George Lizon, General Director of Oxford Institute for Population Ageing, told The BBC: "All social planning is based on the size of the population and the younger structure, and it is still unclear.
The Washington Institute of Health and Evaluation Institute of Washington (IHME) study published in The Lancet and compares health around the world between 1950 and 2017.
Nearly half of the universe In Europe, North and South America, there is insufficient number of countries that help to increase the population. There will be great consequences when locals get more in "grandmothers and grandmothers" than grandchildren.
The results for the researchers were "awesome," BBC reported.
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From 1950 the birth rate in the world decreased almost twice: from 4.7 children per woman to 2.4 per woman in 2017. However, researchers write. The average birth weight of seven babies living in Niger and in Africa and Asia is growing.
According to IHME, Cyprus is the most valuable fertile country in the world – an average Cypriot woman brings a child in her life. On the other hand, the average number of women in Mali, Chad and Afghanistan is equal to six children.
According to Professor of International University of Economics Ali Mokdad, the most important factor for population growth is knowledge.
"If a woman teaches herself, she will spend more time at school, postpone her pregnancy, and have fewer children," she says.
Mokdad says population in developing countries is rising, so their economy is increasing, which usually affects births over time.
"Countries are expected to improve economically, and, above all, fertility reduces and falls further.
It is important that the average birth rate in the country reaches 2.1 children per woman. Then the delivery begins. When the research began in 1950, no country has reached that point.
"In half of the world, we have reached a low flow rate of fertility, so if there is nothing, the population declines in these countries. These are great changes, says Prof. Christopher Murray of IHME.
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In many wealthiest countries, fertility declines do not mean that this is what the people do, because the people of the country are birth, death, and immigration. It may also be desirable for generations to come before the change is observed, but as the researchers say, because many countries have a good economy, the phenomenon is widespread.
We live until the moment we live. Expected global life expectancy for men increased from 48 to 71 in 1950. Women are now expected to live up to 53, 76 in 1950.
Heart disease today The most common cause of global mortality is the IHME. At the end of the 1990s there were neonatal problems, including lung disease and diarrhea.
"Countries are less likely to die from infectious diseases because people are serious, but they have more disabilities because people live longer," said Ali Mokdad.
It has been taking newborn infections since 1990, in spite of a significant reduction in mortality from infectious diseases such as malaria and tuberculosis.
– There are certain behaviors that lead to cardiovascular disease and malignant neoplasms. Obesity is the first figure – it grows every year and our behavior influences it, he says.
If development does not deteriorate, we have a few children, but the population of a very young age increases.
There are three things the country can do to counter the effects of the poor: researchers: immigration, women's political reform and retirement.
None of these measures were successful, but the study.
Countries that have migratory migration have struggled with social and political difficulties, blockages to increase the birth rate have not had a significant impact on fertility women and have often been met with protests against high retirement age.
Migration, from youth According to the research, poor countries are moving to richer countries, and at the global level.
George Lizbon is still optimistic and believes he does not need to solve the problem of aging if it is adapted to society.
Demography influences all aspects of our lives; traffic, living, consumption. All this is about demography, but we need to plan the changed structure, which we are still unaware of, "he told the BBC.
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