BackgroundThe avoidance of inhaled allergens or tobacco smoke has been known to have
favorable effects on asthma control. However, it remains unclear whether
other lifestyle-related factors are also related to asthma control.
Therefore, a comprehensive study to examine the associations between various
lifestyle factors and asthma control was conducted in Japanese asthmatic
patients.MethodsThe study subjects included 437 stable asthmatic patients recruited from our
outpatient clinic over a one-year period. A written, informed consent was
obtained from each participant. Asthma control was assessed using the asthma
control test (ACT), and a structured questionnaire was administered to
obtain information regarding lifestyle factors, including tobacco smoking,
alcohol drinking, physical exercise, and diet. Both bivariate and
multivariate analyses were conducted.ResultsThe proportions of total control (ACT = 25), well controlled (ACT = 20-24),
and poorly controlled (ACT < 20) were 27.5%, 48.1%, and 24.5%,
respectively. The proportions of patients in the asthma treatment steps as
measured by Global Initiative for Asthma 2007 in step 1, step 2, step 3,
step 4, and step 5 were 5.5%, 17.4%, 7.6%, 60.2%, and 9.4%, respectively.
Body mass index, direct tobacco smoking status and alcohol drinking were not
associated with asthma control. On the other hand, younger age (< 65
years old), passive smoking, periodical exercise (> 3 metabolic
equivalents-h/week), and raw vegetable intake (> 5 units/week) were
significantly associated with good asthma control by bivariate analysis.
Younger age, periodical exercise, and raw vegetable intake were
significantly associated with good asthma control by multiple linear
regression analysis.ConclusionsPeriodical exercise and raw vegetable intake are associated with good asthma
control in Japanese patients.