Background: There is little research concerning infant formula or the age at introduction to solid foods and pediatric acute lymphoblastic leukemia (ALL). The purpose of this case-control study was to estimate the association of age at introduction of solids and pediatric ALL.
Methods: 171 ALL cases aged 0-14 years were recruited at Texas Children's Cancer Center and matched on sex, age, and ethnicity to 342 population-based controls. Data were collected on infant feeding and known risk factors for ALL. Multivariable logistic regression was used to model the odds ratio of ALL by quartile of age at introduction of solids with the first/earliest quartile (0-4 months) as the reference group.
Results: In adjusted models, the odds ratio of ALL among children in quartile 3 (7-9 months) was 4.08, 95% confidence interval (CI) 1.42-11.71; for children in quartile 4 (≥10 months) the odds ratio (OR) was 6.03, 95% CI 2.06-17.72. For each additional month of milk formula feeding, the OR of ALL was 1.16, 95% CI 1.08-1.25.
Conclusions: These results suggest a window when later introduction to solids is positively associated with ALL and recommend compliance with the American Academy of Pediatrics guidelines.