Correlates of pedometer-measured and self-reported physical activity among young Australian adults.

Accurately quantifying physical activity is important for investigating relations with potential correlates, but past studies have mostly relied on self-report measures, which may be susceptible to error and biases, limiting interpretability. This study aimed to examine correlates of pedometer-determined physical activity and compare them with correlates of self-reported physical activity. Cross-sectional data were taken from 2017 Australian adults (aged 26-36 years) who were involved in the Childhood Determinants of Adult Health follow-up study during 2004-2006. Daily steps were recorded for seven days using Yamax pedometers and physical activity (total min/week) was reported via the long International Physical Activity Questionnaire. Demographic, biological, behavioral, psychological, social and environmental factors were assessed. Lower education, blue collar occupation and higher mental health score (men) and low-moderate alcohol intake (women) were positively associated with self-report and pedometer-measured activity. Among men, body mass index (BMI) was inversely and physical health score was positively associated with pedometer-measured activity while smoking, low to moderate alcohol intake, higher general health and urban area of residence were positively associated with self-reported activity. Among women, age and general health status were positively associated and number of live births inversely associated with pedometer-measured activity, while lower education, blue collar occupation, part time employment, smoking, diet, higher physical health score and higher mental health score were positively associated and white collar occupation inversely associated with self-reported activity. Many physical activity correlates differed depending on the measure employed; researchers should be mindful of these differences when selecting measures of physical activity.