New data from the SEARCH for Diabetes in Youth study, published in the Journal of the American Medical Association, indicates a dramatic increase in the prevalence of Type 1 and Type 2 diabetes in US children under twenty years old. The greatest prevalence increase of Type 2 diabetes was observed in Hispanic youth from ten to nineteen years old. The greatest prevalence increase of Type 1 diabetes was observed in children aged 15 through 19 years.
The study was particularly important because it was the first to estimate changes in the prevalence of type 1 and type 2 diabetes in US youth, by sex, age, and race/ethnicity. Prior to this study there was limited data with regard to the prevalence of either type 1 or type 2 diabetes across US race and ethnic groups. The researchers explained that understanding changes in prevalence according to population subgroups is important to inform clinicians about care that will be needed for the pediatric population living with diabetes and may provide direction for other studies designed to determine the causes of the observed changes. Moreover, the increases in prevalence reported in the study are important because youth with diabetes will enter adulthood with several years of disease duration, difficulty in treatment, an increased risk of early complications, and increased frequency of diabetes during reproductive years, which may further increase diabetes in the next generation.
Type 1 diabetes, which was previously called insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes, develops most often in young people. However, type 1 diabetes can also develop in adults. In type 1 diabetes, your body no longer makes insulin or enough insulin because the body’s immune system, which normally protects you from infection by getting rid of bacteria, viruses, and other harmful substances, has attacked and destroyed the cells that make insulin.
Type 2 diabetes, which was previously called non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes, can affect people at any age, even children. However, type 2 diabetes develops most often in middle-aged and older people. People who are overweight and inactive are also more likely to develop type 2 diabetes. Type 2 diabetes usually begins with insulin resistance—a condition that occurs when fat, muscle, and liver cells do not use insulin to carry glucose into the body’s cells to use for energy. As a result, the body needs more insulin to help glucose enter cells. At first, the pancreas keeps up with the added demand by making more insulin. Over time, the pancreas doesn’t make enough insulin when blood sugar levels increase, such as after meals.
The study compared the prevalence of Type 1 and Type 2 diabetes over an eight-year period from 2001 to 2009. The study looked at data from five geographic regions in California, Colorado, Ohio, South Carolina, and Washington, as well as data from selected American Indian reservations in Arizona and New Mexico. The study reports the prevalence (per 1000) of physician-diagnosed type 1 diabetes in youth aged 0 through 19 years and type 2 diabetes in youth aged 10 through 19 years. Type 2 diabetes prevalence was reported only for those aged 10 through 19 years because there were not enough children younger than 10 years to establish stable rates. There were only five children under ten suffering from Type 2 diabetes in 2001, which increased to nineteen in 2009. The children were sorted into race/ethnic categories including Hispanic, white, black, Asian Pacific Islanders, and American Indians.
In 2001, 4958 of 3.3 million youth were diagnosed with type 1 diabetes for a prevalence of 1.48 per 1000 (95% CI, 1.44-1.52). In 2009, 6666 of 3.4 million youth were diagnosed with type 1 diabetes for a prevalence of 1.93 per 1000 (95% CI, 1.88-1.97). In 2009, the highest prevalence of type 1 diabetes was 2.55 per 1000 among white youth (95% CI, 2.48-2.62) and the lowest was 0.35 per 1000 in American Indian youth (95% CI, 0.26-0.47). Type 1 diabetes increased between 2001 and 2009 in all sex, age, and race/ethnic subgroups except for those with the lowest prevalence (age 0-4 years and American Indians).
There was a 21.1% (95% CI, 15.6%-27.0%) increase in type 1 diabetes over 8 years, adjusted for completeness of ascertainment. Statistically significant increases were observed within each age, race/ethnic, and sex subgroup evaluated except for youth age 0 through 4 years and American Indians, which were the two population subgroups with the lowest prevalence of type 1 diabetes in 2001 and 2009. The greatest prevalence increase was observed in those aged 15 through 19 years (prevalence, 2.42 per 1000 in 2001 to 3.22 in 2009; P < .001).
Historically, type 1 diabetes has been considered a disease that affects primarily white youth. However, the study’s findings highlight the increasing burden of type 1 diabetes experienced by youth of minority racial/ethnic groups as well. The increase in prevalence among US minorities documented by the study is of concern, given that minority youth are more likely to have poor glycemic control, known to be associated with the serious complications of type 1 diabetes.
Increases in the prevalence of type 1 diabetes could reflect increases in disease incidence, decreases in mortality, or both. Mortality due to diabetes in youth is low (1.05 per million for aged ≤19 years in 2008-20095). Therefore, an increase in type 1 diabetes incidence is the most likely primary explanation.
In 2001, 588 of 1.7 million youth were diagnosed with type 2 diabetes for a prevalence of 0.34 per 1000 (95% CI, 0.31-0.37). In 2009, 819 of 1.8 million were diagnosed with type 2 diabetes for a prevalence of 0.46 per 1000 (95% CI, 0.43-0.49). In 2009, the prevalence of type 2 diabetes was 1.20 per 1000 among American Indian youth (95% CI, 0.96-1.51); 1.06 per 1000 among black youth (95% CI, 0.93-1.22); 0.79 per 1000 among Hispanic youth (95% CI, 0.70-0.88); and 0.17 per 1000 among white youth (95% CI, 0.15-0.20). Significant increases occurred between 2001 and 2009 in both sexes, all age-groups, and in white, Hispanic, and black youth, with no significant changes for Asian Pacific Islanders and American Indians.
There was a 30.5% (95% CI, 17.3%-45.1%) overall increase in type 2 diabetes, adjusted for completeness of ascertainment. A statistically significant increase was seen in both sexes, in those aged 10 through 14 years and 15 through 19 years, and in white, black, and Hispanic youth. No significant changes were seen in Asian Pacific Islander or American Indian youth. The prevalence of type 2 diabetes was higher in both periods among those aged 15 through 19 years than among those aged 10 through 14 years and higher among females than among males.
The report presented the first multiethnic data on changes in the prevalence of type 2 diabetes in youth. The prevalence of type 2 diabetes in 2009 among adolescents aged 10 through 19 years was 0.46 per 1000 or 0.046%, with highest prevalence in American Indians, followed by black, Hispanic, and Asian Pacific Islander youth, with lowest prevalence in white youth, a pattern that is almost the inverse of that seen in type 1 diabetes.
The results indicate an alarming 75.6% increase in the prevalence of Type 2 diabetes among Hispanics aged 10 through 19 years. The prevalence of Type 2 diabetes increased significantly among Hispanics, blacks, and whites. The magnitude of the increase was greatest among Hispanics (prevalence, 0.45 per 1000 in 2001 to 0.79 in 2009; P < .001), followed by blacks (0.95 to 1.06 per 1000; P = .02), and whites (0.14 to 0.17 per 1000; P < .001). No significant changes were observed among Asian Pacific Islanders (P = .73) or American Indians (P = .83).
Several reasons for the increasing type 2 diabetes prevalence are possible. Most likely are real changes in population risk for type 2 diabetes, such as minority population growth, obesity, exposure to diabetes in utero and perhaps endocrine-disrupting chemicals. Similarly, changing awareness of type 2 diabetes in youth leading to different diagnostic practices may have contributed to the increases.
The authors noted that the study had limitations and strengths. For example, the last year of data was 2009, five years ago, so the authors were not able to comment on whether current prevalence has changed. There were relatively small numbers of youth in some groups by race/ethnicity (especially American Indian and Asian Pacific Islanders) making these estimates of changes in prevalence less precise. The study’s authors concluded that further studies are required to determine the causes of these dramatic increases.
See the Journal of the American Medical Association Article
See also Medical Law Perspectives, May 2014 Report: Diabetes and Its Complications: Malpractice and Other Liability Issues