Cognitive decline before and after incident chronic respiratory disease

Few studies have comprehensively measured the changes in cognition occurring in the years before and after the onset of specific respiratory disease type, which could help tailor the timing and design of future intervention strategies. Here we aimed to explore the temporal pattern of cognitive change before and after incident COPD and asthma. Data from wave 1 to wave 9 (2002-2018) of the English Longitudinal Study of Ageing were used. Global cognition, assessed by orientation, memory, and executive function, was measured in each wave. Incident COPD and asthma was ascertained using self-reported physician diagnosis and further verified by the records of corresponding medication use and spirometry measurement. During a median 12.5-year follow-up, 389 incident COPD and 329 incident asthma cases were recorded among 7,948 individuals (mean age 63.0 years, 56.2% women). The annual rates of change in global cognition (β = -0.055 SD/year; 95% CI -0.080 to -0.029), orientation (-0.040 SD/year; -0.074 to -0.006), memory (-0.033 SD/year; -0.052 to -0.014), and executive function (-0.032 SD/year; -0.052 to -0.011) were accelerated after COPD diagnosis compared with before the event. The post-asthma annual changes in memory (-0.029 SD/year; -0.049 to -0.010) were also accelerated compared with the pre-diagnosis stage. However, the rate of cognitive decline before diagnosis in participants with future incident COPD, or asthma, was similar to the rate in matched control participants who remained event-free. Also, no significant short-term change was observed during its onset. Both incident COPD and asthma are associated with accelerated cognitive decline after, not before, the event onset.