Worldwide, the incidence of type 1 diabetes increased, on average, 3% per year between 1960 to 1996 in children under age 15 (Onkamo et al. 1999). Between 1990 and 1999, the worldwide average rate of incidence increase in children under 15 was 2.8%, reaching 3.4% during the 1995-1999 time period. Incidence increased in most continents, with a rise of 5.3% in North America , 4% in Asia, and 3.2% in Europe. This trend is especially troubling in the youngest children; from 1990-1999, for every hundred thousand children under age 5, 4% more were diagnosed every year, on average, worldwide (Diamond Project Group 2006).
Essentially all researchers agree that changes of this magnitude cannot be explained by genetic changes alone. In fact, studies are finding that high risk susceptibility genes for type 1 diabetes are becoming less frequent over time in children, while more children with low to moderate risk genes are developing the disease more now than in years past (Vehik et al. 2008; Steck et al. 2011). An interesting study from Poland analyzed susceptibility genes from exhumed skeletons from the Middle Ages, and found that genetic predisposition to type 1 diabetes is lower today than it was 700 years ago (Witas et al. 2010).
Around World War 2, in developed countries, but more recently in later developing countries.
The incidence of type 1 diabetes has been rising in children since about the mid-20th century in many European and North American countries (Gale 2002b). What has changed during this time period? A number of things changed that may influence the development of type 1 diabetes, including: breastfeeding rates, diet, height and weight, vitamin D levels, infectious disease, vaccines, earlier puberty, factors relating to gestation and birth, and more. A major change that has garnered less attention in studies of type 1 diabetes is environmental contamination. Yet perhaps we should pay attention: the historical patterns of contamination are consistent with historical patterns of type 1 diabetes incidence.
The rise in type 1 diabetes incidence is coincidental with the large-scale production and use of many industrial and agricultural chemicals. Like the rising incidence of type 1 diabetes, large-scale chemical production also began around the middle of the 20th century (Tanabe 2002). In 1975 about 60,000 chemicals were manufactured or processed in the U.S.; in 1997 there were over 75,000 (Endocrine Disruptor Screening and Testing Advisory Committee (1998) Final Report U.S. EPA). Chemical production increased during this time as well.
Maybe, depending on where you live.
A study from Sweden provides some hope that the trend is leveling off: it found that incidence was increasing in children born through the year 2000, but after that the trend might be flattening. It is too early to say whether this is in fact the case, or just a blip in the data (Berhan et al. 2011). Data from Norway show that the rising incidence has essentially leveled off since 2004 (Skirvarhaug et al. 2014).
Data from Finland, however, show that type 1 incidence appears to be increasing even more rapidly since the mid-1990s than in earlier decades (Harjutsalo et al. 2008).
Data from China show that the prevalence of childhood diabetes is rapidly starting to increase (Fu et al. 2013).
I have been making a list of countries that have documented increases in type 1 diabetes published in scientific journals. These include 58 countries:
Algeria, Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, Chile, China, Colombia, Croatia, Cyprus, Czech Republic, Denmark, Dominican Republic, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Israel, Italy, Japan, Jordan, Kuwait, Latvia, Libya, Lithuania, Luxembourg, Macedonia, Malta, Mexico, Netherlands, New Zealand, Norway, Peru, Poland, Portugal, Romania, Russia, Saudi Arabia, Singapore, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Thailand, Tunisia, Turkey, United Kingdom, United States of America, Uruguay, Virgin Islands.