The War on Longevity: Men versus Women

In the rich world, men are closing the longevity gap with women

Reg Dean, who died on 05 January 2012 at the ripe age of 110, was unusual. Centenarians are rare in themselves, of course, but male centenarians particularly so. In Britain, where Mr Dean lived, five times as many women as men receive the famed card of congratulations from the queen when they celebrate their 100th birthdays. That may, however, cease to be the case in the future, for the fact that women tend to live longer than men, though still true, is less true than it was, and the gap is shrinking-in rich countries, at least-every year.

In England and Wales, the biggest peacetime difference between the life expectancies at birth of the two sexes was 6.3 years. That was in 1967. It is now 4.1 years, and falling. In the early 1980s women who made it to 65, the traditional age of retirement for British men, could expect to live four years longer than their male counterparts. The gap now is less than three years, though there is still some way to go before things return to the nine month gap that prevailed in the 1840s, when records began. Other industrialised countries, except Japan and Russia, show something similar.

This trend is superimposed on another: that life expectancy in most developed countries has been improving for both sexes. But of late it has been improving more for men than for women.

A report about to be published by the Longevity Science Advisory Panel (a group of scientists and actuaries set up by Legal & General, an insurance company) examines the factors behind these trends. The biggest by far is changes in the use of tobacco.

All are Equal

Approximately half of the difference in the longevity of the sexes can be explained by smoking. One reason why Russia bucks the trend towards equal life expectancies for the two sexes (women there live 12 years longer than men) is that its men have not followed their Western confreres and cut down on the cancer sticks.

In Britain in the 1960s, when the habit was commonplace, men were much more likely to be smokers than women. But they have also been more likely than women to give up cigarettes over the past half-century. As a result, between 1979 and 2009 male smoking-related deaths fell by 64% and the male-to-female ratio of such deaths fell from 2.1 to 1.7. Deaths from cancers of the lung, trachea and bronchus in particular fell by 39% between 1991 and 2005 among Englishmen over 49. For women the comparable figure was 3%.

A further fifth of the longevity gap between the sexes is explained by alcohol. In this case, however, the gap is widening. In 1979 two men died from alcohol-related causes for every woman who succumbed. In 2009 it was 2-4.

A third important factor is obesity-or, rather, the physiological complications obesity brings, such as high blood pressure and type-2 diabetes, On the face of things, there is little difference between the sexes in this area: 15.6% of women in the EU are obese, compared with 15.4% of men. But obesity may have a greater impact on women because it increases the risks of both hypertension and diabetes in their sex more than it does in men. And men are also closing the gap in another area related to obesity and high blood pressure: coronary heart disease. In England, deaths from this fell more than 50% between 1991 and 2005 for both men and women. But, because heart disease kills twice as many men as it does women, the reduction in the male mortality rate has been greater.

All of which is good news if you are male. Men do, nevertheless, have the deck stacked against them by biology. One way the cards are marked is that female mammals (women included) have two x chromosomes, whereas males have an x and a v-the latter being a runty little thing with only a small complement of genes. Females’ “spare” x chromosome protects them from genetic mutations on the other one. Males have no such protection. Women are thus carriers of, but rarely suffer from, diseases like haemophilia which are caused by the mutation of x-chromosome genes. In birds, by contrast, it is the males who have matched chromosomes while females sport the runt. As a result, male birds tend to outlive their mates.

A further biological difference between the sexes is in the lengths of their telomeres. These are sections of DN A that protect the ends of chromosomes from decay. Men’s telomeres are shorter than those of women, and also degrade more quickly. Both of these attributes have been linked to reduced life spans.

Source: The Economist. (2013) Lifespan and the Sexes: Catching Up. The Economist. 12 Jan 2013, pp.68-69.

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