By Priyanjana Pramanik, MSc. Reviewed by Lily Ramsey, LLM Aug 26 2024
In a recent study published in ERJ Open Research, researchers investigated the heritability of chronic cough, considering different types of cough (productive vs. nonproductive).
Their findings indicate chronic cough may be heritable, with the kind of cough in parents showing associations with the same type of cough in their offspring.
Study: Heritability of cough across two generations: the RHINESSA study . Image Credit: Pixel-Shot/Shutterstock.com Background
Chronic cough affects about 10% of the population and can negatively affect the quality of life while resulting in lost work days.
It is thought to result when the reflex related to coughing becomes sensitized, known as cough hypersensitivity syndrome. However, the exact causes of this phenomenon remain unclear.
Some research suggests that certain biological processes and certain genetic factors may increase the chance of chronic cough. For example, a specific genetic variant called RE-RFC1 has been linked to chronic cough in some patients.
Despite this, little research has been done on whether chronic cough is inherited, especially when considering different types of cough, such as productive cough, which produces mucus and or phlegm and thus helps clear the respiratory tract of irritants or infections, and nonproductive cough, also known as dry cough. About the study
In this study, researchers aimed to determine if chronic cough among parents is linked to similar conditions in their children, focusing on whether the specific cough type is also inherited.
They hypothesized that chronic cough may be a heritable condition and that the type of cough may also be passed from one generation to the next.
The researchers examined the heritability of chronic cough by analyzing data from two large-scale studies, one of which included parents from Northern Europe and another study which focused on the offspring of participants in the first study from Australia, Spain, and Northern Europe. Related StoriesNew tool shows promise for assessing neurobehavioral difficulties in children with Duchenne muscular dystrophyStudy highlights mismatch in child injury data from crashesStudy reveals a paradigm shift in the understanding of T-lineage acute lymphoblastic leukemia
The former collected data from more than 21,000 individuals at multiple time points (1990, 2000, 2010), while the latter study included over 10,000 offspring participants between 2012 and 2019.
Chronic cough was classified into two types: productive (with phlegm) and nonproductive (without phlegm), based on participants' self-reports.
The analysis explored the relationship between chronic cough in parents and their offspring, using statistical models that accounted for factors such as age, sex, body mass index, smoking status, asthma, and other health conditions.
The researchers also conducted sensitivity analyses to examine the influence of factors like asthma, smoking, and sex on the heritability of chronic cough. The study followed ethical guidelines, with all participants providing informed consent, and findings were analyzed according to established guidelines for observational studies. Findings
The study analyzed data from 7,155 parents and 8,176 offspring to explore the heritability of chronic cough. It found that offspring with chronic cough were more often female smokers and had more cough-related health issues, such as asthma and gastroesophageal reflux.
A strong association was observed between chronic cough in parents and their offspring, particularly when parents had persistent coughs over time.
Specifically, 29% of offspring reported chronic cough if their parents had it twice, compared to 18% if the parents never had a chronic cough.
The type of cough also mattered: offspring were more likely to develop the same kind of cough as their parents—nonproductive or productive.
Additionally, the study found that chronic cough in female offspring was linked to both male and female parents, while chronic cough in male offspring was not significantly associated with male parents.
Sensitivity analyses confirmed these findings, though the link between productive cough in parents and offspring became less significant when accounting for non-smokers and those without asthma.
Overall, the study suggests that chronic cough, especially its type, is heritable across generations. Conclusions
The study’s findings indicate that adult offspring of parents with chronic cough are more likely to suffer from the same condition, particularly when considering the kind of cough—nonproductive or productive.
This association persists even after adjusting for various confounding factors, suggesting chronic cough may be heritable.
These findings align with limited previous research, such as a Korean study that also highlighted a family history of long-standing chronic cough. The heritability appears stronger in female offspring, though this needs further investigation.
The study's strengths include large, well-characterized population cohorts and consistent findings across different statistical analyses.
However, limitations include the lack of data from both parents in most cases, potential underreporting of chronic cough in younger offspring, and the absence of objective measurements like lung function.
Moreover, the study did not account for certain confounders like sleep apnea or air pollution, which could affect the results.
Future research should explore genetic factors contributing to this heritability, especially for nonproductive cough, and consider the role of environmental exposures and behavioral factors in chronic cough transmission. Understanding these mechanisms could lead to new treatments for chronic cough. Journal reference:
Emilsson, O.I., Johansson, H., Johannessen, A., Janson, C., Palm, A., Franklin, K.A., Oudin, A., Real, F.G., Holm, M., Gislason, T., Lindberg, E., Jõgi, R., Schlünssen, V., Callejas-González, F.J., Zhang, J., Malinovschi, A., Svanes, C., Ekström, M. (2024) Heritability of cough across two generations: the RHINESSA study. ERJ Open Research. doi: 10.1183/23120541.00071-2024. https://openres.ersjournals.com/content/10/4/00071-2024
