Association of alcohol intake, cigarette smoking, and occupational status with the risk of idiopathic osteonecrosis of the femoral head.

To investigate the association of alcohol intake, cigarette smoking, occupation, and other factors with the development of idiopathic osteonecrosis of the femoral head, a nationwide multicenter case-control study was conducted in Japan during 1988-1990, comparing 118 cases with no history of systemic corticosteroid use with 236 controls matched for sex, age, ethnicity, clinic, and date of initial examination. The risks of developing femoral head necrosis associated with potential risk factors were estimated by adjusted relative odds obtained by a conditional logistic regression model. The elevated relative odds were observed for occasional drinkers (relative odds = 3.2, 95% confidence interval 1.1-9.2) and regular drinkers (relative odds = 13.1, 95% confidence interval 4.1-42.5) with a significant dose-response relation (p < 0.001). For current drinkers, the relative odds were 2.8, 9.4, and 14.8 for < 320, 320-799, and > or = 800 g/week of ethanol intake, respectively. An increased risk was found for current smokers (relative odds = 4.7, 95% confidence interval 1.5-14.5), but a linear increasing trend in the cumulative effect of smoking was not evident at 20 pack-years or over. A weak but significant dose-response relation was observed for daily occupational energy consumption (p < 0.05). The present study confirmed the strong association of alcohol intake and positive association of cigarette smoking and suggested the role of heavy physical work.