To the best of our knowledge, this is the first study that has
investigated the impact of BMI on COPD or asthma while
taking into account the smoking habit in the same large
population. Our results demonstrate that an increase in BMI
is frequently associated with the diagnosis of COPD or
asthma, suggesting that the probability of suffering from
these diseases increases with the increase in body weight
regardless of the smoking status. The association between
an increase in BMI and COPD or asthma appears to be
greater in women than in men. Our data also show that
underweight is significantly associated with COPD in men,
while being underweight apparently protects from the
possibility of suffering from asthma. Interestingly, our study
confirms the importance of smoking status in patients with
COPD, but not in those with asthma.