• Bone mineral density
  

• physical activity
  
• dietary calcium intake
  
• calcium supplement use
  
• smoking status
  

Fractures due to osteoporosis are a major public health problem. Bone density is one of the major predictors of these osteoporotic fractures and is the result of the amount of bone gained in early life (i.e peak bone mass) and subsequent bone loss. Cigarette smoking, physical inactivity and inadequate calcium intake are widely regarded as risk factors for osteoporosis (as well as for other common diseases for the former two). Despite this information being widely available and actively promoted, the prevalence of these risk factors in the population remains unacceptably high. In women (mean age 33) taking part in a study of the determinants of bone mass in children, we recently reported substantial change in these behaviours at 12 months follow-up when women received an information leaflet and individualised bone density feedback. These women were highly selected and it is unclear if this response is representative of all women. With this study, we aim to test whether individualised bone density feedback, combined with either an information leaflet or small group education will change women's osteporosis preventive behaviors and/or bone density.

Specifically, we aimed to test the following hypotheses:

1. Women are more likely to change calcium intake and physical activity if their BMD is low.
2. Group education (in the form of the Osteoporosis Prevention and Self Management course) will be more efficacious at changing these lifestyle behaviours than an information leaflet alone.
3. Bone density feedback and educational intervention have independent effects on behavior and BMD change.
4. Women who improve their physical activity or dietary calcium intake will have a change in bone mass over 2 years that is 0.34-0.54% per annum better (depending on site and lifestyle factor) than those who do not alter their behaviour.