Frequency of Exposure to Secondhand Smoke Outside the Home Is Associated with a Lower FEV₁/FVC in Male Workers Regardless of Smoking Status

Decreased respiratory function associated with aging leads to the onset of chronic obstructive pulmonary disease (COPD) and increased risk of death in the elderly. Prevention of a decline in respiratory function from a young age is important. This study aimed to clarify the factors that affect decreased forced expiratory volume in one second (FEV1)/forced vital capacity (FVC), an index of obstructive respiratory disorder caused by airway...