Abstract
Abstract 5174
The U.S. Government's “2008 Physical Activity Guidelines for Americans” recommends children perform at least 60 minutes of moderate to vigorous intensity physical activities (PA) a day while the recommendation for adults is 30 minutes per day at least 5 days a week. As fewer Americans meet these guidelines, it is unknown where patients with thalassemia (Thal) stand. Based on anecdotal evidence, it is assumed that patients with Thal have decreased PA due to their severe anemia and cardiomyopathies secondary to iron overload. However, there is a paucity of objective data on physical activity patterns in Thal. The primary objective of this prospective observational study is to examine PA patterns in a small group of representative patients with Thal using a 3-dimensional accelerometer, compared to age-matched national reference data. Additionally we will explore the relationship between PA and body composition.
Nine pediatric (4 M; 13.8 ± 1.7 yrs) and 10 adult (6M, 31.0 ± 8.4 yrs) patients were provided an Actigraph GT3X accelerometer to wear for 7 days on 2 separate occasions, 3 months apart. Partial results from the baseline measurement will be presented here. Accelerometer output, defined as counts or records of acceleration, was valid if the patient wore the Actigraph for >10 hrs/day for at least 3 weekdays and 1 weekend day. Based on published criteria using mean counts per minute, time spent in sedentary, moderate and vigorous physical activity intensity was compared to National Health and Nutrition Examination Survey (NHANES) data from 2003–2004 and to the 2008 PA guidelines. Whole body lean and fat mass was assessed by Dual Energy X-ray Absorptiometry. Lean mass index (LMI = kg/m2) Z-score was calculated and compared to national averages from the NHANES study.
Preliminary results show that Thal are less active than their healthy counterparts. Adults with Thal spend less time in vigorous intensity activities compared to the pediatric patients (p<0.05). Both groups spend more sedentary time per day than their age-matched reference group (Adult Male Thal: 9.3± 0.8 vs. NHANES: 7.2±0.13 hrs/day; Females: 12.1± 5.2 vs. 7.5±0.9 hrs/day, Pediatric Female Thal: 12.1±0.4 vs. 7.7±0.08 hrs/day). The mean counts per minute in Thal was less than in their healthy counterparts (Adult Male Thal: 211 ± 27.4 vs. NHANES: 385.7 counts/min; Adult Female: 282 ± 73.5 vs. 378.1±17.6 counts/min; Pediatric Female: 170 ± 82 vs. 309.7± 5 counts/min) indicating less overall PA. Only 12.5% of Thal met the PA guidelines for moderate and vigorous intensity PA for their age. LMI Z-scores were significantly lower than reference data for both pediatric and adult patients (p<0.001) indicating lower lean mass than in the general population. There appears to be a relationship between lean mass and physical activity but more patients will be needed to assess this relationship.
In conclusion, we have shown that Thal are less physically active and have significantly reduced muscle mass compared to the general US population. Physical activity may improve patients' quality of life (reduce depression, pain, improve sleep) and reduce comorbidities associated with the disease (muscle wasting, low bone mass, diabetes). However, more research is needed with larger samples to relate these measures of PA with functional patient outcomes.
This research was funded in part by a grant from the Cooley's Anemia Foundation.
No relevant conflicts of interest to declare.
This icon denotes an abstract that is clinically relevant.
