Abstract Lung function level and decline are each pre- dictive of morbidity and mortality. Evaluation of the combined effect of these measurements may help further identify high-risk groups. Using Copenhagen City Heart Study longitudinal spirometry data (n = 10,457), 16–21 year risks of chronic obstructive pulmonary disease (COPD) morbidity, COPD or coronary heart disease mor- tality, and all-cause mortality were estimated from com- bined effects of level and decline in forced expiratory volume in one second (FEV1). Risks were evaluated using Cox proportional hazards models for individuals grouped by combinations of baseline predicted FEV1 and quartiles of slope. Hazard ratios (HR) and 95 % con¿dence intervals (CI) were estimated using strati¿ed analysis by gender, smoking status, and baseline age (B45 and [45). For COPD morbidity, quartiles of increasing FEV1 decline increased HRs (95 % CI) for individuals with FEV1 at or above the lower limit of normal (LLN) but below 100 % predicted, reaching 5.11 (2.58–10.13) for males, 11.63 (4.75–28.46) for females, and 3.09 (0.88–10.86) for never smokers in the quartile of steepest decline. Signi¿cant increasing trends were also observed for mortality and in individuals with a baseline age B45. Groups with ‘normal’ lung function (FEV1 at or above the LLN) but excessive declines (fourth quartile of FEV1 slope) had signi¿cantly increased mortality risks, including never smokers and individuals with a baseline age B45.