Chronic Coughs Could Be Genetic – Which May Transform Treatments

Long-lasting coughs affect around 1 in 10 of us, and because they have many potential triggers, they're not easy to diagnose or treat. But recent research points to a new avenue to explore – it found chronic coughs could be hereditary.

The type of cough seems to be important too. Parents were found to often pass on the same cough to their children, either a non-productive (dry) cough or a productive cough that brings up mucus or phlegm.

It's not clear which genetic and environmental conditions contribute to a cough continuing across a generation, though human genome analysis is underway, according to the international team behind the study published in October.

"These results suggest that there is a genetic link to chronic cough," says medical scientist Össur Ingi Emilsson, from Uppsala University in Sweden.

"This could provide a better understanding of the occurrence of chronic cough, which may ultimately result in better treatments for this difficult-to-treat condition."

Emilsson and his colleagues analyzed data on 7,155 parents and 8,176 adult children (aged 20 years and over) across northern Europe. In families where one of the parents had a chronic, non-productive cough, 11 percent of the children had also developed the same cough.

For comparison, with no chronic, non-productive cough in the parents, 7 percent of the kids had that type of cough. To put it another way, if a parent had a non-productive cough, the likelihood of their child having one increased by a little more than 50 percent.

The team accounted for factors such as biological sex, asthma, and smoking, and the association still held. A link was found for productive coughs too, though here the other factors lessened the statistical significance.

"A similar relationship was seen for productive cough, but in those cases smoking had a greater impact on prevalence," says Emilsson.

A treatment study has already begun to dig into this further: the researchers are hoping to identify the specific genetic variants linked to a chronic cough, which could then potentially be targeted by therapeutic drugs.

Having a cough you can't get rid of greatly reduces a person's quality of life, and has been linked to having to take significantly more sick leave from work. Understanding the role that genetics plays in its development will be important in efforts to ensure fewer people develop the condition in the future.

In another study, a team including some of the same researchers looked at data from 62,963 adults in Sweden, finding that between 2016 and 2018 only 1–2 percent of the population looked for help with a chronic cough – most of them women aged between 40 and 70 years old.

"For me, it was unexpected that only 1–2 percent of patients seek help for a troublesome cough when over 10 percent are affected," says Emilsson. "This can be partly explained by the lack of effective treatments."

The research has been published in the European Respiratory Journal.