Improved asthma control linked to increased cardiovascular fitness
MedWire News: Improvements in asthma control are associated with significant increases in daily physical activity and cardiovascular fitness in children, researchers have found.
Writing in the journal Allergy, Signe Vahlkvist (University of Southern Denmark, Kolding) and colleagues explain that "although several cross-sectional studies have assessed daily physical activity in children with asthma, the impact of the level of asthma control remains unknown."
To investigate the effects of treatment-induced changes in asthma control on daily physical activity, cardiovascular fitness, and body composition, the team enrolled 55 children, aged 6-14 years, with recently diagnosed, untreated asthma and 154 healthy, age- and gender-matched children without the condition.
Among the children with asthma, treatment with inhaled corticosteroids was initiated after a baseline period of 4 weeks.
All of the children were assessed for physical activity levels, cardiovascular fitness, and body composition during the baseline period and after 1 year. At 1 year, children with asthma aged less than 13 years were assessed for disease control using the Childhood Asthma Control Test (C-ACT) and older asthmatic children were assessed using the Asthma Control Test (ACT).
Most of the children with asthma experienced a significant improvement in asthma control between baseline and 1 year, with mean scores on the C-ACT (scale=0-27) increasing from 19.7 to 24.2, and mean scores on the ACT (scale=0-25) increasing from 18.4 to 20.6.
The researchers found that the mean number of minutes spent per day in light to vigorous physical activity increased significantly among children in the asthma group, from 170.1 min/day at baseline to 195.4 min/day at 1 year.
In contrast, the mean number of minutes spent per day in light to vigorous physical activity did not increase significantly among children in the control group, from 179.2 min/day at baseline to 188.0 min/day at 1 year.
Cardiovascular fitness, measured using an ergometer cycle test, also increased significantly during the study period in asthmatic children, from a mean of 34.7 to 37.0 ml O2/min/kg - an increase of 2.3 ml O2/min/kg (7%). Cardiovascular fitness improved to a lesser extent in the control group, from a mean of 39.2 to 40.4 ml O2/min/kg - an improvement of just 1.1 ml O2/min/kg (3%).
There were no statistically significant differences in changes to body fat, bone mineral density, or lean tissue levels between the two groups over the study period, the researchers note.
Vahlkvist and team conclude: "Treatment-induced improvements in asthma control are associated with a clinically relevant increase in daily physical activity and cardiovascular fitness."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Mark Cowen