LONDON (Reuters) - Smokers'' heavily wrinkled faces could be an early warning of serious lung disease, researchers said.

They found that smokers with pronounced wrinkles are five times more likely than those without marked facial lines to suffer from chronic obstructive pulmonary disease (COPD), which includes bronchitis and emphysema.

COPD, a leading cause of death worldwide, is caused by smoking, which also prematurely ages the skin. So researchers at the Royal Devon & Exeter NHS Foundation in southwest England studied whether there was a link between the two.

"This data suggests that if you are a smoker and you are wrinkled you are more likely to have lung disease," said Dr Bipen Patel who conducted the study published in the journal Thorax.

"We found that cigarette smokers who had a large amount of facial wrinkling were five times more likely to have COPD than smokers who were less wrinkled."

COPD begins with a persistent cough and increased mucous. It eventually leads to fatigue, shortness of breath and difficulty breathing as the lungs are destroyed.

Because the disease develops gradually, Patel and his team believe facial wrinkling could be an a sign of the illness before it is diagnosed.

The researchers studied 149 former and current middle-aged smokers and compared how much they smoked during their lifetime and their sun exposure, which also damages the skin.

Two dermatologists scored the severity of wrinkling from photographs of the smokers. Breathing tests and scans were also done to detect any signs of COPD.

The smokers who were the most wrinkled were far more likely to have changes in their lungs suggesting COPD, according to the scientists.

They suspect there could be an unknown common mechanism linking COPD and wrinkling.

"This is the first time that it has been shown that the two are more likely to occur together," he added.

Deaths from COPD are increasing in most countries. The World Health Organization (WHO) estimates it will become the third-biggest cause of death worldwide by 2020.

The illness afflicts people over 40 who have been smoking for many years. It contributes to other disorders such as pneumonia, heart disease and stroke. There is no cure for COPD but treatment can relieve the symptoms and therapies to slow its progression are being tested.