Age
At 80, a Nigerian and a Norwegian are far closer than at birth
Nigeria's life expectancy at birth is about 19 years below Norway's. Among people who have already reached the 80–84 age band, the same WHO life tables put their expected age at death within 1.9 years of each other.
SnapLongevity4 min read
In the WHO Global Health Estimates for 2021, life expectancy at birth is 63.4 years in Nigeria and 82.9 in Norway. Follow the same two life tables to people who have already reached the 80–84 band and the picture changes almost beyond recognition: expected age at death is 87.1 years in Nigeria and 89.0 in Norway.
A difference of about 19 years at birth has become a difference of 1.9. Nothing about Nigeria improved between those two rows. The population being described changed: the second row refers only to people who survived to eighty, and survival to eighty is exactly what the first row was measuring the absence of.
- 19years
- Nigeria–Norway difference at birth
- 1.9years
- Difference in expected age at death, 80–84 band
- 7.1years
- Remaining life expectancy in Nigeria at 80–84
63.4 against 82.9 years
87.1 against 89.0 years
Norway: 9.0 years
WHO Global Health Estimates abridged life tables, both sexes, 2021. Values are read at the start of the published 80–84 age band; the source does not publish single years of age.
Two numbers, moving in opposite directions
Every age in a life table carries two figures, and they behave differently as a person gets older. Remaining life expectancy generally falls with age — an eighty-year-old has fewer years ahead than a fifty-year-old. Expected age at death, which is simply the age reached plus those remaining years, generally rises.
Remaining life expectancy
The average number of further years expected from the age already reached. In these tables it declines as the age reached rises.
Expected age at death
That figure plus the current age. It rises with the age reached, because surviving to an age removes the possibility of having died before it.
How far apart are countries once people have already grown old?
Expected age at death, by the age already reached
At birth
Already reached age 50(50–54 band)
Already reached age 60(60–64 band)
Already reached age 70(70–74 band)
Already reached age 80(80–84 band)
Nigeria: at age birth, expected age at death 63.4 years; at age 50, expected age at death 76.1 years; at age 60, expected age at death 78.5 years; at age 70, expected age at death 82.1 years; at age 80, expected age at death 87.1 years. Norway: at age birth, expected age at death 82.9 years; at age 50, expected age at death 84.1 years; at age 60, expected age at death 84.8 years; at age 70, expected age at death 86.3 years; at age 80, expected age at death 89.0 years. Japan: at age birth, expected age at death 84.5 years; at age 50, expected age at death 85.7 years; at age 60, expected age at death 86.6 years; at age 70, expected age at death 88.2 years; at age 80, expected age at death 90.8 years.
WHO Global Health Estimates abridged life tables, both sexes, 2021. Each row uses the start of a published age band (0, 50–54, 60–64, 70–74, 80–84); no value between bands is interpolated. Expected age at death is the age reached plus remaining life expectancy at that band.
The same pattern in three countries at once
Swipe the table sideways to see all columns.
| Age reached | Nigeria | Norway | Japan | Widest gap |
|---|---|---|---|---|
| At birth | 63.4 | 82.9 | 84.5 | 21.1 |
| 50–54 | 76.1 | 84.1 | 85.7 | 9.6 |
| 60–64 | 78.5 | 84.8 | 86.6 | 8.1 |
| 70–74 | 82.1 | 86.3 | 88.2 | 6.2 |
| 80–84 | 87.1 | 89.0 | 90.8 | 3.7 |
WHO Global Health Estimates abridged life tables, both sexes, 2021. The first row is life expectancy at birth; the remaining rows show expected age at death — the start of the age band plus remaining life expectancy at that band. No value is interpolated between bands.
Read down the last column: the spread between these three countries falls at every step. Japan, the longest-lived country in the dataset, keeps an advantage at every age, but the size of it shrinks as the comparison moves to older survivors. Try any age and country in the explorer.
Why the differences compress
Two mechanisms are at work, and they are worth separating because only one of them is good news.
- Arithmetic: each death at a young age removes more potential years than a death in old age, so mortality earlier in life can weigh heavily on life expectancy at birth. Once those ages are behind a person, whatever difference they created no longer applies to them.
- Selection: in a high-mortality country, reaching eighty means having survived risks that many contemporaries did not. Those survivors are not a random sample of the population they were born into, and comparing them to Norwegian eighty-year-olds is not comparing like with like.
The convergence is therefore not evidence that later-life conditions are similar across countries. It is evidence about where in the age range national differences are generated — and a warning against reading an at-birth figure as a statement about the future of anyone who is already old.
The sex difference narrows too
Sex differences follow the same shape. In Japan, female life expectancy at birth exceeds male by 5.4 years. In remaining years at the 50–54 band the difference is 5.0, and at the 80–84 band it is 2.1.
The gap does not vanish, but in the 2021 Japanese life table the female advantage in remaining years is smaller in the 80–84 band than it is at birth. Why the sex difference takes the size it does is a separate question, addressed by the research on excess male mortality. The sex gap across 185 countries.