Periconceptional vitamin use and leukemia risk in children with Down syndrome: A children's oncology group study

BACKGROUND. Periconceptional vitamin supplementation reduces the risk of neural tube defects, and possibly may reduce the risk of certain childhood malignancies, including acute lymphoblastic leukemia (ALL). Because children with Down syndrome (DS) experience a 20-fold higher risk of leukemia than the general population, the authors evaluated whether periconceptional vitamin supplementation reduced the risk of leukemia in children with DS. METHODS. From 1997 to 2002, 158 children ages birth-18 years with DS and acute leukemia (n = 61 children with acute myeloid leukemia [AML] and n = 97 children with ALL) were enrolled through the Children's Oncology Group in North America. Children with DS alone (n = 173) were identified through the cases' pediatric clinics and frequency matched to cases on age. Mothers of cases and controls completed a telephone interview that included questions regarding vitamin supplement use in the periconceptional period and after knowledge of pregnancy. RESULTS. A decreased risk of leukemia was observed with vitamin supplementation in the periconceptional period (odds ratio [OR] = 0.63; 95% confidence interval [95% CI], 0.39-1.00). When stratified by leukemia type, the reduced risk was observed for ALL (OR = 0.51; 95% CI, 0.30-0.89), but not for AML (OR = 0.92; 95% CI, 0.48 -1.76). Compared with vitamin use in the periconceptional period, use only after knowledge of pregnancy was associated with an increased risk of leukemia (OR = 1.61; 95% CI, 1.00-2.58). This was observed for both ALL and AML. CONCLUSIONS. These data added to a growing body of evidence that suggests that periconceptional vitamin use may be protective in the development of certain childhood cancers.