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© 2004 American Public Health Association
RESEARCH AND PRACTICE |
S. A. Boseila and A. A. Gabr are with the Child Health Department, National Research Center, Giza, Egypt. I. A. Hakim is with the College of Public Health, Division of Health Promotion Sciences, University of Arizona, Tucson, Ariz.
Correspondence: Requests for reprints should be sent to Iman Hakim, MD, PhD, MPH, College of Public Health, University of Arizona, 1515 N. Campbell Ave., P.O. Box 245024, Tucson, AZ 85724 (e-mail: ihakim{at}u.arizona.edu).
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INTRODUCTION |
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 TOP INTRODUCTION METHODSRESULTSDISCUSSIONReferences |
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The wide spectrum of damage to the health of children from environmental lead (Pb) is a matter of global concern. The neurotoxicity of long-term low-level exposure to lead has a special relevance in children.1,2 Although the consumption of paint chips or proximity to a lead-emitting smelter has been associated with PbB (blood lead) levels > 40 µg/dL, these 2 factors are not considered contributors to moderately elevated levels (> 10 µg/dL). Therefore, activities that contribute to lower levels of Pb exposure should be identified. The aim of this pilot study was to establish the social variables predictive of higher lead levels in young Egyptian children.
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METHODS |
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TOPINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Children were recruited from 2 different areas in Giza, Egypt: a rural village and a lower-middle-class urban district. Children were selected through a household-sampling frame specifically developed for this research. Informed parental consent was obtained before blood collection.
A structured questionnaire was used to collect the following information: first, demographic, socioeconomic, and environmental information (age, gender, parents’ education, parents’ occupation, use of traditional cosmetics or remedies, smoking, housing condition, and street width and paving condition), and second, the child’s hygiene practices and hand-to-mouth activities (hand washing, eating with fingers, sucking thumbs and fingers, chewing nails, use of pacifier, pica [an abnormal desire to eat substances not normally eaten], and carrying preferred toy all day).
Houses were evaluated with respect to building materials, pavement, condition of paint, sleeping site of children, and the type of floor in the house.
Blood specimens were analyzed for lead by flameless atomic absorption at the Air and Industrial Hygiene Laboratory, California State Department of Health Services, Berkeley, Calif.
Data analysis was conducted using Intercooled Stata 6 (Stata Corp, College Station, Tex). Kruskal–Wallis 1-way analysis of variance was used to examine the effect of social and environmental factors on PbB. Linear regression analyses were carried out using the natural logarithm of PbB levels as the dependent variable. Significant variables were then retested in a multiple regression analysis model. The variables included in the final model were site, age, gender, traffic, mother’s occupation, mother’s education, father’s education, condition of paint in the house, and sleep site.
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RESULTS |
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TOPINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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PbB levels for the 164 tested children averaged 12.96 µg/dL. Forty-six percent of rural children had PbB levels higher than 15 µg/dL, whereas only 20% of the urban children had levels exceeding 15 µg/dL (Table 1
). Younger children had significantly higher PbB levels than older children.
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No statistically significant differences were found in PbB levels of children who reported hand-to-mouth activities compared with those who did not. Significant differences in PbB associated with housing quality and location are presented in Table 2
.
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Results of multiple linear regression analysis showed that PbB was significantly affected by age (P < .001; negative correlation), traffic (P = .004; negative correlation), mother’s occupation (P = .007), sleep site (P = .046), and street pavement (P = .019).
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DISCUSSION |
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TOPINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Childhood lead exposure is a multivariate problem, with the effects of multiple sources of lead being mediated by multiple sociodemographic factors. Although numerous studies have reported the individual influence of various factors on PbB levels, few have addressed the multivariate aspects of the problem.3,4 Of the children studied, 55.8% had PbB levels above the intervention level of 10 µg/dL adopted in the United States.1 The Egyptian children’s PbB levels were higher than those reported from several developed countries5–7 but were comparable to those reported from Saudi Arabia8 and Mexico.9 In the general population, children under the age of 5 have the highest PbB levels because of increased gastrointestinal absorption and exposure through behaviors such as playing outdoors and increased hand-to-mouth activity.10 The observed negative correlation between PbB and age is in agreement with results reported earlier.5,11 The differences in the prevalence of elevated PbB levels between rural and urban children are likely to represent differences in housing characteristics and environmental exposure.
Lead-contaminated soil and dust in high-traffic areas significantly contribute to the children’s lead intake.12 The finding that children living in high-traffic streets had significantly lower PbB levels than those living in low-traffic streets was unexpected. Given that children living in low-traffic areas are more likely to spend most of their time playing in the street (being quite and safe), it is possible that some Pb in dust or soil in the contaminated outdoor environments contributed to their higher PbB levels. In addition, the low-traffic streets are more likely to be narrow and unpaved or unmaintained, thus increasing the possibility of lead exposure.
Our data as well as previous data3,13 showed that PbB levels differed considerably among children classified by housing quality. Of particular interest was the question of whether children sleep on the floor. The concern was that children who sleep on the floor might have greater contact with lead than those who sleep in beds. The finding that the mother’s occupation remained in the final model and had a direct significant link with PbB was unexpected. It is more likely that housewives spend more time cleaning their houses and taking care of their young children.
These observations led us to conclude that young Egyptian children, like children from other countries, are especially susceptible to Pb exposure, despite the differences in the sources of exposure. In this context, lead poisoning in Egypt constitutes a public health challenge, but no simple solutions are envisioned. Perhaps one of the few real options at hand in the short term is the implementation of vigorous, community-based health education programs.
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Acknowledgments |
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This research was supported by a small grant from the Ford Foundation Office in Egypt.
We thank Drs Soheir Salem (National Research Center, Egypt), Osman Galal and Gail Harrison (University of California Los Angeles School of Public Health), and G. Guirguis (Air and Industrial Hygiene laboratory, California State Department of Health Services, Berkeley, California) for their support throughout the project.
Human Participation Protection
The protocol was approved by the scientific review committee of the Child Health Department at The National Research Center, Cairo, Egypt.
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Footnotes |
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Peer Reviewed
Accepted for publication December 6, 2002.
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References |
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TOPINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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1. Preventing Lead Poisoning in Your Children: A Statement by the Centers for Disease Control and Prevention. Atlanta, Ga: Centers for Disease Control and Prevention; 1991.
2. Finkelstein Y, Markowitz ME, Rosen JF. Low-level lead-induced neurotoxicity in children: an update on central nervous system effects. Brain Res Brain Res Rev. 1998;27(2):168–176.[Medline]
3. Bornschein RL, Succop P, Dietrich KN, Clark CS, Que Hee S, Hammond PB. The influence of social and environmental factors on dust lead, hand lead and blood lead levels in young children. Environ Res. 1985;38:108–118.[Medline]
4. Rabinowitz M, Leviton A, Needleman H, Bellinger D, Waternaux C. Environmental correlates of infant blood lead levels in Boston. Environ Res. 1985;38:96–107.[Medline]
5. Schutz A, Barregard L, Sallsten G, Wilske J, Manay N, Pereira L, Cousillas ZA. Blood lead in Uruguayan children and possible sources of exposure. Environ Res. 1997;74:17–23.[Medline]
6. Stromberg U, Schutz A, Skerfving S. Substantial decrease in blood lead in Swedish children, 1978–94, associated with petrol lead. Occup Environ Med. 1995;52:764–769.
7. Amodio-Cocchieri R, Arnese A, Prospero E, Roncioni A, Baruffo L, Ullucci R, Romano V. Lead in human blood from children living in Campania, Italy. J Toxicol Environ Health. 1996;47:311–320.[Medline]
8. Al-Saleh I, Mustafa A, Dufour L, Taylor A, Hiton R. Lead exposure in the City of Arar, Saudi Arabia. Arch Environ Health. 1996;51:73–82.[Web of Science][Medline]
9. Lopez-Carrillo L, Torres-Sanchez L, Garrido F, Papaqui-Hernandez J, Palazuelos-Rendon E, Lopez-Cervantes M. Prevalence and determinants of lead intoxication in Mexican children of low socioeconomic status. Environ Health Perspect. 1996;104:1208–1211[Web of Science][Medline]
10. Wilhelm M, Lombeck I, Kouros B, Wuthe J, Ohnesorge FK. Duplicate study on the dietary intake of some metals/metalloids by children in Germany: Part II. Aluminum, cadmium and lead [in German]. Zentralbl Hyg Umweltmed. 1995;197(5):357–369.[Medline]
11. Lin-Fu JS. (1982) Children and lead. N Engl J Med. 307:615–616[Web of Science][Medline]
12. Rahman, H, Alkhayat, A, Menon, N. (1986) Lead poisoning in infancy-unusual causes in the U.A.E. Ann Trop Paediatr. 6:213–217[Web of Science][Medline]
13. Clark CS, Bornschein RL, Succop P, Que Hee S, Hammond PB, Peace B. Condition and type of housing as an indicator of potential environmental lead exposure and pediatric blood lead levels. Environ Res. 1985;38:46–53[Medline]
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