A case-control study of association between life-style, alcohol dehydrogenase 2 and aldehyde dehydrogenase 2 genotype and idiopathic osteonecrosis of the femoral head.

A case-control study of idiopathic osteonecrosis of femoral head (ION) was carried out to investigate the association between workload intensity, smoking, drinking, ADH2 and ALDH2 genotype and other factors and development of ION by comparing 43 cases (34 males and 9 females) without history of systemic corticosteroid use with 86 matched controls (68 males and 18 females). Univariate analysis by conditional logistic regression for males showed statistically significant odds ratios (OR) for heavier workload (OR = 4.661), cumulative alcohol consumption (OR trend per drink-years = 1.015), ALDH2(1/1) (OR = 3.310), consumption of green tea less than 3 or 4 times/week (OR = 2.705), body weight over 60 kg at examination (OR = 0.413), or body mass index of over 25 at examination (OR = 0.208). Multivariate analysis based on a hierarchically well-formulated model strategy for males revealed that heavier workload (OR = 5.785, 95% confidence interval (CI): 1.211, 27.635) and cumulative alcohol consumption (OR = 1.016, 95% CI: 1.005, 1.026) remained as the significantly associated risk factors for ION after adjusting the remaining confounders. The reason for the insignificant multivariate OR of ALDH2(1/1) may be due to the strong confounding of alcohol consumption on the association between ALDH2 genotype and ION. For females, the small sample size made it impossible to produce any meaningful univariate analysis.