Having a lung disease could raise the risk of heart conditions regardless of other risk factors such as smoking or age, a recent study has revealed.

The researchers from the University of Birmingham made the interesting finding using a trial involving more than 220 patients with a rare genetic condition called Alpha-1 antitrypsin deficiency (AATD) which causes lung disease similar to Chronic obstructive pulmonary disease(COPD). The results were published in the Orphanet Journal of Rare Diseases.

AATD causes the body to make low levels of a protein that protects the lungs. The affected individuals may develop symptoms including chronic cough, shortness of breath, and wheezing.

For the trial, patients with AATD were evaluated against patients with COPD and a control group of participants with no lung disease for risk factors of cardiovascular disease such as vascular stiffness. Vascular stiffness typically occurs with age and is closely associated with the progression of cardiovascular disease. The participants were followed up for four years to see if they developed any heart disease.

"The patients with the rare genetic condition AATD had the highest adjusted scores among all participants for vascular stiffness, but had lowest scores for the standard associated risk factors of CVD and nearly half (45%) of patients had discordant scores where one was high and other low," the researchers said in the University news release.

Despite having lower risk factors typically associated with developing cardiovascular disease such as being younger and having a higher proportion of individuals who had never smoked, 12.7% of the participants with AATD developed cardiovascular disease within the follow-up period.

Meanwhile, the patients with COPD and control group participants had similar scores across the direct and indirect measures of cardiovascular disease risk.

"This long-term study has enabled us to see the relationship between lung disease and heart disease in a unique way by following a group of patients with this rare genetic disease. Our study has shown that there is an increased risk for people with lung conditions of going on to develop cardiovascular conditions and that only looking at conventional factors such as age and smoking doesn't give the full picture of the relationship between these two essential systems in the body," said Robert Stockley, a senior author of the study.

A blood test conducted among the participants with AATD analyzed an enzyme linked with lung damage called Proteinase 3. The study found that there was a link between elevated levels of Proteinase 3 and vascular stiffness which in turn raises the risk of heart disease. The team believes that this enzyme has a direct impact on the development of heart and lung disease by breaking down fibers that support the large arteries and lungs.

Based on their finding, the researchers suggest the use of Proteinase 3 inhibitors as a novel therapeutic strategy to prevent cardiovascular disease, particularly among AATD patients.

"The role of Proteinase 3 acts as a powerful link between lung and heart disease. The action that the enzyme has in attacking elastin fibers found in the lungs and major arteries suggests that inhibiting its action could have a dual effect to slow both lung and cardiovascular diseases," Louise Crowley, a corresponding author of the paper said.