It’s a Northeastern state famed for its lobster rolls and peaceful lifestyle. But data shows Maine has quietly become a hotspot for type 1 diabetes.
New state-by-state data reveals the state has the highest incidence rate in the nation at 27.4 per 100,000, significantly above the national average of 24.0.
Nationwide, Vermont, New Hampshire and West Virginia also ranked among the top five, while the lowest rates are found in Hawaii, New Mexico and California.
Most diabetics in the US have type 2 diabetes, which is when the body is no longer able to control blood sugar levels because cells no longer respond to the hormone insulin.
But more people are now being diagnosed with type 1 diabetes, where the body no longer makes insulin, often because the immune system has mistakenly destroyed insulin-producing cells.
The exact cause of type 1 diabetes is unclear. But researchers warn that genetics, being from a white ethnic background and exposure to viruses and other environmental factors may play a role.
Now, researchers in New York have analyzed state-level population data to establish which areas of the country have the highest rates of the disease.
Nationwide, an estimated 2.07 million Americans are now living with the condition, a number projected to grow by 10 percent by 2033.
More than 60,000 people are diagnosed with the disease every year, with half of all new cases now diagnosed in adults, most commonly in those 45 to 64 years old.
The latest data, published in JAMA Network Open, analyzed incidence rates – number of cases newly diagnosed – for type 1 diabetes nationwide in 2024.
Data was converted to cases per 100,000 people to allow for comparisons between states, which have different population sizes.
By state, West Virginia recorded the highest incidence rate at 27.8 per 100,000, followed closely by Maine and Vermont, both at 27.4.
New Hampshire, with 26.9, and Kentucky – 26.8 – rounded out the top five.
Researchers caution, however, that West Virginia’s figure is based on a smaller population, and that Maine and West Virginia are statistically tied.
At the other end of the scale, Hawaii had the lowest incidence rate at just 17.0 per 100,000. New Mexico’s rate was 20.5.
California, at 20.6, also ranked among the lowest, along with Alaska, with 20.9, and Arizona with 22.5.
Separate data on the prevalence for type 1 diabetes – the total number of people living with the disease – in 2024 showed that California and Texas had the highest rates.
These states also have the largest overall patient populations.
The researchers did not speculate on why certain states had higher rates for type 1 diabetes compared to others.
In the paper, the scientists added that their results showed that more pediatric endocrinologists were needed across the country.
More than 70 percent of type 1 diabetes cases have been diagnosed in white adults, while 15 percent are in Hispanic individuals and 10 percent are in Black and Asian individuals.
Maine has the highest proportion of adults from a white ethnic background in the US, according to statistics, which make up 90 percent of its population, followed by West Virginia and Vermont, both at 89 percent.
At the other end of the scale, Hawaii has the lowest proportion of adults from a white ethnic background, 21.6 percent, followed by California, 35 percent.
It is not clear why individuals from a white ethnic background may be more likely to develop type 1 diabetes than those in other groups, but researchers say it may be down to a genetic mutation.
White adults are more likely to have a mutation on the HLA-DR3 or HLA-DR4 genes, which are linked to autoimmune disease, which scientists say may raise the likelihood of the immune system misfiring and destroying insulin-producing cells, causing the condition.
Some environmental exposures have also been linked to the condition.
A landmark 2025 study found that 83 percent of people with type 1 diabetes showed signs of an infection with enteroviruses, a group of viruses that cause colds, pink eye and polio.
They suggested the virus does not directly cause diabetes but may act as a trigger in genetically susceptible people.
Another theory is that overly clean environments and reduced exposure to microbes in early life can disrupt immune system development, increasing the risk of autoimmune diseases.
A 2025 mouse study found that antibiotic exposure during a critical developmental window stunted growth of insulin-producing cells, while a specific fungus – Candida dubliniensis – found in healthy infants promoted beta-cell growth and reduced diabetes risk.
Higher type 1 diabetes rates at greater distances from the equator point, such as Maine, to vitamin D deficiency as a potential factor.
Vitamin D has immunosuppressive effects, and deficiency may allow the autoimmune response to proceed unchecked. Evidence on supplementation is mixed, but some studies suggest higher sun exposure or vitamin D sufficiency during pregnancy or early life may lower risk.
Obesity and insulin resistance may accelerate beta-cell destruction, known as the accelerator hypothesis. Environmental chemicals like phthalates and heavy metals, which can disrupt immune function and hormone systems, are also under investigation.
