The study from the Institute of Health Metrics and Evaluation (IHME) at the University of Washington, Seattle, has been published in The Lancet magazine and compares public health in the world between 1950 and 2017.
In almost half of the world's countries, mainly in Europe and North and South America, not enough children are born to maintain their population size. At the same time, childbirth continues to increase in Africa and Asia, with the average woman in Niger who births seven children during her lifetime.
Education the main factor
Ali Mokdad, professor at IHME, says that the single most important factor for population growth is education.
If a woman trains herself, she spends more years in school, postpones her pregnancies and, therefore, will have fewer children, he says.
According to IHME, Cyprus is the world's least fertile country – an average Cypriot woman is giving birth to a child in her life. On the other hand, women in Mali, Chad and Afghanistan have on average more than six children.
Mokdad says that while the peoples of developing countries continue to rise, their economies generally increase, which usually has a declining effect on childbirth over time.
Countries are expected to get it better economically and it is more likely that fertility will decrease and level out.
Increased service life
We also live longer than ever before. The expected global life expectancy for men has increased to 71 years from 48 in 1950. Women are now expected to live to 76 compared to 53 in 1950.
Heart disease is now the most common cause of death globally, states IHME. As late as 1990 there were neonatal problems, followed by lung diseases and diarrhea.
You see less mortality from infectious diseases as countries get richer, but also more disabilities because people live longer, says Ali Mokdad.
He pointed out that even though deaths from infectious diseases such as malaria and tuberculosis have decreased significantly since 1990, new non-transmissible diseases have taken place.
There are certain behaviors that lead to more cases of cardiovascular disease and cancer. Obesity is number one – it increases every year and our behavior contributes to it, he says.