Worldwide, research looking at the period 1990 to 2008 suggested that the incidence of type 1 diabetes is increasing by 2.8% to 4.0% per year. Similar trends have been observed in the US for white and Hispanic youth, although data has been limited.
Another previous study reported that, by the year 2050, the number of youth living with type 1 and type 2 diabetes would primarily be among children and adolescents in minority ethnic groups.
Identifying a lack of data on recent trends in the prevalence of type 1 and type 2 diabetes among American youth, the researchers behind the new study analyzed cases of doctor-diagnosed diabetes from centers located in California, Colorado, Ohio, South Carolina and Washington state. Data was also supplied from selected American Indian reservations in Arizona and New Mexico.
At the start of the study period, in 2001, 1.48 in 1,000 children within the study group had type 1 diabetes. By 2009, this had increased to 1.93 children in 1,000. After adjustments, this rise was calculated to be a 21% increase over the 8-year study period.
Increase in type 1 diabetes not confined to traditional at-risk group of white youth
The greatest increase, the study reports, was in teenagers between 15 and 19 years of age. Although diabetes tends to affect different ethnic groups in different ways, the researchers noted an increase across both sexes and in white, black, Hispanic and Asian Pacific Islander youth.
"Historically," the authors write, "type 1 diabetes has been considered a disease that affects primarily white youth; however, our findings highlight the increasing burden of type 1 diabetes experienced by youth of minority racial/ethnic groups as well."
For type 2 diabetes, the study reports a 30.5% rise between 2001 and 2009 in youth aged 10-19. However, despite increases in white, Hispanic and black youth, the researchers found no rise in Asian Pacific Islander and Native American youth.
This study had a very large sample size and it was able to include a racial/ethnic composition that accurately reflects the distribution of races in the US.
But because the study only took into account youth who had been diagnosed with diabetes by a physician, they may have missed undiagnosed children and adolescents who may meet the criteria for type 2 diabetes if they had been screened.
Also, the study period ended in 2009, so the study cannot provide any information about how diabetes trends have changed in the past 5 years.
Commenting on their findings, the authors say:
"The increases in prevalence reported herein are important because such 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. Further studies are required to determine the causes of these increases."