Jordan Tewhaiti-Smith used his gang connections to organise a study into the health of the Mongrel Mob.

A young Māori medical student used his family's gang connections for a ground-breaking new study on the health of the Mongrel Mob.

Dozens of Mongrel Mob members, affiliates and extended family were assessed on the health of their liver by University of Otago researchers.

That included Jordan Tewhaiti-Smith, now a fifth-year medical student based in Wellington, who utilised his family connections to organise the ground-breaking study.

Lawrence Smith/Stuff Growing up around gang members was a "normal" part of Tewhaiti-Smith's childhood.

His father and three of his uncles were Mongrel Mob members, and his connection paved the way for the research, published in the Royal Society Open Science on Wednesday.

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​The study, which included 52 Mongrel Mob Notorious gang members from Dunedin, Lower Hutt and Turangi, found New Zealand's largest gang's high incarceration rate, common intravenous drug use, and uncertified tattooing put them at a higher risk of contracting Hepatitis C.

"Nothing surprised me, because I grew up with this, but some of the rest of the team expressed surprise at how welcomed they were," Tewhaiti-Smith told Stuff.

He said his family moved from Martinborough to Dunedin when he was about 9-years-old to be closer to Otago University.

"I was raised quite well by my parents and they put us first. It wasn't forced on me but it was expected that I take it [education] seriously."

His interest in medicine grew from his exposure to hospitals as a child, he said. His grandparents were "always quite sick" and two of his younger sisters, now in primary school, spent about five months in a neonatal intensive care unit (NICU).

"It was pretty touch and go whether they were going to survive at some stages.

"The team in the NICU were just so cool. That's what persuaded me to do it, because they were really cool and put us at ease."

While the study was "challenging" to help organise, that was only due to logistics rather than any trouble from the gang members, Tewhaiti-Smith said.

It was important to do brief health interventions, not just for the gang members but for their whanau to "plant the seed, even if they are small".

"It is quite crazy because this research is the first of its kind, that we know."

And despite some initial hesitancy, the health checks ended up feeling "normal and natural" for the visiting researchers and participants.

Head of the Department of Medicine, associate professor Dr Michael Schultz, said the research provided a unique opportunity to study a group considered to be hard-to-reach and marginalised.

While no cases of hepatitis C were found, two carriers of hepatitis B were identified.

Schultz, from Germany, told Stuff he was "greatly apprehensive" before beginning the research.

"What I knew about the Mongrel Mob was what everyone knows, drugs, violence and shooting, these kind of things."

However meeting Tewhaiti-Smith changed that perspective, he said.

"He really opened the door."

The only difference in the research was having to arrange a neutral spot to conduct the research, or "on their turf".

"That was the only condition."

He recalled one moment when a member of a rival gang turned-up, and the Lower Hutt room went quiet.

"But when he left everyone went back to their normal activities."

The group was also found to have more than two times higher obesity rates than the general population.

"Given that about 35 per cent of the group visited their GP less than once every five years, they are highly concerning findings," Schultz said.

Perhaps of most concern was the "marginal" knowledge the study participants had about viral hepatitis, averaging 43.3 per cent compared to 59.4 per cent in the general population.

The researchers found a significant link between lack of knowledge and risky infection behaviours among the group.

They also identified several areas of concern about the general liver health of the group: participants displayed three times higher rates of liver inflammation and damage compared to the general population.

A fifth had significant to severe levels of liver fibrosis and cirrhosis, and exceptionally high levels of alcohol consumption, in both frequency and quantity.

The planning behind the research was not easy, but "everybody was really open, interested, and asked questions", Schultz said.

"We felt welcome, not threatened at all.