SAN FRANCISCO — From age 15 years onward, Hispanic females in the United States are significantly more likely to be diagnosed with incident type 2 diabetes than type 1 diabetes, according to an analysis of data from the Search for Diabetes in Youth study.
In addition, at ages 10–14 years, Hispanic females in the United States had twice the incidence of type 2 diabetes in 2002–2005, compared with Hispanic males. The study looked at youths less than 20 years old in populations from six states, Jean M. Lawrence and her associates reported at the annual scientific sessions of the American Diabetes Association.
During that period, 635 youths were diagnosed with diabetes out of a population of more than 3 million, with incidence rates peaking for females at ages 5–9 years and for males at ages 10–14 years, said Ms. Lawrence of Kaiser Permanente Southern California, in Pasadena. She had no conflicts of interest related to the study.
Incidence rates for type 1 diabetes in girls were 9/100,000 in ages 0–4 years, 20/100,000 in ages 5–9 years, 16/100,000 in ages 10–14 years, and 7/100,000 in ages 15–19 years. For boys, incidence rates for type 1 diabetes were 11/100,000 in ages 0–4 years, 16/100,000 in ages 5–9 years, 20/100,000 in ages 10–14 years, and 9/100,000 in ages 15–19 years.
Type 2 diabetes rarely was diagnosed in children less than 10 years old. For ages 10–14 years, the incidence of type 2 diabetes was 15/100,000 for girls and 7/100,000 for boys. For ages 15–19 years, the incidence was 13/100,000 for girls and 11/100,000 for boys.
The study identified prevalent diabetes in the year 2001 in 781 out of more than 641,000 Hispanic youths—most of it type 1. Prevalence rates did not differ significantly by sex in any of the age groups for either type of diabetes.
The prevalence increased with age for both diabetes types in both sexes. In those aged 15–17 years, the prevalence of type 1 diabetes was 1.6/1,000 for girls and 1.8/1,000 for boys, and the prevalence of type 2 diabetes was 0.8/1,000 for girls and 0.6/1,000 for boys.
Data from two other studies presented during the same session at the meeting showed steep increases in the incidence and prevalence of diabetes in Canadians and a faster than predicted rise in type 1 diabetes in Finland, which has long held the record for having the highest national incidence of type 1 diabetes.
In the Canadian study, data on diabetes in residents younger than 20 years of age in the province of Alberta showed 2,301 prevalent cases in 840,000 children and adolescents, for a rate of 28/10,000. About 80% of cases were in 10- to 19-year-olds, said Jeffrey A. Johnson, Ph.D., of the University of Alberta, Edmonton, and his associates. The prevalence of diabetes increased by 47% between 1995 and 2006, from 19/10,000 to 28/10,000, said Dr. Johnson, who had no conflicts of interest related to the study.
The annual incidence rate in Alberta increased from 2/10,000 in 1995 to 3/10,000 in 2006, with most of that in patients younger than 10 years. The researchers weren't “able to separate diabetes types” in their study, but Dr. Johnson noted that other epidemiologic data suggest “this is likely an increase in type 1 diabetes.”
Incidence rates increased 68% for ages 1–4 years, 68% for ages 5–9 years, 43% for ages 10–14 years, and 3% for ages 15–19 years. The annual incidence rate rose about 5% annually through 2002, then hit a plateau or declined in subsequent years. It's not clear if the declines were real or artifacts related to changes in the Canadian health system, he said.
In Finland, the most recent analysis of nationwide data shows an even steeper increase in incidence than expected, said Dr. Jaako Tuomilehto of the University of Helsinki. The incidence of type 1 diabetes rose from 34/100,000 residents in 1984 to 64/100,000 in 2005. A 2% annual increase in diabetes incidence before the 1990s doubled in more recent years, with the greatest relative increase in ages 0–4 years. He has been an adviser, speaker, or board member for, or received research funds from, Novo Nordisk, Merck & Co., and other makers of diabetes drugs or equipment.
ELSEVIER GLOBAL MEDICAL NEWS