Diabetes Statistics

Introduction

The prevalence of type 2 diabetes (T2D) is increasing, not only in the United States, but also around the world. Diabetes affects approximately 537 million people worldwide and is expected to affect 783 million by 2045. The prevalence of diabetes refers to the total number of people known to have the disease at a particular time. In 2017-2020, approximately 37.3 million Americans (11.3% of the US population) had diabetes, with a higher rate of prevalence in certain geographic areas, and approximately one in four of those individuals (23.0%) were estimated to have undiagnosed diabetes. The prevalence has increased from 4.9% in 1990 to 11.3% in 2017-2020. Possible reasons for the substantial increases in the prevalence of diabetes over time include:

• Advancing age of the US population
• Reduced mortality rates among people with diabetes due to improved screening, detection and health care
• An increase in risk factors, such as obesity and physical inactivity.

The prevalence of diabetes increases with advancing age, reaching nearly 29.2% for those in the age category of ≥65 years (Figure 1-1). The prevalence is similar for men and women up to the age of 65; for those over 65, the prevalence rates are slightly higher for men.

The prevalence of individuals with T2D is considerably different depending on the race, ethnicity and gender in the US population. Diabetes is more prevalent in American Indians, Alaska natives, Hispanics and Latinos and non-Hispanic blacks (Figure 1-2). The increasing number of ethnic/racial minorities in the United States may also contribute to the increasing prevalence of T2D.

The lowering of the clinical diagnostic criteria for diabetes from a fasting blood glucose (FBG) of 140 mg/dL to 126 mg/dL has also contributed to the higher prevalence of diabetes. Ethnic and racial minorities not only have a higher prevalence of diabetes, but they also account for a greater number of individuals with undiagnosed diabetes as well as prediabetes, which is a major risk factor for the development of T2D.

Undiagnosed T2D is a serious problem. The prevalence rate of undiagnosed diabetes increases with age in both men and women. In 2019, approximately 8.5 million people were estimated to have undiagnosed diabetes. An estimated 38.0% of US adults aged 18 years or older had prediabetes in 2017-2020 based on their fasting glucose or A1C level. The estimated percentage of prediabetes among adults aged 18 years and older is shown in Figure 1-3.

Insulin resistance and the associated macrovascular complications are well known to develop 10 to 15 years before the typical diagnosis of T2D, because of the asymptomatic nature of T2D, especially in the early stages. In the United Kingdom Prospective Diabetes Study (UKPDS), 21% of newly diagnosed diabetics already had diabetic retinopathy. Since diabetic retinopathy requires at least 4 to 7 years of hyperglycemia to develop, this indicates that diabetes had likely been undiagnosed for this period of time. In addition, these newly diagnosed subjects also had a two to three times higher incidence of myocardial infarction (MI) and stroke compared with the general population. The UKPDS data are from over 2 decades ago but unfortuately have not changed much in recent years.

The incidence of diabetes is the number of new cases diagnosed during a certain period of time, usually within the previous year. In 2019, approximately 1.4 million adults aged 18 years and older were newly diagnosed with diabetes.

From 1980 through 2015, the incidence of diagnosed diabetes was lower among adults aged 18 to 44 years compared with older age groups. During this period, the incidence of diagnosed diabetes increased among adults aged 18 to 44 years and 65 to 79 years. Among adults 45 to 64 years, the incidence of diagnosed diabetes showed little change during the 1980s but increased beginning in the 1990s through 2015. However, the overall incidence rates have shown a decreasing trend in the period 2008-2019. The estimated incidence of diabetes among adult aged ≥18 years in the United States in 2018-2019 is shown in Figure 1-4. 

In a similar fashion to prevalence, the incidence rates for African Americans, Latinos, American Indians, Pacific Islanders and Asian Indians are higher than for Whites.

Some experts believe that the high incidence of diabetes is due to a genetic predisposition to diabetes commonly referred to as “the thrifty gene hypothesis,” which theorizes that in the distant past, most individuals were hunters and gatherers doing physical labor for their daily existence. In times of famine, any individual who was not thin and had insulin resistance would be in a prime position to survive and not perish from starvation during periods of drought. In a relatively short period of time, individuals in our westernized societies are doing less physical labor, growing older, becoming much more obese, and consuming foods in greater amounts and with a much higher percentage of fat. What was a physiologic advantage in the past is now a physiologic disadvantage. All of these factors are thought to contribute to the increasing incidence of T2D over the centuries.

In conclusion, diabetes has achieved or is nearing epidemic proportions in many ethnic groups, not only in the United States, but also in other populations around the globe. Diabetes was the eighth leading cause of death in the United States in 2020. Much of the increase is due to our westernized society and lifestyle, in addition to genetic influences, which contribute significantly to the overall morbidity and mortality associated with the presence of T2D. Overall, the risk of death for people with diabetes is about two times that of people without diabetes. In order to reduce the emotional and physical suffering of people with T2D, a concerted effort should be undertaken toward the prevention, early detection, and aggressive management of this devastating medical condition.

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