title: Physical activity levels across adult life and grip strength in early old age: updating findings from a British birth cohort.
abstract: BACKGROUND
  observational studies do not always find positive associations between physical activity and muscle strength despite intervention studies consistently showing that exercise improves strength in older adults. In previous analyses of the MRC National Survey of Health and Development (NSHD), the 1946 British birth cohort, there was no evidence of an association between leisure time physical activity (LTPA) across adulthood and grip strength at age 53. This study tested the hypothesis that cumulative benefits of LTPA across mid-life on grip strength will have emerged by age 60-64.
  
  
  METHODS
  data from the MRC NSHD were used to investigate the associations between LTPA at ages 36, 43, 53 and 60-64 and grip strength at 60-64. Linear regression models were constructed to examine the effect of activity at each age separately and as a cumulative score, including adjustment for potential confounders and testing of life course hypotheses.
  
  
  RESULTS
  there were complete longitudinal data available for 1,645 participants. There was evidence of a cumulative effect of LTPA across mid-life on grip strength at 60-64. Compared with the third of participants who reported the least LTPA participation across the four time points, those in the top third had on average 2.11 kg (95% CI: 0.88, 3.35) stronger grip after adjustments.
  
  
  CONCLUSIONS
  increased levels of LTPA across mid-life were associated with stronger grip at age 60-64, in both men and women. As these associations have emerged since age 53, it suggests that LTPA across adulthood may prevent decline in grip strength in early old age.
authors: Academic Geriatric Medicine, School of Medicine, University of Southampton, Southampton, UK.
authors: Richard
authors: R
authors: Dodds
authors: Diana
authors: D
authors: Kuh
authors: Avan
authors: A
authors: Aihie Sayer
authors: Rachel
authors: R
authors: Cooper
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D005260:Female; D018737:Hand Strength; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000502:physiology*; D013997:Time Factors; D006113:United Kingdom
keywords: grip strength; life course models; longitudinal study; older people; physical activity
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