Changes in loneliness prevalence in Denmark in the 21st century: Age-period-cohort analysis.

Aim: The aim of this study was to investigate changes in the prevalence of loneliness in Denmark from 2000 to 2021 by conducting age-period-cohort analysis. Methods: Our study was based on a sample (N =83,437; age: ⩾16 years) of the Danish Health and Morbidity Surveys conducted in Denmark in 2000, 2005, 2010, 2013, 2017 and 2021. We used logistic regression models by gender to estimate the age-period-cohort effects, with loneliness as the dependent variable and age, survey year and birth cohort as independent variables, mutually adjusted. Results: The prevalence of adult loneliness increased by each survey year over the entire period (from 13.2% in 2000 to 27.4% in 2021 among men and from 18.8% to 33.7% among women). Overall, a U-shaped curve, for the prevalence of loneliness among different age groups, was observed, which was most pronounced among women. The greatest increase in the prevalence of loneliness from 2000 to 2021 was observed among the youngest age group (16–24 years), with 28.4 and 30.7 percentage points for men and women. No significant cohort effect was observed. Conclusions: The observed increase in loneliness prevalence from 2000 to 2021 was driven by period and age effects rather than cohort effects. It should be noted that data from 2021 were collected during a national lockdown due to an outbreak of COVID-19, which could explain part of the large increase in loneliness from 2017 to 2021. [ABSTRACT FROM AUTHOR]