Tim K. Takaro

The Seattle-King County Healthy Homes Project: A Randomized, Controlled Trial of a Community Health Worker Intervention to Decrease Exposure to Indoor Asthma Triggers

OBJECTIVES We assessed the effectiveness of a community health worker intervention focused on reducing exposure to indoor asthma triggers. METHODS We conducted a randomized controlled trial with 1-year follow-up among 274 low-income households containing a child aged 4-12 years who had asthma. Community health workers provided in-home environmental assessments, education, support for behavior change, and resources. Participants were assigned to either a high-intensity group receiving 7 visits and a full set of resources or a low-intensity group receiving a single visit and limited resources. RESULTS The high-intensity group improved significantly more than the low-intensity group in its pediatric asthma caregiver quality-of-life score (P=.005) and asthma-related urgent health services use (P=.026). Asthma symptom days declined more in the high-intensity group, although the across-group difference did not reach statistical significance (P=.138). Participant actions to reduce triggers generally increased in the high-intensity group. The projected 4-year net savings per participant among the high-intensity group relative to the low-intensity group were 189-721 dollars. CONCLUSIONS Community health workers reduced asthma symptom days and urgent health services use while improving caregiver quality-of-life score. Improvement was greater with a higher-intensity intervention.

Monitoring and Reducing Exposure of Infants to Pollutants in House Dust

The health risks to babies from pollutants in house dust may be 100 times greater than for adults. The young ingest more dust and are up to ten times more vulnerable to such exposures. House dust is the main exposure source for infants to allergens, lead, and PBDEs, as well as a major source of exposure to pesticides, PAHs, Gram-negative bacteria, arsenic, cadmium, chromium, phthalates, phenols, and other EDCs, mutagens, and carcinogens. Median or upper percentile concentrations in house dust of lead and several pesticides and PAHs may exceed health-based standards in North America. Early contact with pollutants among the very young is associated with higher rates of chronic illness such as asthma, loss of intelligence, ADHD, and cancer in children and adults. The potential of infants, who live in areas with soil contaminated by automotive and industrial emissions, can be given more protection by improved home cleaning and hand washing. Babies who live in houses built before 1978 have a prospective need for protection against lead exposures; homes built before 1940 have even higher lead exposure risks. The concentration of pollutants in house dust may be 2-32 times higher than that found in the soil near a house. Reducing infant exposures, at this critical time in their development, may reduce lifetime health costs, improve early learning, and increase adult productivity. Some interventions show a very rapid payback. Two large studies provide evidence that home visits to reduce the exposure of children with poorly controlled asthma triggers may return more than 100% on investment in 1 yr in reduced health costs. The tools provided to families during home visits, designed to reduce dust exposures, included vacuum cleaners with dirt finders and HEPA filtration, allergy control bedding covers, high-quality door mats, and HEPA air filters. Infants receive their highest exposure to pollutants in dust at home, where they spend the most time, and where the family has the most mitigation control. Normal vacuum cleaning allows deep dust to build up in carpets where it can be brought to the surface and become airborne as a result of activity on the carpet. Vacuums with dirt finders allow families to use the three-spot test to monitor deep dust, which can reinforce good cleaning habits. Motivated families that receive home visits from trained outreach workers can monitor and reduce dust exposures by 90% or more in 1 wk. The cost of such visits is low considering the reduction of risks achieved. Improved home cleaning is one of the first results observed among families who receive home visits from MHEs and CHWs. We believe that proven intervention methods can reduce the exposure of infants to pollutants in house dust, while recognizing that much remains to be learned about improving the effectiveness of such methods.

Childhood asthma and environmental interventions.

Background Contaminants encountered in many households, such as environmental tobacco smoke, house dust mite, cockroach, cat and dog dander, and mold, are risk factors in asthma. Young children are a particularly vulnerable subpopulation for environmentally mediated asthma, and the economic burden associated with this disease is substantial. Certain mechanical interventions are effective both in reducing allergen loads in the home and in improving asthmatic children’s respiratory health. Results Combinations of interventions including the use of dust mite-impermeable bedding covers, improved cleaning practices, high-efficiency particulate air vacuum cleaners, mechanical ventilation, and parental education are associated with both asthma trigger reduction and improved health outcomes for asthmatic children. Compared with valuated health benefits, these combinations of interventions have proven cost effective in studies that have employed them. Education alone has not proven effective in changing parental behaviors such as smoking in the home. Conclusions Future research should focus on improving the effectiveness of education on home asthma triggers, and understanding long-term children’s health effects of the interventions that have proven effective in reducing asthma triggers.

A Randomized Controlled Trial of Asthma Self-management Support Comparing Clinic-Based Nurses and In-Home Community Health Workers The Seattle-King County Healthy Homes II Project

OBJECTIVE To compare the marginal benefit of in-home asthma self-management support provided by community health workers (CHWs) with standard asthma education from clinic-based nurses. DESIGN Randomized controlled trial. SETTING Community and public health clinics and homes. PARTICIPANTS Three hundred nine children aged 3 to 13 years with asthma living in low-income households. INTERVENTIONS All participants received nurse-provided asthma education and referrals to community resources. Some participants also received CHW-provided home environmental assessments, asthma education, social support, and asthma-control resources. OUTCOME MEASURES Asthma symptom-free days, Pediatric Asthma Caretaker Quality of Life Scale score, and use of urgent health services. RESULTS Both groups showed significant increases in caretaker quality of life (nurse-only group: 0.4 points; 95% confidence interval [CI], 0.3-0.6; nurse + CHW group: 0.6 points; 95% CI, 0.4-0.8) and number of symptom-free days (nurse only: 1.3 days; 95% CI, 0.5-2.1; nurse + CHW: 1.9 days; 95% CI, 1.1-2.8), and absolute decreases in the proportion of children who used urgent health services in the prior 3 months (nurse only: 17.6%; 95% CI, 8.1%-27.2%; nurse + CHW: 23.1%; 95% CI, 13.6%-32.6%). Quality of life improved by 0.22 more points in the nurse + CHW group (95% CI, 0.00-0.44; P = .049). The number of symptom-free days increased by 0.94 days per 2 weeks (95% CI, 0.02-1.86; P = .046), or 24.4 days per year, in the nurse + CHW group. While use of urgent health services decreased more in the nurse + CHW group, the difference between groups was not significant. CONCLUSION The addition of CHW home visits to clinic-based asthma education yielded a clinically important increase in symptom-free days and a modest improvement in caretaker quality of life.

Effect of environmental interventions to reduce exposure to asthma triggers in homes of low-income children in Seattle

The effectiveness of community health workers (CHWs) assisting families in reducing exposure to indoor asthma triggers has not been studied. In all, 274 low-income asthmatic children were randomly assigned to high- or low-intensity groups. CHWs visited all homes to assess exposures, develop action plans and provide bedding encasements. The higher-intensity group also received cleaning equipment and five to nine visits over a year focusing on asthma trigger reduction. The asthma trigger composite score decreased from 1.56 to 1.19 (Δ=−0.37, 95% CI 0.13, 0.61) in the higher-intensity group and from 1.63 to 1.43 in the low-intensity group (Δ=−0.20, 95% CI 0.004, 0.4). The difference in this measure due to the intervention was significant at the P=0.096 level. The higher-intensity group also showed improvement during the intervention year in measurements of condensation, roaches, moisture, cleaning behavior, dust weight, dust mite antigen, and total antigens above a cut point, effects not demonstrated in the low-intensity group. CHWs are effective in reducing asthma trigger exposure in low-income children. Further research is needed to determine the effectiveness of specific interventions and structural improvements on asthma trigger exposure and health.

Pulmonary and Neurobehavioral Effects of Formaldehyde Exposure

Two groups of male workers who were exposed to formaldehyde, the first group in phenol-formaldehyde-plastic foam matrix embedding of fiberglass (batt making), and the second in the fixation of tissues for histology, were studied for work-related neuro-behavioral, respiratory, and dermatological symptoms; and for pulmonary functional impairment. Forty-five male fiberglass batt makers who were studied across the initial work-shift after a holiday had average frequencies of combined neurobehavioral, respiratory, and dermatological symptoms of 17.3 for the hot areas and 14.7 for the cold areas of the process. Their symptom counts were significantly greater than those for 18 male histology technicians who averaged 7.3, and for 26 unexposed male hospital workers who averaged 4.8. During their first workshift after holidays, 58% of the batt makers had a decrease in one or more tests of pulmonary function. Nine nonsmokers had decreases more frequently than did 35 smokers; forced expiratory volume in one second FEV1.0 decreased in 16%, diffusing capacity for carbon monoxide (sb) decreased in 30%, forced expiratory flow 25-75 decreased in 16%, and forced expiratory flow) 75-85 decreased in 36%. Thirty-five percent of all 44 men had drops in FEV1.0, forced vital capacity, or in diffusing capacity (sb).

The Canadian Healthy Infant Longitudinal Development (CHILD) Study: examining developmental origins of allergy and asthma

The Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study recruited 3624 pregnant women, most partners and 3542 eligible offspring. We hypothesise that early life physical and psychosocial environments, immunological, physiological, nutritional, hormonal and metabolic influences interact with genetics influencing allergic diseases, including asthma. Environmental and biological sampling, innate and adaptive immune responses, gene expression, DNA methylation, gut microbiome and nutrition studies complement repeated environmental and clinical assessments to age 5. This rich data set, linking prenatal and postnatal environments, diverse biological samples and rigorous phenotyping, will inform early developmental pathways to allergy, asthma and other chronic inflammatory diseases.

Iraq War mortality estimates: A systematic review

BackgroundIn March 2003, the United States invaded Iraq. The subsequent number, rates, and causes of mortality in Iraq resulting from the war remain unclear, despite intense international attention. Understanding mortality estimates from modern warfare, where the majority of casualties are civilian, is of critical importance for public health and protection afforded under international humanitarian law. We aimed to review the studies, reports and counts on Iraqi deaths since the start of the war and assessed their methodological quality and results.MethodsWe performed a systematic search of 15 electronic databases from inception to January 2008. In addition, we conducted a non-structured search of 3 other databases, reviewed study reference lists and contacted subject matter experts. We included studies that provided estimates of Iraqi deaths based on primary research over a reported period of time since the invasion. We excluded studies that summarized mortality estimates and combined non-fatal injuries and also studies of specific sub-populations, e.g. under-5 mortality. We calculated crude and cause-specific mortality rates attributable to violence and average deaths per day for each study, where not already provided.ResultsThirteen studies met the eligibility criteria. The studies used a wide range of methodologies, varying from sentinel-data collection to population-based surveys. Studies assessed as the highest quality, those using population-based methods, yielded the highest estimates. Average deaths per day ranged from 48 to 759. The cause-specific mortality rates attributable to violence ranged from 0.64 to 10.25 per 1,000 per year.ConclusionOur review indicates that, despite varying estimates, the mortality burden of the war and its sequelae on Iraq is large. The use of established epidemiological methods is rare. This review illustrates the pressing need to promote sound epidemiologic approaches to determining mortality estimates and to establish guidelines for policy-makers, the media and the public on how to interpret these estimates.

Where's the pump? Associating sporadic enteric disease with drinking water using a geographic information system, in British Columbia, Canada, 1996-2005

We investigated whether risk of sporadic enteric disease differs by drinking water source and type using surveillance data and a geographic information system. We performed a cross-sectional analysis, at the individual level, that compared reported cases of enteric disease with drinking water source (surface or ground water) and type (municipal or private). We mapped 814 cases of campylobacteriosis, cryptosporidiosis, giardiasis, salmonellosis and verotoxigenic Escherichia coli infection, in a region of British Columbia, Canada, from 1996 to 2005, and determined the water source and type for each cases residence. Over the 10-year period, the risk of disease was 5.2 times higher for individuals living on land parcels serviced by private wells and 2.3 times higher for individuals living on land parcels serviced by the municipal surface/ground water mixed system, than the municipal ground water system. Rates of sporadic enteric disease potentially differ by drinking water source and type. Geographic information system technology and surveillance data are accessible to local public health authorities and used together are an efficient and affordable way to assess the role of drinking water in sporadic enteric disease.

Effects of phthalates on the development and expression of allergic disease and asthma

OBJECTIVE To review recent evidence relating phthalate exposures to allergies and asthma and to provide an overview for clinicians interested in the relevance of environmental health research to allergy and who may encounter patients with concerns about phthalates from media reports. DATA SOURCES PubMed, TOXLINE, and Web of Science were searched using the term phthalate(s) combined with the keywords allergy, asthma, atopy, and inflammation. STUDY SELECTIONS Articles were selected based on relevance to the goals of this review. Studies that involved humans were prioritized, including routes and levels of exposure, developmental and early-life exposures, immunotoxicity, and the development of allergic disease. RESULTS The general public and those with allergy are exposed to significant levels of phthalates via diet, pharmaceuticals, phthalate-containing products, and ambient indoor environment via air and dust. Intravenous exposures occur through medical equipment. Phthalates are metabolized and excreted quickly in the body with metabolites measured in urine. Phthalates, which are known endocrine disrupting compounds, have been associated with oxidative stress and alterations in cytokine expression. Metabolites in human urine, particularly of the higher-molecular-weight phthalates, have been associated with allergies and asthma in multiple studies. CONCLUSION Despite mounting evidence implicating phthalates, causation of allergic disease by these compounds cannot currently be established. In utero and early-life exposures and possible transgenerational effects are not well understood. However, considering the current evidence, reducing exposures to phthalates by avoiding processed and foods packaged and stored in plastics, personal care products with phthalates, polyvinyl chloride materials indoors, and reducing home dust is advised. Further longitudinal, molecular, and intervention studies are needed to understand the association between phthalates and allergic disease.