Soaring birth rates in developing nations are fuelling a global baby boom while women in dozens of richer countries are not producing enough children to maintain their population levels there, according to figures released Friday.
Thousands of datasets are evaluated on a country-by-country basis.
The Institute for Health Metrics and Evaluation (IHME), set up at the University of Washington by the Bill and Melinda Gates Foundation, uses more than 8,000 data sources – more than 600 new ones – to compile one of the most detailed looks at global public health.
Their sources included in-country investigations, social media and open-source material.
In Niger, women have – on average – 7.1 kids, according to Bill and Melinda Gates's team at the University of Washington. Another nine low-income countries have astronomically high birth rates, with more than five per woman
This graph shows the percentage change in total fertility rates from 1975 to 2017 for women aged 30 to 54 years old. The map reveals huge changes (ie drops) in fertility rates in developed countries such as the US, the UK and Australia
In Africa and Asia continue to grow while Europe and North and South America are not producing enough children to sustain their current populations. PICTURED: The global total fertility rate distributed by number of live births per region for both sexes from 1950 to 2017
PICTURED: The global total fertility rate distributed by maternal age for both sexes from 1950 to 2017
It found that while the world's population skyrocketed from 2.6 billion in 1950 to 7.6 billion last year, that growth was deeply uneven according to region and income.
Ninety-one nations, mainly in Europe and North and South America, were not producing enough children to sustain their current populations, according to the IHME study.
But in Africa and Asian fertility rates continue to grow with the average woman in Niger.
Ali Mokdad, professor of Health Metrics Sciences at HIM, told AFP that the most important factor in determining population growth was education.
'It's down to socioeconomic factors but it's a function of a woman's education,' he said. 'She is spending more years in school, she is delaying her pregnancies and so wanting to have babies.'
The IHME found that Cyprus is the least fertile nation on Earth.
By contrast, women in Mali, Chad and Afghanistan have on average more than six babies.
This graph, published today, shows which countries have higher fertility rates, and where the rates are dropping
'Less mortality, more disability'
The United Nations predicts there will be more than 10 billion humans on the planet by the middle of the century, broadly in line with IHME's projection.
This raises the question of how many people our world can support, known as Earth's 'carrying capacity'.
Mokdad said that while in developing nations continue to rise, so in general are their economies growing.
This typically has a knock-on effect on fertility rates over time.
'In Asia and Africa the population is still increasing and people are moving from poverty to better income – unless there are wars or unrest,' he said.
There are declining and level out. '
Not only are they now more than 70 years ago, but we are living longer than ever before.
71 years from 48 in 1950. Women are now expected to live to 76, compared with 53 in 1950. The study was published in The Lancet medical journal.
Living longer brings its own health problems, as we grow and deteriorate and place greater burdens on our healthcare systems.
The IHME said: heart disease is now the leading cause of death globally. As recently as 1990, neonatal disorders were the biggest killer, followed by lung disease and diarrhea.
The report also claims that the cause of death is global
Fertility rates in many African nations continue to rise, the study showed
Uzbekistan, Ukraine and Azerbaijan had the highest death rates from heart disease, while South Korea, Japan and France had among the lowest.
'You see less mortality from infectious diseases as countries get richer, but more disability as people are living longer,' Mokdad said.
He pointed out that although deaths from infectious diseases like malaria and tuberculosis are down significantly since 1990, new, non-communicable killers have taken their place.
In cardiovascular diseases and cancer. Obesity is number one – it is increasing every year and our behavior is contributing to that. '