Maternal obesity and other in-utero events are important risk factors for colorectal cancer (CRC) in offspring and may contribute to increasing incidence rates among younger adults, according to a study published in Gut.

Obesity is known to be a risk factor for CRC, with studies suggesting that the fetal or developmental origins of obesity may also have an effect on cancer prevalence in adulthood. Researchers aimed to determine the associations of maternal obesity, pregnancy weight gain, and birth weight with CRC in adult offspring who were included in the Child Health and Developments Studies; this consisted of a population-based cohort of 18,751 live births among 14,507 mothers who received prenatal care at the Kaiser Foundation Health Plan in Oakland, California. The mothers were followed for 60 years.

The researchers obtained clinical information from mothers’ medical records from 6 months prior to pregnancy through delivery. Diagnoses of CRC in adult offspring were determined through 2019 via the California Cancer Registry.


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The researchers found that 68 offspring were diagnosed with CRC over 738,048 person-years of follow-up, with 48.5% being diagnosed while aged less than 50 years. Maternal obesity (body mass index (BMI) ≥30 kg/m2) increased the risk for CRC in adult offspring (adjusted hazard ratio [aHR], 2.51).

Trajectories of pregnancy weight gain, which may be markers of fetal growth and development, also increased the risk for CRC. Additionally, researchers noted an elevated association between high birth weight and CRC risk (≥4000 g; aHR, 1.95) compared with average birth weight (2000–3999 g; aHR, 1.00).

Investigators acknowledge associations with CRC risk may have been affected by factors such as diet and microbiome, which were not included in the Child Health and Development Studies. Additionally, screening for gestational diabetes was not standard of care during the time of the mothers’ pregnancies, and thus this association with CRC risk could not be analyzed.

“In summary, our results provide compelling evidence that in utero events are important risk factors of CRC and may contribute to increasing incidence rates in younger adults,” concluded the authors. They added, “There may also be other as yet unknown exposures during gestation and early life that give rise to this disease and warrant further study.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Murphy CC, Cirillo PM, Krigbaum NY, et al. Maternal obesity, pregnancy weight gain, and birth weight and risk of colorectal cancer. Gut. Published online August 24, 2021. doi: 10.1136/gutjnl-2021-325001