"The incidence of type l diabetes (T1D), one of the most prevalent chronic diseases in children, has increased worldwide," write Valma Harjutsalo, Ph.D., of the Diabetes Prevention Unit, Helsinki, Finland, and colleagues, who conducted a study to examine the incidence rates of T1D between 2006 and 2011 in Finnish children younger than 15 years as well as the 32-year trend (1980-2011).
As reported in a Research Letter, all children with newly diagnosed T1D were ascertained using several nationwide registers. Age-standardized and age-specific annual incidence rates for age groups 0-4, 5-9, and 10-14 years were calculated. A total of 14,069 children (7,695 boys and 6,374 girls) were diagnosed with T1D between 1980 and 2011, of whom 3,332 were new cases between 2006 and 2011. The peak incidence was observed in 2006. Analysis indicated 2 significant changes in the longer-term trend. After a modest increase until 1988, the incidence increased annually by 3.6 percent until 2005, followed by a plateau until the end of 2011.
"The encouraging observation in this study is that the incidence of T1D in Finnish children younger than 15 years has ceased to increase after a period of accelerated increase. This may be due to changes in the environment, such as vitamin D intake. The amount of vitamin D recommended for supplementation in infants had been reduced to one-tenth since the 1950s, during which time the incidence of T1D increased 5-fold. The fortification of dairy products with vitamin D after 2003 may have contributed to the leveling off of T1D incidence," the authors write.