AIM: This study depicts the age trajectories of loneliness and gender differences among older adults in Taiwan and Japan. METHODS: Two nationally representative data sets for older adults in Taiwan and Japan were obtained from the Taiwan Longitudinal Study on Aging (TLSA, 1996-2011) and the National Survey of the Japanese Elderly (NSJE, 1996-2012), respectively. The analytic sample included 3037 and 1974 older adults aged 65 and over at baseline in Taiwan and Japan, respectively. RESULTS: The prevalence rate of loneliness for adults aged 65+ living in the community was 23.64% in Taiwan and 17.03% in Japan. Higher average levels (β CONCLUSIONS: Lonliness in old age is very different between men and women. Women's loneliness curve shows an inverted U state: Although they feel more lonely than men during midlife, it has a downward trend as they get older. On the contrary, men's loneliness curve shows an upward U-shaped curve: After retirement, both Japanese and Taiwanese men continue to rise. Geriatr Gerontol Int 2025
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