Data is limited on influence of forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) in a large adult population, including individuals with normal spirometry at baseline.

Using the UK Biobank cohort, a multivariable Cox regression analysis was conducted on 406,424 individuals to examine the association between FEV₁ and FVC, categorized into three groups based on their percentage of predicted values (%pred) (≥80, 60–80 and < 60), and overall mortality, cardiovascular mortality, myocardial infarction, stroke, and heart failure over approximately 12.5 years. Moreover, a subgroup analysis was conducted on 295,459 individuals who had normal spirometry.

Reduced FEV₁ and FVC %pred values were associated with an elevated risk across all studied outcomes. Individuals with the lowest FEV₁ and FVC %pred values (<60 %) exhibited HR of 1.83 (95 % CI 1.74–1.93) and 1.98 (95 % CI 1.76–2.22) for overall mortality, and 1.96 (95 % CI 1.83–2.1) and 2.26 (95 % CI 1.94–2.63) for cardiovascular mortality. Moreover, a graded association was observed between lower FEV₁ and FVC %pred, even among never smokers and individuals with normal spirometry at baseline.

Reduced FEV₁ and FVC represent robust risk factors for cardiovascular disease and mortality. The fact that the increased risk was evident also at FEV₁ and FVC levels exceeding 80 %pred challenges the contemporary classification of lung function categories and the notion that the entire FEV₁- and FVC-range above 80 % of predicted represents a normal lung function.