Seasonal variation in month of diagnosis in children with type 1 diabetes registered in 23 European centers during 1989-2008: little short-term influence of sunshine hours or average temperature

BACKGROUND

The month of diagnosis in childhood type 1 diabetes shows seasonal variation.

OBJECTIVE

We describe the pattern and investigate if year-to-year irregularities are associated with meteorological factors using data from 50 000 children diagnosed under the age of 15 yr in 23 population-based European registries during 1989-2008.

METHODS

Tests for seasonal variation in monthly counts aggregated over the 20 yr period were performed. Time series regression was used to investigate if sunshine hour and average temperature data were predictive of the 240 monthly diagnosis counts after taking account of seasonality and long term trends.

RESULTS

Significant sinusoidal pattern was evident in all but two small centers with peaks in November to February and relative amplitudes ranging from ± 11 to ± 38% (median ± 17%). However, most centers showed significant departures from a sinusoidal pattern. Pooling results over centers, there was significant seasonal variation in each age-group at diagnosis, with least seasonal variation in those under 5 yr. Boys showed greater seasonal variation than girls, particularly those aged 10-14 yr. There were no differences in seasonal pattern between four 5-yr sub-periods. Departures from the sinusoidal trend in monthly diagnoses in the period were significantly associated with deviations from the norm in average temperature (0.8% reduction in diagnoses per 1 °C excess) but not with sunshine hours.

CONCLUSIONS

Seasonality was consistently apparent throughout the period in all age-groups and both sexes, but girls and the under 5 s showed less marked variation. Neither sunshine hour nor average temperature data contributed in any substantial way to explaining departures from the sinusoidal pattern.

Treatment during a vulnerable developmental period rescues a genetic epilepsy

The nervous system is vulnerable to perturbations during specific developmental periods. Insults during such susceptible time windows can have long-term consequences, including the development of neurological diseases such as epilepsy. Here we report that a pharmacological intervention timed during a vulnerable neonatal period of cortical development prevents pathology in a genetic epilepsy model. By using mice with dysfunctional Kv7 voltage-gated K(+) channels, which are mutated in human neonatal epilepsy syndromes, we demonstrate the safety and efficacy of the sodium-potassium-chloride cotransporter NKCC1 antagonist bumetanide, which was administered during the first two postnatal weeks. In Kv7 current-deficient mice, which normally display epilepsy, hyperactivity and stereotypies as adults, transient bumetanide treatment normalized neonatal in vivo cortical network and hippocampal neuronal activity, prevented structural damage in the hippocampus and restored wild-type adult behavioral phenotypes. Furthermore, bumetanide treatment did not adversely affect control mice. These results suggest that in individuals with disease susceptibility, timing prophylactically safe interventions to specific windows during development may prevent or arrest disease progression.

Classifying insulin regimens--difficulties and proposal for comprehensive new definitions

Modern insulin regimens for the treatment of type 1 diabetes are highly individualized. The concept of an individually tailored medicine accounts for a broad variety of different insulin regimens applied. Despite clear recommendations for insulin management in children and adolescents with type 1 diabetes there is little distinctiveness about concepts and the nomenclature is confusing. Even among experts similar terms are used for different strategies. The aim of our review--based on the experiences of the Hvidoere Study Group (HSG)--is to propose comprehensive definitions for current insulin regimens reflecting current diabetes management in childhood and adolescence. The HSG--founded in 1994--is an international group representing 24 highly experienced pediatric diabetes centers, from Europe, Japan, North America and Australia. Different benchmarking studies of the HSG revealed a broad variety of insulin regimens applied in each center, respectively. Furthermore, the understanding of insulin regimens has been persistently different between the centers since more than 20 yr. Not even the terms 'conventional' and 'intensified therapy' were used consistently among all members. Besides the concepts 'conventional' and 'intensified', several other terms for the characterization of insulin regimens are in use: Basal Bolus Concept (BBC), multiple daily injections (MDI), and flexible insulin therapy (FIT) are most frequently used, although none of these expressions is clearly or consistently defined. The proposed new classification for insulin management will be comprehensive, simple, and catchy. Currently available terms were included. This classification may offer the opportunity to compare therapeutic strategies without the currently existing confusion on the insulin regimen.

Differential regulation of AMPK activation in leptin- and creatine-deficient mice

AMP-activated protein kinase (AMPK) is a key sensor and regulator of energy homeostasis. Previously, we demonstrated that intracellular energy depletion by L-arginine:glycine amidinotransferase (AGAT) deficiency resulted in AMPK activation and protected from metabolic syndrome. In the present study, we show tissue-specific leptin dependence of AMPK activation by energy depletion. We investigated leptin-dependent AMPK regulation in AGAT- and leptin-deficient (d/d ob/ob) mice. Like ob/ob mice, but unlike d/d mice, d/d ob/ob mice were obese and glucose intolerant. Therefore, leptin is a prerequisite for resistance to metabolic syndrome in AGAT-deficient mice. Quantitative Western blots revealed a 4-fold increase in AMPK activation in skeletal muscle of d/d ob/ob mice (P<0.001). However, AMPK activation was absent in white adipose tissue (WAT) and liver. Compared with blood glucose levels in ob/ob mice, fasting levels were still reduced and therefore did not show leptin dependence (wild-type, 79.4±3.9 mg/dl; d/d, 68.4±3.2 mg/dl; P<0.05). In ob/ob mice and wild-type mice, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), in combination with leptin, augmented glucose tolerance compared with AICAR alone, whereas no improvement was found under conditions of high-fat-diet feeding. These findings reveal a previously unknown synergistic AMPK activation by leptin and intracellular energy depletion, suggesting that AMPK activation can be therapeutically effective in metabolic syndrome only if leptin sensitivity is preserved.

L-arginine:glycine amidinotransferase deficiency protects from metabolic syndrome

Phosphorylated creatine (Cr) serves as an energy buffer for ATP replenishment in organs with highly fluctuating energy demand. The central role of Cr in the brain and muscle is emphasized by severe neurometabolic disorders caused by Cr deficiency. Common symptoms of inborn errors of creatine synthesis or distribution include mental retardation and muscular weakness. Human mutations in l-arginine:glycine amidinotransferase (AGAT), the first enzyme of Cr synthesis, lead to severely reduced Cr and guanidinoacetate (GuA) levels. Here, we report the generation and metabolic characterization of AGAT-deficient mice that are devoid of Cr and its precursor GuA. AGAT-deficient mice exhibited decreased fat deposition, attenuated gluconeogenesis, reduced cholesterol levels and enhanced glucose tolerance. Furthermore, Cr deficiency completely protected from the development of metabolic syndrome caused by diet-induced obesity. Biochemical analyses revealed the chronic Cr-dependent activation of AMP-activated protein kinase (AMPK), which stimulates catabolic pathways in metabolically relevant tissues such as the brain, skeletal muscle, adipose tissue and liver, suggesting a mechanism underlying the metabolic phenotype. In summary, our results show marked metabolic effects of Cr deficiency via the chronic activation of AMPK in a first animal model of AGAT deficiency. In addition to insights into metabolic changes in Cr deficiency syndromes, our genetic model reveals a novel mechanism as a potential treatment option for obesity and type 2 diabetes mellitus.

Trends in childhood type 1 diabetes incidence in Europe during 1989-2008: evidence of non-uniformity over time in rates of increase

AIMS/HYPOTHESIS

The aim of the study was to describe 20-year incidence trends for childhood type 1 diabetes in 23 EURODIAB centres and compare rates of increase in the first (1989-1998) and second (1999-2008) halves of the period.

METHODS

All registers operate in geographically defined regions and are based on a clinical diagnosis. Completeness of registration is assessed by capture-recapture methodology. Twenty-three centres in 19 countries registered 49,969 new cases of type 1 diabetes in individuals diagnosed before their 15th birthday during the period studied.

RESULTS

Ascertainment exceeded 90% in most registers. During the 20-year period, all but one register showed statistically significant changes in incidence, with rates universally increasing. When estimated separately for the first and second halves of the period, the median rates of increase were similar: 3.4% per annum and 3.3% per annum, respectively. However, rates of increase differed significantly between the first half and the second half for nine of the 21 registers with adequate coverage of both periods; five registers showed significantly higher rates of increase in the first half, and four significantly higher rates in the second half.

CONCLUSIONS/INTERPRETATION

The incidence rate of childhood type 1 diabetes continues to rise across Europe by an average of approximately 3-4% per annum, but the increase is not necessarily uniform, showing periods of less rapid and more rapid increase in incidence 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 is warranted.

Increased hospitalizations and death in patients with ESRD secondary to lupus

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect almost any organ system, including the kidneys. Using a large national dataset, our goal was to compare the morbidity as measured by hospitalization and mortality rates between hemodialysis patients with end-stage renal disease (ESRD) secondary to SLE to those with ESRD due to other causes.

METHODS

The risk of hospitalization was calculated by Poisson regression with clustering for repeated measures using the United States Renal Data System (USRDS) Hospitalization Analytic File in strata of pediatric and adult patients. Cox proportional hazard ratio was used to assess the mortality risk in hospitalized patients. Subjects were censored at transplantation or end of follow-up.

RESULTS

Adult patients with ESRD secondary to SLE were hospitalized more frequently than other adults (incidence rate ratio (IRR): 1.43, 95% confidence interval (CI): 1.15-1.77) and had a higher risk of death (hazard ratio (HR): 1.89, 95% CI: 1.66-2.5). Mortality was higher in hospitalized pediatric patients with SLE compared to pediatric patients with other causes of ESRD (HR: 2.01, 95% CI: 1.75-2.31) and adults with SLE (HR: 2.05, 95% CI: 1.79-2.34).

CONCLUSION

Our study demonstrates that there is a trend toward increased hospitalization rates in pediatric and adult patients with SLE. Among these hospitalized patients with SLE, there is an increased risk of death due to cardiovascular disease.

Incidence of type 1 diabetes in childhood before and after the reunification of Germany--an analysis of epidemiological data, 1960-2006

OBJECTIVE

To examine the impact of rapidly changing environmental factors on the incidence of type 1 diabetes mellitus (T1D).

METHOD

We compared the frequency of T1D in children before and after the reunification of Germany by means of the registries of the German Democratic Republic (GDR, 1960-1989) and of Baden-Wuerttemberg (BW, 1987-2006). The number of cases of diabetes onset in East Germany after the reunification was predicted by a mathematical model. The observed incidence rate in the Eastern part of Germany after the reunification was taken from the literature 1.

RESULTS

In Germany, the incidence rate of T1D in children aged 0-14 was 7.2/100 000/year (95%-CI 6.9-7.5, GDR, 1980-1987), and 10.4/100 000/year (95%-CI 9.5-11.4, BW, 1987-1994). For the whole observation period (1960-2006), the observed incidence rates y could be described by the square of a linear function [GDR: y=(1.86 + 0.040 * (year - 1960))²; r²=0.85; BW: y=(3.03 + 0.085 * (year - 1987))², r²=0.89]. The mean rise in incidence before the reunification was less than half the mean rise after the reunification (mean slope: BW 0.085, 95%-CI 0.080-0.090 vs. GDR 0.040, 95% CI 0.036-0.044). The observed incidence for East Germany after 1989 was higher than the prediction on the basis of the GDR -registry (GDR 12.3/100 000/year vs. Saxony 15.7/100 000/year, 95%-CI 14.2-17.3, n=412; 1999-2003).

CONCLUSION

We conclude that the basis for the disease progress is a genetic predisposition. Environmental factors may modify changes in incidence of type 1 diabetes but do not determine the overall risk.

[Frequency and influencing factors of ketoacidosis at diabetes onset in children and adolescents--a long-term study between 1995 and 2009]

BACKGROUND

Diabetic ketoacidosis (DKA) is a frequent acute complication at onset of type 1 diabetes. It is assumed that increased public awareness about diabetes symptoms may reduce DKA rate at diabetes onset. To investigate the time-dependent trend in DKA prevalence we analysed the frequency and determinants of DKA at disease onset over 15 years in pediatric patients.

PATIENTS AND METHODS

The prevalence of DKA at disease onset was analysed in individuals aged ≤18 years treated for the first time from 1995-2009 within 7 days after diagnosis in pediatric centers. Simple and multiple logistic regression analysis was performed to investigate influencing factors on DKA prevalence. Change of the probability of ketoacidosis over years were modelled in the logistic regression as linear trend.

RESULTS

16 562 individuals from 170 institutions were studied with a mean age of 9.2 ± 4.2 years. DKA (pH <7.3) was present in 20.8% of patients without a significant trend between 1995 and 2009 (p=0.222). DKA prevalence was higher in children ≤5 years (26.3%) and in the age group 10-15 years (21.7%) than in individuals aged 5-10 years (16.4%) and 15-18 years (16.9%, p<0.001). Girls had DKA more often than boys (21.2% vs. 19.3%, p=0.002). DKA frequency was increased in individuals with migration background (26.5% vs. 19.2%, p<0.001).

CONCLUSIONS

DKA prevalence at diabetes onset was constant at about 21% during the last 15 years. Very young children, pubertal adolescents, girls and individuals with migration background are at higher risk for DKA at diagnosis. To prevent DKA earlier diagnosis of type 1 diabetes is warranted especially in these patient groups.