The systemic use of steroids and habitual alcohol intake are two major causative factors in the development of idiopathic osteonecrosis of the femoral head (ONFH). To examine any interaction between oral corticosteroid use and alcohol intake on the risk of ONFH, we conducted a hospital-based case-control study of 71 cases with ONFH (mean age 45 years (20 to 79)) and 227 matched controls (mean age 47 years (18 to 79)). Alcohol intake was positively associated with ONFH among all subjects: the adjusted odds ratio (OR) of subjects with ≥ 3032 drink-years was 3.93 (95% confidence interval (CI) 1.18 to 13.1) compared with never-drinkers. When stratified by steroid use, the OR of such drinkers was 11.1 (95% CI 1.30 to 95.5) among those who had never used steroids, but 1.10 (95% CI 0.21 to 4.79) among those who had. When we assessed any interaction based on a two-by-two table of alcohol and steroid use, the OR of those non-drinkers who did use steroids was markedly elevated (OR 31.5) compared with users of neither. However, no further increase in OR was noted for the effect of using both (OR 31.6). We detected neither a multiplicative nor an additive interaction (p for multiplicative interaction 0.19; synergy index 0.95), suggesting that the added effect of alcohol may be trivial compared with the overwhelming effect of steroids in the development of ONFH.
Cite this article: Bone Joint J 2013;95-B:320–5.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This study was supported by a research grant from the Research Committee on Idiopathic Osteonecrosis of the Femoral Head of the Ministry of Health, Labour, and Welfare of Japan.
Other members of the Idiopathic ONFH Multicenter Case-Control Study Group are: Dr. S. Jingushi, Kyushu University; Drs. T. Nishii and N. Sugano, Osaka University; Drs. K. Sakai and K. Ohzono, Osaka Medical Center; Drs. A. Kaneuji and T. Matsumoto, Kanazawa Medical University; Drs. H. Horiuchi and S. Kobayashi, Shinshu University; Drs. M. Kawasaki and Y. Hasegawa, Nagoya University; Drs. T. Teranishi and T. Matsuno, Asahikawa Medical College; Dr. K. Takaoka, Osaka City University; and Dr. M. Fujioka, Kyoto Prefectural University of Medicine.
This article was primary edited by A. Ross and first-proof edited by G. Scott.
- Received September 7, 2012.
- Accepted October 30, 2012.
- ©2013 The British Editorial Society of Bone & Joint Surgery