The relationships between Physical activity and asthma control and Body Mass Index (BMI) in patients with asthma

Objective: Asthma is one of the most common chronic conditions in developed countries. We examined whether physical activity (PA) is related to asthma control and body mass index (BMI) in asthma patients. Methods: Cross-sectional data collected on PA (ActiGraph GT3X-BT), asthma control (the Asthma Control Questionnaire; ACQ), and BMI were examined in 206 adults (mean[sd] age 47.2[13.8] years; 49.5% had an obese BMI) with clinically diagnosed asthma. Relationships between PA and continuous BMI and asthma control were assessed using linear regression. Differences in PA across obesity (non-obese: <30 Kg/m(2)/obese: >= 30 Kg/m(2)) and asthma control categories (controlled: <= 0.75/uncontrolled: >0.75 ACQ score) were also examined. Results: Median (p25, p75) steps counts and peak cadence were 6035 (4248, 8461) steps/day and 123 (115, 133) steps in a minute, respectively. There were nearly 2000 fewer steps/day among those with uncontrolled asthma versus controlled and among those with obese BMI versus nonobese, respectively (both p < 0.05). In regression models adjusted for relevant covariates each 1-unit increase in ACQ score was associated with -686 [95%CI -997, -13] (p <= 0.05) average steps/day. The statistical significance of these findings was attenuated (p >= 0.05) when BMI was added to the model. However, the point estimate was not reduced (-766 [95%CI -1060, 34]. Conclusions: Overall step counts were low in this population despite peak cadence values suggesting that most participants could perform moderate intensity activity. Increasing step counts should be considered an important lifestyle intervention goal in obese and non-obese asthma patients with low PA levels.