Clinical characteristics of type 1 diabetes over a 40 year period in Turkey: secular trend towards earlier age of onset.
OBJective: To determine the demographic and clinical characteristics of type 1 diabetes (T1D) in the past two decades, and to analyze changing trends over the past 40 years.


METHODS
Patients with a diagnosis of T1D in 1990-2010 were included. Patients diagnosed in the first half of the period comprised Period I, and those from the second half comprised Period II. Age at onset, gender, seasonal distribution, infectious etiology, and clinical picture at onset are analyzed and compared in two periods. In addition, we compared these data with that of the preceding two decades (1969-1991), which was reported in a previous publication.


RESULTS
A total of 354 children with T1D were included in the study. The median age at diagnosis of T1D was 7 years in the period 1990-2010 in comparison to 9.5 years during the period 1969-1991. Patients were diagnosed mostly in winter and autumn, and 32.3% of the children had an infection at the time of diagnosis. Frequency of diabetic ketoacidosis was 50.8% at diagnosis. The peak age at onset was 4 to 6 years.


CONCLUSIONS
Our study provides substantial information about the clinical characteristics of Turkish children. The age of onset of T1D decreased in the past 20 years, as observed in other parts of the world. Our findings also suggest seasonality at onset of T1D. This study shows the changes of demographic and clinical characteristics of T1D in central and northeastern parts of our country over a 40 year period.
Didem
D
Ardicli
Nurgun
N
Kandemir
Ayfer
A
Alikasifoglu
Alev
A
Ozon
Nazli
N
Gonc
D017668:Age of Onset; D001327:Autoimmune Diseases / Q000150:complications; D002648:Child; D002675:Child, Preschool; D003241:Consanguinity; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000453:epidemiology*; D016883:Diabetic Ketoacidosis / Q000453:epidemiology / Q000209:etiology; D005192:Family Health; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012189:Retrospective Studies; D012621:Seasons; D014421:Turkey / Q000453:epidemiology