We have estimated the future burden of diabetes in youth by type in the major race/ethnic groups in the U.S., using the most recent population-based estimates of diabetes incidence and prevalence and taking into account demographic changes over time. Our model projected that over the next 40 years, at the current incidence rates, the number of youth with T1DM and T2DM may increase by 23% and 49%, respectively. However, if the incidence of T1DM or T2DM increases, there may be more than a threefold increase in the number of youth with T1DM and about a fourfold increase in the number of youth with T2DM, especially among minority youth.
Very little is known about effective prevention of T1DM, and more research is needed. However, T2DM can be prevented in high risk adults. Additional research is needed to examine the most effective methods for T2DM prevention in youth and should address strategies applicable to obesity prevention and control, as well as strategies for youth at high risk for T2DM. The projected increase in the prevalence of T2DM should serve as a call to action so that by 2050 the actual number of affected youth will fall markedly short of our projections.
Because of the early age of onset and longer diabetes duration, children and adolescents are at risk for developing diabetes-related complications at a younger age. As these youth age, this profoundly affects their productivity, quality of life, and life expectancy and increases health care costs. Even in childhood, the medical expenditures of youth with diabetes are approximately 6.2 times of those without diabetes (19
). The health care system and society as a whole will need to plan and prepare for the delivery of quality health care to meet the needs of the growing number of youth with diabetes. This may need to include the training of additional health care professionals to treat and manage children and adolescents with T1DM and T2DM.
Strengths of the current study include the use of contemporary population-based estimates of the prevalence and incidence of T1DM and T2DM from the SEARCH study for the major race/ethnic groups in the U.S. This enabled us to quantify race/ethnicity–specific future diabetes burden. Prevalence and incidence estimates were based on physician’s diagnosis of T1DM or T2DM, and case definitions met consistent eligibility criteria (2
). Moreover, physician’s diagnosis of diabetes type was in good agreement with the etiologic biochemical and clinical characteristics of the two major types of diabetes (20
The projections have some limitations. First, the recent estimated increase in the incidence of T1DM is limited and only available in one U.S. study conducted in Colorado (18
). The Colorado study found a slightly lower annual increase in T1DM incidence among youth than a large registry-based study conducted in 17 European countries (EURODIAB; overall yearly average increase 2.3% in Colorado vs. 3.9% in Europe) (18
). However, the pattern of the increase in Colorado was similar to that observed in Europe, with children younger than 5 years old experiencing the greatest relative increase. If the actual rate of increase in the U.S. is more similar to that observed in Europe, then our projections may underestimate the future burden of T1DM in the U.S. However, it should be noted that EURODIAB included only children aged 0–15 years and the greatest relative increase in the incidence rate was observed in countries with low baseline incidence. Second, in our study we applied the same rate of increase across all race/ethnic groups. The Colorado study population included only NHWs and Hispanics, and the overall rate of increase in Hispanics was slightly lower than that of NHWs (1.6 vs. 2.7% per year, respectively). The U.S. Census projections indicate that the proportion of the youth population of NHW race/ethnicity will diminish from 62% in 2001 to 41% in 2050 (22
). Because of this demographic shift and the possibility that youth of other races/ethnicities than NHW may experience a lower increase in the incidence, it is possible that the number of youth with T1DM could be lower than that estimated by our study under the increasing incidence scenario. Third, we assumed constant increases in T1DM incidence over time and did not account for the possible effect of yet to be identified primary prevention strategies that may influence our predicted number of youth with T1DM. Given our current knowledge, the increased incidence scenario should be taken with caution. However, we would like to point out that recent findings from Europe indicated a constant linear trend over a 15-year period (21
) or, starting in the early 1990s, even a steeper increase (23
Finally, because of the lack of population-based estimates of T2DM incidence trends in youth aged <20 years, we used a yearly increase of 2.3% in our increasing incidence scenario, based on the overall increase of T1DM in the Colorado study (18
). In the Pima Indians, a population at very high risk of developing T2DM (24
), among youth aged 5–14 years, between 1965 and 2003 the incidence of T2DM increased almost sixfold (25
). In Finnish adolescents and young adults (aged 15–39 years) during a 10-year period from 1992 to 2002, the incidence of T2DM increased on average by 4.3% per year, while that of T1DM increased by 3.9% per year (26
). Obesity is a major risk factor for the development of T2DM. Since the 1980s, obesity prevalence among U.S. children and adolescents tripled; however, recent national data indicate that during the last decade obesity prevalence may be leveling off at 17% (27
). If obesity remains stable for the next 40 years, it is plausible that the current T2DM incidence rate will remain steady. However, even under this scenario, the number of youth with T2DM may increase by 49%. On the other hand, implementation of interventions for the prevention of childhood obesity at the individual or population level may result in decreasing T2DM incidence over time (28
In both scenarios in our study, increasing the relative risk of death to 1.5 did not affect our estimates. This might be partially explained by the very low number of diabetes-related deaths in this age-group (1.15 per million youths) (30
Our projections suggest a shift in the proportional distribution of racial/ethnic groups among youth with T1DM. By 2050, about half of T1DM youths will be of minority race/ethnic groups. This change may influence potential trends in clinical presentation, treatment patterns, and quality of care. Minority youth are more likely to be overweight or obese (27
) and this may lead to a misdiagnosis of T2DM. Among SEARCH study participants, minority youth with T1DM were significantly more likely to have poor glucose control (glycated hemoglobin >9%) than NHW youth (31
). Minority youth with T1DM are also more likely to live in households with low income and parental education (7
). This in turn may affect their access to and quality of health care (32
). Because of the changing demographics of the youth population with T1DM, health care policies and delivery systems need to assure that less advantaged youth receive appropriate care.
Our projections indicate a serious picture of the future national diabetes burden in youth. Even if the incidence remains at 2002 levels, because of the population growth projected by the U.S. Census the future numbers of youth with diabetes is projected to increase, resulting in increased health care needs and costs. Future planning should include strategies for implementing childhood obesity prevention programs and primary prevention programs for youth at risk for developing T2DM. Likewise, to prevent future human suffering and health care costs, effective interventions for the prevention of diabetes-related complications should be available to all youth with diabetes (34
). At the same time, it is crucial to continuously monitor diabetes trends at the population level, as well as complications and quality of care among youth.