Oral bisphosphonate use and lung cancer incidence among postmenopausal women

Background: Bisphosphonates are common medications for the treatment of osteoporosis in older populations. Several studies, including the Women's Health Initiative (WHI), have found inverse associations of bisphosphonate use with risk of breast and endometrial cancer, but little is known about its association with other common malignancies. The objective of this study was to evaluate the association of bisphosphonate use on the incidence of lung cancer in the WHI. Patients and methods: The association between oral bisphosphonate use and lung cancer risk was examined in 151 432 postmenopausal women enrolled into the WHI in 1993-1998. At baseline and during follow-up, participants completed an inventory of regularly used medications including bisphosphonates. Results: After a mean follow-up of 13.3 years, 2511 women were diagnosed with incident lung cancer. There was no evidence of a difference in lung cancer incidence between oral bisphosphonate users and never users (adjusted hazard ratio=0.91; 95% confidence intervals, 0.80-1.04; P=0.16). However, an inverse association was observed among those who were never smokers (hazard ratio=0.57, 95% confidence interval, 0.39-0.84; P < 0.01). Conclusion: In this large prospective cohort of postmenopausal women, oral bisphosphonate use was associated with significantly lower lung cancer risk among never smokers, suggesting bisphosphonates may have a protective effect against lung cancer. Additional studies are needed to confirm our findings.