Type 1 diabetes (T1DM) has been previously associated with northern latitude and vitamin D insufficiency. This study investigates the geospatial association between average daily ultraviolet B (UVB) irradiance and T1DM across the province of Newfoundland (NL), Canada. NL has one of the highest documented incidences of T1DM worldwide. A complete list of patients diagnosed (1987-2005) with T1DM in the province of Newfoundland and Labrador (NL) was constructed using multiple sources. All places of habitation at diagnosis were ascertained. Ecological analysis using Bayesian estimation was performed employing both NASA UVB data and latitude. Correlation of T1DM to both UVB irradiation and latitude was measured. A statistically significant correlation of erythemal UVB irradiance was observed (-0.0284: 95% CI -0.0542 to -0.0096). A more significant correlation of T1DM was observed with erythemal UVB irradiance than with latitude. This study suggests that erythemal UVB radiation may be geospatially associated with the incidence of T1DM in NL.
The aim of this study was to determine the incidence of type 1 diabetes among children aged 0-14 years in the Avalon Peninsula in the Canadian Province of Newfoundland.
This was a prospective cohort study of the incidence of childhood type 1 diabetes in children aged 0-14 years who were diagnosed with type 1 diabetes from 1987 to 2002 on the Avalon Peninsula. Identified case subjects during this time period were ascertained from several sources and verified using the capture-recapture technique. Data were obtained from the only pediatric diabetes treatment center for children living on the Avalon Peninsula.
Over the study period, 294 children aged 0-14 years from the Avalon Peninsula were diagnosed with type 1 diabetes. The incidence of type 1 diabetes in this population over the period 1987-2002 inclusive was 35.93 with a 95% CI of 31.82-40.03. The incidence over this period increased linearly at the rate of 1.25 per 100,000 individuals per year.
The Avalon Peninsula of Newfoundland has one of the highest incidences of type 1 diabetes reported worldwide. The incidence increased over the 16-year study period.
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.
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.
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).
This study suggests that erythemal UVB radiation may be temporally associated with the incidence of T1DM.
Vitamin D deficiency is associated with poor bone health, colorectal cancer, type 1 diabetes and multiple sclerosis. Two national health-related societies in Canada have made recommendations for vitamin D supplementation, yet little research has been reported on the vitamin D status of Canadians. Lifestyle changes, such as sunscreen use, spending less time outdoors and insufficient intake of vitamin D-containing foods as well as northern latitude, may be affecting human vitamin D status. A cross-sectional analysis of 25-hydroxyvitamin D [25-(OH)D] was conducted in pregnant women, newborns (umbilical cord blood) and children. Samples were analysed by liquid chromatography mass spectrometry. Published ranges for 25-(OH)D were used to determine vitamin D status. The prevalence of 25-(OH)D deficiency for the three groups studied revealed most concentrations in the 25-(OH)D deficiency or insufficiency ranges. There were significant differences in all groups studied between seasons, with the exception of maternal blood and female cord blood samples. 25-(OH)D insufficiency was common in all groups for winter and summer, more so in winter. 25-(OH)D insufficiency was common in the three groups studied. The Newfoundland and Labrador population may be at increased risk for vitamin D insufficiency because of factors such as northern latitude and lifestyle issues. Further research on the vitamin D status of this population is important, considering the potential adverse health-related outcomes and the recommendations on supplementation being made.