Women who develop gestational diabetes may not have a higher likelihood of being diagnosed with breast cancer, according to recent findings that will be presented by Christensen et al at the upcoming European Association for the Study of Diabetes Annual Meeting 2024 (Abstract 180).
Background
Gestational diabetes affects 14% of pregnant women globally and is becoming more common. Those who have obesity, a family history of diabetes, and are older may have a greater risk of developing the disease. Race and ethnicity may also affect risk.
Although gestational diabetes typically resolves after giving birth, women who have had it are more likely to develop type 2 diabetes in the years to come. Gestational diabetes is also associated with a higher risk of developing cardiovascular disease, metabolic syndrome, chronic kidney disease, and mental health conditions such as postnatal depression. Insulin resistance is a key feature of gestational diabetes and has been previously linked to breast cancer.
Prior research has found that gestational diabetes may be associated with a higher risk of receiving a breast cancer diagnosis. However, other studies have concluded that the risk of breast cancer may be lower or that there is no link at all in this patient population.
“Breast cancer is the most common cancer, as well as the leading cause of cancer deaths in women worldwide. It also has a very high treatment cost compared with other cancer types,” explained lead study author Maria Hornstrup Christensen, MHS, PhD, of the Steno Diabetes Center Odense at the Odense University Hospital in Denmark. “If we know who is more likely to develop breast cancer, we might be able to detect it earlier when it is easier to treat, reducing deaths and treatment costs and the psychological and physical toll on women,” she stressed.
Study Methods and Results
In the study, investigators used patient and other national registers to examine the outcomes of all women who gave birth in Denmark over a 22-year period. They included 708,121 women who gave birth between 1997 and 2018 in the analysis, excluding those with preexisting diabetes or breast cancer.
The investigators discovered that 3.4% of the women (n = 24,140) were diagnosed with gestational diabetes in one or more pregnancy. The median age at pregnancy was 28 in both those with and without gestational diabetes.
After a follow-up of 11.9 years, the investigators identified 7,609 women who were diagnosed with breast cancer. Compared with those who didn’t have gestational diabetes, the women who had gestational diabetes were not more likely to develop breast cancer overall, premenopausal breast cancer, or postmenopausal breast cancer—even after accounting for factors such as age, parity, ethnicity, income, occupation, education, and preexisting health problems such as hypertension. The analyses that factored in prepregnancy body mass index, smoking during pregnancy, and obstetric complications such as preeclampsia also found no association between gestational diabetes and breast cancer.
Conclusions
The investigators emphasized that they did not find gestational diabetes to be linked to a higher risk of breast cancer. They noted that the women included in the study were predominately White and living in a country with free health care and free breast cancer screening. Therefore, the findings will not necessarily apply to other populations and health-care systems.
“It will be reassuring for women who have had gestational diabetes to know that they are not a higher risk of developing breast cancer. They do, however, need to be alert to the fact that they are at higher risk of some conditions, including type 2 diabetes,” underscored Dr. Christensen. “And all women, regardless of whether or not they have had gestational diabetes, should be breast aware and check their breasts regularly for changes,” she concluded.
Disclosure: For full disclosures of the study authors, visit cattendee.abstractsonline.com.
