Incidence of type I diabetes in the Liguria Region, Italy. Results of a prospective study in a 0- to 14-year age-group

Prevalence and incidence of type 1 diabetes in the world: a systematic review and meta-analysis

Background: Diabetes is referred to a group of diseases characterized by high glucose levels in blood. It is caused by a deficiency in the production or function of insulin or both, which can occur because of different reasons, resulting in protein and lipid metabolic disorders. The aim of this study was to systematically review the prevalence and incidence of type 1 diabetes in the world. Methods: A systematic search of resources was conducted to investigate the prevalence and incidence of type 1 diabetes in the world. The databases of Medline (via PubMed and Ovid),ProQuest, Scopus, and Web of Science from January 1980 to September 2019 were searched to locate English articles. The located articles were screened in multiple levels of title, abstract,and full-text and final studies that met the inclusion criteria were retrieved and included in the study. Results: From 1202 located articles, 193 studies were included in this systematic review. The results of meta-analysis showed that the incidence of type 1 diabetes was 15 per 100,000 people and the prevalence was 9.5% (95% CI: 0.07 to 0.12) in the world, which was statistically significant. Conclusion: According to the results, the incidence and prevalence of type 1 diabetes are increasing in the world. As a result, insulin will be difficult to access and afford, especially in underdeveloped and developing countries.

Global and regional estimates of the morbidity due to type I diabetes among children aged 0-4 years: a systematic review and analysis

Background

Epidemiology of type 1 diabetes mellitus (T1DM) among children aged 0-4 years globally is not well understood. We aim to assess the incidence of T1DM in low- and middle-income countries (LMIC) by conducting a systematic review of previous reports. We also aim to address possible contribution to child mortality and to identify any temporal trends.

Methods

A systematic review was performed using a carefully designed search strategy to explore MEDLINE, EMBASE and Global Health databases. Data was extracted from all studies that satisfied the inclusion criteria –a total of 83 records extracted from 26 830 sources that were analysed. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process to assess quality of evidence and applied meta-analysis approaches to assess global and regional incidence and time trends.

Results

The overall pooled incidence of T1DM in children aged 0-4 years globally is 11.2 (95% CI = 10.0-12.3) per 100 000 child years. The regional incidence were the highest for European Region A (EUR A) at 15.5 (95% CI = 13.5-17.5) per 100 000 child years. EUR C had the incidence of 10.0 (95% CI = 6.5-13.6) and EUR B 5.8 (95% CI = 4.7-7.0), Region of the Americas A (AMR A) 11.4 (95% CI = 7.8-14.9), AMR B of 2.5 (95% CI = 0.2-4.8), Eastern Mediterranean Region (EMR B) 7.1 (95% CI = 4.2-10.0) and Western Pacific Region (WPR A) 7.0 (95% CI = 2.9-11.0) per 100 000 child years, while other regions had very low rates or no data. When data points were categorised in the study periods and re-analysed, an increasing trend of the T1DM incidence was observed, with the incidence of 20.9 (95% CI = 7.8-34.1) per 100 000 child years in the years 2010-2015, preceded by 13.2 (95% CI = 11.0-15.5) in 2000-2009 study period, 10.0 (95% CI = 8.4-11.7) in 1990-1999 and 8.3 (95% CI = 5.1-11.6) in 1980-1989, respectively. Although the data are scarce, and variation and uncertainty are large, we estimated that the number of new cases of T1DM among children aged 0-4 years in the world each year is between 100 000 and 150 000.

Conclusions

The identified large variation in incidence estimates for different parts of the world, along with scarcity of information and the identified strong temporal increase in T1DM incidence suggest a clear need for further research into this subject.

Diabetes incidence in 0- to 14-year age-group in Italy: a 10-year prospective study

OBJECTIVE

The Registry for Type 1 Diabetes Mellitus in Italy (RIDI) Study Group was established to coordinate the registries of type 1 diabetes in Italy. This report is based on 3,606 children younger than 15 years diagnosed with type 1 diabetes and prospectively registered during 1990-1999 by nine centers, covering >35% of the Italian population.

RESEARCH DESIGN AND METHODS

Registries were pooled in four geographic macro-areas: north, central, south, and insular. The completeness of registration was assessed by the capture-recapture method. Poisson regression analysis was used to evaluate temporal trend in incidence.

RESULTS

Large variations in incidence were confirmed not only between Sardegna and the mainland but also among peninsular areas. In Sardegna, there was an excess of boys (the boy-to-girl incidence ratio was 1.4). The overall incidence showed average increases of 3.6% (P <0.001) and 3.7% (P <0.001) per year in peninsular Italy and in Sardegna, respectively. Significant increases in incidence rates were found in boys aged 10-14 years (6.7%, 95% CI 0.5-13.3) and in girls aged 5-9 years (6.6%, 0.5-13.1) living in the southern area. The incidence rate also increased in boys aged 10-14 years (5.0%, 0.3-10) and in girls aged 0-4 years (4.9%, 0.8-9.1) living in Sardegna.

CONCLUSIONS

Italy is a country with large geographical variations in incidence rates of type 1 diabetes. However, the rates are evenly increasing both in the mainland and Sardegna, suggesting that similar environmental factors are operating over populations that have different genetic backgrounds.

Hidden diabetes in the UK: use of capture-recapture methods to estimate total prevalence of diabetes mellitus in an urban population

An early requirement of the UK's Diabetes National Service Framework is enumeration of the total affected population. Existing estimates tend to be based on incomplete lists. In a study conducted over one year in North Liverpool, we compared crude prevalence rates for type 1 and type 2 diabetes with estimates obtained by capture-recapture (CR) analysis of multiple incomplete patient lists, to assess the extent of unascertained but diagnosed cases. Patient databases were constructed from six sources-a hospital diabetes centre; general practitioner registers; hospital admissions with a diagnosis of diabetes; a hospital diabetic retinal clinic; a research list of patients with diabetes admitted with stroke; and a local children's hospital. Log linear modelling was used to estimate missing cases, hence total prevalence. The crude prevalence of diabetes was 1.5% (95% confidence interval [CI] 1.41, 1.52), compared with a CR-adjusted rate of 3.1% (CI 3.03, 3.19). Age-banded CR-adjusted prevalence was always higher in males than in females and the difference became more pronounced with increasing age. Among males, CR-adjusted prevalence rose from 0.4% at age 10-19 years to 18.3% at 80+ years; in females the corresponding figures were 0.4% and 9.3%. The gap between crude and CR-estimated prevalence points to a rate of 'hidden diabetes' that has substantial implications for future diabetes care.

Hidden diabetes in the UK: use of capture-recapture methods to estimate total prevalence of diabetes mellitus in an urban population

An early requirement of the UK's Diabetes National Service Framework is enumeration of the total affected population. Existing estimates tend to be based on incomplete lists. In a study conducted over one year in North Liverpool, we compared crude prevalence rates for type 1 and type 2 diabetes with estimates obtained by capture-recapture (CR) analysis of multiple incomplete patient lists, to assess the extent of unascertained but diagnosed cases. Patient databases were constructed from six sources-a hospital diabetes centre; general practitioner registers; hospital admissions with a diagnosis of diabetes; a hospital diabetic retinal clinic; a research list of patients with diabetes admitted with stroke; and a local children's hospital. Log linear modelling was used to estimate missing cases, hence total prevalence. The crude prevalence of diabetes was 1.5% (95% confidence interval [CI] 1.41, 1.52), compared with a CR-adjusted rate of 3.1% (CI 3.03, 3.19). Age-banded CR-adjusted prevalence was always higher in males than in females and the difference became more pronounced with increasing age. Among males, CR-adjusted prevalence rose from 0.4% at age 10-19 years to 18.3% at 80+ years; in females the corresponding figures were 0.4% and 9.3%. The gap between crude and CR-estimated prevalence points to a rate of 'hidden diabetes' that has substantial implications for future diabetes care.

High incidence of childhood type 1 diabetes in Liguria, Italy, from 1989 to 1998

OBJECTIVE

Assessing updated incidence of type 1 diabetes in 0- to 14-year-old children in Liguria, a Northwest region of Italy.

RESEARCH DESIGN AND METHODS

Incident cases were recorded prospectively from 1989 to 1998. Incidence rates (IRs) were standardized to the 1999 world population using the direct method. The independent effect of sex, age, residence, and calendar year was estimated with Poisson regression model. The degree of ascertainment was calculated in accordance to capture/recapture method.

RESULTS

During 10 full calendar years, 219 new cases of type 1 diabetes in children were diagnosed in Liguria. The standardized IR over the 10-year period was 12.56 cases per 100,000 per year (95% CI 11.0-14.3). The sex-specific IR among men and women was 14.15 and 10.88, respectively. The age-specific IR was higher in the 10- to 14-year-old age-group (15.01/100,000) than in 0- to 4-year-old age-group (9.01/100,000) and in the 5- to 9-year-old age-group (13.03/100,000).

CONCLUSIONS

The IR of type 1 diabetes in Liguria is among the highest in Southern Europe and approaches IRs of Northern European countries. In particular it is much higher than those reported in the surrounding Italian regions except for Sardinia. Therefore, the geographical distribution of type 1 diabetes does not seem to reflect the simple North-South gradient reported in several previous works.

Seasonal variation in the incidence of Type 1 diabetes mellitus during 1983 to 1992 in the countries around the Baltic Sea

AIM

To examine seasonal patterns of incidence of Type 1 diabetes mellitus incidence in children aged 0-14 years in Finland, Sweden, Estonia, Latvia and Lithuania during 1983-1992 (1987-1992 for Finland).

METHODS

The study used a method that models incidence data using combinations of sine waves to model seasonal variation around a possible linear trend.

RESULTS

In Finland, a significant pattern was found for combined sexes and age groups 0-9 and 10-14 years. A significant pattern was also confirmed for 10-14 year-old boys. In Sweden, the best model with significant pattern was found separately for boys and girls and age groups 0-9 and 10-14 years, however, a significant pattern was confirmed for older girls only. A seasonal pattern in older boys in Finland and girls in Sweden was characterized by two cycles with decreased incidence in June and November-December. The pattern among younger children (0-9 or 5-9 years) had one cycle with a decreased incidence in May-June. In Estonia, a significant pattern was found for the age group 0-14 years and combined sexes. No significant seasonal patterns were found in Latvia and Lithuania.

CONCLUSIONS

The seasonal pattern with two cycles among older children and one cycle only among younger children may indicate different triggers of Type 1 diabetes mellitus for different age groups.

The epidemiology of Type 2 diabetes and its current measurement

Type 2 diabetes is globally increasing in prevalence and is widely recognized as a major cause of morbidity and mortality, as well as being a burden to the health-care services. Planning for current and future diabetes services requires up-to-date prevalence information. The enumeration of Type 2 diabetes is, however, surprisingly difficult. Large numbers of people are undiagnosed, and those known cases have variable loci of care. Traditional techniques include cross-sectional diagnostic surveys, postal or house-to-house surveys and cohort surveys. All are time-consuming and expensive, and may potentially undercount. The use of multiple patient lists (e.g. hospital clinic data, general practitioner (GP) lists, prescribing information, etc.) can, however, increase accuracy and, if the data are computerized, may be rapid and inexpensive. A new and potentially exciting tool to utilize multiple lists in Type 2 diabetes prevalence assessment is known as 'capture-recapture'. In this, statistical models are used to estimate prevalence from the degree of overlap between lists. Capture-recapture is emerging as a valuable tool in the epidemiological assessment of Type 2 diabetes.

New insights into the epidemiology of type 1 diabetes in Mediterranean countries

In Mediterranean countries, the incidence (per 100,000 per year) of Type 1 diabetes in children aged under 15 years shows wide variation from country to country, ranging from 2.45 in Macedonia to 34.4 in Sardinia. By interacting with environmental factors such as diet, toxins or viral infections, the HLA plus non-HLA genes of susceptibility or resistance to Type 1 diabetes so far identified are the strongest determinants of the disease as far as incidence, age at onset and sex ratio are concerned. The distribution of these genes in the Mediterranean region is still not completely known. Sardinians are the most suitable population for studying such phenomena for three main reasons: their genetic features have been repeatedly analysed in depth; their incidence rate of Type 1 diabetes is by far the highest in the Mediterranean area; and considerable colonies of Sardinian emigrants settled in neighbouring low-incidence Italian regions. Studies on Spaniards and Jews have also contributed to a better understanding of the respective roles of genetic and environmental factors. From a body of research on the Mediterranean populations, it can be concluded that great genetic heterogeneity accounts for the wide variation in incidence of Type 1 diabetes, while rather ubiquitious environmental factors trigger the disease in genetically predisposed individuals.

Regional variability in the epidemiology of childhood diabetes in Italy

The incidence rates of IDDM in Italy show remarkable variability. Sardinia, a region with the second highest incidence rate in the world, co-exists with other regions with lower rates. We review and compare epidemiologic data on the incidence of childhood-onset IDDM in Italy. papers published from 1980 to 1996 reporting incidence data in Italian areas were found by search of Medline and non-indexed Italian journals. The incidence data found cover only 57% of the Italian population. The analysis of our results shows how difficult it is to make a careful study of epidemiology of IDDM in Italy. The RIDI (the Registry for Insulin-dependent Diabetes mellitus in Italy) project started in 1996 according to international guidelines. The aims is to coordinate local IDDM registries, to promote the start of new registries in uncovered areas, and to standardize registration and data collection.

Regional differences in the incidence of insulin-dependent diabetes mellitus among children in Finland from 1987 to 1991. Childhood Diabetes in Finland (DiMe) Study Group

The regional pattern of insulin-dependent diabetes mellitus (IDDM) incidence among children in Finland was analysed applying several methods attempting to describe the geographical variation in occurrence of IDDM. From 1987 to 1991 the number of newly diagnosed cases aged 14 years or less at diagnosis was 1728. The incidence, the incidence rate ratio and the Bayes relative risk (RR) for IDDM were calculated by municipality, by functional area (an urban centre with a subordinated surrounding area) and by area with a population of equal size at risk employing the Geographical Information Systems. The association of IDDM incidence with the degree of urbanization was assessed using the population density as a criterion for the degree of urbanization. The overall mean of the IDDM incidence was 35 per 100000 persons per year. Between municipalities the incidence varied from 4 to 245 per 100000 persons per year, whereas a clear regional pattern was seen among the functional areas and the incidence varied from 26 to 43 per 100000 persons per year. The RR for IDDM among the municipalities ranged from 0.82 to 1.34 and from 0.73 to 1.27 among the functional areas. The incidence determined in four zones with the same size of population was the highest in the middle part of the country. There was a strong inverse correlation between population density and the incidence of IDDM and this also applied to the relationship between child population density and incidence.