Researchers have revealed that Covid-19 pandemic came as a double blow for people with non-communicable diseases (NCDs) such as diabetes, cancer, respiratory problems or cardiovascular conditions in countries like India, Bangladesh, Pakistan and others.

The study, published in the journal Frontiers in Public Health, found people with NCDs are more vulnerable to catching and dying from Covid-19 and their exposure to NCD risk factors - such as substance abuse, social isolation and unhealthy diets - has increased during the pandemic.

The researchers also found Covid-19 disrupted essential public health services which people with NCDs rely on to manage their conditions.

They reviewed the literature on the synergistic impact of Covid-19 on people with NCDs in low and middle-income countries such as Brazil, India, Bangladesh, Nepal, Pakistan and Nigeria.

The paper, which analysed almost 50 studies, was a collaboration between the University of New South Wales (UNSW) in Sydney, and public health researchers in Nepal, Bangladesh and India.

Study lead author Uday Yadav from UNSW, said the interaction between NCDs and Covid-19 was important to study because global data showed Covid-19-related deaths were disproportionally high among people with NCDs.

"This illustrates the negative effect of the Covid-19 'syndemic' - also known as a 'synergistic epidemic' - a term coined by medical anthropologist Merrill Singer in the 1990s to describe the relationship between HIV/AIDS, substance abuse and violence," Yadav said.

"We applied this term to describe the interrelationship between Covid-19 and the various biological and socio-ecological factors behind NCDs," he added.

"So, people are familiar with Covid-19 as a pandemic, but we analysed it through a syndemic lens in order to determine the impact of both Covid-19 and future pandemics on people with NCDs," Yadav explained.

According to the researchers, Covid-19 syndemic would persist, just as NCDs affected people in the long-term.

"NCDs are the result of a combination of genetic, physiological, environmental and behavioural factors and there is no quick fix, such as a vaccine or cure," he said.

"So, it's no surprise we found that NCD patients are more vulnerable to catching Covid-19 because of the syndemic interaction between biological and socio-ecological factors," the author wrote.