Abstract
The Septuagenarian, Octogenarian, Nonagenarian Investigation with Centenarian (SONIC) study was established considering population trends and targeting the oldest-old population. This study is unique in its narrow age range, consisting of individuals aged in their 70s, 80s and 90s, and is carried out as a longitudinal cohort study with follow ups every 3 years in urban and rural areas of eastern and western Japan. The aims of the SONIC study are primarily to clarify aging-related changes in multiple domains of human functioning, explore the dynamics of interactions among these domains and identify factors influencing healthy longevity, including psychological well-being. Investigations spanning medical, dental, nutritional, psychological and sociological fields were carried out by specialists, yielding important results. Findings from the SONIC study in Japan, a super-aged society, will provide valuable information for addressing the global aging trend. This review introduces the results from the SONIC study, and explains factors contributing to healthy longevity and happy aging. Geriatr Gerontol Int 2025; 25: 346-355.