The risk of premature death is reduced by 11 per cent if men marry a woman seven to nine years younger.

The study at Germany’s Max Planck institute also found that men marrying older women are more likely to die early.

The results suggest that women do not experience the same benefits of marrying a boy toy or a sugar daddy.

Women with husbands older or younger by between seven and nine years increase their chances of dying early by 20 per cent.

This rises to 30 per cent if the age difference is close to 15 and 17 years.

Scientists say the figures for men may be the result of natural selection – that only the healthiest, most successful older men are able to attract younger mates.

“Another theory is that a younger woman will care for a man better and therefore he will live longer,” said institute spokesman Sven Drefahl.

The study examined deaths between 1990 and 2005 for the entire population of Denmark.

On average in Europe, most men marry women around three years younger.