Mild asthma and chronic bronchitis seem to influence functional exercise capacity: a multi-case control study.
BACKGROUND
In the Genes Environment Interaction in Respiratory Diseases population-based multi-case control study, we investigated whether asthma, chronic bronchitis (CB) and rhinitis were associated with a reduced 6-minute walk distance (6MWD), and whether the 6MWD determinants were similar for subjects with/without respiratory diseases.


METHODS
Cases of asthma (n = 360), CB (n = 120), rhinitis (n = 203) and controls (no respiratory diseases: n = 302) were recruited. The variation in the 6MWD across the groups was analyzed by ANCOVA, adjusting for gender, age, height, weight and comorbidity. The 6MWD determinants were studied by linear regression, and heterogeneity across the cases and controls was investigated.


RESULTS
The 6MWD differed across cases and controls (p = 0.01). It was shorter for cases of asthma (-17.1, 95% CI -28.3 to -5.8 m) and CB (-20.7, 95% CI: -36.6 to -4.8 m) than for controls (604 ± 68 m on average), but not for cases of rhinitis. The negative association between age and the 6MWD was significant for cases of CB, but not for the other groups (p = 0.001).


CONCLUSIONS
Even at the level of severity found in the general population, asthma and CB could influence the 6MWD, which seems to reflect the functional exercise level for daily physical activities. The negative association between ageing and the 6MWD was particularly strong in subjects with CB. Our report adds to the mounting evidence that CB is not a trivial condition, especially in the ageing adult population, and it supports the importance of monitoring functional capacity and of physical reconditioning in mild asthma.
Unit of Epidemiology and Medical Statistics, Department of Public Health and Community Medicine, University of Verona, Verona, Italy. alessandro.marcon@univr.it
Alessandro
A
Marcon
Paolo
P
Girardi
Marcello
M
Ferrari
Mario
M
Olivieri
Simone
S
Accordini
Cristina
C
Bombieri
Oscar
O
Bortolami
Marco
M
Braggion
Veronica
V
Cappa
Lucia
L
Cazzoletti
Francesca
F
Locatelli
Morena
M
Nicolis
Luigi
L
Perbellini
Silvia
S
Sembeni
Giuseppe
G
Verlato
Maria Elisabetta
ME
Zanolin
Roberto
R
de Marco
D000328:Adult; D000367:Age Factors; D001249:Asthma / Q000503:physiopathology*; D029481:Bronchitis, Chronic / Q000503:physiopathology*; D016022:Case-Control Studies; D015331:Cohort Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012220:Rhinitis / Q000503:physiopathology*; D012737:Sex Factors; D055815:Young Adult