Dunedin Multidisciplinary Health and Development Study

The Dunedin Multidisciplinary Health and Development Study (also known as the Dunedin Study) is a detailed study of human health, development and behaviour. Based at the University of Otago in New Zealand, the Dunedin Study has followed the lives of 1037 babies born between 1 April 1972 and 31 March 1973 at Dunedin's former Queen Mary Maternity Centre since their birth. Teams of national and international collaborators work on the Dunedin Study, including a team at Duke University in the United States. The research is constantly evolving to encompass research made possible by new technology and seeks to answer questions about how people's early years have an impact on mental and physical health as they age.

The study is now in its fifth decade and has produced over 1300 publications and reports, many of which have influenced or helped inform policy makers in New Zealand and overseas; many of these can be found on the publications section of their website.

History
The Dunedin Study was the idea of psychology student Phil Silva, who worked on a neonatology survey involving 250 children with learning and behavioural issues. He identified that 10% had significant problems that had previously been undiagnosed, a topic that he researched in his 1978 doctoral thesis. He realised that a larger sample size was needed; this resulted in the Dunedin Study. The original pool of study members was selected from children born at the Queen Mary Maternity Centre in Dunedin who were still living in the wider Otago region three years later. In early years the study was not well funded and the local community helped collect data. The study members include 535 males and 502 females, 1013 singletons and 12 sets of twins. At the age 38 assessment, only one-third of members still resided in Dunedin; most of the remainder lived elsewhere in New Zealand and Australia. Study members were assessed at age three, and then at ages 5, 7, 9, 11, 13, 15, 18, 21, 26, 32, 38 and, most recently, at age 45 (2017–2019). Future assessments are scheduled for age 52. Silva directed the study until he retired from the role in 2000. Professor Richie Poulton was the study's director from 2000 to 2023, and was succeeded by Associate Professor Moana Theodore. She first worked for the study as an assistant in 1998, and returned in 2010 to work with Poulton.

During an assessment, study members are brought back to Dunedin from wherever in the world they live. They participate in a day of interviews, physical tests, dental examinations, blood tests, computer questionnaires, and surveys. Sub-studies of the Dunedin Study include the Family Health History Study which involved the parents of Dunedin Study members to find out about the health of family members (2003–2006); the ongoing Parenting Study which focuses on the Dunedin Study member and their first three-year-old child; and the Next Generation Study which involves the offspring of Dunedin Study members as they turn 15 and looks at the lifestyles, behaviours, attitudes, and health of today's teenagers. It aims to see how these have changed from when the original Study Members were 15 (in 1987–88). This means that information across three generations of the same families will be available.

Great emphasis is placed on retention of study members. At the most recent (age 45) assessments, 94% of all living eligible study members, or 961 people, participated. This is unprecedented for a longitudinal study, with many others worldwide experiencing more than 40% drop-out rates.

The resulting database has produced a wealth of information on many aspects of human health and development. over 1,200 papers, reports, book chapters and other publications have been produced using findings from the study. The multidisciplinary aspect of the study has always been a central focus, with information ranging across:
 * Cardiovascular health and risk factors
 * Respiratory health
 * Oral health
 * Sexual and reproductive health
 * Mental health
 * Psychosocial functioning
 * Other health, including sensory, musculo-skeletal, and digestive

A book, From Child to Adult: Dunedin Multidisciplinary Health and Development Study, was published in 1996 and aimed at presenting the major findings in a form accessible to the non-specialist. It only includes information up to the age-21 assessment. Future plans for the Dunedin Multidisciplinary Health and Development Study include another popular science book, upgrading their website for more non-specialist appeal, and introducing more resources for the general public.

This study was awarded the 2016 Prime Minister's Science Prize. In 2022 it was awarded the Royal Society Te Apārangi's Rutherford Medal.

Findings
The Dunedin Study has found that walking speed is related to small brain differences, that the speed of ageing of one's brain relates to their general speed of ageing, a link between the amount of white matter hyperintensities and a person's rate of cognitive decline, that there are differences in brain structure of people with and without antisocial behaviour in their teenage/young adult years, a link between IQ and brain size; the correspondence of brain structure with poor mental state, cardiovascular fitness, lead exposure, difficult childhoods, childhood self-control, and cannabis use. They have also found that children experiencing social isolation between the ages of 5 and 11 were more likely to have poor cardiovascular health, and increased age-related cognitive decline compared to those who were not socially isolated.

The Dunedin Study has also suggested that poor mental health can cause poor physical health, and increased rates of ageing.