Time series analysis of ultraviolet B radiation and type 1 diabetes in Newfoundland.
BACKGROUND
Type 1 diabetes mellitus (T1DM) has been previously been associated with decreased levels of vitamin D. This study investigates the temporal association between average daily ultraviolet B (UVB) irradiance and T1DM in Newfoundland.


METHODS
A complete list of patients diagnosed with T1DM in the province of Newfoundland and Labrador was constructed using multiple sources. Pooled and unpooled monthly incidence data along with monthly UVB measurements were used to build a time series transfer function model. The model was used to predict the future incidence of T1DM based on previous monthly trends, and these predictions were compared with actual measured incidences.


RESULTS
A seasonal variation in pooled monthly incidence was observed. The transfer function model was able to reasonably predict the future incidence of T1DM based on previous observations and monthly UVB measurements. Tests of seasonality demonstrated a significant seasonal trend (p = 0.0003).


CONCLUSIONS
This study suggests that erythemal UVB radiation may be temporally associated with the incidence of T1DM.
Sloka
Scott
S
Faculty of Neurology, Memorial University of Newfoundland, St John's, NL, Canada. p97jss@mun.ca
Grant
Marie
M
Newhook
Leigh Anne
LA
D017668:Age of Onset; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D009523:Newfoundland and Labrador / Q000453:epidemiology; D012189:Retrospective Studies; D012621:Seasons; D014466:Ultraviolet Rays / Q000009:adverse effects