The Nottingham Longitudinal Study of Activity and Ageing: a methodological overview.
OBJECTIVE
first, to describe the background and methodological approach to the assessment of customary physical activity, health and psycho-social status used by the Nottingham Longitudinal Study of Activity and Ageing; second, to provide information on the sampling strategy and survey response rates for three waves of data collection; and, third, to provide information on the reliability and validity of the survey assessments.


METHODS
longitudinal study.


METHODS
1042 people originally aged 65 and over, randomly sampled from general practitioner lists in Nottingham, UK.


METHODS
a descriptive overview of response rates (%), instrument reliability (alpha coefficients) and intercorrelations among measured outcomes (correlation coefficients and principal components analysis).


METHODS
questionnaire-assessed levels of physical activity; instrumental measurements of handgrip strength, weight, demi-span and shoulder flexibility; brief assessments of depression, social engagement, life-satisfaction and cognitive impairment.


RESULTS
the study achieved a baseline (TI) response rate of 80%, with re-interview rates of 88% and 73% for T2 (1989) and T3 (1993) surveys respectively. For both men and women, factor scores derived from first principal components extracted from T1 survey data showed significant (r > or = 0.4; P < 0.001) product moment correlations with instrumental measurements of handgrip strength and shoulder flexibility. All the brief assessment measures showed satisfactory levels of reliability (alpha > or = 0.7).
Centre for Ageing and Rehabilitation Studies, School of Health and Related Research, University of Sheffield, Northern General Hospital, UK. k.morgan@sheffield.ac.uk
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Morgan
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology; D001835:Body Weight; D003071:Cognition; D003863:Depression; D005260:Female; D005500:Follow-Up Studies; D018737:Hand Strength; D006801:Humans; D007407:Interviews as Topic; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009013:Morale; D012107:Research Design; D012785:Shoulder Joint / Q000502:physiology; D011795:Surveys and Questionnaires; D006113:United Kingdom