Sierra Leone registered the shortest male life expectancy at 37 years — the same as that of girls in Swaziland, who were at the bottom of the female list, WHO's "World Health Statistics 2007" show.
Females in Japan, who traditionally lead the world tables, have a life expectancy of 86 years, the same as last year's statistics. San Marino men, who tied with Japanese men last year at 79, added a year to get ahead.
Men in the United States have a 75-year life expectancy; U.S. women could reach 80.
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. Cuba was among the countries that tied the U.S. for 33rd place at 75 years.
Countries with long-living 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. Costa Rica and Denmark tied the United States for 32nd place at 80 years.
Afghanistan is the toughest place for babies, 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.