Recommendations for the Prevention of Lead Poisoning in Children (1976) / Chapter Skim
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Appendix D: Etiology and Consequences of Childhood Lead Poisoning
Appendix D: Etiology and Consequences of Childhood Lead Poisoning
Pages 37-44
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From page 37... ...
in the East and Midwest only. The incidence of lead poisoning is highest among one- to five-yearold inner city children who live in substandard housing containing multiple layers of old lead paint.12,60,70 A relatively small number of cases result from exposure to improperly glazed pottery or exposure to industrial point sources such as smelters and battery factories.
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From page 38... ...
Kostial's studies of rats show greater absorption of lead if administered in milk than if administered in dry feed.5l,52 Animal studies involving dietary deficiencies of calcium, copper and iron have shown that these deficiencies increase the absorption of lead.^'47,64,92 In iong-terin experiments in growing rats, restriction of dietary iron and calcium to 20 percent of the Recommended Daily Allowance for growing young rats increased the absorption and retention of lead by a factor of two or more.64.92 This degree of reduction in dietary intake of calcium and iron has been reported in two- to three-year-old children from low-income families.63,98 ^ population survey of American children showed less than optimal calcium intake ranging between 12-14 percent for white children and 23-25 percent for black children. Iron deficiency, defined as hemoglobin levels <10 grams, was seen in approximately 4 percent of white children from families above the poverty line, 10.8 percent of white children in families below the proverty line, 17.6 percent of Negro children in families above the poverty line and 15 percent of Negro children from families below the poverty line.1 Others93,98 have also reported dietary deficiencies of calcium and iron in young children.
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From page 39... ...
Based on the data presented above, the most hazardous "high dose" source available to the average child is paint. Average Daily Intake of Lead in Normal Children - Alexander's studies in eight healthy children receiving a normal diet, showed a mean daily intake of 10.61 yg Pb/kg body weight.^ Of this amount, 5.47 yg Pb/kg/day were absorbed and 5.13 yg Pb/kg/day were excreted in the feces.
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From page 40... ...
in blood. European studies have shown that increases in free erythrocyte protoporphyrin begin to occur in women and children when blood lead levels reach a range of 25-30 yg Pb/dl, and in men at 35-45 yg Pb/dl.8l,97,104,105 It is now known that it is zinc protoporphyrin rather than the free protoporphyrin IX which is present in excess in the circulating erythrocytes in lead poisoning and iron deficiency.
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From page 41... ...
Mothers were followed during pregnancy and delivery and children followed for eight postnatal years. The study group consisted of 67 asymptomatic children who had a positive history of pica for paint or plaster, lived in deteriorated old housing, had positive urinary coproporphyrin tests and either a blood lead level >40 yg Pb/dl or blood lead >30 yg Pb/dl and positive radiographic findings for lead lines in the long bones.
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From page 42... ...
The control group consisted of 70 children who had a negative history of pica for paint or plaster, lived in modern housing, did not visit older housing for day care and had negative tests for coproporphyrin in urine. In addition, all children were excluded from both groups who showed neurologic abnormalities or developmental lag either during the newborn period or at four months, if abnormalities were noted on the Bayley scale at eight months, or if confirmed or suspected disease of the central nervous system was noted anytime before seven years of age.
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From page 43... ...
Clinical records revealed that 37 of the 65 children in Group III had symptoms compatible with lead poisoning. Perino and Ernhart reported a significant negative relationship between blood lead levels and cognitive, verbal and perceptual abilities in 80 asymptomatic children, ages 3 years to 5 years, ll months, who had blood lead levels ranging from 10-70 yg Pb/dl.
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From page 44... ...
Lansdown's^° study of British children exposed to lead emission from an ore smelter showed no significant correlation between blood lead levels and either intelligence quotients or behavior ratings. However, of the 215 school age children studied, only 12 had >50 yg Pb/dl and 31 had 40-49 yg Pb/dl.
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