Breast-feeding, fetal loss and childhood acute leukaemia

Abstract

The results presented support the hypothesis that prolonged breast-feeding may protect against childhood acute leukaemia and suggest an association with a maternal history of repeated miscarriages.Several recent studies have suggested that breastfeeding reduces the risk of childhood acute leukaemia and some prenatal factors, such as maternal history of fetal loss, have also been considered to play a role. This paper reports on perinatal data generated by a French casecontrol study which, overall, was designed to assess the role of perinatal, infectious, environmental and genetic factors in the aetiology of childhood acute leukaemia.A hospital-based, case-control study was conducted between 1995 and 1999 in the hospitals of Lille, Lyon, Nancy and Paris (France). The hospital-based design of the study was chosen since case and control blood samples were required. In order to be eligible for the study, the cases were required to present with newlydiagnosed primary leukaemia, be aged 15 years or less, and reside in the hospital catchment area. The controls were children hospitalised in the same hospital as the cases, mainly in orthopaedic and emergency departments, and residing in the same area as the cases. However, children hospitalised for cancer or major congenital birth defects were not eligible for the study. For both cases and controls, only French speaking mothers were eligible for the interview. The mothers of two cases and two controls refused to participate. Thus, a total of 280 cases of acute leukaemia (AL) and 288 controls were included in the study. Recruitment was frequency matched by age, gender, hospital, hospital catchment area and ethnic origin.Face-to-face interviews were carried out with the mothers of the cases and of the controls, using a standard questionnaire. Case mothers were interviewed when the index child was in complete remission or in good condition (on average, 2 months post-diagnosis). Interviews of case and control mothers were performed at about the same time in order to minimise recall bias. The mothers were asked to provide certain birth characteristics, lifestyle and medical history of the index child (breast-feeding) and a detailed maternal reproductive history (miscarriages, therapeutic or voluntary abortions, extra-uterine pregnancies, stillbirths). All analyses were performed using the SAS software package. Odds ratios (OR) were estimated using an unconditional logistic regression model including stratification variables. The analyses of breast-feeding were conducted on the children aged over 2 years in order to be certain that weaning had already taken place for both cases and controls.

Infection During the First Year of Life and Acute Leukemia: Epidemiological Evidence

“…The authors reported that if the child suffered from recurrent infections before 2 years of age, he/she would be protected from the development of acute leukemia, with an OR = 0.6 (95% CI: 0.4-1.0). These results were statistically significant and consistent with those reported by Neglia et al [21,22,32,68] However, Schüz et al (1999) conducted a case-control study in Germany during 1992-1997. They studied 1184 families of children with acute leukemia (cases) and 2588 families of healthy children (controls) and found no association between common infections and an increased incidence of leukemia.…”

“…These indicators are designated as "proxies" and include socioeconomic status, surgical history, allergic diseases, immunizations, attendance at daycare, breastfeeding, neonatal infections, and prenatal history, among others. [14][15][16][17][18][19][20][21][22][23][24][25] …”

“…For example, SteenselMoll et al measured socioeconomic status in The Netherlands (1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980) according to the parents' education, while other authors have used, for example, the number of people per room, home ownership, and family income as indicators of socioeconomic status. [15][16][17]21,22,[31][32][33] …”

“…[47][48][49][50] In most epidemiological studies, it has been documented that breastfeeding favorably influences both the response to infection and the modulation of the child's immune system. [21,33,[51][52][53][54][55][56][57][58][59][60][61][62][63][64] These factors require further investigation, as there is inconsistency among the epidemiological studies conducted thus far regarding whether a child's immune system will respond appropriately to an infectious agent after the child has been breastfed for the first six months of life. However, if the child has had recurrent common infections, his/her immune system will have an adequate response to a delayed infection.…”

“…Furthermore, no association was observed between day care and the development of common acute lymphoblastic leukemia (ALL), with an OR of 1.05 (95% CI: 0.80-1.37). [32] Using a design similar to that of Perillat et al (2002) and Neglia et al (2000), Jourdan-Da et al evaluated the role of childhood infections in the risk of developing acute leukemia in France. This study included 473 cases of acute leukemia and 567 population-based controls.…”