The findings, published in The BMJ today, identify important data gaps, particularly in low- and middle-income countries, and substantial geographical variation in loneliness, with northern European countries consistently showing lower levels compared with other regions.
While in recent years there has been an increase in research in this area in Australia, a lack of comparable data on loneliness did not allow for comparison with other countries. This highlights the need for Australia to approach loneliness as a public health issue and for extensive long-term surveillance to assess how widespread it is, especially given the impact of the COVID-19 pandemic.
Senior author Associate Professor Melody Ding from the University of Sydney said the study is important because existing evidence shows that loneliness not only affects mental health and wellbeing but is also linked to a range of physical health problems and early death.
“It’s a commonly held belief that around one in 12 people experience loneliness at a level that can lead to serious health problems, however, the source of such data are unclear and researchers have never established how widespread loneliness is on a global scale. That is why we were interested in conducting the review,” said Associate Professor Ding from the University’s Charles Perkins Centre and Faculty of Medicine and Health.
The team of Australian researchers set out to summarise the prevalence of loneliness globally to help decision makers gauge the scope and severity of the problem.
They trawled research databases and found 57 observational studies reporting national estimates of loneliness from 113 countries or territories during 2000-19.
The researchers used data available for adolescents (12-17 years) in 77 countries or territories,
young adults (18-29 years) in 30 countries, middle aged adults (30-59 years) in 32 countries, and older adults (60 years or older) in 40 countries.
There was notably more extensive data in high income countries (particularly Europe) compared with low- and middle-income countries.
Overall, 212 estimates for 106 countries from 24 studies were included in the meta-analysis. For adolescents, pooled prevalence of loneliness ranged from 9.2 percent in South-East Asia to 14.4 percent in the Eastern Mediterranean region.
For adults, meta-analysis was conducted for the European region only, and a consistent geographical pattern was found for all age groups.
For example, the lowest prevalence of loneliness was consistently seen in northern European countries (2.9 percent for young adults; 2.7 percent for middle aged adults; and 5.2 percent, for older adults) and the highest in eastern European countries (7.5 percent for young adults; 9.6 percent for middle aged adults; and 21.3 percent for older adults).
Data were also insufficient to make conclusions about trends of loneliness over time on a global scale, but the researchers point out that even if the problem of loneliness had not worsened during their search period (2000-19), COVID-19 might have had a profound impact on loneliness.
“We anticipate that COVID-19 and associated public health restrictions increased isolation for many people across the globe so this review will provide important baseline data for researchers to assess the impact of the pandemic on loneliness moving forward,” said lead author and University of Sydney PhD student Daniel Surkalim.
The authors acknowledge their review was subject to limitations, such as different sampling procedures and measures adopted by studies. They also note that the data gaps in low- and middle-income countries raise an important issue of equity.
However, considering the negative effects of loneliness on health and longevity, the authors say their findings reinforce the urgency of approaching loneliness as an important public health issue.
“Public health efforts to prevent and reduce loneliness require well-coordinated ongoing surveillance across different life stages and broad geographical areas,” they write.
“Sizeable differences in prevalence of loneliness across countries and regions call for in-depth investigation to unpack the drivers of loneliness at systemic levels and to develop interventions to deal with them.”
Declaration: The authors declare no competing interests. No funding was received.