Nick Jonas
Nick Jonas reflects on 21 years with diabetes, revealing resentment, hard lessons and unexpected friendships @nickjonas/Instagram

Nick Jonas has laid bare the emotional toll of living with type 1 diabetes, admitting in a new open letter that 'part of me resents you' after 21 years of managing the condition.

The Jonas Brothers singer, 34, who was diagnosed with type 1 diabetes at 13, shared the essay this week in the United States through A Letter to Diabetes, an initiative run by glucose monitor maker Dexcom.

'Hello, old friend. How long has it been? Twenty-one years. Twenty-one years, and you haven't changed a bit,' he began.

'Hundreds of Little Decisions' With Diabetes

Jonas described checking his glucose levels on his phone every few minutes and reaching for his insulin pump to deliver a dose before eating something containing 17 carbohydrates.

He called these 'a couple of the hundreds of little decisions I make every week', most of which go unseen by those around him. Living with the condition, he wrote, had become 'an ongoing conversation between your body, your mind, and your devices'.

He said there were days when he and his diabetes felt 'on the same team', when his readings were steady and the technology behaved. On others, he wrote, the condition went 'on a solo mission', however careful he was.

Jonas was diagnosed in 2005, as he and his brothers Joe and Kevin were forming the band that would bring them global fame. He made the diagnosis public two years later at a Carnival for a Cure concert, asking fans with diabetes to raise their hands.

Jonas, who co-founded the charity Beyond Type 1 in 2015, has long worked with Dexcom, whose sensors let people track their glucose levels continuously. He is also a paid spokesperson for the company.

Type 1 diabetes is a lifelong autoimmune condition in which the body produces little or no insulin, the hormone that regulates blood sugar, so people with it need insulin for life.

Nick Jonas on Control, Belonging and Type 1 Diabetes

'I'd built my whole life around this unrealistic structure and belief that I was in control. You took that apart over the years, bit by bit,' he wrote, addressing the condition directly.

He continued: 'Part of me is grateful I learned that lesson. Part of me resents you for it. Full stop. There are days I wonder what life would feel like without you.'

Jonas wrote that he had 'always struggled to feel like I belonged anywhere' and felt 'misunderstood' at school, having juggled lessons with life as a child performer.

He said that changed through community. 'It wasn't until I started talking openly about life with type 1, and meeting other people who were living it too, that I finally felt like I belonged somewhere,' he wrote.

'I never wanted to be a victim, or to come across like one,' he added. Instead, he framed his openness as a duty, imagining 'the 13-year-old who just got diagnosed and is lying in a hospital bed, scared to death'.

He wants that child to see 'someone out there living their dreams while managing all of this, every single day'.

Jonas closed by thanking his 'old friend' for 'the lessons I never asked for' and pledging to keep speaking honestly about his diabetes so that 'someone out there feels a little less alone'.