Lung disease may increase dementia risk, finds American study

Dementia refers to a series of neurodegenerative diseases, such as Alzheimer's, where a person's memory and other cognitive abilities decline. A recent study may have found a new risk factor that might predispose people to dementia -  lung disease

alzheimers

Dementia refers to a series of neurodegenerative diseases, such as Alzheimer’s, where a person’s memory and other cognitive abilities decline. A recent study may have found a new risk factor that might predispose people to dementia: lung disease.

New U.S. research has found that middle-aged adults with lung disease may have a higher risk of also developing dementia or cognitive impairment later in life. Led by researchers at the University of Minnesota, the new study analysed data from 14,184 participants with an average age of 54 who were taking part in the Atherosclerosis Risk in Communities (ARIC) study.

The participants were followed for an average of 23 years, during which time they completed spirometry tests, which assess lung function, answered questions about their lung health, and were assessed for dementia or cognitive impairment.

The findings, published in the American Journal of Respiratory and Critical Care Medicine, showed that adults who had restrictive or obstructive lung disease also appeared to have a higher risk of dementia, including Alzheimer’s disease, and mild cognitive impairment.

In obstructive lung diseases, something obstructs the air flow in or out of the lungs. The most common type of obstructive lung disease is chronic obstructive pulmonary disease (COPD).

“Preventing dementia is a public health priority, and previous studies have suggested that poor lung health, which is often preventable, may be linked to a greater risk of developing dementia,” notes the study’s lead author, Dr. Pamela Lutsey, from the University of Minnesota’s School of Public Health.

“In this study,” she explains, “we looked at the long-term association between poor lung function and the risk of developing dementia, using high-quality measures.”

The study found that compared to those without lung disease, the odds of dementia or mild cognitive impairment were:

  • 58 per cent higher among those with restrictive lung disease.
  • 33 per cent higher among those with obstructive lung disease.

The study also found that low results on two spirometry tests–forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)–were associated with dementia. FEV1 is the amount of air a person can forcefully exhale in one second. FVC is a measurement of lung size.

The researchers noted that the study did have its limitations, and cannot prove a cause and effect relationship between lung disease and dementia or mild cognitive impairment. However, if the relationship is causal it could mean that improving air quality and helping people to quit smoking could not only lower rates of lung disease but also dementia.

“Preventing dementia is a public health priority, and previous studies have suggested that poor lung health, which is often preventable, may be linked to a greater risk of developing dementia,” said Dr Pamela L. Lutsey, lead study author.

“Preventing lung disease is inherently important,” Lutsey said. “If other studies confirm our study’s findings, both individuals and policymakers will have an added incentive to make changes that protect lung health, as doing so may also prevent dementia.”