1. ¹Department of Clinical Epidemiology, Aarhus University and Aalborg Hospital, Vennelyst Boulevard 6, Building 260, DK-8000 Aarhus C, Denmark
2. ²Department of Medicine, Vanderbilt University Medical Center and the Vanderbilt-Ingram Cancer Center, Nashville, TN, USA
3. ³Institute of Cancer Epidemiology, The Danish Cancer Society, Strandboulevarden 49, DK-2100 Copenhagen Ø, Denmark
4. ⁴International Epidemiology Institute, Ltd, 1455 Research Blvd., Suite 550, Rockville, MD 20850, USA
5. ⁵Unit of Clinical Epidemiology, Department of Medicine, Karolinska Hospital, Box 281, SE-171 77 Stockholm, Sweden
6. ⁶Departments of Medicine and Community and Family Medicine, Dartmouth Medical School, Hanover, NH 03756, USA

Correspondence: Dr HT Sørensen, Department of Clinical Epidemiology, Vennelyst Boulevard 6, Building 260, DK-8000 Aarhus C, Denmark. E-mail: hts@soci.au.dk

Received 5 December 2002; Revised 26 February 2003; Accepted 28 February 2003.

Abstract

There is increasing evidence of an inverse association between use of nonsteroidal anti-inflammatory drugs (NSAIDs) and risk of colorectal cancer. However, data regarding other cancer sites are limited. Using data from the population-based North Jutland Prescription Database and the Danish Cancer Registry, we compared cancer incidence among 172 057 individuals prescribed nonaspirin NSAIDs with expected incidence (based on county-specific cancer rates) during a 9-year study period. A total of 6081 incident cancer cases were diagnosed among NSAID users vs 5722 expected (standardised incidence ratio (SIR) 1.1, 95% confidence interval (CI)1.0–1.1). The SIRs for colon and rectal cancer among persons who obtained 10 or more prescriptions were 0.7 (95% CI 0.6–0.9) and 0.6 (95% CI 0.4–0.9), respectively. Similarly, reduced risk estimates were found for stomach (SIR 0.7, 95% CI 0.4–1.1) and ovarian cancer (SIR 0.7, 95% CI 0.4–1.0). Standardised incidence ratios for other cancers among those with 10 or more prescriptions tended to be close to 1.0, except for lung, kidney, and prostate cancers with SIRs of 1.3 (95% CI 1.1–1.6), 1.4 (95% CI 0.9–2.1), and 1.6 (95% CI 1.3–2.0), respectively. We found protective associations of NSAIDs against colon, rectal, stomach, and ovarian cancer. Reasons for the increased risk for some cancer sites are not clear.