Rogers MAM, et al. - This longitudinal study was performed to compare the incidence of type 1 diabetes in youth (0–19 years) to that of adults (20–64 years) using nationwide data. In the United States, the researchers found more new cases of type 1 diabetes occurring annually than previously recognized. Findings suggested that in comparison to the adults, incidence rates were higher in youth. Thereby, suggesting precipitating factors of youth-adult disease could differ from those of adult-onset disease.

Methods

• The researchers used the Clinformatics Data Mart Database, which contains information from 61 million commercially insured Americans (years 2001-2015).
• They calculated incidence rates and exact Poisson 95% confidence intervals by age group, sex, census division, and year of diagnosis.
• They evaluated changes in rates over time by negative binomial regression.

Results

• The cohort comprised a total of 32,476 individuals who developed type 1 diabetes.
• In youth aged 10-14 years, the incidence rate was greatest (45.5 cases/100,000 person-years).
• However, there was a greater number of new cases in adults than in youth (n = 19,174 adults; n = 13,302 youth) because adulthood spans over a longer period than childhood.
• In males, predominance was evident by age 10 and persisted throughout adulthood.
• In this study, the male to female incidence rate ratio was 1.32 (95% CI 1.30-1.35).
• From 2001 to 2015, the incidence rate of type 1 diabetes in youth increased by 1.9% annually (95% CI 1.1-2.7%; P < 0.001), but there was variation across regions.
• They observed the greatest increases in the East South Central (3.8%/year; 95% CI 2.05.6%; P < 0.001) and Mountain divisions (3.1%/year; 95% CI 1.6–4.6%; P < 0.001).
• In addition, there were increases in the East North Central (2.7%/year; P=0.010), South Atlantic (2.4%/year; P < 0.001), and West North Central divisions (2.4%/year; P < 0.001).
• However, the incidence decreased from 2001 to 2015 (-1.3%/year; 95% CI -2.3% to -0.4%; P=0.007) in adults.
• For both youth and adults, greater percentages of cases were diagnosed in January, July, and August.
• In the United States, the number of new cases of type 1 diabetes (ages 0-64 years) was estimated at 64,000 annually (27,000 cases in youth and 37,000 cases in adults).