Abstract
Objective: Lung age, which is calculated from height, sex and 1-second forced expiratory volume, is an index of respiratory function.
When the lung ages are higher than actual ages, the question is whether they deviate from reference intervals or not. However, as yet no reference intervals have been established.With this in mind, we investigated the basic statistical ranges of lung age in non-smokers.
Methods: Our subjects were 2,707 non-smokers (30-79 years old) without respiratory diseases taken from among 7,935 persons who underwent ningen dock at the Shimbashi Medical Checkup Office of Jikei University Hospital. They comprised 1,134 males and 1,573 females.We calculated lung ages according to age group, and considered lung age reference intervals based on respiratory function.
Results: The average lung ages of the non-smokers with normal lung function (Average age: males 49.7±10.5 yrs, females 50.3±11.1 yrs) were 52.3±15.6 yrs for males, and 45.6±15.7yrs for females and the differences with actual ages were 2.6±12.3 yrs for males, and -4.7±12.4 yrs for females. When lung age was more than the actual age, the reference intervals were 24.1 yrs in males, and 24.3yrs in female. These figures were obtained by multiplying the standard deviations by 1.96.
Conclusions: There would be limitations on using lung age in educating people regarding prevention of chronic obstructive pulmonary disease because at more than 24 years, the standard deviation in normal subjects was very broad.
