Anemia as a risk factor for infectious diseases in infants and toddlers: results from a prospective study.

Anemia due to iron deficiency is the most prevalent form of micronutrient malnutrition in the world, however, the causal relationship between anemia and infection remains unclear. We examined prospectively, the association between anemia and infection among Bedouin infants. We recruited 293 families and newborns from the Bedouin population, which is ongoing major lifestyle changes, during the periods of 1989-1992 and 1994-1997 and followed them to age 18 months. The number of diarrhea and respiratory disease episodes as well as total days of diarrhea were ascertained weekly. Hemoglobin levels were obtained at age 6 months. Additional data on feeding practices, environmental, household and demographic characteristics were obtained throughout the 18 months. Diarrhea before 6 months of age was found to be a risk factor for diarrhea after that age. After controlling for early morbidity < 6 months, anemia (Hb < 11 g/dl) at 6 months was an independent risk factor for diarrhea and respiratory illness from 7 to 18 months of age. This associations remained significant even after controlling, in addition, for environmental and socio-economic factors. In the multivariable models, anemia at age 6 months increased the risk for diarrhea after that age by 2.9-fold (95% confidence interval 1.6 - 5.3; p = 0.001) and that of respiratory disease by 2-fold (1.1 - 3.7; p = 0.03). Our findings suggest that anemia may increase the rates of infections in toddlers. The possibility that reducing anemia in infants may be a preventive measure to lower disease burden from infectious disease in this and other vulnerable populations should be tested in further studies.