While excess calories, junk food, and lack of exercise certainly play a major role in the increasing prevalence of type 2 diabetes, prevalence has also increased along with chemical production. While correlation does not prove causation, these trends could be related.

While excess calories, junk food, and lack of exercise certainly play a major role in the increasing prevalence of type 2 diabetes, prevalence has also increased along with chemical production. While correlation does not prove causation, these trends could be related.

Both the incidence and prevalence of type 1, type 2, and gestational diabetes has increased over the past decades, worldwide. There is some evidence of recent plateaus in some countries.

This page looks at these trends in more detail, focusing on type 1 diabetes, and includes information on ethnicity, age, gender, seasonality, and geography, as well as type 1 diabetes clusters-- yes, clusters do exist.

None of the environmental factors linked to type 1 diabetes so far appear to be able to explain the increasing incidence trends ( Norris et al. 2020 ), except, I would argue, environmental chemical exposures.

For the most current information on the number of people with type 2 diabetes around the world, see the International Diabetes Federation Diabetes Atlas . Here are some numbers:

In the U.S., subgroups within various racial groups also have a differing prevalence of type 2 diabetes. In a sample of U.S. adults, the prevalence of total diabetes was 12% for non-Hispanic whites, 20% for non-Hispanic Blacks, 22% for Hispanics, and 19% for non-Hispanic Asians. Among Hispanic adults, the prevalence of total diabetes was 25% for Mexicans, 22% for Puerto Ricans, 21% for Cuban/Dominicans, 19% for Central Americans, and 12% for South American subgroups. Among Asians, the prevalence of total diabetes was 14% for East Asians, 23% for South Asian, and 22% for Southeast Asian subgroups. The prevalence of undiagnosed diabetes was 4% for non-Hispanic whites, 5% for non-Hispanic Blacks, 8% for Hispanics, and 8% for Asians ( Cheng et al. 2019 ).

Really. In Texas, perhaps the youngest person ever to develop type 2 diabetes was 3 1/2 years old. It was caught early and reversed with dietary changes and metformin ( Yafi et al. 2015 ). Also in Texas, a 5 year old was also diagnosed with type 2 diabetes ( Hutchins et al. 2017 ). While these cases are rare enough to merit publication as case studies, the trend is alarming!

In the U.S., racial minority groups tend to have the highest incidence of type 2 diabetes. The cause of these differences is not known; certainly diet, an unsafe environment, poverty, and lifestyle could play a role, as could exposure to environmental chemicals ( Golden et al. 2019 Sargis and Simmons, 2019 ). In the U.S., racial minority groups tend to develop type 2 diabetes at a lower body weight (BMI) than whites ( Zhu et al. 2019 ).

In U.S. youth, the latest data show that the prevalence of type 2 diabetes increased by over 30% between 2001 and 2009 ( Dabelea et al. 2014 ). In addition, nearly 1 in every 5 U.S. teenagers has abnormally high blood glucose levels ( Menke et al. 2016 ). In fact, in the U.S., the rates of type 2 diabetes in children are now increasing faster than type 1 diabetes: between 2002 and 2012, the incidence of type 2 diabetes in children increased by 4.8% per year, and was especially high in minority groups ( Mayer-Davis et al. 2017 ). As of 2016, about 1 of 5 adolescents and 1 of 4 young adults had prediabetes ( Andes et al. 2019 ).

Of U.S. adults, 12-14% have type 2 diabetes (in 2011-12). The numbers are higher for Blacks, Hispanics, and Asians than for whites. The prevalence of diabetes in the U.S. has increased over the past few decades (it was 9.8% in 1988-1994) ( Menke et al. 2015 ). The good news, however, is that in U.S. adults since 2009, diabetes prevalence has flattened out, and incidence has actually decreased (especially in non-Hispanic whites). However, rates are still high, and obesity continues to increase ( Benoit et al. 2019 ). In fact, in many developed countries, the increasing type 2 diabetes incidence may be leveling out. From 2006-14, increasing trends were found in only 33% of populations, whereas 30% and 36% had stable or declining incidence (these data are mostly from higher income countries) ( Magliano et al. 2019 ). For more on this study, see article in Medpage Today, Is Diabetes Becoming Mainly a Third World Problem?— Incidence declines seen predominantly in high-income countries

Type 1 Diabetes Incidence and Prevalence

There are approximately 500,000 children aged under 15 with type 1 diabetes in the world ( Patterson et al. 2014 ). No wait, that was in 2013. In 2017, it's an estimated 586,000 children, and over 1 million if adolescents age 16-19 are included. No wait, it's 600,900 children and 1,110,100 with adolescents in 2019. numbers have increased in most regions ( Patterson et al. 2019 ). (Check the current IDF Diabetes Atlas for the most recent numbers.) The most recent numbers as of 2019 show that 600,900 children have type 1 diabetes in the world, and that 98,200 more are diagnosed each year. Incidence remains highest in Finland, Sardinia and Sweden, followed by Kuwait, some other northern European countries, Saudi Arabia, Algeria, Australia, New Zealand, USA and Canada. The lowest incidence is seen across East and South-East Asia. Globally, the average increase in incidence has been 3-4%/year over past decades, being steeper in low-incidence countries ( Tuomilehto et al. 2020 ).





In the U.S., the CDC collects nation-wide data on diabetes, but does not differentiate between type 1 and type 2 diabetes. In 2016, supplemental questions to help distinguish diabetes type were added to the National Health Interview Survey (NHIS). Based on self-reported type and current insulin use, 0.55% of U.S. adults had diagnosed type 1 diabetes, representing 1.3 million adults; 8.6% had diagnosed type 2 diabetes, representing 21.0 million adults. Of all diagnosed cases, 5.8% were type 1 diabetes, and 90.9% were type 2 diabetes; the remaining 3.3% of cases were other types of diabetes ( Bullard et al. 2018 ).





In the U.S., as elsewhere, type 1 diabetes prevalence varies by race or ethnicity. For example, the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), of four U.S. locations, found that the overall prevalence of type 1 diabetes in Hispanics/Latinos was 1.8/1000 persons. This is similar to the estimates obtained through other studies, such as NHANES (2.6/1000) and the SEARCH for Diabetes in Youth Study (1.5/1000). The prevalence varying by specific Hispanic/Latino background, and is highest in people of Dominican ancestry ( Kinney et al. 2019 ). Note that each of these studies uses different definitions of type 1 diabetes, based on criteria such as age of onset or insulin use, and are not necessarily based on a doctor's diagnosis, autoimmune antibody testing, c-peptide testing, or other more accurate measures of type 1 diabetes diagnosis. We really need better diagnosis and tracking of type 1 diabetes in the U.S.!





The prevalence of type 1 also varies a lot by state (among those with private insurance), to see the prevalence in your state, see here: Rogers et al. 2018 . Expect more numbers in the future, as researchers are figuring out ways to determine exactly how many children have type 1 (or type 2) diabetes in the U.S. using electronic health records ( Zhong et al. 2016 ). I wish them luck!

Trends Over Time

Worldwide, the incidence of type 1 diabetes increased, on average, 3% per year between 1960 to 1996 in children under age 15 ( Onkamo et al. 1999 ). Between 1990 and 1999, incidence increased in most continents, with a rise of 5.3% in North America, 4% in Asia, and 3.2% in Europe. This trend is especially troubling in the youngest children; for every hundred thousand children under age 5, 4% more were diagnosed every year, on average, worldwide ( Diamond Project Group 2006 ). Between 1989-2013, on average in Europe, a continued 3.4% annual increase continues, despite a slower rate of increase in some high-incidence countries ( Patterson et al. 2018 ).

In the U.S., the prevalence of type 1 diabetes increased by 21% in children between 2001 and 2009 (Dabelea et al. 2014), and the incidence of type 1 diabetes in non-Hispanic whites increased by 2.7% per year between 2002 and 2009 (Lawrence et al. 2014). More recent numbers show that overall, type 1 diabetes incidence in children increased by 1.8-1.9% per year between 2002 and 2012 (Mayer-Davis et al. 2017), and continuing into 2015 (Divers et al. 2020). Those numbers are from the SEARCH for Diabetes in Youth study, which has study centers in 5 U.S. states. In those who use Medicaid, the annual prevalence of type 1 diabetes in children increased continuously from 2002 to 2016 (Chen et al. 2019).

A study of a large population of U.S. patients with commercial health insurance found that type 1 (and type 2) prevalence increased between 2002-2013 in children (Li et al. 2016). Another study of U.S. patients-- both children and adults-- with commercial health insurance found that the type 1 diabetes incidence rate increased 1.9% in children between 2001 and 2015, and varied by area. The incidence decreased during that same time period in adults, although more people are diagnosed as adults than as children. They estimate that the number of new cases of type 1 diabetes (ages 0-64 years) in the U.S. is 64,000 annually (27,000 cases in youth and 37,000 cases in adults), which is more than previously thought (Rogers et al. 2017).

Data from the Children's Hospital of Alabama show that there was an increase in type 1 incidence between 2000-2017, with an annual percent change of 10% from 2000-2007 and a 1.7% decrease from 2007-2017. The incidence for whites and Blacks both increased, with an average annual percentage change of 4.4% and 2.8%, respectively. The increase plateaued in 2006 for whites and 2010 for Blacks (Correya et al. 2019).

Geographic Variations

Of the 500,000 children with type 1 diabetes in the world, the most live in Europe (129,000) and North America (108,700). Countries with the highest estimated numbers of new cases annually (highest incidence) were the United States (13,000), India (10,900) and Brazil (5000) ( Patterson et al. 2014 ). In the U.S., an estimated 191,986 U.S. youth under age 20 have diabetes; 166,984 have type 1 diabetes; 20,262 have type 2 diabetes; and 4,740 have "other types" ( Pettitt et al. 2014 ).Type 1 diabetes incidence ranges from very low in South America and Asia, to very high in Europe, especially northern Europe ( Onkamo et al. 1999 ). Finland, Sardinia (Italy), and Sweden have the highest incidence of type 1 diabetes in the world ( Diamond Project Group 2006 Tuomilehto 2013 ). In fact, the longer you live in Sweden, the higher your risk of type 1 diabetes-- offspring of immigrant women living in Sweden for 11 years or more have a 22% higher risk than offspring of women living in Sweden for 5 years or less ( Hussen et al. 2015 ). Other countries show changes in incidence when after immigration, for example, immigrants to Israel from lower incidence countries lose their protection against diabetes around adolescence; the younger they are when the immigrate, the more likely they are to get type 1 ( Peled et al. 2017 ).As an example of a country with low incidence, black children in Dar es Salaam in Tanzania have very low incidence of type 1 diabetes, at 1.5 people diagnosed per 100,000 people, which is much lower than rates for black children in the U.S., Virgin Islands, or Cuba. In Tanzania, only one child under age 5 was diagnosed during one 10 year study period ( Swai et al. 1993 ). In Ghana, rates remain low, although there have been some changes over time, with increasing rates in adolescents but decreasing rates overall (from 1992-2018) ( Sarfo-Kantanka et al. 2020 ). The Sudan, however, has higher rates than most other African countries ( Saad et al. 2020 ), and Algeria has a very high incidence ( Khater et al. 2020 ). The Raikas, a tribal group in India, have a far higher genetic risk of type 1 diabetes than other North Indians, yet the incidence of type 1 is almost nil ( Bhat et al. 2014 )-- implying that genetics do not tell the whole story.