Female hormone protects, prolongs life

BOB BROCKIE

In good or bad times, women outlive men – especially during famines, pestilence or slavery. In January, a team of American scientists reported on these claims. In the

they observed that men are at a disadvantage because they are cursed with the hormone testosterone.

This chemical drives men to stressful jockeying for social status, to smoke, drink and take more risks than women. Testosterone suppresses the immune system and makes men more vulnerable to infections.

Women are blessed with the hormone estrogen, which helps protect their immune systems, makes them less vulnerable to disease and more risk averse.

In virtually every country, women outlive men by a few years. But the American team was not interested in life expectancy under normal circumstances but what happened to populations during famines, epidemics or periods of slavery.

As examples, they looked at:

❚ Freed slaves returned to Liberia. Between 1820 and 1843, tens of thousands of freed US slaves were sent to Liberia, in West Africa. There, horrendous conditions and disease caused the highest mortality ever recorded in human history – 43 per cent of the slaves died in their first year.

❚ Plantation slaves in the British Caribbean. In the early 19th century, many worked in sugar mills or domestic service seven days a week, often for 30 hours at a stretch.

❚ The Ukrainian famine. Stalin’s failed attempt at agricultural collectivisation resulted in more than three million Ukrainians starving to death in 1932-33.

❚ The Swedish famine. Between

1771 and 1773, crop failures resulted in devastating starvation. ❚ Icelandic epidemics. In 1846 and

1882 foreign fishing boats brought measles to Iceland. Having no resistance to the disease, the population was overwhelmed.

❚ Irish potato famine. In the 1840s, potatoes were the staple diet of the Irish but blight killed all potatoes over three consecutive years. A million Irish starved to death.

The American researchers took other disastrous historic famines into account – Madras, Bombay. Bengal, China, Pakistan and wartime Holland. They found that in all these famines, epidemics or periods of slavery, deaths fell heaviest on the male populations, leaving the females to outlive them.

The biggest differences were between male and female infants, with girls surviving babyhood and harsher conditions better than baby boys.

Other studies provide evidence of women surviving cardiovascular diseases, cancers and disabilities longer than men.

Though they may live longer, many women survive in poor health for a large part of the extra life.

This sex difference persists among people living similar lifestyles. Whether in religious groups like cloistered nuns or monks, devout Mormons or nonsmokers, the gap in life expectancy persists.

The researchers conclude that life expectancy is shaped by complex interactions between biological, environmental and social factors.

Useful tip. By cutting down on testosterone, a man can expect to live much longer. The trick is youthful castration. In ancient Byzantium, China and Korea, eunuchs lived about 20 years longer than intact men.