If you visit your country's national statistics website, you may find buried within the pages a set of tables known as the Life Tables. These tables provide information on life expectancy1 for men and women at each age. Usually, there are separate tables for males and females. Such tables are used by actuaries, demographers and social scientists for a variety of purposes. For the general reader, the tables are interesting in their own right.
The tables are based on a hypothetical group (cohort) of 100,000 people in the population. At age zero, everybody in the group is alive, but by age one, this number has decreased somewhat due to infant deaths. The tables continue through each year until by age 100, the number is reduced to a very small proportion of individuals still alive. The tables can indicate to you, roughly, how many of your peers are still alive, what the probability of death within the next year is, and how many years you can expect to live at your current age.
The Life Profile From Cradle to Grave
Presented graphically, the life tables tell a fascinating story about the lifestyles we lead, the afflictions we face and the risks we take.
The Infant Year - Birth to Age One.
The most dangerous year for a human being during their first 50 years of life is the first one. Despite advances in medical science, many infants still die during the first few weeks, with approximately 40% of infant deaths occurring on the day of birth. That said, this number is considerably less than 1% of all births in most developed countries.
Childhood and Adolescence - One to 16
If a child survives their first year, the probability of death drops off dramatically. The tables show that children, particularly those between the ages of five and twelve, are least likely to die of any age group, with typically ten to 20 deaths expected per 100,000 of population per year. The fact that most children are at their healthiest and the role of parental influence contribute to this favourable statistic.
Late Adolescence and Early Adulthood - 17 to 25
Mortality statistics begin to increase in late adolescence, so much so that a person at age 20 may be four times more likely to die than at age ten. The statistics are even more interesting when males are compared to females. In many countries, a noticeable 'hump' appears in the statistics for men - there is an increased risk of death during these years, and in some cases a 23-year-old may have the same risk of imminent death as a 35-year-old. The reasons for this include deaths due to motor accidents2, misadventure due to risk-taking and increasingly, suicide among young men.
Early Middle Years - 26 to 39
Mortality statistics among men and women level off during the late twenties and thirties, due in part to good health and less risk-taking behaviour. That said, males may be twice as likely to die during these years as females, with approximately 100 male deaths per year3 compared to 50 female deaths per year in many developed countries.
Middle Years - 40 to 65
From age 40 onwards, yearly mortality begins to increase. This is due in the most part to the onset of age-related health problems such as cancer and heart disease. In the general population, the yearly death rate doubles approximately every ten years, so that by age 65, over 1,000 members of the initial cohort of 100,000 will die that year alone.
Senior Years - 66 to 90
The death rate in the senior age group increases from 1,000 to 4,000 per year, so that by age 80, only 50% of the entire initial cohort of 100,000 people will be expected to be alive. This age is somewhat earlier in males, and somewhat later in females. Mortality rates usually peak in the eighties, so that by age 90, less than 25% of the cohort will be alive.
By age 100, the numbers of survivors will range from 2% to 0.5% of the initial cohort of 100,000. Even at this great age, women survivors may exceed men by three to one. The clear message is, if you want to live to 100, be a woman.
Differences in Death Rates Between Men and Women
Throughout the early and middle years of life, women are at less risk of premature death and are more likely to live longer. The difference in life expectancy between males and females can be as much as ten years in many countries. In addition, even though slightly more men are born than women4, by age 25 women are in the majority in the peer group. Men's increased capacity for risk-taking and aggressiveness is one factor, but the presence of high levels of testosterone in males put them at a higher risk of heart disease and strokes in later years. The presence of oestrogens in females may reduce their premature mortality risk. Longevity studies in other animal species show similar differences in mortality between the sexes. Other factors contributing to the increased rates include genetic abnormalities carried on the male Y-chromosome and increased male metabolism contributing to an earlier death.
As you get older, your life expectancy increases. A male baby aged 0 might have a life expectancy of 75 years for instance, but by the time they have reached 40, their life expectancy has increased to 77, and by the time they are 60 it has jumped to 79. This is simply due to the mathematics of averaging: people who die younger will reduce the overall life expectancy of the cohort, and as people get older the effect of premature death on future life expectancy reduces.
Improvements in Life Expectancy
Life expectancy of both males and females has improved markedly in the past century. In the 1920s for example, the life expectancy of males and females was in the late fifties in many developing countries. This increase is due primarily to a huge reduction in infant mortality rates in the intervening period. The life expectancy of seniors has not changed very significantly in that time. A sixty-year-old now can expect to live into his or her early eighties (an increase from 1920 of just three or four years) and many more people5 are reaching the age of sixty than were doing so in 1920.
Life Tables in Developing Countries
The profile among many developing countries is different to developed countries. This is particularly the case for sub-Saharan Africa, where HIV/AIDS has been such a rampant killer amongst young people and where the life expectancy in some countries is under 40 years. In addition, child mortality is much higher in many developing countries, taking away over 10% of infants in parts of Asia and Africa. Female life expectancy exceeds male life expectancy in all regions of the world, but developed countries show the most marked differences between the sexes.
Below are sites containing life tables for selected countries:
- UK Government Actuary Department
- USA National Center for Health Statistics
- Australian Bureau of Statistics
- Statistics Canada
- Irish Central Statistics Office