Pregnancy, maternal tobacco smoking, and early age leukemia in Brazil

Abstract

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.

Maternal Benzene Exposure during Pregnancy and Risk of Childhood Acute Lymphoblastic Leukemia: A Meta-Analysis of Epidemiologic Studies

“… Considering study type may be the source of heterogeneity ( P = 0.032), studies are divided into two subgroups (seventeen case-control studies ( P = 0.134) and one cohort study). For studies of Abadi-Korek et al [48] and Ferreira et al [45] , Crude odds ratios are calculated from the data provided. …”

“…Although non-statistically significant associations were shown between maternal smoking during pregnancy and ALL in this meta-analysis, parental cigarette smoking should also be strictly prohibited. It is suggested that parental smoking affects many childhood diseases, such as respiratory tract infection, asthma and otitis media, which are much more prevalent than childhood leukemia [45] .…”

“…Our study may have the following limitations. First, interviewer bias: 1) The data in most studies we analyzed were collected by personal interview [1] , [2] , [18] , [37] – [39] , [42] , [43] , [45] , [49] , [51] , [53] , [56] , [58] , [60] , [62] or independent telephone interviews [44] , [47] , [48] , [50] , [52] , [54] , [55] , [57] , [59] , [61] . Several studies’ data were collected by self-administered questionnaire [40] , [46] or ascertained from the birth certificates [41] .…”

Maternal Alcohol Consumption during Pregnancy and Early Age Leukemia Risk in Brazil

“…After the written informed consent was signed, a face-to-face interview was applied to mother of cases and controls. Previous data about different maternal exposures and smoking during pregnancy used herein as a basis for interaction analysis are described elsewhere [ 30 , 32 ]. The content of questionnaires included data about family income, maternal age at child birth, education level, illness previous history to conception, medication use, occupation, personal habits, and the child's birth characteristics.…”

Biases Inherent in Studies of Coffee Consumption in Early Pregnancy and the Risks of Subsequent Events

“…Tobacco smoke exposure is a known carcinogen. [59] Some studies have reported that maternal tobacco exposure during pregnancy is associated with increased risk of the offspring developing childhood leukemia, [13,19,[60][61][62] whereas others report that paternal tobacco exposure during pregnancy (a source of second-hand smoke for the mother) is associated with the child's heightened risk of childhood leukemia. [25,29,63] Successful adjustment in multivariable models of the risk of a disorder depends on highquality exposure data.…”