Peak bone mass is increased in the hip in daughters of women with osteoarthritis.

The mechanism behind the inverse association between osteoporosis and osteoarthritis shown in large epidemiological studies remains unclear. Because both diseases often demonstrate a family history, the objective of the present study was to compare peak bone density in daughters categorized according to the presence or absence of hand osteoarthritis in their mothers. Radiographs of the hands were obtained in women aged 50-75 years from a well-defined community population group. X-rays were graded for hand osteoarthritis (OA) using the Kellgren and Lawrence criteria. In 60 daughters (mean age 33.6 years) of these women, bone mineral density (BMD) was measured at five regions of the hip and lumbar spine and quantitative ultrasound (QUS) at the calcaneus. Daughters whose mothers had hand OA (i.e., OA at either the carpometacarpal [CMC] or distal interphalageal [DIP] joints) had significantly higher mean BMD, when adjusted for body mass index (BMI) (5.1%-8.1%, p < 0.05), at all hip regions except the trochanter. However, differences in lumbar BMD and calcaneal QUS were not statistically significant. In multiple regression analysis, maternal hand OA status was found to be a significant predictor of daughters' hip BMD when daughters' BMI and mothers' BMD were included in the model. These findings suggest that the observation of higher BMD in older patients with OA may be due in part to achievement of a higher peak bone mass at some sites.