Trends in Incidence of Type 1 and Type 2 Diabetes Among Youths

Selected Counties and Indian Reservations, United States, 2002-2015

Jasmin Divers; Elizabeth J. Mayer-Davis; Jean M. Lawrence; Scott Isom; Dana Dabelea; Lawrence Dolan; Giuseppina Imperatore; Santica Marcovina; David J Pettitt; Catherine Pihoker; Richard F. Hamman; Sharon Saydah; Lynne E. Wagenknecht

Disclosures

Morbidity and Mortality Weekly Report. 2020;69(6):161-165.

Discussion

From 2002 to 2015, the annual incidence of both type 1 and type 2 diabetes increased at constant rates among persons aged <20 years in selected counties and Indian reservations in the United States. Rates of increase in incidence were higher for type 2 diabetes (4.8% per year) than for type 1 (1.9%). Since 2012, the rate of increase in type 2 diabetes has not changed, and has also remained constant for type 1 diabetes, except among Asians and Pacific Islanders. These findings provide indicators of the number of new cases of type 1 and type 2 diabetes among U.S. youths and identify groups with increased incidences of both type 1 and type 2 diabetes. Diabetes is a chronic disease that requires lifelong treatment and management. Better understanding of the number of new cases of diabetes among youths helps in planning for health care needs and resources.

The findings in this report are subject to at least two limitations. First, a small number of cases was ascertained across years, in subgroups by diabetes type, and especially across racial/ethnic groups, possibly leading to less precision in the annual rates. Second, these findings might not be generalizable to other populations because SEARCH was not designed to be nationally representative; it includes populations from five U.S. sites. A major strength of this study is that data come from a complete, population-based registry covering approximately a decade, including both type 1 and type 2 diabetes in persons aged <20 years across multiple racial/ethnic groups.

The incidence of type 1 diabetes continues to increase in U.S. youths, with steeper increases observed in black and Hispanic youths. Since 2011, the incidence of type 1 diabetes has also significantly increased among Asians and Pacific Islanders. Reasons for this recent increase are unknown. In parallel with increased obesity prevalence in U.S. youths,^[9] the incidence of type 2 diabetes among adolescents has increased at a higher rate than that of type 1 diabetes, especially among racial/ethnic minority youths. There are no known prevention interventions for type 1 diabetes; in adults the onset of type 2 diabetes can be prevented or delayed with lifestyle changes programs, such as the National Diabetes Prevention Program (https://www.cdc.gov/diabetes/prevention/index.html). Although the effectiveness of these programs among youths is unknown, promoting healthy eating and lifestyles provides many health benefits (https://www.cdc.gov/diabetes/prevent-type-2/type-2-kids.html). One program targeting the prevention of type 2 diabetes in American Indian youths is the Native Diabetes Wellness Program (https://www.cdc.gov/diabetes/ndwp/index.html). This collaboration between CDC and other partners provides resources to promote healthy eating and physical activity in American Indian and Alaska Native youths. To assess public health needs and prevention efforts for type 1 and type 2 diabetes among youths, it is important to enhance and continue surveillance efforts to monitor incidence in this population.

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Acknowledgments
Researchers and participants in the SEARCH for Diabetes in Youth Study.

Table 1. Incidence of type 1 diabetes per 100,000 persons per year and annual percent change (APC) in incidence in youths aged <20 years, overall and by age at diagnosis, sex, and race/ethnicity — SEARCH for Diabetes in Youth Study (SEARCH), United States,* 2002–2015
Characteristic	Incidence rate (95% CI)		Adjusted APC^§ 2002–2010 (95% CI)	Incidence rate (95% CI)		Adjusted APC^† 2011–2015 (95% CI)	Adjusted APC^§ 2002–2015 (95% CI)	Change from 2002–2010 to 2011–2015 (95% CI)
Characteristic	2002–2003	2009–2010	Adjusted APC^§ 2002–2010 (95% CI)	2011–2012	2014–2015	Adjusted APC^† 2011–2015 (95% CI)	Adjusted APC^§ 2002–2015 (95% CI)	Change from 2002–2010 to 2011–2015 (95% CI)
Overall	19.5 (18.3 to 20.8)	20.4 (19.2 to 21.7)	2.0 (0.9 to 3.2)^¶	21.7 (20.4 to 23.0)	22.3 (21.0 to 23.6)	1.9 (0.9 to 2.9)^¶	1.93 (1.34 to 2.51)^¶	−0.1 (−1.9 to 1.6)
Age group at diagnosis (yrs)
0–4	16.5 (14.3 to 19.1)	13.8 (11.9 to 16.0)	0.3 (−2.2 to 3.0)	14.3 (12.4 to 16.6)	14.4 (12.4 to 16.7)	0.8 (−1.4 to 3.0)	0.6 (−0.72 to 1.93)	0.4 (−3.5 to 4.5)
5–9	24.0 (21.3 to 27.0)	27.5 (24.7 to 30.6)	3.3 (1.2 to 5.3)^¶	27.7 (25.0 to 30.8)	27.1 (24.4 to 30.1)	0.9 (−0.8 to 2.7)	1.91 (0.86 to 2.98)^¶	−2.3 (−5.3 to 0.8)
10–14	26.4 (23.7 to 29.3)	28.7 (25.9 to 31.8)	1.7 (−0.2 to 3.7)	31.8 (28.8 to 35.0)	33.5 (30.5 to 36.8)	3.0 (1.3 to 4.8)^¶	2.4 (1.39 to 3.42)^¶	1.3 (−1.7 to 4.4)
15–19	11.0 (9.2 to 13.0)	12.0 (10.3 to 14.1)	2.7 (0.1 to 5.4)^¶	12.9 (11.1 to 15.0)	13.6 (11.8 to 15.8)	2.3 (0.1 to 4.6)^¶	2.44 (1.09 to 3.8)^¶	−0.4 (−4.3 to 3.7)
Sex
Female	19.2 (17.5 to 21.0)	19.7 (18.1 to 21.6)	2.5 (0.8 to 4.2)^¶	19.9 (18.3 to 21.8)	20.4 (18.7 to 22.3)	1.0 (−0.4 to 2.4)	1.5 (0.68 to 2.33)^¶	−1.4 (−3.9 to 1.1)
Male	19.8 (18.2 to 21.7)	21.0 (19.3 to 22.9)	1.8 (0.2 to 3.4)^¶	23.4 (21.6 to 25.3)	24.1 (22.2 to 26.0)	2.6 (1.3 to 4.0)^¶	2.33 (1.54 to 3.12)^¶	0.8 (−1.6 to 3.3)
Race/Ethnicity
White	23.9 (22.2 to 25.7)	25.4 (23.7 to 27.4)	1.2 (−0.1 to 2.6)	27.0 (25.2 to 29.0)	27.3 (25.5 to 29.3)	0.5 (−0.7 to 1.7)	0.73 (0.02 to 1.44)^¶	−0.8 (−2.9 to 1.4)
Black	14.7 (12.1 to 17.7)	15.5 (12.9 to 18.6)	1.2 (−1.5 to 3.9)	19.0 (16.1 to 22.4)	20.8 (17.7 to 24.4)	4.0 (1.7 to 6.3)^¶	2.72 (1.42 to 4.03)^¶	2.8 (−1.4 to 7.1)
Hispanic	13.7 (11.4 to 16.4)	16.3 (14.0 to 18.9)	5.9 (3.4 to 8.6)^¶	14.8 (12.7 to 17.3)	16.3 (14.1 to 18.8)	2.5 (0.5 to 4.6)^¶	4.05 (2.84 to 5.28)^¶	−3.2 (−6.7 to 0.4)
Asian/Pacific Islander	7.9 (5.0 to 12.3)	5.5 (3.4 to 8.9)	−1.5 (−7.4 to 4.8)	9.8 (6.8 to 13.9)	9.4 (6.6 to 13.3)	8.5 (3.2 to 14.0)^¶	4.36 (1.44 to 7.37)^¶	10.1 (0.1 to 21.1)^¶
American Indian**	6.6 (3.5 to 12.8)	5.0 (2.3 to 10.7)	−2.0 (−12.2 to 9.5)	6.5 (3.3 to 12.9)	6.2 (3.0 to 12.9)	3.7 (−5.8 to 14.2)	1.17 (−4.05 to 6.68)	5.8 (−11.2 to 26.1)

Abbreviation: CI = confidence interval.
*SEARCH includes data on youths (<20 years) in Colorado (all 64 counties plus selected Indian reservations in Arizona and New Mexico under the direction of Colorado), Ohio (eight counties), South Carolina (all 46 counties), Washington (five counties), and in California for Kaiser Permanente Southern California health plan enrollees in seven counties.
^†APC based on model with change point at 2011 and adjusted as follows: overall results adjusted by age, sex, and race/ethnicity; results by age adjusted for sex and race/ethnicity; results by sex adjusted for age and race/ethnicity; results by race/ethnicity adjusted for age and sex.
^§APC based on model without a change point from 2002 to 2015 and adjusted as follows: overall results adjusted by age, sex, and race/ethnicity; results by age adjusted for sex and race/ethnicity; results by sex adjusted for age and race/ethnicity; results by race/ethnicity adjusted for age and sex.
^¶APC and change from 2002–2010 to 2011–2015 significantly different from zero (as indicated by 95% CI that does not include zero).
**Primarily persons from one southwestern tribe.

Table 2. Incidence of type 2 diabetes per 100,000 persons per year and annual percent change (APC) in incidence in youths aged 10–19 years, overall and by age at diagnosis, sex and race/ethnicity — SEARCH for Diabetes in Youth Study (SEARCH), United States,* 2002 to 2015
Characteristic	Incidence rate (95% CI)		Adjusted APC^† 2002–2010 (95% CI)	Incidence rate (95% CI)		Adjusted APC^† 2011–2015 (95% CI)	Adjusted APC^† 2002–2015 (95% CI)	Change from 2002–2010 to 2011–2015 (95% CI)
Characteristic	2002–2003	2009–2010	Adjusted APC^† 2002–2010 (95% CI)	2011–2012	2014–2015	Adjusted APC^† 2011–2015 (95% CI)	Adjusted APC^† 2002–2015 (95% CI)	Change from 2002–2010 to 2011–2015 (95% CI)
Overall	9.0 (7.9 to 10.2)	12.2 (10.9 to 13.6)	5.1 (2.9 to 7.4)^¶	12.5 (11.2 to 13.9)	13.8 (12.4 to 15.3)	4.6 (2.7 to 6.4)^¶	4.81 (3.7 to 5.92)^¶	−0.6 (−3.8 to 2.7)
Age group at diagnosis (yrs)
10–14	8.0 (6.6 to 9.7)	12.0 (10.2 to 14.0)	5.2 (1.9 to 8.5)^¶	12.1 (10.3 to 14.1)	12.4 (10.6 to 14.5)	3.9 (1.3 to 6.6)^¶	4.57 (2.95 to 6.22)^¶	−1.2 (−5.8 to 3.6)
15–19	10.0 (8.4 to 11.9)	12.4 (10.7 to 14.5)	5.0 (2.0 to 8.2)^¶	12.9 (11.1 to 15.0)	15.2 (13.2 to 17.5)	5.1 (2.6 to 7.7)^¶	5.02 (3.48 to 6.58)^¶	0.1 (−4.3 to 4.7)
Sex
Female	11.1 (9.4 to 13.1)	15.8 (13.8 to 18.2)	6.6 (3.7 to 9.7)^¶	16.1 (14.1 to 18.5)	16.7 (14.6 to 19.1)	3.9 (1.6 to 6.4)^¶	5.11 (3.6 to 6.64)^¶	−2.5 (−6.5 to 1.7)
Male	7.0 (5.7 to 8.6)	8.7 (7.2 to 10.4)	3.1 (−0.3 to 6.5)	9.0 (7.5 to 10.7)	11.1 (9.4 to 13.0)	5.4 (2.6 to 8.3)^¶	4.41 (2.69 to 6.15)^¶	2.3 (−2.6 to 7.5)
Race/Ethnicity
White	4.4 (3.4 to 5.5)	4.8 (3.8 to 6.1)	1.9 (−2.3 to 6.3)	3.9 (3.0 to 5.0)	4.5 (3.5 to 5.7)	−0.1 (−3.7 to 3.5)	0.77 (−1.35 to 2.94)	−2.0 (−8.2 to 4.6)
Black	20.0 (16.0 to 25.1)	31.0 (25.8 to 37.2)	6.3 (2.6 to 10.1)^¶	32.5 (27.2 to 38.9)	37.8 (31.9 to 44.7)	5.8 (2.8 to 8.8)^¶	5.97 (4.14 to 7.85)^¶	−0.5 (−5.6 to 5.0)
Hispanic	13.3 (10.2 to 17.4)	17.2 (14.0 to 21.2)	6.3 (2.2 to 10.5)^¶	18.4 (15.2 to 22.4)	20.9 (17.4 to 24.9)	6.6 (3.4 to 9.9)^¶	6.45 (4.44 to 8.49)^¶	0.3 (−5.4 to 6.3)
Asian/Pacific Islander	11.0 (6.5 to 18.7)	12.9 (8.3 to 20.1)	7.9 (−0.8 to 17.4)	12.2 (7.8 to 19.0)	11.9 (7.8 to 18.3)	7.6 (1.0 to 14.6)^¶	7.72 (3.44 to 12.19)^¶	−0.3 (−11.8 to 12.7)
American Indian**	22.6 (13.9 to 36.8)	30.1 (19.4 to 46.5)	5.1 (−2.1 to 12.8)	45.0 (31.1 to 65.1)	32.8 (20.8 to 51.6)	2.6 (−3.2 to 8.8)	3.69 (0.11 to 7.39)^¶	−2.3 (−12.3 to 8.7)

Abbreviation: CI = confidence interval.
*SEARCH includes data on youths (<20 years) in Colorado (all 64 counties plus selected Indian reservations in Arizona and New Mexico under the direction of Colorado), Ohio (eight counties), South Carolina (all 46 counties), Washington (five counties), and in California for Kaiser Permanente Southern California health plan enrollees in seven counties.
^†APC based on model with change point at 2011 and adjusted as follows: overall results adjusted by age, sex, race/ethnicity; results by age adjusted for sex and race/ethnicity; results by sex adjusted for age and race/ethnicity; results by race/ethnicity adjusted for age and sex.
^§APC based on model without a change point from 2002–2015 and adjusted as follows: overall results adjusted by age, sex, race/ethnicity; results by age adjusted for sex and race/ethnicity; results by sex adjusted for age and race/ethnicity; results by race/ethnicity adjusted for age and sex.
^¶APC and change from 2002–2010 to 2011–2015 significantly different from zero (as indicated by 95% CI that does not include zero).
**Primarily persons from one southwestern tribe.