Doubt over reported drop in SA's life expectancy

Pali Lehohla is South Africa’s statistician general and the Head of Statistics South Africa. (Deaan Vivier)
Pali Lehohla is South Africa’s statistician general and the Head of Statistics South Africa. (Deaan Vivier)

Experts in South Africa have poured cold water on a report finding a big drop in life expectancy in the country.

"That life expectancy declined in South Africa is not a secret,” statistician general Pali Lehohla told Health24, but he said a drop of 4.3 years since 1990 is exaggerated.

He has lashed out at a study indicating that South Africa is one of just 11 countries out of 188 that recorded a decline in average life expectancy between 1990 and 2013.

The research, co-ordinated by the Institute of Health Metrics and Evaluation (IHME) of University of Washington and published in the journal Lancet, found that globally people live on average 6.2% years longer than they did in 1990, with life expectancy rising to just under 72 years in 2013.

Women living longer

In South Africa it found that the average life expectancy in 2013 for women was 63 years and men 57.7 years, compared to 1990 when women lived on average to 68.9 years and men 60.5 years.

According to Stats SA, the 2014 mid-year population estimates life expectancy at birth in South Africa in 2013 at 58.2 years for males and 62.1 years for females.

"The contrast between the estimate of IHME for 1990 and one of 2013 on life expectancy in comparison to that of StatsSA is palpable,” Lehohla said.

He believes the estimates provided by the IHME for the period 1990 to 2006 are higher than what would be expected for South Africa during that time.

IHME's major flaw

Lehohla claims that the major flaw of the IHME is that it has not tempered their base data and therefore their "intellectual work" with that of population groups other than that of the then white minority.

“The study is misleading in that the life expectancy they provide for 1990 is impossible based on any source of data.”

He said by 1990 there were no scientific study of the aggregate South African population, let alone one that related to causes of death.

"[The study] is scientifically barren and it is a rather lazy piece of work hiding behind a facade of the so called cross country comparative studies.”

Lehohla pointed out that in cross country studies, global agencies and researchers often ignore country sources in order for their global model to work.

This view was supported by Professor Bongani Mayosi from the University of Cape Town and Professor Eric Udjo from the University of South Africa.

Doubt over 1970 census

Even the 1970 census, described as the only most accurate account of the population under both colonial occupation and apartheid, still failed dismally as a census, Lehohla said.

"This is because only a sample of 5% of black census records were processed, just demonstrating how cavalier the apartheid state institutions was even in matters of scientific inquiry.
"So an imputation of life expectancy and cause of death in the light of such scant information and discrepant data history requires a more elaborate scientific process than the shallow grave approach dished to us by the IHME.

“Whilst their wild guess comes against a backdrop of lack of data before 1996, it is just inexplicable why they have not used the available body of data at least to inform their 1990 estimate given that they are compiling their report two and half decades later when demographic data is plentiful in South Africa,” said Lehohla.

He noted that the best estimate of female life expectancy as of 1990 would have been 63 years and not 68.9 years as IHME estimated, according to all sources of data from Stats SA.

"This is a gap of about six years, which is statistically and demographically very significant," said Lehohla.

"So the claim by the IHME is indeed a fallacy and can only reflect the then prevalent measurement bias of mortality experience amongst the measured population and therefore that largely of the white population."  
For 2013 the life expectancy estimate generated by StatsSA and one generated by IHME are very close at respectively 62 and 63 for females and 58.2 and 57.7 for males.

Support for Lehohla

Professor Mayosi told Health24 that he concurs with Lehohla."The statistician general is correct and the most important issue is the estimates of life expectancy in South Africa in 1990."

He said the estimates are unreliable."The records are atrocious because of the apartheid system. Under apartheid a lot of data on black people have been ignored."

"He is right in saying that international agencies, including the IHME have ignored this issue,” said Mayosi.

"The massive drop in life expectancy is probably exaggerated.”

Professor Eric Udjo, who for the past 17 years analysed mortality from various Stats SA data, told Health24 that he shared Lehohla's view regarding global estimates.

"I am generally wary of them because either there is not sufficient detail about their methodology or sometime questionable methodology carried from a group of countries and imposed on other countries."

However, he made it clear that there is no consensus about the level of mortality in South Africa saying "it remains a controversial subject".

Also read:

Life expectancy in SA drops by 4.3 years
SA's life expectancy: Why new report is misleading
Superbugs threaten to kill 10 million a year

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