CONTEXT:Thousands of lead-based paint (LBP) inspections and risk assessments have been completed by professionals in recent years, but they have not yet been assembled into a suitable database to support a housing surveillance system. OBJECTIVE:This study was completed to determine if a database can be developed by uploading results of lead paint risk assessments; inspections; and evaluations of homes of children with elevated blood lead levels to support the creation of a LBP housing surveillance system. METHODS:Working with local private and public lead poisoning prevention professionals and laboratories, data from 2128 pre-1978 dwelling units, comprising 350 104 interior and 45 685 exterior LBP XRF measurements; 12 619 floor dust lead measurements; 8772 windowsill dust lead measurements; and other variables were assembled and analyzed. RESULTS:Although all reports complied with the US Department of Housing and Urban Development (HUD) guidelines, their report formats varied widely. The percentage of homes with any interior LBP was 62% (28%-88%, depending on risk categorization, that is, homes without or with children with elevated blood lead levels; the percentage with exterior LBP was 63% (28%-88%); and the percentage with both interior and exterior LBP was 51% (8%-86%). Room names, number, and building component naming systems were highly variable, making data cleaning needlessly complex. CONCLUSIONS:Increased standardization of LBP report formats, including standardized room, building component, and surface nomenclature, is needed to create a national housing surveillance system. All current commercially available XRF portable LBP analyzers can download data into electronic files, making handwritten data obsolete. Most labs can provide electronic files with dust and soil data. Improved standardization will help optimal targeting of remediation and future research to ensure children are adequately protected. Such standardization could be accomplished by a revised edition of the HUD lead paint guidelines and/or the establishment of a consensus standard-setting organization, such as the American Society for Testing and Materials (ASTM).

Housing is a social determinant of health, acting as both a driver and indicator of social inequity. For migrant and seasonal farmworkers, it is difficult to tease apart the interaction between the environmental and social factors related to their housing, in conjunction with extreme poverty, immigration, precarious employment, and linguistic, cultural, and educational factors. The relationship of housing with employment and the transient nature of farmworkers' occupancy add to the complexity. To assess the strengths, weaknesses, and research gaps and to identify areas requiring further investigation, we performed a critical review of the scientific and gray literature on farmworker housing and health. We propose a framework to focus research and suggest housing policy interventions to improve the health and wellbeing of this essential workforce.

BackgroundLead can be present in drinking water in soluble and particulate forms. The intermittent release of lead particulates in drinking water can produce highly variable water lead levels (WLLs) in individual homes, a health concern because both particulate and soluble lead are bioavailable. More frequent water sampling would increase the likelihood of identifying sporadic lead "spikes," though little information is available to aid in estimating how many samples are needed to achieve a given degree of sensitivity to spike detection.ObjectiveTo estimate the number of rounds of tap water sampling needed to determine with a given level of confidence that an individual household is at low risk for the intermittent release of lead particulates.MethodsWe simulated WLLs for 100,000 homes on 15 rounds of sampling under a variety of assumptions about lead spike release. A Markovian structure was used to describe WLLs for individual homes on subsequent rounds of sampling given a set of transitional probabilities, in which homes with higher WLLs at baseline were more likely to exhibit a spike on repeated sampling.ResultsAssuming 2% of homes had a spike on the first round of sampling and a mid-range estimate of transitional probabilities, the initial round of sampling had a 6.4% sensitivity to detect a spike. Seven rounds of sampling would be needed to increase the sensitivity to 50%, which would leave unrecognized the more than 15,000 homes that intermittently exhibit spikes.SignificanceFor assessing household risk for lead exposure through drinking water, multiple rounds of water sampling are needed to detect the infrequent but high spikes in WLLs due to particulate release. Water sampling procedures for assessment of lead exposure in individual homes should be modified to account for the infrequent but high spikes in WLL.ImpactIt has been known for decades that intermittent "spikes" in water lead occur due to the sporadic release of lead particulates. However, conventional water sampling strategies do not account for these infrequent but hazardous events. This research suggests that current approaches to sampling tap water for lead testing identify only a small fraction of homes in which particulate spikes occur, and that sampling procedures should be changed substantially to increase the probability of identifying the hazard of particulate lead release into drinking water.

Abstract Housing plays a crucial role in all aspects of childhood health. Inadequate housing can contribute to childhood asthma and injury, be the source of pediatric lead poisoning, and be the locus of exposure to a range of toxic chemicals and carcinogens. Many experts argue that inadequate housing is fundamentally a child health problem and that the various diseases associated with poor housing are symptoms of this root cause. This chapter focuses on aspects of the home environment that influence the physical health of children and other building occupants: conditions such as asbestos, lead and mold; chemical exposures such as pesticides, cleaning materials, toys, arts and crafts, cosmetics, and radon; drinking water; and indoor air pollution in the home. The chapter argues that piecemeal models for addressing residential hazards that focus on only one disease or exposure at a time are no longer adequate. Instead, a new, more holistic and systematic approach is needed if issues of housing and health are to be fully integrated.

Lead is known to impair neurocognitive development in children. Drinking water is routinely monitored for lead content in municipal systems, but private well owners are not required to test for lead. The lack of testing poses a risk of lead exposure and resulting health effects to rural children. In three Illinois counties, we conducted a cross-sectional study (n = 151 homes) examining water lead levels (WLLs), water consumption, and water treatment status to assess risk of lead exposure among residents using private water wells. Since blood lead levels (BLLs) were not available, EPA’s Integrated Exposure Uptake Biokinetic (IEUBK) modeling was used to estimate the incremental contribution of WLL to BLL, holding all other sources of lead at their default values. Nearly half (48.3%) of stagnant water samples contained measurable lead ranging from 0.79 to 76.2 µg/L (median= 0.537 µg/L). IEUBK modeling showed BLLs rose from 0.3 to 0.4 µg/dL when WLLs rose from 0.54 µg/L (the tenth percentile) to 4.88 µg/L (the 90th percentile). Based on IEUBK modeling, 18% of children with a WLL at the 10th percentile would have a BLL above 3.5 µg/dL compared to 27.4% of those with a WLL at the 90th percentile. These findings suggest that the consumption of unfiltered well water likely results in increased blood lead levels in children.

Improved lead paint hazard identification and remediation methods emerged in the mid- to late 1980s through research that was translated into practice through nationwide training consortia. Despite attempts to water it down and successful resistance from scientists, a major report to Congress from a government agency in 1988 declared that “Corrective actions have been a clear failure.” Yet Congress failed to redefine what a lead paint hazard meant in light of the new exposure pathway science. Public housing authorities were ordered to inspect for lead paint but were not provided with funding to solve it, placing them in an untenable position from growing lawsuits. Many banded together to insure themselves through the Housing Authority Risk Retention Group, which developed scientifically based risk assessment and interim control procedures until permanent abatement could be implemented, marking the first significant involvement of the housing profession. The risk assessment focused on validated dust lead measurements and targeted remediation that protected the largest number of children in the shortest period of time, a rejection of the simplistic and harmful lead paint removal “all-or-nothing” earlier approach. Yet in its 1990 interim public housing guidelines, the Department of Housing and Urban Development (HUD) persisted in requiring only paint removal due to the Ashton v Pierce court decision. HUD also failed to assign clear responsibility for lead paint, describing it as either a "policy" or a "public housing" problem. Following an investigation into a New Orleans public housing scandal, where hundreds of poisoned children had been identified, in 1991 Congress ordered an end to the finger pointing by creating a new office within the office of the HUD Secretary with department-wide authority. Congress also provided the first grants for privately owned low-income housing where the problem was most severe. HUD released a so-called Comprehensible and Workable Plan that put the price tag for remediation at a paralyzing $500 billion. The decades-long paralysis continued until Congress passed Title X of the 1992 Housing and Community Development Act. For the first time, Congress used the new pathway science to redefine the legal meaning of a lead paint hazard and made primary prevention the law of the land, instead of limited blood lead screening. The Centers for Disease Control and Prevention produced a new strategic plan in 1991, when the nation’s health secretary declared that lead poisoning was the number one children’s environmental disease, over White House objections. Two new nonprofit organizations, the Alliance to End Childhood Lead Poisoning and the National Center for Lead Safe Housing, were founded in 1990 and 1992, respectively to help create political will and standards.

The US government banned lead in new residential paint in 1978, half a century after many other countries did so through the International Labor Organization in the 1920s. The delay resulted in tens of millions of homes coated with lead paint. The lead, paint, and pigment industries argued that other sources of lead were more important, that parents were not supervising their children, and that landlords were not maintaining their properties. They successfully lobbied the US government to require lead paint in federal properties, which it did until 1971 when Congress pushed back and passed the first lead paint poisoning prevention act. An internal secret memo from Sherwin Williams in 1969 showed that the industry was aware of the problem but continued to sell lead paint. A 1978 HUD report to Congress alleged that gasoline was the problem and exposure pathway science was unimportant. FDA and EPA regulated other lead sources but lead in paint was largely ignored. Limitations in accurate methods of detecting lead in blood, paint, dust, and other media as well as the failure to measure lead exposure pathways contributed to inaction. Early efforts to overcome measurement problems included the appearance of experimental X-Ray Fluorescence portable lead paint analyzers in the early 1970s, but they would not be standardized until 20 years later. The historical amounts of lead used in gasoline, paint, and water pipes are documented here. Although there are more than 20,000 studies on lead toxicity, there are less than 40 studies on housing interventions. The chapter closes with an examination of the implications of proactive and retroactive bans of lead paint, applying the hierarchy of controls to the lead paint issue.

CONTEXT:Sources and pathways of lead exposure in young children have not been analyzed using new artificial intelligence methods.OBJECTIVE:To collect environmental, behavioral, and other data on sources and pathways in 17 rural homes to predict at-risk households and to compare urban and rural indicators of exposure.DESIGN:Cross-sectional pilot study.SETTING:Knox County, Illinois, which has a high rate of childhood lead poisoning.PARTICIPANTS:Rural families.METHODS:Neural network and K-means statistical analysis.MAIN OUTCOME MEASURE:Children's blood lead level.RESULTS:Lead paint on doors, lead dust, residential property assessed tax, and median interior paint lead level were the most important predictors of children's blood lead level.CONCLUSIONS:K-means analysis confirmed that settled house dust lead loadings, age of housing, concentration of lead in door paint, and geometric mean of interior lead paint samples were the most important predictors of lead in children's blood. However, assessed property tax also emerged as a new predictor. A sampling strategy that examines these variables can provide lead poisoning prevention professionals with an efficient and cost-effective means of identifying priority homes for lead remediation. The ability to preemptively target remediation efforts can help health, housing, and other agencies to remove lead hazards before children develop irreversible health effects and incur costs associated with lead in their blood.

By the end of the 1990s, the US lead paint experience was used to address other housing-related diseases and injuries. Following a Congressionally mandated investigation into infant fatalities related to mold exposure in Cleveland, a US Department of Housing and Urban Development report to Congress launched the US healthy homes initiative in 1999. Scientists traced the cause of the problem to deficient ventilation and inadequate moisture control. Later, the healthy homes concept expanded to ten key areas: injuries, pests, maintenance, cleaning, toxic substances, accessibility, thermal controls, ventilation, moisture control and affordability. New research and demonstration efforts were launched to determine how interventions could yield significant health improvements. In 2009 the US Surgeon General issued a Call to Action on healthy homes, and a systematic review of the evidence demonstrated which housing interventions were beneficial, which ones did not have sufficient evidence, and which ones were harmful. A National Safe and Healthy Housing Coalition was founded to coordinate the many community groups, local governments, housing health and environmental professionals and policymakers. The World Health Organization and other countries started healthy housing work many years before the United States. It launched large surveys of housing and health in nine European countries and held major international conferences in 2002 and 2004. WHO later estimated the burden of disease attributed to inadequate housing and in 2018 WHO released its Housing and Health Guidelines, which are being implemented around the world.

Context: Childhood lead poisoning prevention in the United States was marked by a largely failed medical approach from 1971 to 1990; an emergent (but small) healthy housing primary prevention strategy from 1991 to 2015; and implementation of large-scale proven interventions since then. Program: Childhood Lead Poisoning Prevention & Healthy Housing. Methods: Historic and recent health and housing data from the National Health and Nutrition Examination Survey (NHANES) and the American Healthy Homes Survey (AHHS) were retrieved to analyze trends and associated policy gaps. Evaluation: Approximately 590 000 US children aged 1 through 5 years had elevated blood lead levels of 3.5 μg/dL and greater in 2016, and 4.3 million children resided in homes with lead paint in 2019. Despite large improvements, racial and other disparities remain stubbornly and statistically significant. The NHANES and the AHHS require larger sample sizes. The Centers for Disease Control and Prevention has not published children's blood lead surveillance and NHANES data in several years; the Department of Housing and Urban Development (HUD) has no analogous housing surveillance system; and the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) have not updated training, Superfund, and occupational standards in decades. Discussion: The nation has been without a plan and an associated budget for more than 2 decades. Congress has not reformed the nation's main lead poisoning prevention laws in more than 30 years. Such reforms include stopping US companies from producing new residential lead paint in other countries; enabling the disclosure law to identify all residential lead hazards; closing loopholes in federally assisted housing regulations and mortgage insurance standards; harnessing tax policy to help homeowners mitigate lead hazards; streamlining training requirements; increasing the size of health and housing surveys and surveillance systems; and updating housing codes, medical guidance, dust lead standards, training, Superfund, and worker exposure limits. Congress and the president should reauthorize a cabinet-level task force (dormant since 2010) to develop a new strategic plan with an interagency budget to implement it. These reforms will scale and optimize markets, subsidies, enforcement, and other proven interventions to end ineffective, costly, harmful, and irrational cost shifting that threatens children, workers, and affordable housing.

There has been little research on childhood lead exposure pathways since the 1990s. New data from Michigan in 2017-2021 for 429 children in 345 homes included lead in blood, paint, dust, soil, water, and other housing, demographic, and behavioral metrics. Fifty-three percent of these children had blood lead (BPb) >= 5 mu g/dL. A repeated measures pathway model that accounted for multiple children in the same home was constructed using weighted least squares mean estimation and included variance-covariance model multiple imputation. Results showed that children's BPb was directly predicted by lead in settled floor house dust, child's age, season, and mouthing behavior and indirectly predicted by window sill and trough dust lead (DPb), bare soil lead (SPb), proportion of floors with carpets, and exterior building deteriorations. Paint lead (PPb) was also an indirect predictor of BPb through the soil and settled dust pathways. Water lead (WPb), water consumption and other lead sources/pathways were not significant predictors of BPb in this cohort. Although risk factors for individual children are highly variable and worthy of investigation to pinpoint their exposures, this study shows that the main direct and indirect pathways of lead exposure for most children in older housing remain paint and the contaminated dust and soil it generates. Pathway analyses in other jurisdictions using current data should be performed to confirm these results. This study suggests both DPb and BPb in high-risk homes may have declined since the 1990s and that lead in dust, soil, and paint all should be measured to predict risk and target remediation. Because most homes still have not been assessed for lead hazards and remediated, too many children remain at needless risk.

CONTEXT:To determine if radon mitigation is needed to protect occupants of multifamily housing, reliable testing procedures are needed. Yet, protocols on how many ground-contact housing units must be tested vary from 10% to 25% to 100%.OBJECTIVES:To estimate the probability of failing to identify a building containing at least one unit with elevated radon level when all ground-contact units are not tested.DESIGN:Retrospective analysis of previously collected data from licensed (ie, certified) radon measurement professionals using hypergeometric and Monte Carlo statistical methods to estimate the confidence that there are no units with radon levels of 4 picoCuries/liter of air (pCi/L) or more based on various testing percentages.SETTING:Testing data were obtained from 29 US states for 7892 ground-contact units in 687 multifamily buildings, primarily 5 to 20 units per building.MAIN OUTCOME MEASURE:Probability of failing to identify elevated radon levels in untested units.RESULTS:About 15% (n = 1163) of the units had radon levels of more than 4 pCi/L (the EPA action level); 59 units had more than 20 pCi/L (maximum of 96 pCi/L). For building sizes of 5 to 20 ground-contact units, the 2018 federal testing protocols that currently require testing of 10% and 25% of ground-contact units in each building failed to identify 47%-69% and 32%-46% of the units, respectively, depending on building size.CONCLUSIONS:Measurement of 90% of the ground-contact units in buildings with 5 to 20 ground-contact units results in up to 4% of the units with elevated radon levels being missed. To achieve 95% confidence that no units in the building have radon levels of 4 pCi/L or more in buildings up to 20 units, 100% sampling is required. For the vast majority of multifamily buildings, all ground-contact units in multifamily buildings should be tested for radon.

Context: Millions of US homes receive water from private wells, which are not required to be tested for lead (Pb). An approach to prioritizing high-risk homes for water lead level (WLL) testing may help focus outreach and screening efforts, while reducing the testing of homes at low risk. Objective: To (1) characterize distribution of WLLs and corrosivity in tap water of homes with private residential wells, and (2) develop and evaluate a screening strategy for predicting Pb detection within a home. Design: Cross-sectional. Setting: Three Illinois counties: Kane (northern), Peoria (central), and Jackson (southern). Participants: 151 private well users from 3 Illinois counties. Intervention: Water samples were analyzed for WLL and corrosivity. Main Outcome Measures: (1) WLL and corrosivity, and (2) the sensitivity, specificity, and predictive value of a strategy for prioritizing homes for WLL testing. Results: Pb was detected (>0.76 ppb) in tap water of 48.3% homes, and 3.3% exceeded 15 ppb, the US Environmental Protection Agency action level for community water systems. Compared with homes built in/after 1987 with relatively low corrosivity, older homes with more corrosive water were far more likely to contain measurable Pb (odds ratio = 11.07; 95% confidence interval, 3.47-35.31). The strategy for screening homes with private wells for WLL had a sensitivity of 88%, specificity of 42%, positive predictive value of 58%, and negative predictive value of 80%. Conclusions: Pb in residential well water is widespread. The screening strategy for prioritizing homes with private wells for WLL testing is greater than 85% sensitive.

Energy retrofits can reduce air exchange, raising the concern of whether indoor radon and moisture levels could increase. This pre/post-intervention study explored whether simple radon interventions implemented in conjunction with energy retrofits can prevent increases in radon and moisture levels. Treatment homes (n = 98) were matched with control (no energy retrofits or radon intervention) homes (n = 12). Control homes were matched by geographic location and foundation type. t-tests were used to determine whether post-energy retrofit radon and moisture level changes in treatment homes significantly differed from those in control homes. The radon interventions succeeded in preventing statistically significant increases in first floor radon using arithmetic (P = 0.749) and geometric means (P = 0.120). In basements, arithmetic (P = 0.060) and geometric (P = 0.092) mean radon levels statistically significantly increased, consistent with previous studies which found that basement radon levels may increase even if first floor levels remain unchanged. Changes in infiltration were related to changes in radon (P = 0.057 in basements; P = 0.066 on first floors). Only 58% of the change in infiltration was due to air sealing, with the rest due to weather changes. There was no statistically significant association between air sealing itself and radon levels on the first floor (P = 0.664). Moisture levels also did not significantly increase.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The impact of sealing ventilation shafts, installing self-balancing dampers and larger capacity exhaust fans on indoor air quality has not yet been thoroughly investigated. We examined IAQ outcomes in two groups of high-rise multifamily public housing. Both study and control group dwellings received ventilation shaft cleaning. The study group also received higher horsepower rooftop fans and ventilation shaft sealing to prevent leakage, and self-balancing dampers. We conducted interviews with residents 1 year before ventilation work and again 1 year after ventilation work completion ( n = 96 households; 45 in the study group and 51 in the control group) that asked about housing conditions. In some dwellings, we also tested airflow and indoor air quality, including volatile organic compounds, carbon dioxide (CO 2 ), and formaldehyde. Ventilation improved in the study group and decreased in the control group. Across both groups, dwellings had statistically significant decreases in musty odors and presence of cockroaches. The study group’s ventilation upgrades increased airflow inside those dwellings, and the airflow in study group bathrooms was significantly better than that of control group bathrooms. These increased ventilation rates were associated with statistically significant improvements in relative humidity, CO 2 , and formaldehyde in the study group. Enhanced ventilation should be implemented in multifamily housing to improve indoor air quality.

Cantor AG, Hendrickson R, Blazina I, Griffin J, Grusing S, McDonagh MS. Screening for Elevated Blood Lead Levels in Childhood and Pregnancy: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA 2019;321:1510-26. What is the level of evidence for lead screening in asymptomatic children? Systematic review. Largely US communities. Children 1-5 years of age. Screening, testing, and treatment for elevated blood lead levels. Screening effectiveness, test accuracy, and benefits of screening and interventions. The Task Force concluded that questionnaires and other clinical prediction tools cannot accurately identify asymptomatic children with elevated lead levels. The Task Force also found inadequate evidence for the treatment of elevated blood lead levels in asymptomatic children. There is insufficient evidence to assess the utility of screening for elevated blood lead levels in asymptomatic children ("I" statement).

AffiliationsThe author is with the National Center for Healthy Housing, Columbia, MD, and the School of Public Health, University of Illinois at Chicago.

Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices and future needs, and 5) sustainability. Overall, it is clear that carpet can influence our exposures to particles and volatile compounds in the indoor environment by acting as a direct source, as a reservoir of environmental contaminants, and as a surface supporting chemical and biological transformations. However, the health implications of these processes are not well known, nor how cleaning practices could be optimized to minimize potential negative impacts. Current standards and recommendations focus largely on carpets as a primary source of chemicals and on limiting moisture that would support microbial growth. Future research should consider enhancing knowledge related to the impact of carpet in the indoor environment and how we might improve the design and maintenance of this common material to reduce our exposure to harmful contaminants while retaining the benefits to consumers.

IMPORTANCE Childhood lead exposure is associated with neurobehavioral deficits. The effect of a residential lead hazard intervention on blood lead concentrations and neurobehavioral development remains unknown. OBJECTIVE To determine whether a comprehensive residential lead-exposure reduction intervention completed during pregnancy could decrease residential dust lead loadings, prevent elevated blood lead concentrations, and improve childhood neurobehavioral outcomes. DESIGN, SETTING, AND PARTICIPANTS This longitudinal, community-based randomized clinical trial of pregnant women and their children, the Health Outcomes and Measures of the Environment (HOME) Study, was conducted between March 1, 2003, and January 31, 2006. Pregnant women attending 1 of 9 prenatal care clinics affiliated with 3 hospitals in the Cincinnati, Ohio, metropolitan area were recruited. Of the 1263 eligible women, 468 (37.0%) agreed to participate and 355 women (75.8%) were randomized in this intention-to-treat analysis. Participants were randomly assigned to receive 1 of 2 interventions designed to reduce residential lead or injury hazards. Follow-up on children took place at 1, 2, 3, 4, 5, and 8 years of age. Data analysis was performed from September 2, 2017, to May 6, 2018. MAIN OUTCOMES AND MEASURES Residential dust lead loadings were measured at baseline and when children were 1 and 2 years of age. At 1, 2, 3, 4, 5, and 8 years of age, the children's blood lead concentrations as well as behavior, cognition, and executive functions were assessed. RESULTS Of the 355 women randomized, 174 (49.0%) were assigned to the intervention group (mean [SD] age at delivery, 30.1 (5.5) years; 119 [68.3%] self-identified as non-Hispanic white) and 181 (50.9%) to the control group (mean [SD] age at delivery, 29.2 [5.7] years; 123 [67.9%] self-identified as non-Hispanic white). The intervention reduced the dust lead loadings for the floor (24%; 95% CI, -43% to 1%), windowsill (40%; 95% CI, -60% to -11%), and window trough (47%; 95% CI, -68% to -10%) surfaces. The intervention did not statistically significantly reduce childhood blood lead concentrations (-6%; 95% CI, -17% to 6%; P=.29). Neurobehavioral test scores were not statistically different between children in the intervention group than those in the control group except for a reduction in anxiety scores in the intervention group (beta = -1.6; 95% CI, -3.2 to -0.1; P=.04). CONCLUSIONS AND RELEVANCE Residential lead exposures, as well as blood lead concentrations in non-Hispanic black children, were reduced through a comprehensive lead-hazard intervention without elevating the lead body burden. However, this decrease did not result in substantive neurobehavioral improvements in children.