A large Danish study led by Odense University suggests women who experience gestational diabetes are not at increased risk of breast cancer compared with the general population.
Although gestational diabetes resolves after birth, women who have had the condition are known to be at higher risk of developing type 2 diabetes, cardiovascular disease and chronic kidney disease, as well as conditions such as postnatal depression, than other women.
Some previous research has suggested that this kind of diabetes, which impacts around 6% of pregnancies in the U.S., may increase breast cancer risk. Whereas other research shows no increase in risk for breast cancer.
To investigate this possible link further, Maria Hornstrup Christensen, a researcher based at Odense University Hospital in Denmark, and colleagues carried out a study using data from a nationwide register-based cohort study in Denmark including 708,121 predominately Caucasian women who gave birth in Denmark between 1997 and 2018, 24,140 of whom had gestational diabetes during at least one pregnancy.
For the purposes of this study, which will be presented at the Annual Meeting of the European Association of the Study of Diabetes in Madrid in early September, Christensen and colleagues excluded women who already had a history of diabetes or breast cancer at enrollment.
Over a median follow-up period of 11.9 years, 7,609 women in the study were diagnosed with breast cancer. However, gestational diabetes did not significantly impact the risk of developing this type of cancer (overall hazard ratio: 0.99).
The researchers also corrected for factors that could have influenced this calculation such as age, number of children, ethnicity, income, occupation, education and preexisting health conditions, but they did not significantly impact risk for breast cancer in women who experienced gestational diabetes (Hazard ratio: 0.96).
“It will be reassuring for women who have had gestational diabetes to know that they are not a higher risk of developing breast cancer,” said Christensen in a press statement.
“They do, however, need to be alert to the fact that they are at higher risk of some conditions, including type 2 diabetes.”
She added that these results do not mean that women who have gestational diabetes have no risk for breast cancer and that “all women, regardless of whether or not they have had gestational diabetes, should be breast aware and check their breasts regularly for changes.”
