Impact of Age-related Diseases on Pulmonary Function Tests in Older Japanese Adults: A Cross-sectional Pilot Study

INTRODUCTION: A widely used reference range for pulmonary function testing was derived from middle-aged, healthy, non-smoking adults in Japan. This study examined the effect of age-related diseases on pulmonary function tests for older Japanese adults. METHODS: All patients aged ≥65 years who underwent spirometry before general and orthopedic surgeries in Itoigawa General Hospital (Niigata, Japan) from January 2014 to June 2019 were identified, and their charts were reviewed. RESULTS: This study included 1050 Japanese patients (median age: 75 years). The median spirometric values of vital capacity, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1/FVC in all patients were 2.66 L [interquartile range; 2.24, 3.25], 2.57 L [2.13, 3.13], 1.98 L [1.66, 2.37], and 77.5% [72.2, 81.9], respectively. Multiple regression analyses revealed that spirometric values were significantly affected by age, body height, sex, smoking status, social dependency, dyslipidemia, diabetes, history of heart failure, peripheral artery disease, end-stage renal disease, neuromuscular disease, and psychiatric disorders. Male sex and height were positively correlated with FVC and FEV1. Other factors, such as a history of heart failure, neuromuscular disease, and independent physical activity, were negatively correlated with FVC and FEV1 to almost the same extent as that of age. CONCLUSIONS: These data will provide clinically useful information to accurately interpret pulmonary function test results in older Japanese adults.