Association Between the Angiotensin-Converting Enzyme Gene Insertion/Deletion Polymorphism and Avascular Necrosis of the Femoral Head

Objective: This study investigated the association between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and avascular necrosis of the femoral head (ANFH). Materials and Methods: The ACE gene I/D polymorphism was determined in 279 nontraumatic, ANFH Han Chinese patients (divided into idiopathic and steroid- and alcohol-induced subgroups) and 276 age- and gender-matched healthy controls using the polymerase chain reaction. Results: The frequencies of the ACE DD genotype and D allele were significantly higher among the ANFH patients as a whole and also in the idiopathic and steroid- and alcohol-induced ANFH subgroups compared to healthy controls (p < 0.05 for all). Additionally, the DD genotype, compared with the ID+II, ID, and II genotypes, conferred a higher risk of developing ANFH across all clinical subgroups (p < 0.001, odds ratio [OR] = 2.508; p < 0.001, OR = 2.072; p < 0.001, OR = 3.684, respectively) as well in each of the subgroups examined individually, including the idiopathic subgroup (p < 0.001, OR = 2.579; p < 0.001, OR = 2.091; p < 0.001, OR = 3.994, respectively), the steroid-induced subgroup (p = 0.005, OR = 2.345; p = 0.031, OR = 2.050; p = 0.007, OR = 3.000, respectively), and the alcohol-induced subgroup (p < 0.001, OR = 2.488; p = 0.012, OR = 2.050; p = 0.011, OR = 2.659, respectively) of ANFH patients. The ID genotype, compared with the II genotype, conferred a higher risk across all subtypes analyzed together, and in the idiopathic subgroup (p = 0.013, OR = 1.778; p = 0.028, OR = 1.910) analyzed separately. Additionally, the D allele, in comparison with the I allele, conferred a relatively higher risk across all subgroups (p < 0.001, OR = 2.101) as well as in each of the three subgroups examined individually (idiopathic: p < 0.001, OR = 2.178; steroid-induced: p = 0.003, OR = 1.910; and alcohol-induced: p < 0.001, OR = 2.094). Conclusion: The ACE DD and ID genotypes and D allele may be risk factors for susceptibility to ANFH in the Chinese population.