Nicola W. Burton, Gavin Turrell and Brian Oldenburg
This study assessed item nonresponse (INR) in a population-based mail survey of physical activity (PA).
A questionnaire was mailed to a random sample, with a 57% response rate (n = 2532). The magnitude and type of PA INR and the association with sociodemographic variables was examined using logistic regression.
Among survey respondents, 28% had incomplete PA data; 11% missed 1 item, 11% missed 2 items, and 5% missed all 3 items. Respondents missing 3 items tended to be female, less educated, low income, in poor health, and current smokers. The walking item was missed by 8% of respondents, and 18% and 23% missed the vigorous-intensity and moderate-intensity PA items respectively. These groups were sociodemograpically different from those without INR. Incomplete PA data was also associated with sociodemographic INR.
Mail surveys may underrepresent individuals insufficiently active for health, in particular those of low socioeconomic position.
Nicola W. Burton, Gavin Turrell, Brian Oldenburg and James F. Sallis
This study assessed the relative contributions of psychological, social, and environmental variables to walking, moderate- and vigorous-intensity physical activity.
A questionnaire was mailed to a random sample (57% response rate). Analyses used a backwards elimination logistic regression model, removing and replacing individual variables, and adjusting for age, gender, household composition, and education (N = 1827).
The sociodemographic and correlate variables collectively accounted for 43% of the variation in total activity, 26% of walking, 22% of moderate-intensity activity and 45% of vigorous-intensity activity (Nagelkerke R2). Individually, the correlates accounted for 0.0 to 4.0% of unique variation, with habit, efficacy, and support having higher values. Physical health, discouragement, competition, and time management contributed more to vigorous-intensity activity. Anticipated benefits of social interactions and weight management contributed more to moderate-intensity activity. Neighborhood aesthetics contributed more to walking.
Walking, moderate- and vigorous-intensity activity might be associated with different correlates.