Table 3

Estimates of validity of non-occupational continuous physical activity measurements derived from the EPIC questionnaire when compared to accelerometer measurements of total physical activity
Accelerometer versus 10-month EPIC
 MET-hours/week


Correlation (ρ)
 95% CI
Total non-occupational activitya


     Overallb (n = 182)
 0.21
 0.07, 0.35
 **
          Gender


               Males (n = 100)
 0.24
 0.05, 0.42
 *
               Females (n = 82)
 0.16
 -0.06, 0.36
          Body mass index


               < 27.2 (n = 89)
 0.33
 0.14, 0.51
 **
               ≥ 27.2 (n = 92)
 0.12
 -0.09, 0.32
          Age


               < 58 years (n = 95)
 0.25
 0.05, 0.43
 *
               ≥ 58 years (n = 87)
 0.18
 -0.03, 0.37
          Employment status


               Full-time work (n = 113)
 0.17
 -0.02, 0.34
               Other (n = 68)
 0.30
 0.07, 0.50
 *
Vigorous activity, self-ratedc
 0.18
 0.04, 0.32
 *
Vigorous activity, MET-assignedc
 0.23
 0.09, 0.37
 **
Light-moderate activityd
 0.19
 0.05, 0.33
 **

* P < 0.05; ** P < 0.01; *** P < 0.001

EPIC, European Prospective Investigation into Cancer and Nutrition; ρ, Spearman rank correlation coefficient; CI, confidence interval

a EPIC total non-occupational activity = recreational + household physical activity; compared to total accelerometer activity (sum of light, moderate and vigorous activity)

b There were no statistically significant differences in correlations for non-occupational activity between subgroups (Pdiff >0.10)

c Time spent in vigorous non-occupational activity was measured (1) in a separate question about time in activities causing sweating or faster heartbeat, and (2), using the sum of time spent in activities with MET values ≥ 6 (i.e. cycling, sports and stair climbing); these estimates were compared to vigorous-intensity accelerometer activity.

d Time spent in light-moderate non-occupational activity was estimated using the sum of time spent in activities with MET values < 6 (i.e. housework, walking, gardening, home repair); these estimates were compared to light+moderate-intensity accelerometer activity.

Cust et al. International Journal of Behavioral Nutrition and Physical Activity 2008 5:33   doi:10.1186/1479-5868-5-33