Maternal pre-pregnancy and gestational diabetes, obesity, gestational weight gain, and risk of cancer in young children: a population-based study in California.

We aimed to examine the influence of pre-pregnancy diabetes, pre-pregnancy body mass index (BMI), gestational diabetes, and gestational weight gain on childhood cancer risk in offspring.

We identified cancer cases (n = 11,149) younger than age 6 years at diagnosis from the California Cancer Registry registered between 1988 and 2013. Controls (n = 270,147) were randomly sampled from California birth records, and frequency matched by year of birth to all childhood cancers during the study period. Exposure and covariate information were extracted from birth records. Unconditional logistic regression models were generated to assess the importance of pre-pregnancy diabetes, pre-pregnancy BMI, gestational diabetes, and gestational weight gain on childhood cancer risk.

We observed increased risks of acute lymphoblastic leukemia and Wilms' tumor in children of mothers with pre-pregnancy diabetes [odds ratio (OR) 95 % confidence interval (CI) 1.37 (1.11, 1.69); OR (95 % CI) 1.45 (0.97, 2.18), respectively]. When born to mothers who were overweight prior to pregnancy (BMI 25-<30), children were at increased risk of leukemia [OR (95 % CI) 1.27 (1.01, 1.59)]. Insufficient gestational weight gain increased the risk of acute myeloid leukemia [OR (95 % CI) 1.50 (0.92, 2.42)] while excessive gestational weight gain increased the risk of astrocytomas [OR (95 % CI) 1.56 (0.97, 2.50)]. No associations were found between gestational diabetes and childhood cancer risk in offspring.

We estimated elevated risks of several childhood cancers in the offspring of mothers who had diabetes and were overweight prior to pregnancy, as well as mothers who gained insufficient or excessive weight. Since few studies have focused on these factors in relation to childhood cancer, replication of our findings in future studies is warranted.