Racial Disparities in Diabetes Mortality Among Persons Aged 1--19 Years --- United States, 1979--2004

Diabetes is a chronic disease with a U.S. prevalence of 18 cases per 10,000 youths aged <20 years (1). With proper management and access to care, morbidity and mortality from diabetes are preventable, particularly in the pediatric population (2,3). Although diabetes is more common among non-Hispanic white youths, some studies report higher death rates among racial/ethnic minorities and among those in lower socioeconomic strata (3,4). In 2004, age-adjusted diabetes death rates for black persons in the United States were approximately twice those for white persons (5). However, no recent studies on racial disparities that focus specifically on the pediatric population have been conducted. To assess racial disparities in diabetes mortality among youths, CDC analyzed data on deaths with an underlying cause of diabetes among persons aged 1--19 years for the period 1979--2004. This report summarizes the results of that analysis, which determined that, during 1979--2004, diabetes death rates for black youths were approximately twice those for white youths. During 2003--2004, the annual average diabetes death rate per 1 million youths was 2.46 for black youths and 0.91 for white youths. Further study is needed to discern the specific reasons for increased diabetes mortality in black youths. Better identification and management of the disease among youths, especially among black youths, might help decrease racial disparities and prevent deaths from diabetes.

To obtain stable estimates, diabetes death rates were calculated as 2-year annual averages for the period 1979--2004 for all persons aged 1--19 years and for blacks and whites in that age group. The numbers of diabetes deaths in other racial groups were too small to obtain reliable estimates, and Hispanic origin was not recorded on death certificates in all states until 1997. Infants aged <1 year were excluded because of differences in estimating mortality rates among infants in the neonatal and postneonatal period, compared with children aged >1 year. Numbers of deaths for which diabetes was the underlying cause* and population estimates for calculation of rates were obtained from the CDC Wonder online database compressed mortality file of the National Vital Statistics System (NVSS). International Classification of Diseases, Ninth Revision (ICD-9)^† cause-of-death codes for diabetes mellitus (250) were used for 1979--1998, and International Classification of Diseases, Tenth Revision (ICD-10)^§ codes (E10--E14) were used for 1999--2004. Trends over time for 2-year annual averages were assessed using Hudson's algorithm in statistical software (6) to test whether trends were statistically significant (p<0.05) and to identify points (i.e., joinpoints) where trends changed during the study period. Previous analyses of the comparability of underlying cause-of-death classification between deaths coded using the ICD-9 system and those coded using the ICD-10 system have indicated that the change from ICD-9 to ICD-10 in 1999 likely had little impact on the proportion of deaths attributed to diabetes for the age group included in this study and for blacks and whites of all ages (CDC, unpublished data, 2004).^¶ Therefore, the period 1979--2004 was analyzed as a continuous trend. Rate ratios and 95% confidence intervals (CIs) for death rates of blacks compared with death rates of whites were calculated for each 2-year interval. Age-adjusted rates were examined and determined to be identical to crude rates. Thus, crude rates are presented in this report.

During 1979--2004, diabetes death rates among persons aged 1--19 years ranged from 1.34 per million (annual average for 1979--1980) to 0.84 per million (1993--1994) (Table). During 2003--2004, an annual average of 89 diabetes deaths occurred among persons aged 1--19 years (1.15 per million), including 31 among black youths and 55 among white youths. Trend lines for the entire population were similar to those for white youths and indicated a significant decrease in overall diabetes death rates during 1979--1994, with an average annual percentage change (APC) of -2.7% (p<0.05) and a significant increase during 1994--2004 (APC = +3.1%, p<0.05). Diabetes death rates were consistently higher for black youths compared with white youths (Figure), with rate ratios ranging from 1.56 (CI = 1.05--2.31) during 1987--1988 to 2.72 (CI = 2.00--3.70) during 2001--2002 (Table). Trend analysis for black youths indicated a decrease in death rates during 1979--1998 (APC = -0.8%, p>0.05) but an increase after 1998 (APC = +8.0%, p<0.05). Diabetes death rates for white youths decreased significantly during 1979--1994 (APC = -3.0%, p<0.05) but did not change significantly during 1994--2004 (APC = +2.2%, p>0.05) (Figure).

Reported by: LJ Akinbami, MD, SH Saydah, PhD, MS Eberhardt, PhD, National Center for Health Statistics; LL Polakowski, MD, EIS Officer, CDC.

Editorial Note:

Although diabetes deaths among youths were rare during 1979--2004, numbering less than an average of 80 per year for the entire period, diabetes death rates for black youths were consistently higher than those for white youths. Additionally, whereas diabetes mortality did not change substantially for white youths during 1994--2004, death rates for black youths increased significantly. A corresponding increase in black-white disparity was not observed in all-cause mortality for persons aged 1--19 during this period (CDC, unpublished data, 2004). Although implementation of new ICD-10 cause-of-death coding procedures began in 1999, the coding change is probably not the cause of the increase in diabetes deaths among black youths.

Diabetes mortality among adults traditionally includes deaths for which diabetes was a contributing cause and those for which it was an underlying cause. For children, however, diabetes deaths are less likely to be from consequences of long-standing diabetes (e.g., cardiovascular and cerebrovascular disease) and more likely to be from direct complications (e.g., ketoacidosis and hypoglycemia) and to occur among persons with short duration of the disease (3,7). Therefore, this analysis included only underlying cause of death.

The factors contributing to racial disparities in pediatric and adolescent diabetes mortality during 1979--2004 likely are complex. Possible explanations include differences in access to and use of health-care services (8) and differences in the quality of disease education and care (3). More in-depth analyses are needed to assess these factors and the effect of recent increases in type 2 diabetes among children in racial/ethnic minority groups (9).

The findings in this report are subject to at least three limitations. First, deaths attributable to diabetes cannot be examined by the specific type of diabetes because of the small number of these deaths and the high percentage of pediatric and adolescent diabetes deaths unclassified by type (76% in 2004). Second, the use of NVSS data precludes adjustment of data comparing racial groups for potential confounders, such as socioeconomic status or health-insurance status. Finally, this study could not determine the cause of the statistically significant increase in diabetes mortality among black youths during 1998--2004. This increase might be attributed to random variation, given the rarity of diabetes deaths in the 1--19 years age group and the limited period during which the increase was observed. However, further evaluation of this trend is needed.

These findings demonstrate consistent racial disparities in diabetes mortality among youths in the United States during 1979--2004, although, in absolute numbers of deaths, the differences are not sizeable because of the rare occurrence of diabetes-related deaths in this population (annual average of 89 deaths during 2003--2004). However, these disparities remain a public health concern for two reasons. First, diabetes deaths among young persons are predominantly attributed to acute complications, such as ketoacidosis, and thus are preventable (3). Metabolic decompensation from acute diabetes complications is easy to recognize in young persons and requires quality care of high urgency but low technology (3). Second, incidence of type 2 diabetes in children and adolescents is increasing (9). Education of health professionals who care for youths, especially black youths, and improved public awareness of increasing diabetes incidence, particularly among minority racial/ethnic groups, might improve identification of diabetes in black and other minority children and adolescents. These practices might lead to improved management of the disease and decreased morbidity and mortality among youths.

References

1. SEARCH for Diabetes in Youth Study Group. The burden of diabetes mellitus among US youth: prevalence estimates from the SEARCH for Diabetes in Youth Study. Pediatrics 2006;118:1510--8.
2. Todd J, Armon C, Griggs A, Poole S, Berman S. Increased rates of morbidity, mortality, and charges for hospitalized children with public or no health insurance as compared with children with private insurance in Colorado and the United States. Pediatrics 2006;118:577--85.
3. Lipton R, Good G, Mikhailov T, Freels S, Donoghue E. Ethnic differences in mortality from insulin-dependent diabetes mellitus among people less than 25 years of age. Pediatrics 1999;103:952--6.
4. DiLiberti JH, Lorenz RA. Long-term trends in childhood diabetes mortality: 1968--1998. Diabetes Care 2001;24:1348--52.
5. National Center for Health Statistics. Health, United States, 2006. With chartbook on trends in the health of Americans. Hyattsville, MD: US Department of Health and Human Services, CDC, National Center for Health Statistics; 2006. Available at http://www.cdc.gov/nchs/data/hus/hus06.pdf.
6. Yu B, Barrett MJ, Kim H, Feuer EJ. Estimating joinpoints in continuous time scale for multiple change-point models. Computational Statistics and Data Analysis 2007;51:2420--7.
7. Podar T, Solntsev A, Reunanen A, et al. Mortality in patients with childhood-onset type 1 diabetes in Finland, Estonia, and Lithuania. Follow-up of nationwide cohorts. Diabetes Care 2000;23:290--4.
8. Lieu TA, Newacheck PW, McManus MA. Race, ethnicity, and access to ambulatory care among U.S. adolescents. Am J Pub Health 1993;83: 960--5.
9. Bloomgarden ZT. Type 2 diabetes in the young. Diabetes Care 2004;27:998--1010.

* Underlying cause is defined by the World Health Organization as the disease or injury that initiated the train of morbid events leading directly to death or the circumstances of the accident or violence that produced the fatal injury. The underlying cause is selected from the conditions entered by the physician in the cause-of-death section of the death certificate. When more than one cause or condition is entered by the physician, the underlying cause is determined by the sequence of conditions on the certificate, provisions of the International Classification of Diseases, and associated selection rules and modifications. Additional information is available at http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_08.pdf.

^† Available at http://www.cdc.gov/nchs/about/major/dvs/icd9des.htm.

^§ Available at http://www.cdc.gov/nchs/about/major/dvs/icd10des.htm.

^¶ Comparability ratio tables are available at ftp://ftp.cdc.gov/pub/health_statistics/nchs/datasets/comparability/icd9_icd10. Information regarding the calculation of comparability ratios is available at http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_08.pdf.

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Date last reviewed: 11/14/2007