Fifty years have gone by since schoolchildren in Bogalusa began lining up outside a white trailer serving as makeshift clinic to collect health data. The purpose: to understand the connection between childhood health factors and the risk of developing heart disease.

Twelve hundred-plus studies later, the Bogalusa Heart Study has evolved beyond its initial focus. Now, researchers are peering into the middle-aged brains of those same Bogalusa children to draw connections between their childhoods and the aging brain.

“The heart-brain connection is where a majority of our research is going right now,” said Dr. Lydia Bazzano, principal investigator of the study and director of the Center for Lifespan Epidemiology Research at Tulane University. “That, and building technologies that can help improve heart and brain health and help detect brain changes early.”

The heart-brain connection

The brain and heart are intricately connected. In part, it’s a simple plumbing relationship, said Owen Carmichael, a brain health researcher at Pennington Biomedical Research Center in Baton Rouge. 

“You need nutrients to fuel brain activity,” said Carmichael. “The heart pumps the fuel in.”

The heart can also signal distress to the brain, such as when a person starts to develop heart disease, setting off inflammatory cytokines, a signal that deep trouble is afoot.

“It’s the heart saying, ‘Oh, crap, I’m in a bad way,’” said Carmichael. That causes the brain to go into overdrive, eating up toxins in a way Carmichael compares to the Incredible Hulk: combating threats but causing collateral damage. 

“The Incredible Hulk beats up the bad guys,” said Carmichael. “But in the process, he destroys a bunch of buildings that shouldn’t have been because he’s in a kind of a rage state. That’s the other side of the heart-brain connection.”

Already, the study has found how a child’s diet might affect the brain 50 years down the road. Carmichael’s analysis of MRI data revealed a pattern among those with blood sugar on the higher end of normal. 

“The ones who had higher blood sugar as children ended up having crummier-looking brains at age 50,” said Carmichael.

Those with worse-looking brains didn’t have blood sugar that was high enough for a pediatrician to flag. It wasn’t even high enough to be considered prediabetes. But it did show up decades later, when Carmichael’s team watched patterns of blood flow in the brain while participants tried to complete tests that measure how fast and flexible their minds were. Those with higher blood sugar has less vigorous blood flow. 

Technology’s impact

As the study has evolved, so has technology. PET scans allow researchers to see how much build-up there is of amyloid, the protein that forms in clumps in the brains of Alzheimer’s patients.

Participants who once used pencil and paper to fill out cognitive tests now use iPads, which can measure how long it takes someone to draw a clock, a standard cognitive test of executive functioning and how much pressure they use to bear down on the screen.

Joe Culpepper, Bogalusa’s retired police chief who now works as the department’s evidence officer, has been in the study for most of his life.

“We used to wait on them to pull up that house trailer and set it up,” said Culpepper, 61. “We knew we were gonna get out of class for a while.”

Culpepper recalled when biometrics like height, weight, and blood pressure were recorded based on a color-coded piece of yarn participants were given as kids. Now, his data is collected through a watch and an app that directs participants as they complete tasks. 

“I had to walk up and down the driveway, and do some weird math,” said Culpepper. “It was like trying to walk and chew bubblegum at the same time.”

The participants are mostly in their 50s, long before most show symptoms of Alzheimer’s disease or dementia. But they hope what they find will help predict how circumstances over the course of a lifetime contribute to brain disease so that they can one day stop it in its tracks. About 5% of participants who have gotten brain scans have signs of amyloid, the protein that forms into clumps in the brains of Alzheimer’s patients, though it’s too early to tell who might develop symptoms of the disease.

“We don’t expect that anybody has Alzheimer’s disease,” said Bazzano. “But kind of in the same way that in the 1970s people weren’t expecting the children had the origins of heart disease, really, midlife is definitely a critical period for the origins of Alzheimer’s disease.”