likely benefit environmental health, but more research is needed. Allocating some program revenue for climate change adaptation and mitigation would have substantial health benefits. Health impact assessment is a useful tool for health agencies to engage in policy discussions that typically fall outside public health. Our results can inform emission reduction strategies and cap-and-trade policy at the federal level.

Direct measurement of perchlorate exposure biomarkers in a highly exposed population: a pilot study

Exposure to perchlorate is ubiquitous in the United States and has been found to be widespread in food and drinking water. People living in the lower Colorado River region may have perchlorate exposure because of perchlorate in ground water and locally-grown produce. Relatively high doses of perchlorate can inhibit iodine uptake and impair thyroid function, and thus could impair neurological development in utero. We examined human exposures to perchlorate in the Imperial Valley among individuals consuming locally grown produce and compared perchlorate exposure doses to state and federal reference doses. We collected 24-hour urine specimen from a convenience sample of 31 individuals and measured urinary excretion rates of perchlorate, thiocyanate, nitrate, and iodide. In addition, drinking water and local produce were also sampled for perchlorate. All but two of the water samples tested negative for perchlorate. Perchlorate levels in 79 produce samples ranged from non-detect to 1816 ppb. Estimated perchlorate doses ranged from 0.02 to 0.51 µg/kg of body weight/day. Perchlorate dose increased with the number of servings of dairy products consumed and with estimated perchlorate levels in produce consumed. The geometric mean perchlorate dose was 70% higher than for the NHANES reference population. Our sample of 31 Imperial Valley residents had higher perchlorate dose levels compared with national reference ranges. Although none of our exposure estimates exceeded the U. S. EPA reference dose, three participants exceeded the acceptable daily dose as defined by bench mark dose methods used by the California Office of Environmental Health Hazard Assessment.

Diabetes management of elective hospital admissions

AIMS

At any given time, people with diabetes occupy approximately 10-20% of acute hospital beds. In addition, diabetes is associated with a greater length of stay. Patients undergoing elective procedures occupy approximately 50% of hospital beds. The aim of this 12-month project was to improve the quality of diabetes care for elective inpatients. The primary outcome measure was length of stay.

METHODS

A team was established to improve the quality of care and reduce the length of stay of all patients admitted electively with diabetes. Specific areas of focus were surgical pre-assessment, planning the admission, post-operative care and planning a safe discharge. A retrospective audit of all elective patients with a coded diagnosis of diabetes admitted between June 2008 and June 2009 was performed.

RESULTS

Comparing the year of the project with the preceding year day-case rates for patients with diabetes increased by 34.8% for diabetes vs. 13.7% for the total hospital population (P for difference=0.048). There was a significant fall in diabetes length of stay of 0.34 days comparing 2008 and 2009 (P=0.040). Over the same period, we have shown a smaller reduction in length of stay for all other admissions of 0.08 days (p=0.039).

CONCLUSION

A team specifically employed to focus on elective inpatient diabetes care have a significant impact on length of stay of this patient group with potential cost savings.

The 2006 California heat wave: impacts on hospitalizations and emergency department visits

BACKGROUND

Climate models project that heat waves will increase in frequency and severity. Despite many studies of mortality from heat waves, few studies have examined morbidity.

OBJECTIVES

In this study we investigated whether any age or race/ethnicity groups experienced increased hospitalizations and emergency department (ED) visits overall or for selected illnesses during the 2006 California heat wave.

METHODS

We aggregated county-level hospitalizations and ED visits for all causes and for 10 cause groups into six geographic regions of California. We calculated excess morbidity and rate ratios (RRs) during the heat wave (15 July to 1 August 2006) and compared these data with those of a reference period (8-14 July and 12-22 August 2006).

RESULTS

During the heat wave, 16,166 excess ED visits and 1,182 excess hospitalizations occurred statewide. ED visits for heat-related causes increased across the state [RR = 6.30; 95% confidence interval (CI), 5.67-7.01], especially in the Central Coast region, which includes San Francisco. Children (0-4 years of age) and the elderly (> or = 65 years of age) were at greatest risk. ED visits also showed significant increases for acute renal failure, cardiovascular diseases, diabetes, electrolyte imbalance, and nephritis. We observed significantly elevated RRs for hospitalizations for heat-related illnesses (RR = 10.15; 95% CI, 7.79-13.43), acute renal failure, electrolyte imbalance, and nephritis.

CONCLUSIONS

The 2006 California heat wave had a substantial effect on morbidity, including regions with relatively modest temperatures. This suggests that population acclimatization and adaptive capacity influenced risk. By better understanding these impacts and population vulnerabilities, local communities can improve heat wave preparedness to cope with a globally warming future.

Meeting report: consensus statement-Parkinson's disease and the environment: collaborative on health and the environment and Parkinson's Action Network (CHE PAN) conference 26-28 June 2007

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disorder. People with PD, their families, scientists, health care providers, and the general public are increasingly interested in identifying environmental contributors to PD risk.

METHODS

In June 2007, a multidisciplinary group of experts gathered in Sunnyvale, California, USA, to assess what is known about the contribution of environmental factors to PD.

RESULTS

We describe the conclusions around which they came to consensus with respect to environmental contributors to PD risk. We conclude with a brief summary of research needs.

CONCLUSIONS

PD is a complex disorder, and multiple different pathogenic pathways and mechanisms can ultimately lead to PD. Within the individual there are many determinants of PD risk, and within populations, the causes of PD are heterogeneous. Although rare recognized genetic mutations are sufficient to cause PD, these account for < 10% of PD in the U.S. population, and incomplete penetrance suggests that environmental factors may be involved. Indeed, interplay among environmental factors and genetic makeup likely influences the risk of developing PD. There is a need for further understanding of how risk factors interact, and studying PD is likely to increase understanding of other neurodegenerative disorders.

Diabetic complications and glycaemic control in remote North Africa

BACKGROUND

Delivery of diabetes services in resource-poor areas of Africa is difficult. Control is often poor and complications are common. However, adequate robust surveys are uncommon, particularly in remote rural areas. This makes needs assessment difficult and health-care planning impossible.

AIM

To accurately assess the glycaemic control and burden of complications in a group of diabetic patients from a remote area of a resource-limited north African country.

DESIGN

Prospective cohort study.

METHODS

Over a 6-week period, all patients attending the diabetic clinic at Mekelle Hospital in northern Ethiopia were intensively assessed, using imported western technology as necessary. Glycated haemoglobin (HbA(1c)), lipid profile, serum creatinine and urinary albumin-creatinine ratio were measured. Complications were assessed as accurately as possible, including examination of fundi by an ophthalmic specialist, and biosthesiometry for neuropathy.

RESULTS

There were 105 patients, mean (+/- SD) age 41 +/- 16 years and diabetes duration 7 +/- 6 years. There were 74 (70%) males, and 69 (66%) on insulin. Median body mass index was low at 20.6 kg/m(2), but mean HbA(1c) high at 11.3 +/- 2.8% (68% had an HbA(1c) over 10.0%). Cataract (12%), retinopathy (21%), neuropathy (41%) and microalbuminuria (51%) were common; but nephropathy (2%) was rare, as was large vessel disease (6% had peripheral vascular disease, and none had coronary artery disease or cerebrovascular disease). Risk factors such as hypertension (5%) and smoking (2%) were uncommon, and lipid profiles were generally good.

DISCUSSION

We conclude that in this severely resource-limited area of North Africa, glycaemic control amongst diabetic patients is very poor. Neuropathy, retinopathy and microalbuminuria are common; but large vessel disease risk factors are beneficial, and macroangiopathy prevalence is low. Scattered populations, shortage of drugs and insulin and lack of diabetes team care are major factors behind these serious issues of diabetic control and complications.

Environmental public health tracking of childhood asthma using California health interview survey, traffic, and outdoor air pollution data

BACKGROUND

Despite extensive evidence that air pollution affects childhood asthma, state-level and national-level tracking of asthma outcomes in relation to air pollution is limited.

OBJECTIVES

Our goals were to evaluate the feasibility of linking the 2001 California Health Interview Survey (CHIS), air monitoring, and traffic data; estimate associations between traffic density (TD) or outdoor air pollutant concentrations and childhood asthma morbidity; and evaluate the usefulness of such databases, linkages, and analyses to Environmental Public Health Tracking (EPHT).

METHODS

We estimated TD within 500 feet of residential cross-streets of respondents and annual average pollutant concentrations based on monitoring station measurements. We used logistic regression to examine associations with reported asthma symptoms and emergency department (ED) visits/hospitalizations.

RESULTS

Assignment of TD and air pollution exposures for cross-streets was successful for 82% of children with asthma in Los Angeles and San Diego, California, Counties. Children with asthma living in high ozone areas and areas with high concentrations of particulate matter < 10 microm in aerodynamic diameter experienced symptoms more frequently, and those living close to heavy traffic reported more ED visits/hospitalizations. The advantages of the CHIS for asthma EPHT include a large and representative sample, biennial data collection, and ascertainment of important socio-demographic and residential address information. Disadvantages are its cross-sectional design, reliance on parental reports of diagnoses and symptoms, and lack of information on some potential confounders.

CONCLUSIONS

Despite limitations, the CHIS provides a useful framework for examining air pollution and childhood asthma morbidity in support of EPHT, especially because later surveys address some noted gaps. We plan to employ CHIS 2003 and 2005 data and novel exposure assessment methods to re-examine the questions raised here.

Traffic and outdoor air pollution levels near residences and poorly controlled asthma in adults

BACKGROUND

Air pollution may exacerbate asthma.

OBJECTIVE

To investigate associations between traffic and outdoor air pollution levels near residences and poorly controlled asthma among adults diagnosed as having asthma in Los Angeles and San Diego counties, California.

METHODS

We estimated traffic density within 500 ft of 2001 California Health Interview Survey respondents' reported residential cross-street intersections. Additionally, we assigned annual average concentrations of ozone, nitrogen dioxide, particulate matter 2.5 and 10 micrometers or less in diameter, and carbon monoxide measured at government monitoring stations within a 5-mile radius of the reported residential cross-street intersections.

RESULTS

We observed a 2-fold increase in poorly controlled asthma (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.38-3.23) among asthmatic adults in the highest quintile of traffic density after adjusting for age, sex, race, and poverty. Similar increases were seen for nonelderly adults, men, and women, although associations seemed strongest in elderly adults (OR, 3.00; 95% CI, 1.13-7.91). Ozone exposures were associated with poorly controlled asthma among elderly adults (OR, 1.70; 95% CI, 0.91-3.18 per 1 pphm) and men (OR, 1.76; 95% CI, 1.05-2.94 per 1 pphm), whereas particulate matter 10 micrometers or less seemed to affect primarily women (OR, 2.06; 95% CI, 1.17-3.61), even at levels below the national air quality standard.

CONCLUSIONS

Heavy traffic and high air pollution levels near residences are associated with poorly controlled asthma.

Proton magnetic resonance spectroscopy in frontotemporal dementia

This study of frontotemporal dementia (FTD) was carried out to determine whether MR spectroscopy can provide an in vivo marker for the neuronal loss and gliosis that occur in this condition. We compared spectra in frontal and temporal regions known to be affected early in the course of the disease with spectra in the parietal lobe that is spared until late stages of FTD. We were interested in the relative concentrations of two compounds, NAA (a marker of neuronal integrity) and mI (a marker of gliosis), expressed as ratios to creatine (a relatively stable brain constituent). MR spectroscopy was performed on the temporal, parietal, and anterior cingulate cortices of five patients with the established semantic dementia form of FTD, two patients with the frontal form of FTD and 13 age matched controls. Structural MRI and neuropsychometry were also performed. Patients with FTD had reduced NAA/Cr in frontal and temporal, but not parietal lobes. The two patients with the frontal form of FTD had increased mI/Cr in their cingulate cortices. These data show for the first time that MR spectroscopy can reveal regionally selective abnormalities in patients with FTD. This opens up the possibility of using MR spectroscopy as a clinical tool to identify earlier presentations of the condition.

Diabetic ketoacidosis complicated by axillary vein thrombosis

A case is presented of a 39-year-old male with Down's Syndrome, who also had type 1 diabetes of 22 years duration. He presented with diabetic ketoacidosis (DKA)-arterial blood pH 7.17, plasma bicarbonate 13.6mmol/l, plasma glucose 26.4mmol/l and urine heavily positive for ketones. He recovered with standard intravenous fluid and insulin treatment, but on the third day of admission developed a swollen left arm (which had not been used for intravenous cannulation). Doppler ultrasound confirmed a left axillary vein thrombosis. This slowly resolved with anticoagulation. Review of the available literature revealed that though arterial thrombosis is a common complication of DKA, venous thromboembolism is surprisingly rare, and there appear to be no previous specific reports of axillary vein thrombosis complicating DKA.

Comparison of image quality, diagnostic confidence and interobserver variability in contrast enhanced MR angiography and 2D time of flight angiography in evaluation of carotid stenosis

The aim of this study was to compare image quality, level of diagnostic confidence and interobserver agreement in assessment of carotid stenosis with contrast enhanced MR angiography (CE MRA) in comparison with 2D time of flight MR angiography (2D TOF MRA). 60 carotid arteries in 30 patients were examined by three observers. Image quality and diagnostic confidence were assessed on the basis of a visual analogue scale. Interobserver variability was assessed with the help of intraclass correlation coefficient. Median values on the visual analogue scale for image quality and diagnostic confidence were higher for CE MRA compared with 2D TOF MRA for all three observers. Higher intraclass correlation values were recorded for interobserver variability for CE MRA compared with 2D TOF MRA both for visual estimation of carotid stenosis as well as for measurement of carotid stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. CE MRA provides better image quality, higher level of diagnostic confidence and more interobserver agreement compared with 2D TOF MRA.

Should universal hepatitis B immunisation be introduced in the UK?

Yes. But how?

Adipokines and the insulin resistance syndrome in familial partial lipodystrophy caused by a mutation in lamin A/C

AIMS/HYPOTHESIS

Familial partial lipodystrophy (FPLD) and obesity are both associated with increased risks of type 2 diabetes and cardiovascular disease. Although adipokines have been implicated, few data exist in subjects with FPLD; therefore we investigated a family with FPLD due to a lamin A/C mutation in order to determine how abnormalities of the plasma adipokine profile relate to insulin resistance and the metabolic syndrome.

METHODS

Plasma levels of adiponectin, leptin, resistin, IL-1beta, IL-6 and TNF-alpha in 30 subjects (ten patients, 20 controls) were correlated with indices of metabolic syndrome.

RESULTS

Compared with controls, FPLD patients had significantly lower plasma levels of adiponectin (3.7+/-1.0 in FDLP cases vs 7.1+/-0.72 mug/ml in controls, p=0.02), leptin (1.23+/-0.4 vs 9.0+/-1.3 ng/ml, p=0.002) and IL-6 (0.59+/-0.12 vs 1.04+/-0.17 pg/ml, p=0.047) and elevated TNF-alpha (34.8+/-8.1 vs 13.7+/-2.7 pg/ml, p=0.028), whereas IL-1beta and resistin were unchanged. In both groups, adiponectin levels were inversely correlated with body fat mass (controls, r=-0.44, p=0.036; FDLP, r=-0.67, p=0.025), insulin resistance (controls, r=-0.62, p=0.003; FDLP, r=-0.70, p=0.025) and other features of the metabolic syndrome. TNF-alpha concentrations were positively related to fat mass (controls, r=0.68, p=0.001; FDLP, r=0.64, p=0.048) and insulin resistance (controls, r=0.86, p=0.001; FDLP, r=0.75, p=0.013). IL-6, IL-1beta and resistin did not demonstrate any correlations with the metabolic syndrome in either group.

CONCLUSIONS/INTERPRETATION

Low adiponectin and leptin and high TNF-alpha were identified as the major plasma adipokine abnormalities in FPLD, consistent with the hypothesis that low adiponectin and high TNF-alpha production may be mechanistically related, and perhaps responsible for the development of insulin resistance and cardiovascular disease in FPLD.

Hyperglycaemic crises and lactic acidosis in diabetes mellitus

Diabetic ketoacidosis, hyperglycaemic hyperosmolar state, and lactic acidosis represent three of the most serious acute complications of diabetes. There have been some advances in our understanding of the pathogenesis of these conditions over the last three decades, together with more uniform agreement on their treatment and innovations in technology. Accordingly their incidence, morbidity, and mortality are decreasing, but at rates that fall short of our aspirations. Hyperglycaemic crises in particular remain an important cause of morbidity and mortality in diabetic populations around the world. In this article, understanding of these conditions and advances in their management, and the available guidelines for their treatment, are reviewed. As far as is possible, the recommendations are based on clear published evidence; failing that, what is considered to be a common sense synthesis of consensus guidelines and recommendations is provided.

Comparison of the pathology of cerebral white matter with post-mortem magnetic resonance imaging (MRI) in the elderly brain

White matter lesions (WML) on magnetic resonance imaging (MRI) brain scans are associated with ageing. They are unrelated to specific disorders, and their impact on cognitive and other brain functions is poorly characterized. Pathological studies often omit systematic survey of WML because of the need to study multiple full coronal tissue blocks, and uncertainty over the significance of lesions identified in periventricular and deep subcortical regions. Post-mortem MRI provides a means of mapping WML but the sensitivity and specificity of the method are unresolved. In this study post-mortem MRI of WML in fixed brain slices was compared with pathology in 33 brains donated to the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS). This study shows that MRI detection of WML was less sensitive than pathology: periventricaular lesions (PVL) sensitivity = 95% (87-99%), specificity = 71% (44-90%); deep subcortical lesions (DSCL) sensitivity = 86% (79-93%), specificity = 80% (72-88%). False negative MRI was associated with milder pathology, but lesions detected by myelin attenuation alone showed both microglial and endothelial activation. Therefore post-mortem MRI of formalin-fixed brain slices is a reliable method to obtain systematic data on the severity and distribution of cerebral white matter disease, and appears to detect those WML most likely to have clinical impact.

Intensified treatment of type 2 diabetes--positive effects on blood pressure, but not glycaemic control

BACKGROUND

Since publication of the UK Prospective Diabetes Study (UKPDS) in 1998, there has been a clear evidence base for tight glycaemic (HBA(1c) < 7.0%) and blood pressure (BP < 140/85 mmHg) control.

AIM

To determine the effect of UKPDS-based intensified glycaemic and BP targets on the care of type 2 diabetic patients attending a routine diabetes clinic.

DESIGN

Two surveys, each of 500 consecutively attending type 2 diabetic patients.

METHODS

The first survey was in a 3-month period in 1999, shortly after publication of the UKPDS study. The second was identical, but 2 years later. Glycaemic control (by DCCT-aligned HBA(1c)), BP and treatment details were recorded in both.

RESULTS

BP control was significantly improved in the second survey (mean +/- SD systolic BP from 151 +/- 25 to 146 +/- 26 mmHg, p = 0.001; diastolic from 77 +/- 13 to 72 +/- 12 mmHg, p < 0.0001) and the proportion of patients on anti-hypertensive treatment increased from 33% to 60% (p < 0.0001). Mean HbA(1c) however remained unchanged (8.7 +/- 1.8% in 1999 vs. 8.5 +/- 1.8% in 2001), although there was evidence of more intensive treatment patterns, with declining numbers on diet alone and more on oral agents and/or insulin.

DISCUSSION

Intensified BP control may be achievable within the confines of routine diabetes care, but achievement of optimal glycaemic targets remains problematic.

Non-invasive assessment of extracranial-intracranial bypass grafts using advanced ultrasound technology

There have been significant developments in ultrasound technology in the last few years which have resulted in an increase in the clinical value of this technique. An illustrative case is presented of how ultrasound technology has been used in the intraoperative and postoperative period to evaluate graft patency and function in patients undergoing extracranial-intracranial bypass graft surgery.

Neuralgic amyotrophy as a presenting feature of infective endocarditis

A 35 year old man presented to his general practitioner with severe right shoulder pain and subsequent weakness and wasting of the muscles in the affected shoulder girdle three weeks after a dental filling. His symptoms persisted despite standard treatment. He developed malaise, night sweats, weight loss, a petechial rash and a microcytic anaemia. On admission to hospital three months after the start of his symptoms he had also developed splenomegaly and the murmur of aortic regurgitation. Investigations confirmed the diagnoses of infective endocarditis and neuralgic amyotrophy. In this case neuralgic amyotrophy appears to have been the presenting feature of infective endocarditis. This association has not previously been described.

Examining associations between childhood asthma and traffic flow using a geographic information system

Using geographic information systems (GIS) and routinely collected data, we explored whether childhood residence near busy roads was associated with asthma in a low-income population in San Diego County, California. We examined the locations of residences of 5,996 children [less than/equal to] 14 years of age who were diagnosed with asthma in 1993 and compared them to a random control series of nonrespiratory diagnoses (n = 2,284). Locations of the children's residences were linked to traffic count data at streets within 550 ft. We also examined the number of medical care visits in 1993 for children with asthma to determine if the number of visits was related to traffic flow. Analysis of the distribution of cases and controls by quintiles and by the 90th, 95th, and 99th percentiles of traffic flow at the highest traffic street, nearest street, and total of all streets within a 550-ft buffer region did not show any significantly elevated odds ratios. However, among cases, those residing near high traffic flows (measured at the nearest street) were more likely than those residing near lower traffic flows to have two or more medical care visits for asthma than to have only one visit for asthma during the year. The results of this exploratory study suggest that higher traffic flows may be related to an increase in repeated medical visits for asthmatic children. Repeated exposure to particulate matter and other air pollutants from traffic exhaust may aggravate asthmatic symptoms in individuals already diagnosed with asthma.

Examining associations between childhood asthma and traffic flow using a geographic information system

Using geographic information systems (GIS) and routinely collected data, we explored whether childhood residence near busy roads was associated with asthma in a low-income population in San Diego County, California. We examined the locations of residences of 5,996 children [less than/equal to] 14 years of age who were diagnosed with asthma in 1993 and compared them to a random control series of nonrespiratory diagnoses (n = 2,284). Locations of the children's residences were linked to traffic count data at streets within 550 ft. We also examined the number of medical care visits in 1993 for children with asthma to determine if the number of visits was related to traffic flow. Analysis of the distribution of cases and controls by quintiles and by the 90th, 95th, and 99th percentiles of traffic flow at the highest traffic street, nearest street, and total of all streets within a 550-ft buffer region did not show any significantly elevated odds ratios. However, among cases, those residing near high traffic flows (measured at the nearest street) were more likely than those residing near lower traffic flows to have two or more medical care visits for asthma than to have only one visit for asthma during the year. The results of this exploratory study suggest that higher traffic flows may be related to an increase in repeated medical visits for asthmatic children. Repeated exposure to particulate matter and other air pollutants from traffic exhaust may aggravate asthmatic symptoms in individuals already diagnosed with asthma.

Palaeodrainage at Uluru-Kata Tjuta National Park and implications for water resources

The stakeholders in the atypical rangeland area of Uluyu-Kata Tjufa National Park in the Northern Territory are the Aboriginal owners, hundreds of thousands of tourists, and vulnerable desert wildlife species. Sustainable water resources and maintenance of the integrity of the unique geological, ecological and cultural environment at Uluyu are major issues being addressed by the trustees of the Park. The Dune Plains area between Uluyu (Ayers Rock) and Kata Tjula (the Olgas) is the setting for a deep palaeovalley. The flat, dune-covered landscape of the present-day Dune Plains area provides no indication of the existence of the underlying palaeovalley. Integrated datasets including aeromagnetic and airborne gamma-ray spectrometric imagery, processed Landsat Thematic Mapper imagery, a digital elevation model, and water-bore logs, have enabled reconstruction of the Dune Plains palaeoriver valley. The datasets reveal a heterogeneous basement topography of domes and basins with 100 m of vertical relief (a buried 'mini-Kata Tjuia') at depth beneath the Dune Plains area, between the rock monoliths. The ancient valley became completely infilled with lake, river and wind-borne sediments during the Tertiary and Quaternary. Major faults traversing the basement beneath the area influenced early erosion and valley initiation. The palaeovalley was originally a closed valley which later evolved to a through-flowing river that fed Lake Amadeus to the north. The Dune Plains palaeovalley is now the setting for a compound bedrock- Cainozoic-sediment aquifer system which is the major source of water supply for the inhabitants and tourists of Uluyu-Kata Tjufa National Park. Major landscape units making up the Uluyu area include groundwater calcrete, sheetwash slopes of red earth, sandplains and dunefields, and modern ephemeral alluvial braidplains that are constrained to corridors afforded by swale networks. The sheetwash unit forms gently sloping aprons around outcrops and supports banded mulga shrubland. During rainfall, surface run-off acts as a 'sheetflow recharge mechanism'. This mechanism maximises water conservation allowing survival of the mulga groves and associated ecosystems. During major rainfall events, the sheetflow processes augment replenishment of the aquifer system at the base of the slopes. The palaeodrainage configuration and hydrodynamics of both the surface environment and the subsurface aquifer system are complex. The methodology used to reconstruct the Dune Plains palaeodrainage and associated aquifer system, and the hydrodynamic processes described for the Uluru area are applicable to widespread rangeland areas elsewhere across the continent. Keywords: Uluyu, Kata Tjula, Dune Plains, palaeovalley, palaeodrainage, hydrology, groundwater, aquifer, sheetwash, red earths, calcrete, hydrodynamics, mulga (Acacia aneura), run-off, run-on, recharge.

Thermometer use among Mexican immigrant mothers in California

A community-based household survey was utilized to assess the relationship between thermometer use, home treatment and utilization of health care services. Using a cross-sectional design, the study surveyed 688 low income Mexican origin mothers of children between the ages of 8 and 16 months in San Diego County. Mothers were asked how they determine that their child has fever and how often they use a thermometer. Nearly 40% of low income Mexican mothers interviewed in San Diego county never used a thermometer for determining childhood fever. Approximately two-thirds (64.7%) relied either primarily or exclusively on embodied methods such as visual observation or touch to determine fever in their child. A multivariate logistic regression analysis determined that low education and a separated or divorced marital status decreased the odds of thermometer use, whereas regular contact with the health care system doubled the likelihood of thermometer use. Mothers who relied on embodied methods were more likely to use over-the-counter medications than those who relied on thermometers; however, no significant differences were found between groups using other methods of home treatment. Fever determination modalities can be used to screen for lack of access to care and to provide for other health care needs in a culturally appropriate manner. While clinicians' expectations may include parental experience with temperature taking, current pediatric literature questions the need for home-based thermometer use. Possible alternatives to the traditional rectal thermometer might include digital thermometers and color coded thermometer strips.

Health service use among low-risk newborns after early discharge with and without nurse home visiting

BACKGROUND

To examine the potential benefits of routine nurse home visiting after early discharge, we compared health service use among low-risk newborns with and without a nurse home visit and telephone follow-up after short hospital stays.

METHODS

Records of newborns discharged routinely before (n = 83) and after (n = 91) implementation of a universal postpartum home visiting program were reviewed retrospectively. Acute care visits, rehospitalizations, and well-baby visits for newborns up to 74 days of age were compared between the groups.

RESULTS

Acute care visits, rehospitalizations, and missed well-baby visits consistently appeared less likely among newborns receiving home visiting services, in both unadjusted and adjusted analyses. Adjusting for insurance, parity, and breast-feeding, a twofold reduction in acute care visits by 14 days was significant. Although not statistically significant, adjusted analyses of acute care and missed well-baby visits revealed apparently similar patterns at all time intervals. There were too few rehospitalizations for multivariate analysis.

CONCLUSIONS

Despite the limitations of this small retrospective study, the consistency of the findings suggests potentially important benefits of home visiting services after early discharge of low-risk newborns, with substantial implications for clinical and reimbursement policy. Effects could be greater with more vulnerable populations and shorter stays than those in this study.

Magnetic resonance angiographic assessment after extracranial-intracranial bypass surgery

Extracranial-intracranial (EC-IC) bypass operation may be performed to augment the distal cerebral circulation. The bypass patency is usually assessed postoperatively with conventional cerebral angiography. Six patients are reported in whom the bypass patency was assessed using magnetic resonance angiography (MRA): Two had intracavernous carotid aneurysms, three had base of skull tumours encompassing the internal carotid artery, and one had occlusion of the right internal carotid artery with poor collateral reserve as confirmed by an acetazolamide stimulation test. Postoperative conventional cerebral angiography was also obtained in three patients for comparison. The MRA correlated reasonably well with conventional cerebral angiography in showing bypass patency, although conventional cerebral angiography was superior in demonstrating small vessels; MRA has the added advantage of showing the relative flow contribution and flow direction under physiological conditions by using targeted presaturation pulses.