Previous reports link differential DNA methylation (DNAme) to environmental exposures which are associated with lung function. Direct evidence on lung function DNAme is however limited. We undertook an agnostic epigenome-wide association study (EWAS) on pre-bronchodilation lung function and its change in adults. In a discovery-replication EWAS design, DNAme in blood and spirometry were measured twice, six-to-15 years apart, in the same participants of three adult population-based discovery cohorts (n=2,043). Associated DNAme markers (P<5x10-7) were tested...