While older people are far more likely to suffer a stroke, one in 10 stroke patients in Singapore is under 50 years old.

Medical conditions such as high blood pressure or high cholesterol can make a person more likely to get a stroke, say doctors.

Smoking, too, puts you at risk.

Last Saturday, Singaporean businesswoman Linda Koh was found unconscious in her Hong Kong hotel room. The 36-year-old was rushed to hospital, where she died soon after.

Doctors subsequently found that she had suffered a stroke.

Her father,Mr Alan Koh, told Chinese newspaper Shin Min Daily News that his daughter had a history of high blood pressure and was taking medication for it.

Strokes occur when part of the blood supply to the brain is cut off.

The latest figures from the National Registry of Disease Office show that there were 6,943 cases of strokes in 2014, up from 6,642 the previous year.

They are the fourth most common cause of death in Singapore, and tend to occur among men.

The incidence rate for men aged between 35 and 44 who were admitted to public hospitals for stroke in 2014 was 58 per 100,000 people, compared with 24 per 100,000 for women in the same age group.

Doctors who spoke to The Straits Times said there are rarely any warning signs before a stroke happens.

“Some strokes may be preceded by severe headaches or neck pain,” said Dr Carol Tham, a consultant from the National Neuroscience Institute's neurology department.

“Unfortunately, most patients do not have any warning symptoms before the stroke occurs.”

During a stroke, people often experience difficulty speaking and walking, weakness on one side of their bodies, and even temporary blindness.

Dr Ho King Hee, a neurologist at Gleneagles Hospital Singapore, said strokes that result in sudden death are likely to be due to bleeding in the brain from a ruptured blood vessel, rather than a blockage.

“If you are older, it means that there is more time for damage (to the blood vessels) to accumulate,” he said. “But a stroke can happen at any age.”

He advises people who have conditions such as high blood pressure, high cholesterol and diabetes to keep them in check.

Dr Tham added that doctors may also prescribe blood-thinningmedication for people whose blood tends to clot.

“If a person has any symptoms of stroke... he should seek treatment at the emergency department immediately as early treatment can help to reduce the disability caused by strokes,” she said.