Reduced lung function associated with cognitive decline in the elderly

An analysis of longitudinal data from the English Longitudinal Study of Ageing (ELSA) found a connection between lung function and cognitive deterioration in elderly people over an average follow up of 12 years [1].

“Cross-sectional studies have suggested that lung function might be a risk factor for cognitive decline and dementia in the elderly population. However, the evidence from longitudinal studies remains inconsistent,” Dr Yutong Cai (University of Oxford, UK) described the motivation for this cohort study. Thus, Dr Cai and colleagues investigated the possibility of a relation between lung function and decreased cognitive function over time.

Included were 6,107 participants from the 2004/2005 wave of the ELSA cohort whose baseline data included complete cognitive function information. For every participant, at least 1 reassessment was available of their cognition between 2006/2007 and 2016/2017. Testing consisted of an evaluation of global cognitive abilities as well as memory, executive funtion, and orientation. The individual test results were transferred into a Z-score, and a global Z-score was calculated by means of averaging the test specific Z-score and restandardising it to the baseline global Z-score. Lung function parameters at baseline consisted of forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and peak expiratory flow (PEF). Measurement baseline data of continuous FEV₁ was used along with FEV₁ quartiles for men and women. A linear mixed model was used to assess a connection of the baseline lung function with a gradual loss of cognition, adjusting for possible confounders as age, education, weight, marital status, symptoms of depression, physical activity, intake of alcohol, smoking in addition to diagnoses like diabetes, hypertension, chronic bronchitis or emphysema, coronary heart disease, stroke, and cancer.

The results from the 12-year follow-up showed a significant association of FEV₁, FVC, and PEF with declines in all measured dimensions of cognitive function for both sexes of the elderly study population (P<0.001). “Very interestingly, we found the association was particularly stronger in women as opposed to men,” Dr Cai stressed. Looking at the global cognitive Z-scores, the multivariable-adjusted changes associated with per 1 L decrease in FEV₁ were -0.041 standard deviation (SD)/year (P<0.001) for women and -0.019 SD/year (P<0.001) for men. Focusing on mean differences in the rate of change in Z-scores for memory only, the study found values of -0.046 and -0.031 (both for quartile 1 of FEV₁; P<0.001) for women and men, respectively. “The results show a clear relationship: if you have a lower lung function at baseline, then you have a faster decline in cognitive function,” concluded Dr Cai.

 

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   1. Cai Y, et al. Reduced lung function and cognitive decline in ageing: a longitudinal cohort study. Abstract 4186, ERS International Virtual Congress 2020, 7-9 Sept.

 



Posted on 29 October, 202027 March, 2024