Synergistic effects of iron deficiency and lead exposure on blood lead levels in children

Abstract

Lead poisoning is a well recognized environmental health problem in children. Independent association of iron deficiency and lead exposure with elevated blood lead level (BLL) has been reported. Whether iron deficiency in combination with chronic lead exposure increases BLL and susceptibility to its harmful effects in children needs to be elucidated. In this case-control study, 246 children were randomly recruited. They comprised 123 children of lead smelters/battery recycle plant workers living close to the industries at Wah/Gujranwala, Pakistan (lead exposed group) and 123 children living 30 km away from the industrial area (controls). Blood lead analysis was carried out on the anodic stripping voltammeter lead analyzer 3010B. Blood counting was done on a Sysmex hematological analyzer and serum ferritin was determined by kit method on Immulite-1000. Of the 123 children in each group, 42 (34%) were iron deficient in the exposed group while 35 (28%) in the controls. The children's median age was 4 years (69 males and 54 females in each group). Lead exposed iron deficient children had significantly higher BLL median (quartile) 13.1 μg/dL (10.1-16.8) as compared with 9.6 μg/dL (7.6-10.3) in the iron deficient controls (P<0.05). Elevated BLL level was found in 31% of the lead exposed children and in 11% of the controls. Lead exposed children revealed a stronger negative correlation (r= -0.54; P=0.001) between BLL and serum ferritin than the controls (r=-0.36; P=0.01). Iron deficiency in combination with lead exposure synergistically elevates blood lead levels and susceptibility to its harmful effects in children.