Unlocking the Potential: Antihistamine Use and Breast Cancer Risk in Women With Type 2 Diabetes Mellitus.

Background: The association between the use of antihistamines targeting histamine receptor H1 (AH1) and breast cancer risk in individuals with type 2 diabetes mellitus (T2DM) remains understudied, warranting further investigation.

Methods: Using the Taiwan National Health Insurance Research Database from 2008 to 2018, we conducted a cohort study on women aged ≥18 years with T2DM, employing propensity score matching (PSM) to compare breast cancer risk between AH1 users (defined as at least 28 cumulative defined daily doses annually) and nonusers. Cox regression models were used to estimate adjusted hazard ratios (aHRs).

Results: The baseline characteristics of the study population were assessed, with 142,642 women enrolled between 2008 and 2018. After PSM, the AH1 use and nonuse groups showed comparable variables. The aHR for breast cancer was significantly lower in the AH1 use group compared with the nonuse group (aHR, 0.54; 95% CI, 0.44-0.66; P<.0001). Dose-dependent analysis revealed a significant trend (Ptrend=.0002), indicating a lower breast cancer risk with increasing AH1 use. The incidence rate of breast cancer was lower in AH1 users compared with nonusers, with an incidence rate ratio of 0.78 (95% CI, 0.65-0.93).

Conclusions: AH1 use shows promise in reducing breast cancer risk in individuals with T2DM, particularly with higher dosages, warranting further research and consideration by health care practitioners.