Incidence of childhood type 1 diabetes worldwide. Diabetes Mondiale (DiaMond) Project Group.

Abstract

OBJECTIVE: To investigate and monitor the patterns in incidence of childhood type 1 diabetes worldwide. RESEARCH DESIGN AND METHODS: The incidence of type 1 diabetes (per 100,000 per year) from 1990 to 1994 was determined in children < or =14 years of age from 100 centers in 50 countries. A total of 19,164 cases were diagnosed in study populations totaling 75.1 million children. The annual incidence rates were calculated per 100,000 population. RESULTS: The overall age-adjusted incidence of type 1 diabetes varied from 0.1/100,000 per year in China and Venezuela to 36.8/100,000 per year in Sardinia and 36.5/100,000 per year in Finland. This represents a >350-fold variation in the incidence among the 100 populations worldwide. The global pattern of variation in incidence was evaluated by arbitrarily grouping the populations with a very low (<1/100,000 per year), a low (1-4.99/100,000 per year), an intermediate (5-9.99/100,000 per year), a high (10-19.99/100,000 per year), and a very high (> or =20/100,000 per year) incidence. Of the European populations, 18 of 39 had an intermediate incidence, and the remainder had a high or very high incidence. A very high incidence (> or =20/ 100,000 per year) was found in Sardinia, Finland, Sweden, Norway Portugal, the U.K., Canada, and New Zealand. The lowest incidence (<1/100,000 per year) was found in the populations from China and South America. In most populations, the incidence increased with age and was the highest among children 10-14 years of age. CONCLUSIONS: The range of global variation in the incidence of childhood type 1 diabetes is even larger than previously described. The earlier reported polar-equatorial gradient in the incidence does not seem to be as strong as previously assumed, but the variation seems to follow ethnic and racial distribution in the world population.

The epidemiology of Type 1 diabetes mellitus is not the same in young adults as in children

“…A potential problem with this study is the completeness of ascertainment, which was lower than in the childhood studies [4,6,7]. This is a reflection of the difficulties encountered when trying to ascertain young adults, who are less visible in the health care system, while diabetes in this age group is more heterogeneous and classification more complex.…”

“…The incidence of Type 1 diabetes in children varies more than tenfold across Europe and 350-fold between Finland and China [4,7]. We selected study areas with a childhood incidence ranging from 5.3 per 100000 person years (Bucharest) to 41.6 per 100000 person years (Sardinia), and showed that there is far less variation in incidence in young adults from the same regions.…”

“…Studies of the epidemiology of Type 1 diabetes in different populations can provide important clues about putative environmental risk factors. The incidence of the disease in children up to 15 years of age is well documented by two multi-centre studies [4,5,6,7], with incidence varying from less than 1 per 100000 person years in Venezuela and China to more than 35 per 100000 person years in Finland and Sardinia. Furthermore, recent studies suggest a higher rate of increase in disease among children younger than 5 years than in children between 5 and 15 years of age [8,9,10,11], although other studies have not observed a differential rise in incidence [12,13,14].…”

Type 1 diabetes in Japan

“…The incidence was greatest among children of 10-14 years of age at onset (Table 1), as in most populations studied worldwide [21]. The increase in Japan was mainly due to a rapid increase in the number of children aged 10-14 years, in contrast to countries with populations of Caucasoid origin (Fig.…”

Prospective incidence study of diabetes mellitus in New Zealand children aged 0 to 14 years

“…While increasing rates of obesity and sedentary lifestyles appear to account for the increase in type 2 diabetes, relatively little is known about why type 1 diabetes is increasing. Since the earliest registers of type 1 diabetes, it has been evident that a large (at least 35-fold) geographical difference in incidence exists, which has persisted until today [3]. Although these differences are considered to result from varying distributions of genetic and environmental risk factors, the exact variations and contributions of these risk factors remain unknown.…”