The true incidence of chronic obstructive pulmonary disease is largely unknown, because the few longitudinal studies performed have used diagnostic criteria no longer recommended by either the European Respiratory Society or the American Thoracic Society (ATS).We studied the incidence and significance of airflow limitation in a population-based geriatric sample using both an age-dependent predicted lower limit of normal (LLN) value and a fixed-ratio spirometric criterion.Out of 2025 subjects with acceptable spirometry at baseline, 984 subjects aged 65–100 years completed a 6-year follow-up visit. Smoking habits were registered at baseline. Exclusion criteria were non-acceptable spirometry performance according to ATS criteria and inability to communicate. Airflow limitation was defined both according to forced expiratory volume in 1 s (FEV1)/forced vital capacity ratio <0.7 and

Data on longitudinal lung function change in the elderly are scarce. Uncertainty remains about whether to use absolute or relative change and how it relates to subject demographics.We studied absolute and relative forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) change in a population-based geriatric sample using a repeated measurements model adjusted for age, sex, smoking habits, heart failure, hypertension, diabetes, coronary heart disease, educational level, occupation, alcohol consumption, C-reactive protein (CRP) and body mass index. 3736 participants aged 60–102 years completed between one and five spirometries during 13.5 years of follow-up. Lung volumes, FEV1 quotient (Q) and Global Lung Initiative (GLI)-2012 and National Health and Nutrition Examination Survey (NHANES) III z-scores were presented from 6932 spirometries.Adjusted absolute change per year (95% CI) was −51.7 (−63.7–−39.9) mL for FEV1 and −56.2 (−73.6–−38.8) mL for FVC. Adjusted relative change per year was −2.97 (−3.53–−2.40)% for FEV1 and −2.46 (−3.07–−1.85)% for FVC. Risk factors for increased relative FVC and FEV1 decline were female sex, higher age, current smoking habits, elevated CRP (nonsignificant for FEV1, p=0.057) and low educational level. For increased absolute decline the risk factors were male sex and being a current smoker for FEV1 and low education for FVC.Relative but not absolute change correlated significantly with clinically relevant markers of functional status and may be superior to absolute change in risk factor analysis. Cross-sectional reduction in terms of FEV1Q was ∼1 unit per 10 years for both sexes. Proportions of subjects with results below lower limit of normal using NHANES III were close to anticipated, but were two to four times higher than expected using GLI-2012.

We read with great interest the paper on relative and absolute lung function change in a general population aged 62-102 years in the region of Skåne, Sweden [1], since lung function research in the growing age group of older adults, especially those ⩾80 years old, is indeed limited [2, 3]. Spirometry quality and interpretation in very old adults needs to be further researched, especially the use of FEV 1 expressions that are independent of reference equations/values http://bit.ly/2R9vyW6