UVB predicts incidence of type 1 diabetes in Newfoundland 2008
Pediatric Diabetes Volume 9 Issue 2, Pages 81 - 86   Online: 24 Jan 2008
Time series analysis of ultraviolet B radiation and type 1 diabetes in Newfoundland
Scott Sloka a , Marie Grant b Leigh Anne Newhook b
  a Faculty of Neurology, Memorial University of Newfoundland, St John's, NL, Canada; and  bFaculty of Pediatrics, Memorial University of Newfoundland, St John's, NL, Canada
Correspondence to  Scott Sloka
Memorial University of Newfoundland
108 Moss Heather Dr  St John's, NL  Canada, A1B 4S1.  e-mail: p97jss@mun.ca
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.

Submitted 9 March 2007. Accepted for publication 19 July 2007