1. Department of Medicine, University of Calgary , Calgary T2N 2T9 , Canada
2. Department of Medicine, McGill University , Montreal H3A 1G1 , Canada
3. Department of Community Health Sciences, University of Manitoba , Winnipeg R3E 0W2 , Canada
4. Centre for Metabolic Bone Diseases, University of Sheffield Medical School , Melbourne S5 7AU , UK
5. Mary McKillop Institute for Health Research, Australian Catholic University , Melbourne 3000 , Australia
6. MRC Lifecourse Epidemiology Unit , Southampton SO17 1BJ , UK
7. NIHR Southampton Biomedical Research Center, University of Southampton , Southampton SO16 6YD , UK