The Dunedin Study - DMHDRU

What are our main findings so far?

Are brain-structure and walking speed related? We compared the speed at which people walk (measured on the long walkway upstairs) to several different measurements of the brain from the structural MRI scans. It turns out that there are slight structural brain differences, on average, between people with different walking speeds. (See publication)

Is “biological age” seen in the brain as well as the rest of the body? By comparing the structural MRI data with estimates of “biological age” (measured using 19 different things from heart to gum health) we showed that the speed of aging of a person’s brain is related to their speed of aging in general, and to their rate of cognitive decline as they get older. (See publication) 

What do spots (hyperintensities) in the MRI scans mean? We used one of the structural MRI scans to look for spots in the brain called White Matter Hyperintensities (WMHs). Accumulation of WMHs is a normal part of aging - virtually all Study members had some detected in their scans. We also found a statistical link between how many WMHs a person has and their rate of cognitive decline as they got older. (See publication) 

Is antisocial behaviour reflected in the brain? Our data on antisocial behaviour going back to Study members’ teenage years allowed us to show that there are differences in average brain structure between people who have displayed antisocial behaviour (e.g., fighting, theft, property destruction) throughout their lives, those who only did so when they were teenagers/young adults, and those who have never engaged in any. (See publication) 

Can a bigger brain explain higher IQ and education? By using a combination of the structural MRI scans and other data we showed that the link between IQ and level of education is partly related to brain size. (See publication) 

Is poor mental health seen in the brain? In two papers we used the structural scans to look at the relationship between mental health and brain structure. We found that differences in mental health between people (e.g., having one vs multiple mental health issues) were also reflected in differences in brain structure.  

Does cardiovascular fitness affect brain structure? We know that getting physical exercise is good for us in lots of different ways, including for our cardiovascular system.  But what about for our brains?  We found that cardiovascular fitness does seem to be linked to brain structure, and that cardiovascular fitness may in fact influence brain structure. (See publication) 

What effect does lead have on the brain?  When the Study members were children petrol still contained lead. So we wondered what effect childhood exposure to lead had on the brain at age 45.  By using Study members’ childhood data we found that the amount of lead in the blood during childhood is connected to both grey- and white-matter brain structure. (See publication) 

Do we have any advice for other MRI researchers? The papers described so far have all used the MRI data to study the relationship between people’s brains and other aspects of their health and lives. But in two of the papers we took a different approach and used the MRI data to try to improve the way in which MRI research is done. The first paper used both the resting-state scan (the fMRI scan that measured brain activity when your brain was not concentrating on doing something) and the fMRI scans done while you played the games. We found that combining these different data sets gave a better way to measure networks in the brain (in which different parts of the brain become active at the same time) than normally used by researchers. The second paper used the data from the fMRI game scans to show that when a small number of Study members were scanned a second time (see question 10) the fMRI data were not as consistent with their first scan as we had expected. These are both important findings for how we and other researchers will use fMRI scans in the future.

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