The HPP was a component of the larger NI-HON-SAN Study. The HHP investigated the environmental and biological causes of cardiovascular disease among Japanese Americans living in Hawaii in the United States of America. Participants included approximately 8,000 American men of Japanese ancestry born between 1900 and 1919, aged 45 to 68 years at recruitment and living on the island of Oahu in Hawaii in 1965. Baseline assessments were conducted from 1965 to 1968. Participants completed follow-up examinations in 1967 to 1970, 1971 to 1974, and 1991 to 1993, as well as three sub-examinations between 1970 and 1982. Participants were followed up for mortality until 2014 as part of the Hawaii Lifespan and Healthspan Study. At the fourth HHP examination between 1991 and 1993, the HHP was expanded to the Honolulu-Asia Aging Study (HAAS) to encompass the investigation of cognitive ageing, depressive symptoms, and dementia, which is ongoing. Several sub-studies are being conducted, such as the HHP Offspring Study, and offspring of participants were also assessed as part of the ERA JUMP Study.