Risk factors for foot fracture among individuals aged 45 years and older.

A case-control study undertaken among members of five Northern California Kaiser Permanente medical centers sought to identify risk factors for foot fractures among persons aged 45 years and older. Foot fracture cases (n=920) and frequency matched controls (n=2366) were interviewed between October 1996 and May 2001 using a standardized questionnaire. Foot fractures occurred most often while walking or climbing stairs. While 60% of foot fractures resulted from falls, 20% were attributed to other causes, such as hitting the foot or tripping on sidewalks and curbs. Having a self-reported history of physician-diagnosed diabetes [adjusted odds ratio (OR)=1.45, 95% confidence interval (CI)=1.10-1.91] or cataracts (OR=1.40, 95% CI=1.07-1.83), having a self-reported foot problem (OR=1.38, 95% CI=1.06-1.78 for two or more foot problem versus no foot problems), having difficulty walking in minimum light (OR=1.86, 95% CI=1.14-3.05) and having had a prior fracture (OR=1.20, 95% CI=1.05-1.37) were associated with increased risk. Putative protective factors for osteoporotic fractures, such as menopausal hormone therapy use, thiazide or water pill use, high calcium intake, and high body mass index were not associated with foot fracture risk. These findings suggest that risk factors for foot fractures among older people differ in part from risk factors for other fracture sites generally considered to be osteoporotic, such as the hip, vertebrae, and forearm.