Prescription use of paracetamol and risk for ovarian cancer in Denmark.

It has been suggested that paracetamol reduces the risk for ovarian cancer. We examined the association between prescription use of paracetamol and ovarian cancer risk in a nationwide case-control study nested within the Danish female population. Case patients (n = 3471) were all women with a first diagnosis of epithelial ovarian cancer during the period from 2000 to 2009. Population control subjects (n = 50576) were selected by risk set sampling. Data were derived from prescription and other nationwide registries. Conditional logistic regression was used to estimate odds ratios (ORs) and two-sided 95% confidence intervals (CIs) for ovarian cancer associated with use of paracetamol or nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs). All statistical tests were two-sided. Use of paracetamol was associated with a reduced odds ratio for ovarian cancer (OR = 0.82; 95% CI = 0.74 to 0.92; P < .001) compared with nonuse, and the odds ratio decreased further with long-term (≥10 years), high-intensity paracetamol use (OR = 0.45; 95% CI = 0.24 to 0.86; P = .02). Use of nonaspirin NSAIDs was not associated with ovarian cancer risk.