The gap in life expectancy between men and women is at its lowest level for more than 50 years. While both sexes are living longer, the latest figures released yesterday show that men are catching up with women.

Last night health experts said the change owed much to men smoking less, paying more attention to their diet and being less reluctant to go the doctor. Over 20 years, the gap between female and male life expectancy at birth has dropped from 5.8 years to 4.3 years, according to the Office of National Statistics. Boys born in the UK between 2005 and 2007 can expect to live to 77.2 years, while girls can look forward to 81.5 years.

For 1985 to 1987, the comparable figures were 71.9 years for boys and 77.7 years for girls. The gap between the sexes was 4.8 years in 1951, but widened to 6.3 years in the next 20 years. Since the 1970s, experts said, men have benefited from lifestyle changes.

Dr Ian Banks, president of the Men's Health Forum, said: "Probably the biggest single reason is that men are giving up smoking in very large numbers, so cardiovascular disease has been affected by this in terms of numbers and lung cancer – the single greatest cancer killer of men – is on the decline." Men are also paying more attention to their diet, he said.