Ida H Danquah¹, Janne S Tolstrup^1,

Awareness of the health risks related to high amounts of sitting has increased the need for reliable and valid measures to monitor sitting time. The aim of the present study was to test the reliability and validity of a modified version of the Marshall domain-specific questionnaire (called Marshall-D) to monitor sitting time in large population-based studies. A convenience sample of 122 participants was included. The questionnaire, Marshall-D, considered sitting on weekdays and weekend days during transport, work, leisure screen time and other leisure sitting time. The questionnaire was repeated after two weeks. Sitting time was measured objectively by Axivity worn on the thigh 24 h/day for seven days. Correlations between test and retest and between objective and self-reported measures were assessed by Spearman’s rank correlation and Bland Altman plots. Data collection took place in Denmark in 2016. 110 participants had valid data. For test-retest reliability Spearman’s rho was 0.68 and 0.35 for weekdays and weekend days. Correlation between self-report and objectively measured total sitting was Spearman’s rho=0.44 for weekdays and for weekend days 0.18. In conclusion Marshall-D was found to have acceptable reliability and validity to monitor sitting time during weekdays in population-based surveys. For weekend days reliability and validity levels were unacceptable.

marshall domain-specific questionnaire, workforce sitting questionnaire, sedentary behaviour, reliability, validity