BONE-MINERAL DENSITY, MUSCLE STRENGTH AND PHYSICAL-ACTIVITY - A POPULATION-BASED STUDY OF 332 SUBJECTS AGED 15-42 YEARS

The aim of this population-based study was to find out whether differe nces in levels of physical activity have an influence on bone mass qua ntity and whether quadriceps muscle strength is a reliable determinant of bone mass, Included were 175 men and 157 women, aged 15-42 years. Bone mineral density (BMD) was measured at various sites by dual X-ray absorptiometry (DXA) and single photon absorptiometry (SPA). Muscle s trength was assessed using an isokinetic muscle force meter. A questio nnaire was used to estimate the level of physical activity. We found a positive correlation between physical activity and BMD for boys at th e distal forearm and for girls at the trochanter (age group 15-16 year s), Active men (age group 21-42 years) had up to 9% higher BMD levels at the hip than those who were less active. Quadriceps muscle torque w as not an independent predictor of BMD. Our data suggest that a higher level of physical activity-within the limits of a ''normal life style ''-may have a positive effect on BMD in the proximal femur of young ad ults, which in turn may lessen the subsequent risk of fracture.