The clinical relationship between histamine-1 receptor antagonists and risk of cancer: a systematic review and meta-analysis.

Background: A systematic research was performed to review the relationship between use of histamine-1 receptor antagonists and cancer risk.

Method: Databases were searched up to December 2021. Case-control and cohort studies evaluating the relationship between use of histamine-1 receptor antagonists and risk of cancer were selected. The major outcome was cancer risk. Odds ratio (OR) with 95% confidence intervals (CIs) was calculated. Subgroup, cumulative, and sensitivity analysis and Egger test were performed.

Results: Five case-controls and one cohort study were included. According to cohort study, use of antihistamines were not associated with cancer risk (RR = 0.92, 95% CI = (0.78-1.07). In case-controls, the frequency of antihistamine use in cases and controls was 11.28% and 14.82% respectively which was associated with decreased cancer risk (p value = 0.02, OR = 0.93, 95%CI = (0.87, 0.99)). Sensitivity analysis showed a change in direction of pooled OR by omitting some studies. Sub-group analysis according to type of cancer showed a decrease in cancer risk in antihistamine users in glioma (p value = 0.03).

Conclusion: Antihistamines might reduce the risk of certain cancers. More studies with defined background of allergy are needed which can clarify the relevancy of different types of cancer with anti-H1 receptors.