Incidence and Prevalence of Type 1 Diabetes in Children and Adolescents in Benghazi,Libya

The mean annual incidence rates of Type 1 diabetes mellitus in Arab children and adolescents in Benghazi, Libya were assessed as based on prospective registration of patients during the period 1981–1990. Results showed an annual incidence (per 100 000) of 7.0 (6.0–8.2) (males 6.3(5.0–7.9) females 7.8(6.3–9.7)) in 0–14 year olds and 8.8(7.8–10.0) (males 8.3(6.9–10.0), females 9.2(7.7–11.0)) in 0–19 year olds. There were no significant differences between males and females or between season of onset. The commonest age of onset was 15–19 years. Annual variations were significant in the 0–14 years age group (p < 0.001) and non-significant in the 0–19 years age group. In 1981 the age adjusted prevalence rates of Type 1 patients (per 100 000) were 23.5 (17.1–31.5) (males 21.2(13.1–32.3), females 25.9(16.8–38.3)) in 0–14 year olds and 36.2(29.1–45.1) (males 31.4(22.2–43.2), females 41.0(30.2–54.5)) in 0–19 year olds. In 1990 the prevalence rates had increased to 37.3(30.5–45.5) (males 40.7(30.8–53.3), females 33.8 (24.6–45.3)) in 0–14 year olds and 59.5(51.6–58.5) (males 60.3(49.3–73.6), females 58.6 (47.7–72.1)) in 0–19 year olds. Increase in prevalence rates was significant in both sexes and in both age groups (p < 0.001). Increase in prevalence rates in girls in 1981 and in boys in 1990 were not significant. It is concluded that Type 1 diabetes is a common chronic disease of children and adolescents in Benghazi, Libya.     

Further evidence for the rising incidence of childhood Type 1 diabetes in Kuwait.

AIMS: To provide age-gender standardized incidence rate, temporal trend and seasonal variation of Type 1 diabetes in Kuwaiti children aged < or = 14 years. METHODS: Data were prospectively collected over a period of 6 years (1992-1997) according to the DiaMond Project protocol using the capture-recapture method of ascertainment. RESULTS: Data ascertainment varied between 90% and 96%. The incidence rate of Type 1 diabetes was 20.1 per 100,000 children 0-14 years (95% confidence interval (CI) 18.0-22.1); age-standardized incidence rate 20.9 (95% CI 18.8-23.0). The incidence rate among boys, 21.1 per 100,000 (95% CI 18.1-24.1) was slightly higher than that among girls, 19.0 per 100,000 (95% CI 16.1-21.8). The age-standardized incidence rate was 21.9 (95% CI 18.9-24.8) in boys, and 19.9 (95 CI 17.1-22.8) in girls. Incidence rates increased with age in both sexes (boys chi(2) for linear trend = 13.5, P < 0.001; and for girls chi(2) = 27.8, P < 0.0001). There was a significant trend towards increase in overall incidence during the 6-year period (chi(2) = 6.210, P = 0.013), and in age group 5-9 (chi(2) = 10.8, P = 0.001). Seasonality was demonstrated overall, in boys and girls (P < 0.001). CONCLUSION: The incidence of Type 1 diabetes in Kuwait is high compared with the neighbouring Arab countries, and it appears to be increasing as in many European populations.     

Rising incidence of type 1 diabetes in Hungarian children (1978-1987). Hungarian Childhood Diabetes Epidemiology Group

A retrospective epidemiological study using primary data sources and external validation was conducted to assess the incidence of childhood (0 to 14 years) Type 1 diabetes in Hungary (excluding the Budapest region) over a 10-year period. Hospital records and regional diabetes centres' registries served as primary data sources, and data were validated by using the records of summer camps for diabetic children. The degree of ascertainment was 96.2%. Age-specific incidence rates increased until puberty with peak incidence in girls at 10 yr, and in boys at 13 yr. There was a significant seasonal variation of onset with peaks in autumn and winter. The incidence was slightly lower amongst boys than amongst girls. A statistically significant increase in incidence was evident in the last decade, from 3.8 per 100,000 in 1978 to 8.2 per 100,000 in 1987.     

Incidence of Type 1 (insulin-dependent) diabetes mellitus in Catalonia, Spain

Summary The incidence of Type 1 (insulin-dependent) diabetes mellitus was prospectively evaluated in Catalonia, Spain in patients up to 30 years of age during the period 1987–1990. The population at risk (0–29 years) consisted of 2,690,394 inhabitants (total population of Catalonia 5,978,638). All the cases were independently identified from four sources: endocrinologists, sales of blood glucose monitors and insulin pen injectors, diabetes societies and diabetic summer camps. The degree of ascertainment was 90.1 %. The overall observed incidence rate was 10.7 per 100,000 per year, being 11.5 per 100,000 per year in the 0–14 age group. The incidence in males (12.0 per 100,000 per year) was higher than in females (9.3 per 100,000 per year), with a male/female ratio of 1.36/l. The sex differences were only present in cases over 14 years of age. Age specific incidence rates per 100,000 per year were 4.4 (confidence interval 95%: 3.2–5.7) in the age group 0–4, 9.9 (8.5–11.4) in 5–9, 17.5 (15.7–19.4) in 10–14, 11.4 (9.9–13.0) in 15–19, 11.3 (9.7–13.0) in 20–24 and 8.5 (7.2–9.9) in 25–29. There was a seasonal onset pattern, with the highest incidence in winter (December–February). We conclude that the incidence of Type 1 diabetes observed in Catalonia during the period 1987–1990 is higher than that recently reported in other Mediterranean countries. This study offers the first standardized data on Type 1 diabetes incidence in Catalonia, including cases up to 30 years, and contributes to the knowledge of the epidemiology of diabetes in South Europe.     

Epidemiology of childhood diabetes mellitus in Finland--background of a nationwide study of type 1 (insulin-dependent) diabetes mellitus. The Childhood Diabetes in Finland (DiMe) Study Group.

Summary A nationwide study of childhood Type 1 (insulin-dependent) diabetes mellitus was established in 1986 in Finland, the country with the highest incidence of this disease worldwide. The aim of the project called Childhood Diabetes in Finland is to evaluate the role of genetic, environmental and immunological factors and particularly the interaction between genetic and environmental factors in the development of Type 1 diabetes. From September 1986 to April 1989, 801 families with a newly-diagnosed child aged 14 years or younger at the time of diagnosis were invited to participate in this study. The vast majority of the families agreed to participate in the comprehensive investigations of the study. HLA genotypes and haplotypes were determined in 757 families (95%). Our study also incorporates a prospective family study among non-diabetic siblings aged 3–19 years, and two case-control studies among the youngonset cases of Type 1 diabetes. During 1987–1989, the overall incidence of Type 1 diabetes was about 35.2 per 100,000 per year. It was higher in boys (38.4) than in girls (32.2). There was no clear geographic variation in incidence among the 12 provinces of Finland. Of the 1,014 cases during these 3 years only six cases were diagnosed before their first birthday. The incidence was high already in the age group 1–4-years old: 33.2 in boys and 29.5 in girls. Of the 801 families 90 (11.2%) were multiple case families, of which 66 had a parent with Type 1 diabetes at the time of diagnosis of the proband. The prevalence of Type 1 diabetes in the parents of these newly-diagnosed diabetic children was higher in fathers (5.7%) than in mothers (2.6%).     

The incidence of Type 1 (insulin-dependent) diabetes in Toronto

Summary An incidence of 9.0 out of 100,000 children under 19 years of age with Type 1 (insulin-dependent) diabetes was detected in Toronto during a 2 year prospective study. An increased number of cases occurred in the winter months of one of the years but not of the other during the study. The annual incidence was the same in each year. There were slightly more boys than girls but this was not significant. The diabetic children were significantly younger than their non-affected siblings. The incidence of Type 1 diabetes in Toronto is similar to other North American studies.     

Type 1 diabetes mellitus in Czech children diagnosed in 1990-1997: a significant increase in incidence and male predominance in the age group 0-4 years. Collaborators of the Czech Childhood Diabetes Registry.

AIMS: To overview total, age-and sex-specific incidence rates of type 1 diabetes mellitus and their trends in Czech children 0-14 years of age in the period of 1990-1997. METHODS: Type 1 DM cases were ascertained by two independent sources, data of general population were obtained from the annual demographic reports of the State Statistic Bureau. Incidence rates were computed using both ascertainment sources combined. RESULTS: In the study period 1.1.1990-31.12.1997, the total incidence was 10.1 (95% CI 9.6-10.6) per 100,000/year in both sexes, 10.0 (95% CI 9.4-10.7) in boys, and 10.2 (95% CI 9.5-11.0) in girls. The total age-standardized incidence was 9.9 (95% CI 9.4-10.4). The total incidence had a significant increasing trend over the study period (P= 10(-4), annual increment 4.3%). A significant increasing trend was also found in the groups of children 0-4 (P = 0.033, increment 6.9%) and 5-9 years at diagnosis (P = 0.038, increment 4.8%). Statistically significant male predominance was observed in the group diagnosed at age 0-4 years (boys/girls ratio of incidence 1.33, P = 0.035). CONCLUSIONS: We report the first population-based epidemiological data on incidence of childhood Type 1 DM in the Czech Republic. The incidence has increased significantly during the last 8 years. The present incidence is at an intermediate level compared to other European countries.     

Australia’s national trends in the incidence of Type 1 diabetes in 0–14‐year‐olds, 2000–2006

Aims To determine the national incidence of Type 1 diabetes in children aged 0–14 years and examine trends in incidence between 2000 and 2006 by age, sex and calendar year. Methods Case ascertainment was from the Australian National Diabetes Register, a prospective population‐based incidence register established in 1999, with two sources of ascertainment: the National Diabetes Services Scheme and the Australasian Paediatric Endocrine Group’s state‐based registers. Denominator data were from the Australian Bureau of Statistics. Results There were 6350 new cases of Type 1 diabetes (3323 boys and 3027 girls). Case ascertainment was 97.1% complete using the capture–recapture method. The mean adjusted incidence rate for 2000–2006 was 21.6 per 100 000 person‐years [95% confidence interval (CI) 21.0, 22.1], and increased from 19.8 in 2000 to 23.4 per 100 000 in 2006, an average increase of 2.8% (95% CI 1.5, 4.1) per year. Mean incidence for the 7‐year period increased with age, and was significantly higher in boys aged 0–4 years and 10–14 years than in girls of the same age. Conclusions The incidence of Type 1 diabetes among 0–14‐year‐olds in Australia is very high compared with available data from many other countries. The rate of increase observed globally in the last decade has continued well into this decade in Australia. The rising incidence cannot be explained by changes in genetic susceptibility; there is an urgent need to examine the environmental factors that have contributed to this increase. The findings of this study also have important implications for resource planning.     

Incidence of Type 1 diabetes mellitus in children aged 0-14 in Japan, 1986-1990, including an analysis for seasonality of onset and month of birth: JDS study. The Data Committee for Childhood Diabetes of the Japan Diabetes Society (JDS).

AIMS: To detect the incidence of childhood Type 1 diabetes mellitus (DM) (0-14 years) in Japan and to find out whether there is a seasonal pattern in the onset of disease and month of birth of children with diabetes. METHODS: Ascertained data for the period 1986-1990 could be collected in 35 out of 47 local government areas representing 69.4% of the childhood population (aged 0-14 years) of Japan. RESULTS: A total of 1,260 children with Type 1 DM were identified (738 girls, 522 boys). With age there was a progressive increase in incidence from 0.7 to 2.1/10(5) in boys and from 0.6 to 3.5/10(5) in girls. With the exception of 1987, when a coxsackie B3 virus epidemic was registered, no seasonal variation in the month of onset was observed, nor was a seasonal pattern of the month of birth registered in this cohort. CONCLUSIONS: Compared to European countries, the USA and Israel, the Japanese cohort of children with diabetes presents the following differences: the incidence is much lower, there is a preponderance of girls and there is (with one exception) no seasonal pattern.     

Prevalence and incidence of insulin-treated diabetes mellitus in adults in Canterbury, New Zealand.

A population-based diabetes register showed a prevalence of insulin-treated diabetes mellitus (n = 1148) in Canterbury, New Zealand, of 3.3 per 1000 population at 1 January 1984. Median age was 52 years, with equal sex distribution. Eleven percent were aged 0-19 years. Prevalence was highest in those aged 50 years or more, reaching 7.6 per 1000 in the 70-79 years age group. Only 28% of cases presented with diabetes under 20 years of age. Of those diagnosed in adulthood, only 17% did not commence insulin therapy as their permanent treatment modality within 12 months post-diagnosis. Incidence of new insulin-requiring diabetic cases between 1981 and 1986 (excluding persons commencing insulin more than 12 months after diagnosis) was 12.8 per 100,000 per year. There were two incidence peaks, one in adolescence (16.9 per 100,000), the other in the older age group. Rates in the elderly peaked at 25.9 per 100,000 for males aged 60-69 years, and at 19.5 per 100,000 for females aged 70 or more years. Only 83 of the 268 new cases starting insulin within this period were 0-19 years of age. Based on prevalence surveys of diabetes mellitus in Canterbury, New Zealand, it was determined that 14.3% of all known adult diabetic people were insulin-treated.     

Very High Incidence of Type 1 Diabetes Among Children Aged Under 15 Years in Tlemcen,Northwest Algeria (2015-2018)

Objective:In Algeria, there is a lack of epidemiological data concerning childhood type 1 diabetes (T1D). The International Diabetes Federation estimated in 2019 that Algeria ranked 7th among countries with the highest prevalence of T1D. This study aimed to determine the incidence of T1D in children <15 years, living in Tlemcen in Northwest Algeria.Methods:A retrospective study using data from children (<15 years) who have been diagnosed with T1D in Tlemcen between 2015 and 2018, using the two-source capture–recapture method to estimate the completeness of ascertainment (%). Total average incidences, by sex, by onset age group, and by season of onset were calculated per 100,000 and per year.Results:During the study period, 437 new cases of T1D were registered, among them, 233 boys and 204 girls, with a sex ratio of 1.14. The average annual incidence rate of childhood T1D was 38.5/100,000 with a 95% confidence interval (CI): 35.20-41.79; boys: 40.51, 95% CI: 38.16-42.85; girls: 36.49, 95% CI: 34.17-38.80. Overall incidence rates in 2015, 2016, 2017 and 2018 were respectively 36.6 (95% CI: 33.72-39.48), 38.7 (95% CI: 35.43-41.97), 39.3 (95% CI: 35.97-42.62) and 39.5 (95% CI: 36.12-42.87)/100,000. Newly diagnosed children were more likely to present in winter and autumn. Ketoacidosis at diagnosis was diagnosed in 29.2%.Conclusion:The mean incidence of childhood T1D in Tlemcen was 38.5/100,000, this incidence is in the “extremely high” category of the World Health Organization DiaMond project classification of diabetes giving this region a very high risk.     

The age at diagnosis of type 1 diabetes continues to decrease in Belgian boys but not in girls: a 15-year survey

BACKGROUND: The age at clinical onset of type 1 diabetes is decreasing. Preliminary Belgian data suggested that this anticipation occurred preferentially in boys. We investigated whether this gender-specific anticipation could be confirmed over a 15-year observation period. METHODS: In Antwerp, we studied incidence trends between 1989 and 2003 in 746 type 1 diabetic patients under age 40. For 2928 antibody-positive patients diagnosed nationwide during the same period, age at diagnosis was analysed according to gender and calendar year. RESULTS: In Antwerp, the incidence of type 1 diabetes under age 15 increased significantly with time from 10.9/100 000/year in 1989-1993 to 15.8/100 000/year in 1999-2003 (p = 0.008). The rising incidence in children was largely restricted to boys under age 10 where the incidence more than doubled during the 15-year period (6.8/100 000/year in 1989-1993 vs 17.2/100 000/year in 1999-2003; p < 0.001). Such an increase was not found in girls under age 10 (p = 0.54). This selective trend toward younger age at diagnosis in boys was confirmed in the larger group of Belgian patients where the median age at diagnosis decreased in boys-but not in girls-from 20 years in 1989-1993 to 15 years in 1999-2003 (p < 0.001). CONCLUSIONS: Over a 15-year observation period, a selective anticipation of clinical onset of type 1 diabetes was found in boys but not in girls. This suggests that an environmental factor may preferentially accelerate the sub-clinical disease process in young boys.     

Incidence and prevalence of Type 1 (insulin-dependent) diabetes mellitus in Icelandic children 1970–1989

Summary Through use of primary and secondary data sources for registration and validation, the incidence and prevalence of Type 1 (insulin-dependent) diabetes mellitus in children aged 0–14 years in Iceland has been completely ascertained for the years 1970–1989. The age-adjusted mean annual incidence per 100,000 for the 20-year period was 9.4 (95% confidence interval 7.8–11.3); similar for boys (9.9; 7.7–12.7) and girls (8.8; 6.7–11.5). Between 1970–1979 the incidence was 8.0 (6.0–10.6) and between 1980–1989 it was comparable at 10.8 (8.4–13.8) (p>0.10). By Poisson regression analysis the variation in incidence was related to age at diagnosis (p<0.001), while a linear trend for calendar year at diagnosis did not reach statistical significance (p=0.07). A quadratic curve, however, better described the temporal variation in incidence (p<0.05). The total prevalence per 1,000 by the end of 1979 and 1989 was similar, 0.45 (0.30–0.65) and 0.57 (0.40–0.79), respectively. In conclusion, this study confirms that both the incidence and prevalence of childhood Type 1 diabetes in Iceland are low compared to the other Nordic countries. The findings may suggest a causative role for environmental factors that are not related to latitude or ambient temperature.     

The Swedish childhood diabetes study — results from a nine year case register and a one year case-referent study indicating that Type 1 (insulin-dependent) diabetes mellitus is associated with both Type 2 (non-insulin-dependent) diabetes mellitus and autoimmune disorders

Summary From July 1, 1977 to July 1, 1986, 3,503 incident cases of Type 1 (insulin-dependent) diabetes mellitus were registered in the Swedish childhood diabetes study. Using data from this register and from a case-referent study, including all incident Type 1 diabetic children in Sweden during one year and, for each patient, two referent children matched according to age, sex and county, we have studied the associations between Type 1 diabetes and familial Type 1 and Type 2 (non-insulin-dependent) diabetes, thyroid, adrenal, allergic, rheumatic, heart and bowel disease. The mean annual incidence per 100,000 during the nine year period was 25.1 for boys and 23.5 for girls. In 8.5% of the patients, one parent had Type 1 diabetes, 73% of whom were fathers. Fifty-six of the patients (1.7%) had a parent with Type 2 diabetes. The prevalence of parental Type 1 diabetes tended to be higher in patients with younger age at onset; whereas, the opposite was found for patients with parental Type 2 diabetes. In the case-referent study, the age-adjusted odds ratio for Type 1 diabetes when a first and/or second degree relative had Type 1 diabetes was 5.5 (95% confidence limits 4.0–7.7), and in accordance with the findings of the case register, the odds ratio tended to be highest in patients with the youngest age at onset. Season at onset of the patients was not associated with parental Type 1 diabetes. The odds ratio for Type 1 diabetes was significantly increased 3.3 (95% confidence limits: 2.3–4.6) when Type 2 diabetes was reported in relatives (three generations). Odds ratios were also significantly increased (p(0.05) when thyroid or rheumatic diseases were reported among relatives.It is concluded that although the majority of incident Type 1 diabetic children lack family history, parental Type 1 diabetes may influence the age at onset of the disease but has no effect on sex distribution of these children. An increased risk for Type 1 diabetes in children is also indicated when Type 2 diabetes, (non-insulin-treated) thyroid or rheumatic disease is reported in relatives.     

Incidence and prevalence of Type 1 (insulin-dependent) diabetes in Estonia in 1988

Summary The objective of this study was to determine the incidence and prevalence of Type 1 (insulin-dependent) diabetes in Estonia in different sex and age groups. The data collection was based on a centralized retrospective registration of all cases of Type 1 diabetes nationwide using the records of all hospitals and polyclinics where diabetic patients are treated. In 1988, 35 new cases of Type 1 diabetes were diagnosed among children aged 0–14 years (10.3 per 100,000) and 131 among the population over 15 years. The highest incidence of Type 1 diabetes (39.9 per 100,000) was found in the age group 15–19 years. The total number of patients with Type 1 diabetes in Estonia was 2,719 in 1988. The overall prevalence was 1.72 per 1,000. It was highest in the age group 40–49 years (3.04 in males and 2.77 in females). In children under 15 years 204 cases of Type 1 diabetes were identified at the end of 1988. These data suggest that the risk of Type 1 diabetes in Estonia is not low, but is certainly not as high as in Finland where the population is ethnically and linguistically similar and where the highest incidence of Type 1 diabetes is found.     

The epidemiology of diabetes in Swedish children 0–14 years — a six-year prospective study

Summary Since 1 July 1977, all newly diagnosed diabetic children in Sweden aged 0–14 years have been reported to a central register. During the first 6 years, 2300 newly diagnosed diabetic children out of a population of 1.6 million children were registered. The degree of certainty was close to 100%. The mean of the yearly incidence rate for the whole 6 year period was 23.6 per 100000. The prevalence of insulin dependent diabetes mellitus on 1 July 1980 was 1.48 per 1000 and 1.52 on 1 July 1983. Comparing the first and second 3-year periods, an increase was found (22.7–25.1 per 100000). This increase was consistent when analyzing incidence rates by age, sex, and geographical distribution. Cumulative incidence rates revealed a risk of developing diabetes by the age of 15 years of 3.6 per thousand for boys and 3.2 per thousand for girls. The higher incidence for boys was consistent throughout the study period. Seasonal variations in the incidence rate were also consistent, showing yearly incidence peaks in the autumn and winter months. Incidence peaks were noted for both sexes in the pubertal ages. Age- and sex-standardized morbidity ratios varied significantly within the country. 12.8% of the probands had a first degree relative with Type 1 diabetes, and it was twice as common that this relative was a father as a mother. The high and rapidly increasing incidence of Type 1 diabetes in a genetically stable population such as Sweden calls for case-control studies directed towards the identification of environmental pathogens.     

Epidemiology of childhood diabetes in Osaka District, Japan, using the documents from the medical benefits system specific for childhood diabetes.

For an epidemiological study of childhood diabetes, application forms for medical benefits filed in Osaka Prefecture were collected and analyzed. A total of 465 patients with childhood diabetes under 18 yr of age were identified during the period between 1978 and 1988; 371 (175 boys and 196 girls) of them were classified as insulin-dependent diabetes mellitus (IDDM), and the others were either non-insulin-dependent diabetes mellitus (NIDDM) or an unidentified type of diabetes. The mean annual incidence of IDDM was 1.68 for boys and 2.00 for girls per 100,000 population, the rate being slightly higher for girls. The rates increased among older children, with a peak in the 10-14-yr age group. The prevalence estimated on the basis of the cumulative incidence in 1988 was 1.29 for boys and 1.60 for girls per 10,000 population, indicating a marked increasing trend with age. A significant seasonal variation was observed in the months of onset for IDDM, with higher rates during the winter. The mean birth weights of the male and female patients with IDDM were slightly lower than the national means. Use of official documents obtained from the medical benefits system was found to be an effective method for identification of cases of IDDM in the community, although further information is required for more accurate confirmation of such cases.     

Incidence of Type 1 diabetes in children in Cáceres, Spain, during 1988-1999

AIM: To determine the incidence of Type 1 diabetes in Cáceres in children less than 14 years of age. We tested for differences in incidence by age, sex and season at diagnosis. METHODS: All Type 1 diabetes cases with onset <14 years of age between 1988 and 1999 were recorded retrospectively. Pediatric Unit registries provided the primary source of ascertainment. The secondary independent data source was based on the registries of local Diabetic Associations, diabetes camp records and guarantee cards of blood-glucose meters. We used the capture-recapture method for ascertainment. RESULTS: During the 12-year period, 137 new cases of Type 1 diabetes were identified. Completeness of ascertainment was 99.2%. Average annual observed incidence was 16.8/100,000/year (95% C.I. 14.1-19.8). Age-standardised incidence (world population): 16.5/100,000/year (95% C.I. 13.9-19.6). Average annual incidence for 0-4, 5-9 and 10-13-year-old groups: 12.7/100,000 (95% C.I. 8.8-17.9), 18.2/100,000 (95% C.I. 13.7-23.8) and 19.1/100,000 (95% C.I. 14.2-25.1). The highest age-specific annual incidence rate was found in the 10-13-year age group. There was a seasonal onset pattern, with the highest incidence in autumn and winter. November was the month with the highest number of cases (22/137). CONCLUSION: Cáceres has a moderately high incidence of Type 1 diabetes in children less than 14 years of age, similar to that found in other more developed and densely populated regions of Spain, and in the range of other countries of northern Europe. These data do not support the hypothesis of a decrease in the incidence of the disease from north to south over Europe.     

Epidemiology of type 1 (insulin-dependent) diabetes in Scotland 1968–1976: Evidence of an increasing incidence

Summary A computer file of all Scottish hospital admissions in the period 1968–1976 was searched to identify the 2,505 children (aged < 19 years) with a diagnosis of diabetes. The average annual incidence of the disease (based on first hospital admission) was estimated to be 13.8 per 100,000 children aged < 19 years (boys 14.4 per 100,000; girls 13.2 per 100,000). The highest incidence, 20.0 per 100,000 was in the age group 10–14 years and the lowest 7.1 per 100,000 in those aged < 5 years. It is estimated that during the study period there was an 80% increase in the annual incidence of juvenile diabetes, from about 10 per 100,000 in 1968 to about 18 per 100,000 in 1976. First admission rates showed seasonal variations for those aged 5 years or more, with peaks in October/November and January/February. Marked variation was found in the incidence rates in the different counties of Scotland. The central lowlands which includes the cities of Edinburgh and Glasgow was an area of low incidence. There appeared to be an inverse correlation between the incidence rate in each county and population density. In Glasgow, there was an inverse association between the incidence rate in each city ward and the average number of persons per room. There was no evidence of space-clustering of the disease in different years within the parishes (rural districts) of each county and there was no convincing evidence that the variation in the incidence of diabetes between parishes in the same county was more than might have been expected to arise by chance. The observations are compatible with the disease having a viral aetiology but it is difficult to explain the striking rise in incidence over the study period on this basis.