Comparison and validation of accelerometer wear time and non-wear time algorithms for assessing physical activity levels in children and adolescents.

BACKGROUND: Accelerometers are widely used to measure sedentary time and daily physical activity (PA). However, data collection and processing criteria, such as non-wear time rules might affect the assessment of total PA and sedentary time and the associations with health variables. The study aimed to investigate whether the choice of different non-wear time definitions would affect the outcomes of PA levels in youth. METHODS: Seventy-seven healthy youngsters (44 boys), aged 10-17 years, wore an accelerometer and kept a non-wear log diary during 4 consecutives days. We compared 7 published algorithms (10, 15, 20, 30, 60 min of continuous zeros, Choi, and Troiano algorithms). Agreements of each algorithm with the log diary method were assessed using Bland-Altmans plots and by calculating the concordance correlation coefficient for repeated measures. RESULTS: Variations in time spent in sedentary and moderate to vigorous PA (MVPA) were 30 and 3.7%. Compared with the log diary method, greater discrepancies were found for the algorithm 10 min (p < 0.001). For the time assessed in sedentary, the agreement with diary was excellent for the 4 algorithms (Choi, r = 0.79; Troiano, r = 0.81; 30 min, r = 0.79; 60 min, r = 0.81). Concordance for each method was excellent for the assessment of time spent in MVPA (> 0.86). The agreement for the wear time assessment was excellent for 5 algorithms (Choi r = 0.79; Troiano r = 0.79; 20 min r = 0.77; 30 min r = 0.80; 60 min r = 0.80). CONCLUSIONS: The choice of non-wear time rules may considerably affect the sedentary time assessment in youth. Using of appropriate data reduction decision in youth is needed to limit differences in associations between health outcomes and sedentary behaviors and may improve comparability for future studies. Based on our results, we recommend the use of the algorithm of 30 min of continuous zeros for defining non-wear time to improve the accuracy in assessing PA levels in youth. TRIAL REGISTRATION: NCT02844101 (retrospectively registered at July 13th 2016).

Physical activity is associated with improved bone health in children with inflammatory bowel disease.

BACKGROUND & AIMS: Bone health is an important concern in patients with inflammatory bowel disease (IBD). Low bone mineral density (BMD) is a powerful predictor of fracture risk in IBD patients. Physical activity (PA) plays an important role in bone health. However, PA data for children and adolescents with IBD are scarce. The primary aim is to evaluate the relationship between PA and BMD in children with IBD. The secondary aim was to assess the relationship between PA and quality of life. METHODS: Eighty-four IBD paediatric patients (45 boys) aged 14.3 ± 2.7 years were included (disease activity: (i) remission, n = 62; (ii) mild, n = 18; (iii) severe disease, n = 1). BMD was measured using dual-energy X-ray absorptiometry and expressed as age- and sex-based Z-scores. Each patient wore a triaxial accelerometer for seven consecutive days for objective PA quantification. Quality of life was assessed using the PedsQL™ and energy intake was assessed prospectively for three days using a dietary diary. RESULTS: BMD Z-score was -0.96 ± 1.11. Only five patients (6%) fulfilled the recommendation of 60 min of daily moderate-to-vigorous PA (MVPA). The proportion of children with osteopenia and osteoporosis was 51% and 4%, respectively. After adjustment for confounders (pubertal status and body mass index), total PA and time in MVPA were positively associated with BMD (regression coefficient per one standard deviation increase in PA parameters = 0.26; P < 0.05). There was no association between time spent in MVPA and total PA, and total quality of life score. CONCLUSIONS: PA likely is associated with improved bone health in IBD children. Intervention studies investigating a causal relationship between PA and BMD in paediatric patients with IBD are warranted.

Severe hemolytic anemia due to cold agglutinin complicating untreated chronic hepatitis C: efficacy and safety of anti-CD20 (rituximab) treatment.

Autoimmune hemolytic anemia (AIHA) is rare and difficult to treat during chronic hepatitis C. We report herein the case of a hepatitis C patient with severe and resistant AIHA who experienced a good and sustained response with anti-CD20 monoclonal antibody treatment.