Pulmonary function impairment may be an early risk factor for late-life cognitive impairment

To determine the association between change in pulmonary function (PF) and mid- and late-life cognitive function.

Prospective population-based cohort study that included measures of pulmonary function in midlife and brain magnetic resonance imaging data acquired in late life.

The Age, Gene/Environment Susceptibility-Reykjavik Study.

Three thousand six hundred sixty-five subjects who had at least one measure of forced expiratory volume in 1 second (FEV(1)) and were cognitively tested on average 23 years later. A subset of 1,281 subjects had two or three measures of FEV(1) acquired over a 7.8-year period.

Pulmonary function was estimated as FEV(1)/height(2). Rate of PF decline was estimated as the slope of decline over time. Cognitive status was measured with continuous scores of memory, speed of processing, and executive function and as the outcome of mild cognitive impairment (MCI) and dementia.

Lower PF measured in midlife predicted poorer memory, slower speed of processing, poorer executive function, and greater likelihood of MCI and dementia 23 years later. Decrease in PF over a 7.8-year period in midlife was not associated with MCI or dementia.

Low PF measured in midlife may be an early marker of later cognitive problems. Additional studies characterizing early and late PF changes are needed.