Methodologic issues in studying behavioral effects of infant iron-deficiency anemia.

Methodologic challenges proving that iron-deficiency anemia (IDA) ad- versely affects infant behavior and development are examined. This community-based study in Costa Rica included 191 infants aged 12-23 mo with varying degrees ofiron deficiency. The Bayley Scales of Infant Development were administered before and both 1 wk and 3 mo after intramuscular or oral administration of iron. Appropriate placebo-treatment control infants were also tested. Infants with IDA showed significantly lower mental and motor test scores, even after factors relating to birth, nutrition, family background, parental IQ, and the home environment were considered. The methodologic issues raised by the study point to the need to assess behavioral effects in a prospective, randomized trial of measures to prevent iron-