Physical activity level was indexed into five categories (inactive, moderately inactive, moderately active, active or unknown) based on occupational and recreational activities [22].
Total MET-hours/week in walking, cycling and sports were computed to derive a four-category recreational physical activity index: inactive, moderately inactive, moderately active, active.
To adjust for the level of physical activity, a five-level validated variable (inactive, moderately inactive, moderately active, active, and missing) was created [ 11].
In the PRIZE study MTX-naïve early RA patients with moderately active disease activity were treated with etanercept and MTX and DAS28 remission was achieved by 70%% of patients [ 26].
Physical activity was not analysed as a continuous variable, but categorised according to the current recommendations as (1) sufficiently active: >60 min activity daily, (2) moderately active: 30 60 min activity daily and (3) inactive: <30 min activity daily, 1 13 hereby obtaining agreement with the causal exposure estimates used in the analysis.
Living patterns and activity included questions about how the cat was kept (indoors, outdoors, both), general activity (calm, moderately active, very active), physical activity (h/d), and presence of other cats in the household (yes/no, numbers).
The participants were categorized as inactive (<1 h of strenuous activity and <3 h of light physical <span class="lh">activity per week), moderately active (1 3 h of strenuous activity or >3 h of light activity per week), and as physically active (>3 h of strenuous physical activity per week).
Their overall Inter-Correlation Coefficient (ICC) placing respondents into groups of vigorously active, moderately active or inactive activity ranged from 0.32 to 0.85.
Participants were then classified as active (>2.5 h/week of moderate physical activity or >1 h/week of vigorous physical activity), inactive (<1 h/week of moderate physical activity and <1 h/week of vigorous physical <span class="lh">activity), or moderately active (if not active or inactive).
Participants were classified as active (>2.5 h/week of moderate physical activity or >1 h/week of vigorous physical activity), inactive (<1 h/week of moderate physical activity and <1 h/week of vigorous physical <span class="lh">activity) or moderately active (if not active or inactive).
