Preventing deterioration of chronic obstructive pulmonary disease mainly caused by smoking, is a major role of comprehensive medical checkups.
 The “lung age” calculated from the respiratory function test is an index showing the degree of respiratory function compared with the same sex or the same generation.80% of those who undergo medical checkups are nonsmokers. In nonsmokers, 31% had higher lung age than real age by 10 years or more. There were 11% subjects in measured forced expiratory volume in 1 second as percent of forced expiratory volume or forced expiratory volume during the first second less than 70%. When they showed these outliers, we investigated the explaining problem of the cause and countermeasures. In cross-sectional survey, weight gain, especially visceral fat increase, that is, diaphragm elevation was considered to be a cause of deterioration of examination value.
 A longitudinal study confirmed that reducing body weight improved lung age and weight gain got worse. However, it is unknown whether body weight reduction improved true pathological airway inflammation.