The study by the Institute of Metric Health and Assessment (IHME) at Washington University, Seattle, has been published in The Lancet and compares public health in the world between 1950 and 2017.
In most of the world's half, mainly in Europe and North and South America, not enough children are born to maintain the size of their population. At the same time, childbirth continues to grow in Africa and Asia, while the average woman in Niger gives birth to seven children during her lifetime.
Training the main factor
Ali Mokdad, a professor at IHME, says the most important factor for population growth is education.
If a woman educates herself, she spends more years at school, postpones her pregnancies, and therefore has fewer children, she says.
According to IHME, Cyprus is the least fertile country in the world – 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 grow, their economies are generally rising, which usually has a decreasing effect on childbirth over time.
Countries are expected to make it more economical and fertility is more likely to decrease and run out.
Increased service life
We also live more than ever. The expected global life expectancy for men has increased to 71 years from 48 in 1950. Women are now expected to live at 76 compared to 53 in 1950.
Heart disease is now the most common cause of death worldwide, says IHME. By 1990, there were newborn problems, followed by lung disease and diarrhea.
You see less mortality from infectious diseases as countries become richer but more disabilities because people live longer, says Ali Mokdad.
It notes that, although deaths from infectious diseases such as malaria and tuberculosis have declined significantly since 1990, new non-communicable diseases have occurred.
There are some behaviors that lead to more cases of cardiovascular disease and cancer. Obesity is the first – it grows every year and our behavior contributes to it, he says.