@article{3106894,
    title = "Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017",
    author = "Murray, C.J.L. and Callender, C.S.K.H. and Kulikoff, X.R. and Srinivasan, V. and Abate, D. and Abate, K.H. and Abay, S.M. and Abbasi, N. and Abbastabar, H. and Abdela, J. and Abdelalim, A. and Abdel-Rahman, O. and Abdi, A. and Abdoli, N. and Abdollahpour, I. and Abdulkader, R.S. and Abebe, H.T. and Abebe, M. and Abebe, Z. and Abebo, T.A. and Abejie, A.N. and Aboyans, V. and Abraha, H.N. and Abreu, D.M.X. and Abrham, A.R. and Abu-Raddad, L.J. and Abu-Rmeileh, N.M.E. and Accrombessi, M.M.K. and Acharya, P. and Adamu, A.A. and Adebayo, O.M. and Adedeji, I.A. and Adekanmbi, V. and Adetokunboh, O.O. and Adhena, B.M. and Adhikari, T.B. and Adib, M.G. and Adou, A.K. and Adsuar, J.C. and Afarideh, M. and Afshin, A. and Agarwal, G. and Agesa, K.M. and Aghayan, S.A. and Agrawal, S. and Ahmadi, A. and Ahmadi, M. and Ahmed, M.B. and Ahmed, S. and Aichour, A.N. and Aichour, I. and Aichour, M.T.E. and Akanda, A.S. and Akbari, M.E. and Akibu, M. and Akinyemi, R.O. and Akinyemiju, T. and Akseer, N. and Alahdab, F. and Al-Aly, Z. and Alam, K. and Alebel, A. and Aleman, A.V. and Alene, K.A. and Al-Eyadhy, A. and Ali, R. and Alijanzadeh, M. and Alizadeh-Navaei, R. and Aljunid, S.M. and Alkerwi, A. and Alla, F. and Allebeck, P. and Almasi, A. and Alonso, J. and Al-Raddadi, R.M. and Alsharif, U. and Altirkawi, K. and Alvis-Guzman, N. and Amare, A.T. and Ammar, W. and Anber, N.H. and Andrei, C.L. and Androudi, S. and Animut, M.D. and Ansari, H. and Ansha, M.G. and Antonio, C.A.T. and Appiah, S.C.Y. and Aremu, O. and Areri, H.A. and Arian, N. and Ärnlöv, J. and Artaman, A. and Aryal, K.K. and Asayesh, H. and Asfaw, E.T. and Asgedom, S.W. and Assadi, R. and Atey, T.M.M. and Atique, S. and Atteraya, M.S. and Ausloos, M. and Avokpaho, E.F.G.A. and Awasthi, A. and Ayala Quintanilla, B.P. and Ayele, Y. and Ayer, R. and Ayuk, T.B. and Azzopardi, P.S. and Babalola, T.K. and Babazadeh, A. and Badali, H. and Badawi, A. and Bali, A.G. and Banach, M. and Barker-Collo, S.L. and 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Vos, T. and Vosoughi, K. and Vujcic, I.S. and Wagnew, F.S. and Waheed, Y. and Walson, J.L. and Wang, Y. and Wang, Y.-P. and Weiderpass, E. and Weintraub, R.G. and Weldegwergs, K.G. and Werdecker, A. and Westerman, R. and Whiteford, H. and Widecka, J. and Widecka, K. and Wijeratne, T. and Winkler, A.S. and Wiysonge, C.S. and Wolfe, C.D.A. and Wu, S. and Wyper, G.M.A. and Xu, G. and Yamada, T. and Yano, Y. and Yaseri, M. and Yasin, Y.J. and Ye, P. and Yentür, G.K. and Yeshaneh, A. and Yimer, E.M. and Yip, P. and Yisma, E. and Yonemoto, N. and Yoon, S.-J. and Yotebieng, M. and Younis, M.Z. and Yousefifard, M. and Yu, C. and Zadnik, V. and Zaidi, Z. and Zaman, S.B. and Zamani, M. and Zare, Z. and Zeleke, M.M. and Zenebe, Z.M. and Zerfu, T.A. and Zhang, X. and Zhao, X.-J. and Zhou, M. and Zhu, J. and Zimsen, S.R.M. and Zodpey, S. and Zoeckler, L. and Lopez, A.D. and Lim, S.S. and GBD 2017 Population and Fertility Collaborators",
    journal = "The Lancet Neurology",
    year = "2018",
    volume = "392",
    number = "10159",
    pages = "1995-2051",
    publisher = "The Lancet Publishing Group",
    doi = "10.1016/S0140-6736(18)32278-5",
    keywords = "adolescent;  adult;  age;  Article;  child;  cohort analysis;  controlled study;  demography;  female;  fertility;  human;  infant;  live birth;  male;  migration;  mortality;  newborn;  population;  prediction;  priority journal;  reproduction;  sex;  aged;  birth rate;  global disease burden;  global health;  maternal age;  middle aged;  population density;  population growth;  preschool child;  statistics and numerical data;  trends;  young adult, Adolescent;  Adult;  Aged;  Birth Rate;  Child;  Child, Preschool;  Female;  Global Burden of Disease;  Global Health;  Humans;  Infant;  Infant, Newborn;  Male;  Maternal Age;  Middle Aged;  Mortality;  Population Density;  Population Growth;  Young Adult",
    abstract = "Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation. © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license"
}