Is Gestational Diabetes Mellitus a Risk Factor of Maternal Breast Cancer? A Systematic Review of the Literature

Breast cancer in women with previous gestational diabetes: a nationwide register-based cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is a common pregnancy complication characterized by insulin resistance. A link has been suggested between insulin resistance and breast cancer, which is the most common cancer in women. Hence, women with previous GDM may be at increased risk of developing breast cancer, yet, the existing evidence is conflicting. This study explored the association between GDM and incident breast cancer, including age at cancer diagnosis. Additionally, we investigated the potential impact of severity of insulin resistance during pregnancy and of subsequent diabetes development on the breast cancer risk.

METHODS

We conducted a nationwide, register-based cohort study including all women giving birth in Denmark from 1997 to 2018. We defined GDM and breast cancer based on ICD-10 codes. Premenopausal and postmenopausal breast cancer was pragmatically defined as age at outcome < 50 years and ≥ 50 years, respectively. A proxy for severity of insulin resistance during pregnancy was based on insulin treatment; subsequent diabetes was defined as presence of ICD-10 codes and/or antidiabetic medication after pregnancy. The statistical analyses included Cox regression, logistic regression and t-test.

RESULTS

Of 708,121 women, 3.4% had GDM. The median follow-up period was 11.9 years (range 0-21.9). The overall breast cancer risk was comparable in women with and without previous GDM (adjusted hazard ratio 0.96 [95% CI 0.83-1.12]). Premenopausal and postmenopausal breast cancer risk also did not differ; however, women with previous GDM had a breast cancer diagnosis at younger age (42.6 vs. 43.5 years, p-value 0.01). All-cause mortality was similar regardless of GDM history. Severity of insulin resistance during pregnancy and subsequent diabetes did not affect breast cancer risk.

CONCLUSIONS

This large, population-based cohort study showed no higher risk of incident breast cancer in women with previous GDM compared to women without previous GDM after a median of almost 12 years of follow-up. This was evident irrespective of menopausal state. The breast cancer risk was not influenced by the severity of insulin resistance during pregnancy and by subsequent diabetes development. Regardless of GDM history, attention towards prevention, early detection and treatment of breast cancer should be prioritized.

Adverse pregnancy outcomes and multiple cancers risk in both mother and offspring: an umbrella review of systematic reviews with meta-analyses of observational studies

BACKGROUND

Adverse pregnancy outcomes have reached epidemic proportions in recent years with serious health ramifications, especially for diverse cancers risk. Therefore, we carried out an umbrella review to systematically evaluate the validity and strength of the data and the extent of potential biases of the established association between adverse pregnancy outcomes and cancers risk in both mother and offspring.

METHODS

PubMed, Embase, and Web of Science databases were searched from inception until 18 January 2024. Meta-analyses of observational studies investigating the relationship between adverse pregnancy outcomes and multiple cancers risk in both mother and offspring were included. Evidence certainty was assessed using Grading of Recommendations, Assessment, Development, and Evaluation. The protocol for this umbrella review was prospectively registered in PROSPERO (CRD42023470544).

RESULTS

The search identified 129 meta-analyses of observational studies and 42 types of cancer. Moderate certainty of evidence, exhibiting statistical significance, has been observed linking per kilogram increase in birth weight to a heightened risk of breast cancer (OR = 1.07, 95% CI = 1.02-1.12), prostate cancer (OR = 1.02, 95% CI = 1.00-1.05), leukemia (OR = 1.18, 95% CI = 1.13-1.23), and acute lymphoblastic leukemia in offspring (OR = 1.18, 95% CI = 1.12-1.23); rubella infection during pregnancy to an increased risk of leukemia in offspring (OR = 2.79, 95% CI = 1.16-6.71); and a linear dose-response association between an increase in the proportion of optimal birth weight and an elevated risk of acute lymphoblastic leukemia in offspring (OR = 1.16, 95% CI = 1.09-1.24), respectively.

CONCLUSIONS

Although some adverse pregnancy outcomes have clinically promising associations with risk of several cancers in both mother and offspring, it is essential to conduct additional research to solidify the evidence, evaluate causality, and ascertain clinical utility.

Risk Factors for Recurrence of Gestational Diabetes Mellitus and Its Correlation with Maternal and Infant Prognosis

Objective

To explore and analyze the risk factors of recurrence of gestational diabetes mellitus (GDM) and its correlation with maternal and infant prognosis.

Methods

The clinical data of 128 GDM patients admitted to our hospital from May 2018 to May 2020 were retrospectively analyzed, and they were divided into a recurrence group (n = 65) and a nonrecurrence group (n = 63) according to the presence or absence of recurrence after one year of follow-up. The general data and clinical data of the two groups of patients were compared by single factor, and the factors with statistical significance were analyzed by logistic regression, and the maternal and infant outcomes and prognosis of the two groups of patients were compared.

Results

Compared with the nonrecurrence group, the recurrence group had a higher proportion of patients aged ≥35 years, with first fasting blood glucose ≥7.0 mmol/L, and with BMI value index ≥25 kg/m² during repregnancy, and the differences were statistically significant (p < 0.05). Multivariate logistic regression analysis showed that elder maternal age, high blood glucose level in the previous pregnancy, and high BMI index during this pregnancy were all high-risk factors for GDM recurrence (p < 0.05). Compared with the nonrecurrence group, the recurrence group had a lower rate of vaginal delivery, lower rate of premature rupture of membranes, lower rate of premature birth, lower rate of macrosomia, lower rate of neonatal asphyxia, lower rate of postpartum hemorrhage, and lower Apgar score within 1 minute of delivery (p < 0.05).

Conclusion

Older maternal age, high blood glucose level in the previous pregnancy, and high BMI index during the present pregnancy are high-risk factors for GDM recurrence that can further lead to adverse outcomes for mothers and infants. Clinicians should place sufficient emphasis on targeted early measures responding to high-risk factors to minimize the risk of GDM recurrence and optimize maternal and infant outcomes.