Being diagnosed with chronic obstructive pulmonary disease (COPD) in 2014 put an end to more than 35 years of heavy smoking for Mr Ramasamy Sinnasamy.

The warning signs were all there – persistent coughing, shortness of breath, wheezing and chest tightness – but the 59-year-old operations manager had not made an effort to do anything about them.

“If I had known earlier, I would have quit smoking earlier,” said Mr Ramasamy, a father of three who used to smoke two packets of cigarettes a day.

He found out he had the disease only when he went to see a doctor for a persistent cough that did not get better after three months.

He said: “I also used to get very breathless just climbing the steps of overhead bridges.” He had previously attributed this to a combination of ageing and minor illnesses.

More than 80 per cent of chronic obstructive pulmonary disease in Singapore is caused by tobacco smoking. The disease was the 10th leading cause of death here last year, according tothe Ministry of Health. Dr Jessica Tan, an associate consultant at the Singapore General Hospital's (SGH's) department of respiratory and critical care medicine, said: “Other causes of COPD include external factors such as air pollution and exposure to occupational dust and chemicals.”

Industrial workers who are exposed to chemical fumes on a long-term basis are at some risk.

WHAT IS CHRONIC OBSTRUCTIVE PULMONARY DISEASE?

It is a lung disease characterised by damage that reduces the air capacity of the lungs.

When a person breathes, the air enters the windpipe and goes into tubes known as airways, and bunches of tiny, round air sacs known as alveoli.

Oxygen then passes through the air sac walls into the bloodstream. At the same time, carbon dioxide moves from the capillaries – the fine blood vessels – into the air sacs and is expelled when the person exhales.

Long-term exposure to lung irritants, such as tobacco smoke, damages both the airways and air sacs. They become less elastic and their walls are thick and inflamed, or destroyed.

The airways also produce more mucus than usual, which can clog them. As a result, less air flows in and out of the airways.

WHO IS AT RISK?

The disease most commonly affects people over the age of 40 because it is caused by long-term exposure to lung irritants.

More than 80 per cent of patients with the condition here are above the age of 65, said Dr Tan.

PREVENTABLE AND TREATABLE BUT NOT CURABLE

There is no way to reverse the damage done to the airways and air sacs.

Dr Tan emphasised, however, that the disease is preventable and treatable.

“You can prevent it by refraining from smoking, As for treatment, smoking cessation is the most important intervention.”

Patients are treated with a combination of influenza and pneumonia vaccinations to prevent complications, as well as physiotherapy.

Most patients use inhalers, which deliver drugs to relax the muscles around the airways, making breathing easier.

The frequency of use depends on how severe the disease is. Inhaled steroids can also be used, usually in combination with long acting drugs called beta-agonists.

More severe cases can be put on long-term oxygen therapy, where extra oxygen is administered through a mask, for example.

Mr Ramasamy uses an inhaler and makes sure to do exercises at least once a week, such as walking, jogging or cycling.

But the most important step for him was to stop smoking. “I feel a lot better now. I’m breathing better and my appetite has improved,” he said.