In this large population-based study, walking was assessed twice yearly for a week, each time by pedometer, had consistent clinically important associations with hip areal bone mineral density (aBMD) in both sexes which appears most important in those over 65 years of age suggesting that walking becomes more important with increasing age. Introduction Walking is advocated as a preventative strategy for osteoporosis but the evidence is conflicting in females and lacking in males. The aim of this population-based longitudinal study in community dwelling older people (n=875) was to determine the association between pedometer determined ambulatory activity (PAA) and bone mass. Methods Bone mass was assessed as aBMD at the hip and spine using dual X-ray absorptiometry. Steps per day were measured using pedometers for 1 week on four occasions at least 6 months apart. Data were analysed using linear mixed models. Results At baseline, PAAwas positively associated with hip aBMD. An age interaction was present with steps having a stronger association for those aged over 65 years. Longitudinally, the effect of steps on hip aBMD was constant, but not additive over time. For those over 65 years, the difference in hip aBMD between the lowest and highest steps quartiles ranged from 3.1% to 9.4%. With regard to the spine, the relationship between daily steps and spine aBMD was modified by sex. For males; there was no significant relationship between steps and spine aBMD. However, for females, higher steps were associated with higher spine aBMD with the effect being constant over time but not additive. There was no evidence of a threshold effect. Conclusion In conclusion, pedometer-determined ambulatory activity has consistent clinically important associations with hip aBMD in both sexes which appears most important in those over 65 years of age. The associations for spine aBMD were both weaker and inconsistent suggesting site specificity.

Item Type:	Refereed Article
Keywords:	Dual X-ray absorptiometry; Elderly; Pedometers
Research Division:	Biomedical and Clinical Sciences
Research Group:	Clinical sciences
Research Field:	Rheumatology and arthritis
Objective Division:	Health
Objective Group:	Clinical health
Objective Field:	Clinical health not elsewhere classified
UTAS Author:	Foley, S (Ms Stella Foley)
UTAS Author:	Quinn, S (Dr Stephen Quinn)
UTAS Author:	Jones, G (Professor Graeme Jones)
ID Code:	60693
Year Published:	2009
Web of Science® Times Cited:	22
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2010-02-16
Last Modified:	2017-04-26
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