Everton defender Jake O'Brien is the only Type One diabetic playing in the Premier League - and he has offered an insight into his remarkable story.

O'Brien's body can't produce insulin, the hormone that regulates the amount of glucose in your blood. He has a circular device on his arm linked to an app on his phone via Bluetooth that reads his blood sugar levels.

The Republic of Ireland defender will take out a needle and inject the necessary insulin dose into his thigh or stomach, which can often come as a shock to his teammates.

"One or two are taken aback at first," O'Brien, who joined Everton from Lyon in 2024, said in an interview with the Daily Mail. "It can be a bit confusing. “What’s he doing?’’ Or maybe those who are a little squeamish, but they soon get used to it. It's only a small needle."

Jake O'Brien was once 'one day' away from coma

Having come up through the ranks at Cork City, the 25-year-old has since established himself as a solid Premier League defender under David Moyes, primarily playing as a towering centre-back but also filling in at right back when needed.

But O'Brien was once almost denied a career at the top level before his journey had properly started. While tracking glucose levels is now a part of his everyday routine, his life was put in jeopardy before his diagnosis at the age of 16.

The Irishman had extreme tiredness, was losing weight, and had an insatiable thirst despite drinking eight to nine litres of water a day. He had lost seven kilograms in just over a week, and his blood test revealed his blood sugar was 10 times what was considered stable.

"I was told I was a day away from a coma," says O'Brien. "If I had gone to sleep that night without having gone to the doctor, who knows?"

The then-teenager, who had won national titles at boxing and hurling, went into hospital weighing 53kg and, by two weeks post-diagnosis, had put on 7kg before packing on another 30kg within two years.

"Yeah, 30kg, I know it's not normal," he continued. "It must have been some grocery bill for Mum, but I was motivated to put on the weight, going to the gym all the time.

"I was a bit naive about it all. I never expected to have anything, but once I knew what diabetes was, I didn’t wallow in it; I took it as a positive. Everything just clicked for me physically. I just thought, 'Right, now I know what’s wrong; I can get on with my life again."

Jake O'Brien addresses Everton exit rumours

Standing at an imposing 6ft 6 these days and weighing around 96kg, O'Brien's physical attributes have allowed him to excel in the Premier League when he's played his natural centre-back position.

David Moyes currently prefers a defensive partnership of James Tarkowski and Jarrad Branthwaite, leaving the Irishman being shoehorned into right-back.

He spent most of last season in that position when Moyes was without a natural right-back and now shares the responsibility with Ainsley Maitland-Niles, who joined from Lyon on deadline day.

Some have thought that O'Brien would have felt frustration over being used out of his strongest position, fuelling rumours of him possibly leaving the Hill Dickinson Stadium.

According to the man himself, that was never the case. "There was nothing in that. I was never close to leaving," he confirmed.

"People know I'm not a natural right back but I'll play wherever I need to, to help the team. We're only a small squad so it’s important everyone chips in.

"There’s a lot of different right backs. I see Arsenal have centre backs playing at right back so I can take pointers from them but then again, I am 6ft 6in so I’m not the average shape."

O'Brien is currently away on international duty with the Republic of Ireland and is likely to start when they travel to Austria in the Nations League, coincidentally on World Diabetes Day.