This study examines how population aging shapes a crucial aspect of mental health and social well-being: loneliness. Drawing on theories of demographic metabolism, United Nations population estimates and projections, and survey data covering approximately 50 percent of the world's population aged 50 and above living in 27 countries, we estimate the role of population aging in shaping cross-national differences in loneliness from 1990 to 2050. We used survey data to estimate the prevalence of late middle age and older adult loneliness by age and sex and then applied these rates to the evolving age and sex distributions of the populations. Our results highlight massive increases in loneliness at ages 50 and above with a tripling of the number of lonely adults in these age groups in our sample countries from 104.9 million in 1990 to 333.5 million in 2050, increasing variability across countries in the share of their populations composed of lonely adults 50 and above, and the feminization of global later life loneliness with an increasing share of lonely adults in these age ranges being women. These results illustrate the power of demographic modeling to advance our understanding of national profiles of mental health and social well-being.

中文翻译：

---

世界各地的人口老龄化、人口新陈代谢以及中年晚期到老年人孤独感的上升趋势


这项研究探讨了人口老龄化如何影响心理健康和社会福祉的一个重要方面：孤独感。借鉴人口新陈代谢理论、联合国人口估计和预测，以及覆盖 27 个国家约 50% 的 50 岁及以上世界人口的调查数据，我们估计了人口老龄化在塑造跨国孤独感差异方面的作用， 1990年至2050年。我们使用调查数据按年龄和性别估计中年晚期和老年人孤独感的患病率，然后将这些比率应用于不断变化的人口年龄和性别分布。我们的研究结果突显了 50 岁及以上人群的孤独感大幅增加，样本国家中这些年龄段的孤独成年人数量从 1990 年的 1.049 亿增至 2050 年的 3.335 亿，增加了两倍，从而增加了各国人口比例的差异由 50 岁及以上的孤独成年人组成，全球晚年孤独感女性化，这些年龄段的孤独成年人中女性所占比例不断增加。这些结果说明了人口统计模型在增进我们对国民心理健康和社会福祉概况的理解方面的力量。