Pregnancy, maternal tobacco smoking, and early age leukemia in Brazil
- 1Environment and Public Health Post-graduation Program, National School of Public Health, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- 2Pediatric Hematology-Oncology Program, Research Center, Instituto Nacional de Câncer/Rio de Janeiro, Rio de Janeiro, Brazil
- 3Members of the Brazilian Collaborative Study Group of Infant Acute Leukemia, listed in the appendix as co-authors
Background: Cigarette smoking has been associated with acute myeloid leukemia (AML) but hypothesis on the association between maternal smoking during pregnancy and childhood leukemia remains unclear. Objectives: To investigate the association between maternal exposure to tobacco smoking during pregnancy and early age (<2 year) leukemia (EAL). Methods: A hospital-based multicenter case-control study aiming to explore EAL risk factors was carried out in Brazil during 1999–2007. Data were collected by direct interview with the biological mothers using a standardized questionnaire. The present study included 675 children (193 acute lymphoid leukemia – ALL, 59 AML and 423 controls), being the latter age frequency matched and paired by area of residence with the cases. Unconditional logistic regression was performed, and odds ratios (OR) on the association between tobacco smoking (3 months before pregnancy, during pregnancy, and 3 months after delivery) and EAL were ascertained after adjustment for selected variables (maternal age at birth and education, birth weight, infant skin color, and oral contraceptives use during pregnancy). Results: Smoking was reported by 17.5% of case mothers and 20.6% of controls. Among women who reported to have smoked 20 or more cigarettes during the index pregnancy, an adjusted OR = 5.28 (95% CI 1.40–19.95) for ALL was observed. Heavy smoking during breastfeeding yielded an adjusted risk estimate for ALL, OR = 7.78 (95% CI 1.33–45.5). No dose-response effect was observed according to smoking exposure during pregnancy and EAL. An association between secondhand smoking during pregnancy or breastfeeding was not observed. Conclusion: An association between maternal smoking and EAL in the offspring was restricted to women who have reported an intense exposure to tobacco smoke during pregnancy and breastfeeding.
Keywords: smoking, pregnancy, childhood cancer, infant leukemia, lactation
Citation: Ferreira JD, Couto AC, Pombo-de-Oliveira MS, Koifman S and Brazilian Collaborative Study Group of InfantAcute Leukemia (2012) Pregnancy, maternal tobacco smoking, and early age leukemia in Brazil. Front. Oncol. 2:151. doi: 10.3389/fonc.2012.00151
Received: 24 July 2012; Accepted: 06 October 2012;
Published online: 09 November 2012.
Copyright: © 2012 Ferreira, Couto, Pombo-de-Oliveira, Koifman and Brazilian Collaborative Study Group of Infant Acute Leukemia. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Sergio Koifman, Environment and Public Health Post-graduation Program, National School of Public Health, Oswaldo Cruz Foundation, Rua Leopoldo Bulhões 1480, Rio de Janeiro, 21041-210, Brazil. e-mail: email@example.com