Seasonality of month of birth of children and adolescents with type 1 diabetes mellitus in homogenous and heterogeneous populations.
BACKGROUND
Type 1 childhood-onset diabetes mellitus has a multifactorial origin involving an interplay between genetic and environmental factors. We have previously shown that many children who subsequently develop T1DM have a different seasonality of birth than the total live births of the same population, supporting the hypothesis that perinatal viral infection is a trigger for the autoimmune process of T1DM.


OBJECTIVE
To compare the seasonality of children with T1DM in different populations around the world for which data were available.


METHODS
We analyzed large cohorts of T1DM patients with a clinical disease onset before age 14 or 18 years.


RESULTS
We found a seasonality pattern only in ethnically homogenous populations (such as Ashkenazi Jews, Israeli Arabs, individuals in Sardinia and Canterbury, New Zealand, and Afro-Americans) but not in heterogeneous populations (such as in Sydney, Pittsburgh and Denver).


CONCLUSIONS
Our findings attempt to explain the controversial data in the literature by showing that ethnically heterogeneous populations comprising a mixture of patients with various genetic backgrounds and environmental exposures mask the different seasonality pattern of month of birth that many children with diabetes present when compared to the general population.
Laron
Zvi
Z
Endocrinology and Diabetes Research Unit and WHO Collaborating Center, Schneider Children's Medical Center of Israel, Petah Tiqva. laronz@clalit.org.il
Lewy
Hadas
H
Wilderman
Igor
I
Casu
Anna
A
Willis
Jinny
J
Redondo
Maria Jose
MJ
Libman
Ingrid
I
White
Neil
N
Craig
Maria
M
D000293:Adolescent; D018912:Arabs / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000208:ethnology* / Q000235:genetics / Q000821:virology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000208:ethnology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007557:Israel / Q000453:epidemiology; D007585:Jews / Q000706:statistics & numerical data; D008297:Male; D044469:Racial Groups / Q000706:statistics & numerical data; D012621:Seasons; D014777:Virus Diseases / Q000276:immunology