Birth weight linked to cancer risk

High birth weight is associated with a high risk of leukaemia  and acute lymphoblastic leukaemia  (ALL). The increased risk of acute myeloid leukaemia  (AML) appears to be associated with the high and low extremes of birth weight.

Leukaemia  a cancer of the blood or bone marrow characterised by an abnormal proliferation of blood cells, particularly white blood cells.

To examine the association between birth weight, childhood leukaemia , plus ALL and AML, two common leukaemia  subtypes, researchers conducted an analysis of 32 studies. Included in the analysis were 16,501 cases of all types of leukaemia , 10,974 cases of ALL, and 1832 cases of AML.

Compared with normal birth weight, high birth weight was associated with a 35 per cent overall increased risk of leukaemia , a 23 per cent increased risk of ALL and a 40 per cent increased risk of AML. It was found that for every 1000 gram increase in birth weight, the risk ratio for overall leukaemia  increased by 1.18.

While low birth weight was not associated with overall leukaemia  or ALL, there was an association between low birth weight and a 49 per cent increased risk of AML.

The above finings support the notion that childhood leukaemia  is likely to be initiated in utero. Birth weight is a marker for events during pregnancy that may have affected the risk for leukaemia  in the offspring.