Mechanical stress on the cartilage and metabolic and/or hormonal influences have been suggested as possible etiologic factors for osteoarthritis. This paper reports findings from data collected in 1992 that were used to examine associations between osteoarthritis and risk factors in 573 Caucasian women aged 24-45 years from the Michigan Bone Health Study. Radiographs of the dominant hand and both knees were evaluated using the Kellgren and Lawrence grading scale. The prevalence of osteoarthritis (grade 2 or higher) in this population was 2.8% for hands and 3.6% for knees. Using polytomous multiple logistic regression, the authors found older age, increasing bone mineral density, and decreasing testosterone levels to be significantly associated with increasing hand scores. Older age and hand injury were significantly associated with grades of 2 or higher. Increasing osteoarthritis knee scores were associated with older age, increasing bone density, increasing body mass index, and current use of hormone replacement therapy. A knee grade of 2 or higher was associated with increasing estradiol levels, knee injury, and higher blood pressure. This study indicates that age, bone density, and injury are risk factors common to the development of hand and knee osteoarthritis in this non-elderly female population.