A boy born in the mountainous enclave of San Marino in northeast Italy will likely live to 80, the world's longest male life expectancy, but newborn girls in Japan and 30 other countries have even better prospects, the World Health Organization said.

Sierra Leone registered the shortest male life expectancy at 37 years — the same as for girls in Swaziland, the bottom of the female list, according to WHO's "World Health Statistics 2007."

Females in Japan — who traditionally lead the world tables — have a life expectancy of 86, the same as in last year's WHO statistics.

San Marino men, who were tied with Japanese men last year at 79, have added a year to go ahead.

WHO said the life expectancy figures were based on 2005, the latest year available. It said statistics kept by its 193 member countries may vary in some cases because it had computed the figures itself to ensure compatibility.

Following San Marino on the male side were Australia, Iceland, Japan, Sweden and Switzerland at 79 years and then Canada, Israel, Italy, Monaco and Singapore at 78. France was tied for 12th place at 77 years with a group of countries including New Zealand and Britain. Germany was at 76 years, and the United States was tied with Cuba and other countries for 33rd place at 75.

Countries with long-lived women include Monaco, 85 years, and Andorra, Australia, France, Italy, San Marino, Spain and Switzerland at 84. Canada tied Iceland and Sweden at 83 years for women, and Germany was in a group at 82 years. Britain came in at 81 years and the United States tied for 32nd place with Costa Rica and Denmark at 80 years.

Afghanistan is the toughest place for babies to survive, with an infant mortality rate of 165 in 1,000 live births, compared with the two babies who die per 1,000 born in Singapore or Iceland.

But Sierra Leone is worse than Afghanistan for mothers' survival, with a maternal mortality rate of 2,000 per 100,000 live births. The rate for Afghanistan was 1,900. Ireland did best at four deaths, followed by Spain, Italy, Finland, Canada and Austria at five deaths.

Diet is often given as a major factor in life expectancy, but the report did not give specific reasons for each country's showing. However, it noted that many of the countries that fared badly spent much less money on health.

It also noted that tobacco use had a "high prevalence among the world's poorest people," and suggested that the low life expectancy in some countries could be linked to high rates of diseases like HIV/AIDS and tuberculosis.