Paracetamol use and risk of epithelial ovarian cancer: A nationwide nested case-control study

To investigate whether paracetamol use is associated with a reduced risk of epithelial ovarian cancer (EOC).

A nationwide nested case-control study.

Danish female population.

A total of 9589 EOC cases diagnosed from 2000 to 2019 were age-matched with 383 549 randomly selected female controls using risk set sampling.

Paracetamol use, reproductive history, history of medication and history of surgery were retrieved from Danish national registers. Paracetamol use was defined as at least two prescriptions for up to 1 year before the index date, and was further classified according to recency, duration, cumulative dose and intensity of dose.

Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals for the association between paracetamol and EOC risk, overall and by histological subtypes.

'Ever' use of paracetamol was associated with a reduced EOC risk after adjusting for potential confounding factors (OR 0.92, 95% CI 0.87-0.97). The association was only significant among recent users (OR 0.89, 95% CI 0.84-0.95). The risk declined further with the increasing level of cumulative dose and intensity; women from the group with a high cumulative dose and a high intensity had a 13% (OR 0.87, 95% CI 0.80-0.94) and 14% (OR 0.86, 95% CI 0.79-0.93) reduced risk, respectively. In the histological subtype analysis, reduced risk with 'ever' use was most pronounced for serous and clear cell tumours.

Paracetamol use was associated with a decreased risk of EOC in a dose-response manner. Future studies are needed to validate the findings and investigate the mechanisms behind the association.