Predictors of accelerated FEV1 decline in adults with airflow limitation-Findings from the Health2006 cohort

Abstract

To investigate predictors of accelerated decline in forced expiratory volume in 1 s (FEV₁) in individuals with preexisting airflow limitation (AL). Participants in the Health2006 baseline study aged ≥ 35 with FEV₁/ forced vital capacity (FVC) < lower limit of normal (LLN) were invited for a 10-year follow-up. At both examinations, data were obtained on demographics, spirometry, fitness level, allergy, and exhaled nitric oxide. We used multiple regression modeling to predict the annual decline in FEV₁, reported as regression coefficients ( R) and 95% confidence intervals (CIs). A total of 123 (43% of those invited) participated in the follow-up examination, where more had exercise-induced dyspnea but fewer had asthma symptoms. Being female ( R = -29.8 ml, CI: -39.7 to -19.8), diagnosed with asthma ( R = -13.7, CI: -20.4 to -7.0) or atopic dermatitis ( R = -29.0, CI: -39.7 to -18.4), and having current asthma symptoms or nightly respiratory symptoms ( R = -22.1, CI: -31.9 to -12.4 and R = -14.3, CI: -19.9 to -8.7, respectively) were significantly associated with a steeper decline in FEV₁. Although to a smaller extent, a steeper decline was also predicted by age, baseline FEV₁, waist/hip-ratio, and number of pack-years smoked. In individuals with preexisting AL, being female and having ever or current respiratory symptoms were associated with an accelerated annual decline in FEV₁.

Keywords: Airflow limitation; asthma; chronic obstructive pulmonary disease; lung function decline; respiratory symptoms.

Figure 1.

Flowchart over inclusion process of participants from the Health2006 cohort.

Figure 2.

Characteristics of participants from Health2006 (n = 123) at baseline and follow-up. *Self-reported symptoms during the previous 12 months. ^#Doctor diagnosed at any point in life.

Figure 3.

Regression coefficients for prediction of decline in FEV₁ at follow-up for participants at the Health2006 cohort (n = 123), change in ml per year per 1 unit increase in each variable, unless otherwise stated. *Per 10 unit increase. ^€On a scale of 1-5, where 1 is best. ^#Per 0.1 unit increase. FEV₁: forced expiratory volume in 1 s.