title: Factors associated with participant compliance in studies using accelerometers.
abstract: Participant compliance is an important issue in studies using accelerometers. Some participants wear the accelerometer for the duration specified by the researchers but many do not. We investigated a range of demographic factors associated with participant compliance in obtaining analyzable accelerometer data. A total of 3601 participants (aged 47.6±13.1 years, 44.6% male) were included. They were asked to wear an accelerometer (ActiGraph) for four consecutive days after completing a household survey during March 2009-January 2011 in Hong Kong. Participants wore the accelerometer on average for 13.9h in a 24-h day. No significant difference was found between males and females (p=0.38). Using log-linear regression, it was found that older participants (0.5% more wearing hours for each year of age, p<0.001), those with full-time job (p<0.01), with tertiary education (p<0.01), non-smokers (p<0.01) and with high self-reported health (p<0.05) wore the accelerometer for more hours. These results provide details for estimating compliance rates for samples with different characteristics and thus sample size calculation to account for participant compliance.
authors.affiliation: FAMILY: A Jockey Club Initiative for a Harmonious Society, School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Lee
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Macfarlane
authors.forename: T H
authors.initials: TH
authors.lastname: Lam
mesh_terms: D061725:Accelerometry / Q000706:statistics & numerical data*; D000328:Adult; D000367:Age Factors; D015331:Cohort Studies; D004522:Educational Status; D004651:Employment / Q000706:statistics & numerical data; D005260:Female; D006304:Health Status; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000706:statistics & numerical data*; D009043:Motor Activity; D010349:Patient Compliance / Q000706:statistics & numerical data*; D057566:Self Report; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D013997:Time Factors
keywords: Accelerometry; Activity monitor; Adherence; Participation; Physical activity