Bird, M-L and Hill, KD and Robertson, IK and Ball, MJ and Pittaway, J and Williams, AD, Serum [25(OH)D] status, ankle strength and activity show seasonal variation in older adults: relevance for winter falls in higher latitudes, Age and Ageing, 42, (2) pp. 181-185. ISSN 0002-0729 (2013) [Refereed Article]
Copyright 2013 Oxford University Press
Background: seasonal variation exists in serum [25(OH)D] and physical activity, especially at higher latitudes, and these factors impact lower limb strength. This study investigates seasonal variation in leg strength in a longitudinal repeated measures design concurrently with serum vitamin D and physical activity.
Methods: eighty-eight community-dwelling independently mobile older adults (69.2 ± 6.5 years) were evaluated five times over a year, at the end of five consecutive seasons at latitude 41.1°S, recruited in two cohorts. Leg strength, serum [25(OH)D] and physical activity levels were measured. Time spent outside was recorded. Monthly falls diaries recorded falls. Data were analysed to determine annual means and percentage changes.
Results: significant variation in [25(OH)D] (±15%), physical activity (±13%), ankle dorsiflexion strength (±8%) and hours spent outside (±20%) (all P < 0.001) was demonstrated over the year, with maximums in January and February (mid-summer). Low mean ankle strength was associated with increased incidence of falling (P = 0.047). Quadriceps strength did not change (±2%; P = 0.53).Conclusion: ankle dorsiflexor strength varied seasonally. Increased ankle strength in summer may be influenced by increased levels of outdoors activity over the summer months. Reduced winter-time dorsiflexor strength may predispose older people to increased risk of tripping-related falls, and warrants investigation in a multi-faceted falls prevention programme.
|Item Type:||Refereed Article|
|Keywords:||elderly, exercise, preventative measures, physical activity, accidental falls|
|Research Division:||Medical and Health Sciences|
|Research Group:||Medical Biochemistry and Metabolomics|
|Research Field:||Metabolic Medicine|
|Objective Group:||Clinical Health (Organs, Diseases and Abnormal Conditions)|
|Objective Field:||Clinical Health (Organs, Diseases and Abnormal Conditions) not elsewhere classified|
|Author:||Bird, M-L (Dr Marie-Louise Bird)|
|Author:||Robertson, IK (Dr Iain Robertson)|
|Author:||Ball, MJ (Professor Madeleine Ball)|
|Author:||Pittaway, J (Ms Jane Pittaway)|
|Author:||Williams, AD (Associate Professor Andrew Williams)|
|Web of Science® Times Cited:||14|
|Deposited By:||Health Sciences A|
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