Breastfeeding and acute lymphoblastic leukaemia: potential leukemogenesis in children in developing countries

Abstract

Background:Breastfeeding (BF) in infancy is associated with a decreased risk of acute lymphoblastic leukaemia (ALL). However, most of the studies were conducted in developed countries, neglecting developing countries where mothers might be exposed to different carcinogenic substances which could be transferred through breastmilk.Methods: This is a case-control study which was conducted in the major paediatric cancer centre in Syria. Data of case and control groups were obtained from the hospital’s records. Only patients with no hereditary or chromosomal syndrome and aged 4 years and younger were included. The case group included ALL patients and control group contained hospital patients who visited its various clinics. The patients were categorised into 3 groups depending on their feeding habits before the age of 6 months. Results:Our sample contained 70 patients in the case group with 42 (60%) being males and 82 patients in the control group with 52 (55.3%) being males. Sixty (85.7%) cases and 59 (72%) controls were exclusively breastfed. We found a statistically significant difference when comparing cases and controls in BF patterns (P<0.05) as cases were exclusively breastfed more frequently. Exclusive breastfeeding was found more frequently in the case group compared to other patterns of infancy feeding P=0.04 (OR, 2.339; CI, 1.025 -5.336). In case group, parents of a low educational level breastfed their children more frequently (P<0.05). Number of siblings was not associated with ALL or any of its variables. Furthermore, infancy feeding pattern correlation with gender, being born with no complications, consanguinity, CD10, FAB classification, ALL-subtype, risk, and family history were insignificant. Conclusion:There are certain practices among the Syrian people, especially among parents of a low educational level that has possibly exposed their children to carcinogenic substances which were possibly transferred through BF, causing this association between ALL and BF. We speculate certain substances and behaviours being responsible. However, BF had minor effects on the prognosis and subtype of ALL, and number of siblings had no effect on ALL.

Interactions of Consanguinity and Number of Siblings with Childhood Acute Lymphoblastic Leukemia

“…However, a study from Denmark did not find a correlation between ALL and age intervals [ 25 ]. One case-control study in Syria found no association between number of siblings and ALL [ 26 ].…”

“…Finally, high educational level included having a university degree or higher. This system is used in Syria as these groups have distinguished features, and it was used previously in many studies [ 26 , 27 , 32 , 33 ].…”

“…Genetic testings could not be obtained due to unavailability to these tests in many cases in Syria [ 27 ]. The issue for proper funding has affected many studies and rendered it difficult to conduct proper diagnostic tools and to carry on studies other than observational [ 26 , 34 ]. For easier and more reliable comparisons, only pre-B-ALL and pre-T-ALL were included.…”

“…Acute monocytic leukemia and Hodgkin's lymphoma risks increase in large families, particularly in older siblings [ 23 ]. However, there are contradicting data about number of siblings' effect on ALL susceptibly [ 23 – 26 ].…”

“…ALL in Syria has distinguished features that may be from the unique environment and exposure to different substances [ 26 , 27 ]. This is the first study to evaluate the effect of consanguinity and number of siblings on different variables of childhood ALL as this is important for more personal treatment to maximise the outcomes, mainly in countries with high prevalence of these phenomena.…”