長期間経過を観察し得た健常者の換気機能の経年推移

抄録

The annual change in ventilatory function with age was observed in sixty-three healthy subjects over a period of more than two years, during which at least three repeated observations were performed. The annual change in each parameter for every subject was determined by least-squares regression of obtained values against time.
The mean annual change was calculated by averaging these slopes. The results were summarized as follows:
1) The mean annual changes were decreases of 0.05 l/m/yr for VC/Ht, 0.012l/m/yr for FVC/Ht, 0.30%/yr for FEV_1.0%, and 0.026l/yr for FEV_1.0. The decline in these ventilatory parameters was statistically significant (p<0.05). On the other hand, changes in %VC, MVV, %MVV, and the air trapping index were not significant. A constant relationship was not found between these observed annual changes and the values expected by utilizing prediction formulae.
2) A comparison was made between the annual changes in healthy male subjects according to age group. The decline of VC/Ht in young subjects was smaller than that observed in middle-aged and aged subjects. Greater decreases were also observed in aged subjects in FVC/Ht, FEV_1.0, MVV, and %MVV.
3). A significant difference in annual change was only detected in MVV and %MVV when non-smokers were compared with smokers.
4) Observed variation of the ventilatory parameters was represented by the residual standard deviation (R.S.D.) of the regression line in each subject. The coefficient of variation of R.S.D. in overall subjects was
4.08% for VC/Ht, 3.08% for FVC/Ht, 5.11% for FEV_1.0%, and 4.65% for FEV_1.0. That of MVV and %MVV exceeded 10%.