Incidence of Type 1 Diabetes Among Children and Adolescents During Peace and War Times in Yemen

Abstract

Background: The incidence of type 1 diabetes (T1D) among children and adolescents has been reported to be steadily increasing worldwide with considerable regional, national and ethnic differences. We aimed in this study to present a 30-year registry-based incidence data on T1D in Yemen, a low-income country, during peace and war times. Methods: A total of 461 children and adolescents aged more than 6 months to 18 years with newly-diagnosed diabetes were registered between1989-2018. We used a standardized registry protocol according to that established in the 155 center WHO Multinational (DiaMonod) Project for childhood diabetes. The registry as with other WHO DiaMond centers was primarily concerned with counting the frequency of new-onset cases of childhood diabetes over time across Sana’a city according to a standard set of specific criteria. Case reports registered were validated on the basis of a physician’s diagnosed diabetes in the records. Eligibility for registration was based on age < 19 years and permanent residence in Sana’a city. The annual incidence rates (cases/100,000 persons/year) were calculated from the numbers of new reported cases for each year (1989-2018) divided by the estimated numbers of person-years ‘at risk’ (population < 19 years) according to age and sex for that year. Completeness of case ascertainment for the identified number of cases was assessed with the use of the 2-source capture-recapture method throughout the study period. Findings: The mean annual incidence rate in children aged 0-14 years over the full observation period was 1.83/100,000/yr with 95% CI: (0.9, 2.74). With the use of 3-year time periods, the mean annual incidence rate was intermediate (5 per 100,000/yr) in the first time-period (1989-1991), low (1.56-2.3/100,000/yr) during subsequent 5 time-periods (1992-2006) and (1.2/100,000/yr) during the next 2 time-periods (2007-2012). Ultimately, there was a precipitous decline in incidence to a very low rate (0.5/100,000/yr) during the last two time-periods (2013-2018) which was the time when Yemen has experienced the conflict and war. The age-specific mean T1D annual incidence rates with the use of 3-year time periods for children aged 0-4 yr, 5-9 yr, 10-14 yr, and adolescents aged 15-18 yr over the full observation period (1989-2018) were 0.83, 1.82, 3.14, and 2.31/100,000/yr, respectively. On temporal trend analysis of incidence rates with the use of 3-years moving average, all trend curves indicated a decline for all participants aged 0-14 years and for other age groups, especially during the last 6 years of the observation period. The mean annual age-specific and sex-specific incidence rates over the full observation period were found to be increasing with increased age in both males and females, peaking at puberty (10-14 year old) with the associated gender effect. A seasonal trend in incidence of T1D was noted with more diagnoses of cases in the winter and autumn months and fewer in the summer months, a feature that was observed in both sexes and in all age groups. Interpretation: The mean incidence rate of T1D in children and adolescents in Sana’a city was found to be low. In children aged 0-14 years in particular, the rate was low during peace time, followed by a precipitous decline to a very low rate during the time of war. Economic destruction, poverty and shortage of food supply to a large sector of children and adolescents were likely associated with decreased incidence of childhood diabetes during war. Undernutrition and low standards of environmental hygiene with exposure to infections very early in childhood might have operated as a protective factor against pediatric-onset autoimmune diabetes. Funding Statement: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. Declaration of Interests: None declared. Ethics Approval Statement: Patient consent for publication was obtained from patients’ families. Ethical approval statement: This work was approved by the Ethical Committee at the Faculty of Medicine and Health Sciences, University of Sana’a