BACKGROUNDChildhood, often characterized by multiple concurrent risk factors, holds significant influence over long-term respiratory outcomes, with the intricate interplay among these factors representing an intriguing but underexplored avenue for research. We aimed to determine if respiratory risk factors during childhood affect lung function and chronic obstructive pulmonary disease (COPD) in old age.METHODSParticipants were drawn from the Health and Retirement Study cohort. Latent class analysis (LCA) was applied with six variables used to develop the early-life respiratory risk profiles. Linear regressions and logistic regressions were used to assess the associations between childhood respiratory risk profiles and lung function, including peak expiratory flow (PEF) value, PEF value <80% of the predicted value and COPD.RESULTSA total of 12,296 participants (5017 males and 7279 females) with an average age of 68 years were recruited. We identified six distinct childhood respiratory risk profiles: (1) 'Asthma and respiratory disorders in early childhood' (n = 241, 1.96%), (2) 'Unexposed or least exposed' (n = 3874, 31.51%), (3) 'Smokers at home' (n = 7609, 61.88%), (4) 'Ear problems and respiratory disorders in early childhood' (n = 162, 1.32%), (5) 'Allergic conditions and respiratory disorders in early childhood' (n = 220, 1.79%) and (6) 'Allergic conditions and respiratory disorders in later childhood' (n = 190, 1.55%). Profile 2 served as the reference. The highest reduction of PEF was seen for profile 1 (-30.07 L/min), followed by profile 6 (-22.24 L/min) and profile 5 (-18.47 L/min). Profile 6, profile 3 and profile 1 related to 1.98-, 1.52- and 1.66-fold increased risks of diminished PEF values, respectively. The highest risk of COPD was observed in profile 5 (aOR = 4.16, 95% CI: 3.75-4.57), followed by profile 6 (aOR = 4.10, 3.69-4.51), profile 4 (aOR = 3.70, 3.25-4.15), profile 1 (aOR = 3.46, 3.07-3.85) and profile 3 (aOR = 1.41, 1.25-1.57).CONCLUSIONSPeople exposed to early-life respiratory challenges experienced larger declines in lung function and increased risks of COPD later in life. Our findings underscore the importance of early-life respiratory health in shaping lung function trajectories.