Men who are out of work for at least two years may age faster, a new study suggests.

UK and Finnish scientists analysed the DNA samples of over 5,600 men and women who were born in 1966.

They studied DNA structures known as telomeres, which are found at the end of chromosomes. Their function is to protect the genetic code from being degraded.

Over the course of a person's life, telomeres become shorter, therefore their length is considered a marker of a person's biological age. Short telomeres are also associated with an increased risk of age-related diseases, such as heart disease.

The scientists measured the telomere length of the participants, using blood cell samples that had been collected in 1997, when they were all aged 31.

The study found that men who had been unemployed for at least two of the preceding three years were more than twice as likely to have short telomeres compared to men who had been continually employed over the same period.

According to Dr Jessica Buxton of Imperial College London, ‘stressful life experiences in childhood and adulthood have previously been linked to accelerated telomere shortening. We have now shown that long-term unemployment may cause premature ageing too'.

However, the same link was not found in women. The scientists suggested this may be because fewer women in this study were out of work for long periods during their 30s.

"There has been lots of research linking long-term unemployment with ill health. This is the first study to show this type of effect at a cellular level. These findings raise concerns about the long-term effects of joblessness in early adulthood. Keeping people in work should be an essential part of general health promotion," commented Dr Leena Ala-Mursula from the University of Oulu in Finland.

The scientists called for further research to determine if long-term unemployment is also more harmful for men than women in later life.

Details of these findings are published in the journal, PLOS ONE.