Type 1 diabetes mellitus (T1DM) is one of the most common chronic diseases worldwide. Due to the complexity of its management and its chronic nature, it demands a high use of health care resources. Furthermore, it often begins in childhood, meaning that the consumption of these resources continues for decades. Epidemiological studies in T1DM allow us to analyze the distribution of the disease in a geographic area and a specific time or period, as well as temporal variations in its incidence. The data obtained can help plan health care resources dedicated to T1DM, and to study how possible etiological factors impact the incidence rate of this disease.

Standardized diabetes incidence registries began to be developed in the 1970s, allowing for comparisons between different geographical areas and confirming a great variability in the worldwide distribution of the disease. The European project EURODIAB1 and the global DIAMOND2 project by the World Health Organization (WHO) were the first registries with standardized methodology. The DIAMOND study calculates standardized incidence rates by direct adjustment using a standard population with an equal number of children for each age group (0–4 years, 5–9 years, and 10−14 years) and sex, calculating 95% confidence intervals based on the Poisson distribution. This study classifies geographical areas based on T1DM incidence: very low incidence rate: <1 case/100,000 inhabitants-year (c/10⁵ inhab-yr); low incidence rate: 1–4.99 c/10⁵ inhab-yr; intermediate incidence rate: 5–9.99 c/10⁵ inhab-yr; high incidence rate: 10–19.99 c/10⁵inhab-yr; very high incidence rate: ≥20 c/10⁵ inhab-yr.

In Spain, epidemiological studies on T1DM began with Serrano-Ríos in the Autonomous Community of Madrid, during the 1985–1988 period.3 The Diabetes Mellitus Registry of Catalonia started its journey between 1987 and 1990.4 Since then, various regional and local studies with heterogeneous methodologies have been published and communicated, providing data on the incidence of T1DM in various areas of the country.

In 2014, a paper was published that attempted to summarize the data collected in different studies conducted in Spanish autonomous communities, offering an estimate of the mean incidence in Spain of T1DM set at 17.69 c/10⁵inhab-yr.5

In recent years, new studies6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 have provided more recent data from some autonomous communities, using standardized methodology. Some regional registries have remained active,7, 16, 23, 24, 25 providing updated incidence data, as well as, in some cases, an estimation of the progression of T1DM incidence rate over time.7, 24

Currently, the IT systems and databases used in our health care systems (computerized primary care medical records, minimum basic data set [MBDS], electronic health record models) can facilitate the performance of these types of studies in Spain. Furthermore, at the national level, the Primary Care Clinical Database (BDCAP) constitutes a valuable source of information for determining the prevalence of certain diseases in Spain, including diabetes.29 The use of large databases will likely improve epidemiological studies of T1DM in Spain in the coming years.

The present work aims to update the epidemiological data of T1DM in pediatric age in Spain, based on publications and communications made about regional studies, giving relevance to those of higher quality and recency, as well as to analyze the data provided by the BDCAP database regarding diabetes in children younger than 15 years.