Characteristics associated with non-participation in 7-day accelerometry.

OBJECTIVE To assess levels of physical activity the use of objective physical activity measures like accelerometers is promising. We investigated characteristics associated with non-participation in accelerometry within an apparently healthy sample. METHODS Among German participants of a cardiovascular examination program (CEP; 2012-2013), 470 participants aged 40-75 years were invited to wear an accelerometer for 7 days. We used multivariate logistic regression to estimate the association between non-participation and the following characteristics of participants: sex, age, education, smoking, setting of recruitment for the CEP (general medical practices, job agencies, statutory health insurance), self-reported general health, and objective health criteria such as cardiorespiratory fitness and absolute number of cardiometabolic risk factors (elevated waist circumference, blood pressure, triglycerides, blood glucose, and reduced high-density lipoprotein). Subsequently, we stratified this analysis by sex. RESULTS Among all invited individuals, N = 235 (60.0% women) gave consent to participate in accelerometry. Women were more likely to decline participation (odds ratio, 1.7; 95% confidence interval, 1.1-2.7) compared to men. Stratified analyses revealed the absolute number of risk factors as predictor of non-participation for men (1.4; 1.01-2.0), while there was no predictor found in women. CONCLUSION We found a self-selection bias in participation in accelerometry. Women declined study participation more likely than men. The number of cardiometabolic risk factors decreased compliance only in men. Future studies should consider strategies to reduce this bias.