An attack of shingles can increase the risk of having a stroke or heart attack years later, new research suggests.

For people under the age of 40, the viral infection boosted the chances of a stroke by 74% and a heart attack by 50%.

Older people were less affected, but shingles increased their risk of a heart attack by 10% and of a "mini-stroke" or transient ischaemic attack (TIA) by 15%.

Researchers studied data on 106,000 patients with shingles and 213,200 matched non-sufferers. Patient records were reviewed for an average of six years after a shingles diagnosis and for as long as 24 years.

Forty people with shingles went on to experience a stroke, compared with 45 of those without shingles.

People under 40 affected by shingles were more than twice as likely to have a TIA.

Shingles is caused by the same virus responsible for chicken pox, which can lie dormant in nerve roots for years before awakening and producing a painful rash.

Stress and inflammation may explain the link between shingles and stroke, scientists think. Study author Dr Judith Breuer, from University College London, said: "Anyone with shingles, and especially younger people, should be screened for stroke risk factors."