Validity of 12-month falls recall in community-dwelling older women participating in a clinical trial

Objectives. To compare 12-month falls recall with falls reported prospectively on daily falls calendars in a clinical trial of women aged ≥70 years. Methods. 2,096 community-dwelling women at high risk of falls and/or fracture completed a daily falls calendar and standardised interviews when falls were recorded, for 12 months. Data were compared to a 12-month falls recall question that categorised falls status as “no falls,” “a few times,” “several,” and “regular” falls. Results. 898 (43%) participants reported a fall on daily falls calendars of whom 692 (77%) recalled fall(s) at 12 months. Participants who did not recall a fall were older (median 79.3 years versus 77.8 years, ). Smaller proportions of fallers who sustained an injury or accessed health care failed to recall a fall (all ). Among participants who recalled “no fall,” 85% reported zero falls on daily calendars. Few women selected falls categories of “several times” or “regular” (4.1% and 0.4%, resp.) and the sensitivity of these categories was low (30% to 33%). Simply categorising participants into fallers or nonfallers had 77% sensitivity and 94% specificity. Conclusion. For studies where intensive ascertainment of falls is not feasible, 12-month falls recall questions with fewer responses may be an acceptable alternative.

Validation of thigh-based accelerometer estimates of postural allocation in 5-12 year-olds

OBJECTIVES: To validate activPAL3™ (AP3) for classifying postural allocation, estimating time spent in postures and examining the number of breaks in sedentary behaviour (SB) in 5-12 year-olds. DESIGN: Laboratory-based validation study. METHODS: Fifty-seven children completed 15 sedentary, light- and moderate-to-vigorous intensity activities. Direct observation (DO) was used as the criterion measure. The accuracy of AP3 was examined using a confusion matrix, equivalence testing, Bland-Altman procedures and a paired t-test for 5-8y and 9-12y. RESULTS: Sensitivity of AP3 was 86.8%, 82.5% and 85.3% for sitting/lying, standing, and stepping, respectively, in 5-8y and 95.3%, 81.5% and 85.1%, respectively, in 9-12y. Time estimates of AP3 were equivalent to DO for sitting/lying in 9-12y and stepping in all ages, but not for sitting/lying in 5-12y and standing in all ages. Underestimation of sitting/lying time was smaller in 9-12y (1.4%, limits of agreement [LoA]: -13.8 to 11.1%) compared to 5-8y (12.6%, LoA: -39.8 to 14.7%). Underestimation for stepping time was small (5-8y: 6.5%, LoA: -18.3 to 5.3%; 9-12y: 7.6%, LoA: -16.8 to 1.6%). Considerable overestimation was found for standing (5-8y: 36.8%, LoA: -16.3 to 89.8%; 9-12y: 19.3%, LoA: -1.6 to 36.9%). SB breaks were significantly overestimated (5-8y: 53.2%, 9-12y: 28.3%, p<0.001). CONCLUSIONS: AP3 showed acceptable accuracy for classifying postures, however estimates of time spent standing were consistently overestimated and individual error was considerable. Estimates of sitting/lying were more accurate for 9-12y. Stepping time was accurately estimated for all ages. SB breaks were significantly overestimated, although the absolute difference was larger in 5-8y. Surveillance applications of AP3 would be acceptable, however, individual level applications might be less accurate.