PARIS – Growing child birth rates in emerging countries are fueling global child growth, but women in dozens of richer nations do not make enough children to keep their populations there, according to figures released on Friday.
The overall survey of numbers, deaths and disease rates that rank thousands of country-specific data sets also found that heart disease is now the only major cause of death worldwide.
The Institute for Measurement and Assessment of Health Care (IHME), based at the University of Washington from the Bill and Melinda Gates Foundation, has used more than 8,000 data sources – more than 600 of them – to build one of the most comprehensive views on global public health.
Their sources included country investigations, social media, and open source.
He found that while the world's population grew from 2.6 billion in 1950 to 7.6 billion last year, this growth was deeply uneven across regions and incomes.
90 countries, particularly in Europe and North and South America, according to the IHME study, did not make enough children to keep their current population.
But in Africa and Asia, the fertility rate has grown, with the average woman in Niger birthing seven children during her lifetime.
Ali Mokdad, a professor of medical sciences for metrology at IHME, told AFP that education is one of the most important factors in determining population growth.
"It's about socio-economic factors, but it's a female education," he said. "The more the woman is educated, she spends more time at school, gives up pregnancy and has fewer children."
IHME has found that Cyprus is the least fertile nation on earth, with the average woman giving birth only once in her life.
By contrast, women in Mali, Chad and Afghanistan have on average more than six children.
The United Nations predicts that more than 10 billion people will be on the planet by the middle of the century, which is basically in line with the IHME projection.
This raises the question of how many people can support our world, known as the "carrier capacity" of the Earth.
Mokdad said that while the populations in developing countries are still growing, their economies are generally growing.
This usually affects fertility over time.
"In Asia and Africa, the population is rising and people are moving from poverty to better income – unless there are wars or unrest," he said.
"Countries are expected to be more economical, and it is likely that fertility will fall and settle there."
Not only do we have more than a billion people now than we were 70 years ago, but we live longer than ever before.
The study, published in the medical journal The Lancet, showed that the life expectancy of men had increased to 71 years from 48 years in 1950. Women are expected to live at 76 years, compared with 53 in 1950.
Life brings longer its own health problems. thereby putting more burdens on our health care systems.
IHME said heart disease is now the leading cause of death worldwide. Already in 1990 neonatal disorders were the greatest killer, followed by lung disease and diarrhea.
Uzbekistan, Ukraine and Azerbaijan had the highest mortality rates for heart disease; South Korea, Japan and France were among the lowest.
"You see fewer mortality rates for infectious diseases, because countries are richer but also more affected because people live longer," Mokdad said.
He pointed out that, although deaths for infectious diseases such as malaria and tuberculosis have declined significantly since 1990, they have replaced new incurable murderers.
"There are certain behaviors that lead to an increase in cardiovascular disease and cancer. Obesity is number 1 – it grows every year and our behavior contributes to it."