Seasonal variation in month of diagnosis in children with type 1 diabetes registered in 23 EURODIAB centres during 1989-2008

Objectives: To investigate seasonal variation in month of diagnosis in children with type 1 diabetes registered in EURODIAB centres during 1989-2008.
Methods: 23 population-based registers recorded date of diagnosis in new cases of clinically diagnosed type 1 diabetes in children aged under 15 years. Completeness of ascertainment was assessed through capture-recapture methodology and was high in most centres. A general test for seasonal variation (11df) and Edward's test for sinusoidal (sine wave) variation (2df) were employed. Time series methods were also used to investigate if meteorological data were predictive of monthly counts after taking account of seasonality and long term trends.
Results: Significant seasonal variation was apparent in all but two small centres, with an excess of cases apparent in the winter quarter. Significant sinusoidal pattern was also evident in all but two small centres with peaks in December (14 centres), January (5 centres) or February (2 centres). Relative amplitude varied from ±11% to ±39% (median ±18%). There was no relationship across the centres between relative amplitude and incidence level. However there was evidence of significant deviation from the sinusoidal pattern in the majority of centres. Pooling results over centres, there was significant seasonal variation in each age-group at diagnosis, but with significantly less variation in those aged under 5 years. Boys showed marginally greater seasonal variation than girls. There were no differences in seasonal pattern between four sub-periods of the 20 year period. In most centres monthly counts of cases were not associated with deviations from normal monthly average temperature or sunshine hours; short term meteorological variations do not explain numbers of cases diagnosed.
Conclusions: Seasonality with a winter excess is apparent in all age-groups and both sexes, but girls and the under 5s show less marked variation. The seasonal pattern changed little in the 20 year period.

EURODIAB childhood type 1 diabetes incidence registers - results from the first 20 years. Oral presentation at the 47th EASD Annual Meeting, Lisbon, Portugal.

Background and aims: In 1989 a number of registers in Europe began recording new cases of type 1 diabetes diagnosed in children aged under 15 years using a common protocol. Trends in incidence rate during the 20 year period 1989-2008 are described.
Materials and methods: All registers operate in geographically defined regions and are based on a clinical diagnosis. When possible, completeness of registration in each register is assessed using capture-recapture methodology by identifying primary and secondary sources of ascertainment. The completeness estimate is obtained by identifying the numbers of cases identified by the primary source only, by the secondary source only and by both the primary and the secondary sources.
Results: Other registers have joined the Group since 1989, and 21 registers in 15 countries continue to submit registration data. In the first five years (1989-93) incidence rates varied from 3.2 per 100,000 in the Former Yugoslav Republic of Macedonia to 25.8 per 100,000 in the Stockholm area of Sweden. In the last five years (2004-2008) these same two registers again had the lowest and highest incidence, but rates had increased to 5.8 per 100,000 and 36.6 per 100,000, respectively. During the 20 year period all but two of the 21 registers showed statistically significant rates of increase (median rate of increase 4% per annum), and similar figures were obtained when this median rate of increase was estimated for the first half of the period (1989-98) and for the second half (1999-2008) . However, rates of increase differed significantly between the first half and the second half of the period for eight of the 17 registers with adequate coverage of both periods; four registers showing significantly higher rates of increase in the first half and four significantly higher rates in the second half.
Conclusion: The childhood type 1 diabetes incidence rate continues to rise across Europe by approximately 4% per annum, but the increase within a register is not necessarily uniform with periods of less rapid and more rapid increase in incidence occurring in some registers. This pattern of change suggests that important risk exposures differ over time in different European countries. Further time trend analysis and comparison of the patterns in defined regions are warranted.

EURODIAB childhood type 1 diabetes incidence registers - results from the first 20 years

Background and aims: In 1989 a number of registers in Europe began recording new cases of type 1 diabetes diagnosed in children aged under 15 years using a common protocol. Trends in incidence rate during the 20 year period 1989-2008 are described.
Materials and methods: All registers operate in geographically defined regions and are based on a clinical diagnosis. When possible, completeness of registration in each register is assessed using capture-recapture methodology by identifying primary and secondary sources of ascertainment. The completeness estimate is obtained by identifying the numbers of cases identified by the primary source only, by the secondary source only and by both the primary and the secondary sources.
Results: Other registers have joined the Group since 1989, and 21 registers in 15 countries continue to submit registration data. In the first five years (1989-93) incidence rates varied from 3.2 per 100,000 in the Former Yugoslav Republic of Macedonia to 25.8 per 100,000 in the Stockholm area of Sweden. In the last five years (2004-2008) these same two registers again had the lowest and highest incidence, but rates had increased to 5.8 per 100,000 and 36.6 per 100,000, respectively. During the 20 year period all but two of the 21 registers showed statistically significant rates of increase (median rate of increase 4% per annum), and similar figures were obtained when this median rate of increase was estimated for the first half of the period (1989-98) and for the second half (1999-2008) . However, rates of increase differed significantly between the first half and the second half of the period for eight of the 17 registers with adequate coverage of both periods; four registers showing significantly higher rates of increase in the first half and four significantly higher rates in the second half.
Conclusion: The childhood type 1 diabetes incidence rate continues to rise across Europe by approximately 4% per annum, but the increase within a register is not necessarily uniform with periods of less rapid and more rapid increase in incidence occurring in some registers. This pattern of change suggests that important risk exposures differ over time in different European countries. Further time trend analysis and comparison of the patterns in defined regions are warranted.

New susceptibility Loci associated with kidney disease in type 1 diabetes

Diabetic kidney disease, or diabetic nephropathy (DN), is a major complication of diabetes and the leading cause of end-stage renal disease (ESRD) that requires dialysis treatment or kidney transplantation. In addition to the decrease in the quality of life, DN accounts for a large proportion of the excess mortality associated with type 1 diabetes (T1D). Whereas the degree of glycemia plays a pivotal role in DN, a subset of individuals with poorly controlled T1D do not develop DN. Furthermore, strong familial aggregation supports genetic susceptibility to DN. However, the genes and the molecular mechanisms behind the disease remain poorly understood, and current therapeutic strategies rarely result in reversal of DN. In the GEnetics of Nephropathy: an International Effort (GENIE) consortium, we have undertaken a meta-analysis of genome-wide association studies (GWAS) of T1D DN comprising ~2.4 million single nucleotide polymorphisms (SNPs) imputed in 6,691 individuals. After additional genotyping of 41 top ranked SNPs representing 24 independent signals in 5,873 individuals, combined meta-analysis revealed association of two SNPs with ESRD: rs7583877 in the AFF3 gene (P?=?1.2×10(-8)) and an intergenic SNP on chromosome 15q26 between the genes RGMA and MCTP2, rs12437854 (P?=?2.0×10(-9)). Functional data suggest that AFF3 influences renal tubule fibrosis via the transforming growth factor-beta (TGF-ß1) pathway. The strongest association with DN as a primary phenotype was seen for an intronic SNP in the ERBB4 gene (rs7588550, P?=?2.1×10(-7)), a gene with type 2 diabetes DN differential expression and in the same intron as a variant with cis-eQTL expression of ERBB4. All these detected associations represent new signals in the pathogenesis of DN.

Novel susceptibility locus at 22q11 for diabetic nephropathy in type 1 diabetes

Diabetic nephropathy (DN) affects about 30% of patients with type 1 diabetes (T1D) and contributes to serious morbidity and mortality. So far only the 3q21-q25 region has repeatedly been indicated as a susceptibility region for DN. The aim of this study was to search for new DN susceptibility loci in Finnish, Danish and French T1D families.

Analysis of the association between diabetic nephropathy and polymorphisms in the aldose reductase gene in Type 1 and Type 2 diabetes mellitus

To investigate the association between polymorphisms of the aldose reductase gene and diabetic nephropathy in both Type 1 and Type 2 diabetes mellitus, and to carry out a meta-analysis of published results.

Possible association between CTLA4 DNA polymorphisms and early onset type 1 diabetes in a UK population

Linkage and association has been reported between CTLA4 DNA markers and susceptibility to type 1 diabetes in some populations, but not others. We performed case-control and family-based association studies to assess if the CTLA4 A49G and intron 1 C/T polymorphisms were associated with development of early onset type 1 diabetes in the Northern Ireland population. The distribution of A49G and C/T alleles in cases (n = 144) was similar to those observed in controls (n = 307). In contrast, significant distortions in allele transmissions from informative parents to probands were observed for both the A49G (P = 0.02) and C/T (P = 0.01) polymorphisms employing 297 nuclear families. Our results suggest that the CTLA4 gene may play a minor role in the overall genetic predisposition to type 1 diabetes in this UK population.

CD11b+ bone marrow-derived monocytes are the major leukocyte subset responsible for retinal capillary leukostasis in experimental diabetes in mouse and express high levels of CCR5 in the circulation

We investigated the phenotype of cells involved in leukostasis in the early stages of streptozotocin-induced diabetes in mice by direct observation and by adoptive transfer of calcein-AM-labeled bone marrow-derived leukocytes from syngeneic mice. Retinal whole mounts, confocal microscopy, and flow cytometry ex vivo and scanning laser ophthalmoscopy in vivo were used. Leukostasis in vivo and ex vivo in retinal capillaries was increased after 2 weeks of diabetes (Hb A(1c), 14.2 ± 1.2) when either donor or recipient mice were diabetic. Maximum leukostasis occurred when both donor and recipient were diabetic. CD11b(+), but not Gr1(+), cells were preferentially entrapped in retinal vessels (fivefold increase compared with nondiabetic mice). In diabetic mice, circulating CD11b(+) cells expressed high levels of CCR5 (P = 0.04), whereas spleen (P = 0.0001) and retinal (P = 0.05) cells expressed increased levels of the fractalkine chemokine receptor. Rosuvastatin treatment prevented leukostasis when both recipient and donor were treated but not when donor mice only were treated. This effect was blocked by treatment with mevalonate. We conclude that leukostasis in early diabetic retinopathy involves activated CCR5(+)CD11b(+) myeloid cells (presumed monocytes). However, leukostasis also requires diabetes-induced changes in the endothelium, because statin therapy prevented leukostasis only when recipient mice were treated. The up-regulation of the HMG-CoA reductase pathway in the endothelium is the major metabolic dysregulation promoting leukostasis.