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RESEARCH AND PRACTICE |
Michelle Crozier Kegler is with the Department of Behavioral Sciences and Health Education, Rollins School of Public Health, Emory University, Atlanta, Ga. Lorraine Halinka Malcoe is with the Masters in Public Health Program and the Department of Family and Community Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM. At the time of the baseline data collection (1997), both authors were with the College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Okla.
Correspondence: Requests for reprints should be sent to Lorraine Halinka Malcoe, PhD, Masters in Public Health Program, MSC09 5060, 1 University of New Mexico, Albuquerque, NM 871310001 (e-mail: lhmalcoe{at}salud.unm.edu).
| ABSTRACT |
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Objectives. We tested the effectiveness of a community-based lay health advisor intervention for primary prevention of lead poisoning among Native American children who lived in a former mining area.
Methods. We conducted cross-sectional population-based blood lead assessments of Native American and White children aged 1 to 6 years and in-person caregiver interviews before (n=331) and after (n=387) a 2-year intervention.
Results. Mean childhood blood lead levels decreased and selected preventive behaviors improved for both Native American and White (comparison) communities. Several short-term outcomes also improved from pre- to postintervention, but only knowledge and hand-washing self-efficacy increased more among Native Americans than among Whites.
Conclusions. Our findings provide limited support for the effectiveness of lay health advisor interventions as a primary lead poisoning prevention strategy for Native American communities.
| INTRODUCTION |
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Community education is a recommended component of a comprehensive childhood lead poisoning prevention program1012; unfortunately, the effectiveness of education for the primary prevention of lead poisoning has rarely been assessed.13 In one of the few such studies, Lanphear et al. found that home visits by a dust-control advisor, the provision of cleaning supplies, and lead exposure education were not effective in preventing lead poisoning.14 Studies that examined education as a secondary prevention strategy for reducing lead exposure among children who had documented elevated blood lead levels have yielded mixed results.11,15 For example, Lanphear et al. found no significant reduction in childrens blood lead levels after families were educated on cleaning strategies to reduce household lead exposures,16 whereas others have documented decreases in mean blood levels after an educational intervention.17,18 No published studies have evaluated the effectiveness of education as a primary or a secondary lead poisoning prevention strategy among Native Americans.
The purpose of our study was to assess whether community education provided by lay health advisors through existing Native American social networks was an effective strategy for the primary prevention of childhood lead poisoning.
| METHODS |
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The Tribal Efforts Against Lead (TEAL) Project is a community-based research study that was conducted by university researchers in collaboration with the 8 tribes and nations of northeastern Oklahoma: Eastern Shawnee, Miami, Modoc, Ottawa, Peoria, Quapaw, Seneca-Cayuga, and Wyandotte.20,21 The intervention focused on the entire Native American community rather than on specific families, with the expectation that caregivers and the people influential in their lives would be reached through their social networks. Briefly, 40 natural helpers (i.e., respected people to whom others turned for advice and help) were recruited from the Native American community, and they completed 8 hours of training on sources of lead exposure and lead poisoning prevention strategies. These lay health advisors then attended monthly meetings, planned and engaged in outreach activities, and educated individuals in their social networks (average of 5.4 education/outreach activities per month). During the 2-year intervention period, they made nearly 27000 contacts and spent more than 5000 hours conducting TEAL-related community education efforts.22 Topics included sources of lead, the importance of blood lead screening, strategies for removing lead sources, hand washing, playing in grass rather than in dirt or mine tailings, good nutrition, and housecleaning.
Although the intervention targeted all members of local Native American social networks, the primary study outcomes focused on young children and their caregivers. To evaluate the intervention, we conducted 2 cross-sectional population-based blood lead assessments of Native American and White children and completed in-person interviews with their caregivers. The baseline assessment (T1) was conducted before the intervention during the summer and fall of 1997. The 2-year intervention was conducted from March 1998 through February 2000, and the second assessment (T2) was conducted during the summer and fall of 2000. We compared (1) population mean blood lead levels of Native American children before and after the intervention, and (2) lead prevention behaviors and associated beliefs of caregivers of Native American children before and after the intervention. We also tested whether changes observed among Native American children and their caregivers from pre- to postintervention were greater than those observed among White children and their caregivers who lived in the same geographic communities.
Study Population
The study population comprised representative samples of Native American and White children aged 1 to 6 years who lived within 31 contiguous census block groups in northeastern Oklahoma. The study area included the 5 small towns in the Tar Creek Superfund area and the city of Miami, Oklahoma, and other nearby towns and rural areas. The TEAL Project staff conducted a complete census of all residences in the study area at T1 and again at T2. In Miami, city blocks were randomly selected within each block group. All residences in selected blocks and all Superfund residences were visited by 2-person teams who identified and recruited eligible families. When there was more than 1 eligible child per family, the child with the most recent birthday was selected to participate.
At T1, staff visited 5572 residences and identified 550 eligible families. Of these, 137 caregivers refused to participate, 77 could not be interviewed after repeated attempts, and 4 children had incomplete interviews or blood lead data, which resulted in a sample size of 331 eligible families (60.4% response rate). At T2, staff visited 6686 residences and identified 474 eligible families, 387 of whom agreed to participate (81.6% response rate).
Data Collection
Blood lead.
Certified phlebotomists who were experienced in child venipuncture collected venous blood samples from each participating child. Blood samples were kept cool and were shipped for analysis to 1 of 2 state laboratories (the laboratory used at T1 was no longer in operation at T2). Both laboratories followed a Certified Laboratory Integrity Act proficiency plan and performed analysis with graphic-furnace atomic-absorption spectrometry. The detection limit was 1 µg/dL or less. All children (n=37 at T1 and n=20 at T2) who had elevated blood lead levels (
10 µg/dL) were referred to either the county health department or their primary care provider for follow-up education and medical care.
Caregiver interviews. Behavior, belief, knowledge, and sociodemographic data were collected via in-home interviews. Environmental assessments were completed only at T1 and thus were not used as evaluation measures.21,23
Outcome measures. In addition to mean blood lead levels, study outcomes included 4 preventive behaviors (annual blood lead test as recommended by the local health department, hand washing, damp dusting, and playing in safe areas), self-efficacy for each behavior, the perceived health benefit associated with each behavior, perceived susceptibility, and lead poisoning prevention knowledge.
The blood lead test behavior variable classified children into those who had been tested for lead within 1 year of the interview date versus those who had not been tested within the year or who had unknown test dates. We assessed hand-washing behavior by asking how often the participating child washed his or her hands before eating meals and snacks (0 = never to 4 = always). We assessed damp dusting by asking how often the caregiver used a damp cloth instead of a dry cloth when dusting (0 = almost never to 2 = almost always). Children who played mostly on paved or all grass surfaces were categorized as playing on safe surfaces versus those who played on dirt, gravel, or combination surfaces.
Several constructs from the health belief model were examined.24 Perceived susceptibility was measured by asking the caregiver, "Compared to children living in other parts of the state, do you think your childs chances of having a high lead level are (1 = a lot lower to 5 = a lot higher)?" Health benefits were assessed for each behavior except blood lead testing by asking the caregiver, "In your opinion, how likely is it that (behavior) will help prevent or keep (childs name) from having a high lead level?" (1 = not very likely to 3= very likely). Self-efficacy, defined as the confidence one has in his or her ability to perform a behavior, was measured by asking the caregiver, "How easy or hard would it be for you to (behavior)?" (1 = very easy to 4 = very hard). The knowledge score summed the number of "strongly agree" responses a care-giver gave to 4 true statements about lead poisoning prevention (e.g., lead can harm a childs ability to learn, children can get lead in their bodies by swallowing it).
Data Analysis
Data were entered into an EpiInfo database and were validated.25 The sample was stratified by Superfund residence (yes or no) for all analyses, because residents of Super-fund communities were exposed to several confounding events, including soil remediation and lead education by the county health department. Furthermore, recruitment was attempted for all eligible Superfund families, whereas families in non-Superfund communities were randomly sampled.
To evaluate whether the intervention contributed to decreases in childrens blood lead levels and to improvements in preventive behaviors and associated beliefs among the Native American population, we compared Native Americans at T1 with Native Americans at T2. When outcomes were continuous or were measured on an interval scale, we used t tests with a 2-sided test of significance. For dichotomous outcomes, we used a difference of proportions test. To test whether the T1 to T2 difference in each outcome was larger for the intervention population (Native Americans) than for the reference population (Whites in the same geographic area), we performed tests of difference of differences of means and tests of difference of differences of proportions. We calculated z scores for the difference of differences for each outcome with a 2-tailed test of significance. We used SAS, version 8.2 (SAS Institute Inc, Cary, NC), for all analyses.
| RESULTS |
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Lead Levels and Preventive Behaviors
Changes among intervention population.
Among Native American children, mean blood lead levels decreased significantly from T1 (6.00 µg/dL) to T2 (4.97 µg/dL) (P = .047) in Superfund communities and from 4.81 µg/dL to 3.34 µg/dL (P < 0.001) outside the Superfund area (Table 2
). Of the 4 behaviors targeted by the intervention, significant improvements from T1 to T2 among Native Americans were observed only for those living in Superfund communities. At T1, 14% of the Native American children in Superfund communities had received a blood lead test within the past year; this proportion increased to 29% at T2 (P = .019). Use of a damp cloth when dusting also increased among Native Americans in Superfund communities from a mean score of 1.34 at T1 to 1.64 at T2 (P = .015).
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Knowledge, Health Beliefs, and Self-Efficacy
Changes among intervention population.
In Superfund communities, knowledge and perceived susceptibility to lead poisoning increased significantly among Native Americans from T1 to T2 (Table 3
). Among Native Americans who lived in non-Superfund communities, significant T1 to T2 differences were observed for perceived susceptibility and for the health benefits of playing on safe surfaces. Self-efficacy scores among Native Americans improved significantly from T1 to T2 for 3 of the 4 preventive behaviors (obtaining annual blood lead test, hand washing, and playing on safe surfaces) in the Super-fund communities and for 2 of the behaviors (obtaining annual blood lead test and playing on safe surfaces) in the non-Superfund communities (Table 3
).
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| DISCUSSION |
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Among our intervention population, we observed many positive changes from pre- to postintervention. We found significant 1.0 to 1.5 µg/dL declines in population mean blood lead levels among Native American children in both Superfund and non-Superfund communities. Similar size increases in blood lead, at levels below 5 µg/dL, were recently shown to be associated with significant declines in arithmetic and reading scores among a national sample of children.8 Likewise, in Superfund communities, we observed improvements among Native Americans in 2 lead prevention behaviorsknowledge about lead poisoning and perceived susceptibility to leadand in the self-efficacy of 3 lead prevention behaviors. In non-Superfund communities, Native Americans showed improvements in perceived susceptibility to lead, the perceived health benefits of playing on safe surfaces, and self-efficacy of 2 preventive behaviors. However, we also observed several positive changes among the comparison population, and for the most part, the differences observed among the intervention population were not significantly greater than those observed among the comparison population.
Our study underscores several challenges for detecting the significant effects of community-based interventions.2632 One challenge was finding an appropriate comparison community. Our baseline environmental home assessment data revealed that floor dust and yard soil, which were derived largely from mining waste and possibly naturally occurring lead ores, were the primary lead sources associated with elevated (
10 µg/dL) blood lead levels among Native American and White children who lived in the study area.21,23 Lead-based paint accounted for only 1.1% of the variance in blood lead levels among study children.21 Because it was critical that the comparison community have exposures to lead sources that were of similar type and quantity to our intervention population, we selected the White community in the same geographic area for our reference group. However, the 2 "communities" are residentially integrated; thus, it was nearly impossible not to contaminate the comparison community with our preventive messages, which limited our ability to detect differences between the intervention and the comparison communities.
A related challenge was determining the appropriate unit of analysis.3335 The intervention was implemented at the community level; therefore, the most appropriate unit of analysis was the community. However, because the environmental problemwidespread contamination of lead mine tailingswas unique, we could not randomize multiple Native American communities into intervention and control groups. As a result, we could not perform multilevel analyses and instead had to use the individual as the unit of analysis.
The Superfund activities further complicated our study design. Because the US Environmental Protection Agency was conducting front- and backyard soil excavation in the Superfund communities, and because the county health department was conducting community education in these same communities during our intervention, we needed to stratify our sample on the basis of Superfund location. This stratification significantly decreased our power to detect differences between intervention and comparison communities. Furthermore, the nature of the massive local environmental lead problem and the growing community concern created a turbulent backdrop for our study (e.g., a governors task force was formed, residents organized to demand relocation, lawsuits were filed). Such widespread community concern may have resulted in temporal changes in lead poisoning prevention behaviors, attitudes, and beliefs that would have affected participants in both our intervention and comparison communities, which would make it difficult for our study to show a significant intervention effect.
Even though we cannot attribute the changes observed in our study solely to the intervention, our findings suggest that lay health advisor interventions may contribute to declines in mean blood lead levels and to increases in preventive lead-related behaviors and associated beliefs across a rural community. Our intervention was successful in engaging a relatively large number of Native American natural helpers to disseminate lead poisoning prevention information through their social networks.22 Additional research is needed before we will know whether a lay health advisor model is an effective strategy for other types of communities and for other environmental health problems. Finally, resource mobilization, interorganizational collaboration, policy advocacy skills, and other dimensions of community capacity are important additional outcomes that should be assessed when determining the effectiveness of community-based interventions for prevention of lead poisoning and other environmental health problems.28,3638
| Acknowledgments |
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We wish to thank Dr Robert Lynch for directing the environmental assessments that informed the intervention and Sally Whitecrow-Ollis for coordinating the TEAL Project intervention and various data collection activities. We also thank Susan Waldron and Mary Happy for directing the blood lead screening efforts in 1997 and 2000, respectively. Most importantly, we owe special thanks to both Barbara Kyser-Collier for chairing the community advisory board for several years and the 8 tribes and other community partners for their ongoing support of the TEAL Project.
Note. The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS or the National Institutes of Health.
| Footnotes |
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Human Participant Protection
This study was approved by the institutional review boards of the University of Oklahoma Health Sciences Center, the Emory University School of Medicine, and the University of New Mexico School of Medicine. Signed informed consent was obtained from participating care-givers before data collection.
Accepted for publication July 14, 2003.
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