Type 1 Diabetes Incidence Continues To Increase

A study published in the journal Diabetic Medicine last month shows a dramatic increase in the rate of type 1 diabetes in the UK, mirroring increases in other developed countries over the last couple of decades.

The report, which compared type 1 diabetes incidence in the UK between 1991 and 2008 showed some dramatic increases, particularly among boys aged 0-14 years where the rate more than doubled from 11 cases per 100,000 person-years to 24 cases per 100,000 person-years. The rate for girls aged 0-14 years increased from 15 to 20 cases per 100,000 person-years (a 33% increase). For young adults aged 15-34 rates increased from 13 to 20 per 100,000 for men (a 54% increase) and 7 to 10 per 100,000 in women (a 43% increase).

Despite the increasing rates if type-1 diabetes the causes are still unknown. One theory is that a low intake of vitamin D increases the likelihood of developing autoimmune diseases such as type-1 diabetes. A study, published in the journal The Lancet in 2001, found that infants who regularly received 2000 IU of vitamin D during the first year of their life were 78% less likely to develop type 1 diabetes compared to other infants.

Further evidence of a link between vitamin D and type 1 diabetes comes from the observation that countries close to the equator tend to have lower type-1 diabetes rates than countries further away from the equator. Other autoimmune conditions such as multiple sclerosis also tend to be more common in countries far from the equator.

Other studies have found that advanced maternal age is a strong risk factor for type 1 diabetes. A study published in the British Medical Journal found that a 5 year increase in a mothers age at birth increased their child’s chances of developing type-1 diabetes by 25%. A child born to a 45 year old mother was found to be at a 211% greater risk of developing type-1 diabetes compared with a child born to a 20 year old mother. This finding may explain part of the increasing trend in worldwide diabetes rates because women, particularly in developed countries, tend to have children much later in life than was the norm in the past. In 2009, women aged 35+ accounted for 14.3% of live births in the United States compared to just 4.6% of live births in 1975.

Finland currently has the highest rate of childhood type-1 diabetes in the world with a rate of 37 per 100,000 people per year while Venezuela has the lowest rate in the world with just 0.15 cases per 100,000 people per year. The childhood rate in the USA is currently 15 per 100,000 people which is slightly above the worldwide average. Other countries with high childhood rates of type-1 diabetes include Sweden, Norway, Canada, New Zealand, and the United Kingdom.

The incidence of type-1 diabetes worldwide is estimated to be increasing by 3.9% annually however type-2 diabetes still accounts for almost 90% of total cases. The CDC estimates that if current diabetes trends continue, as many as 1 in 3 Americans will be living with either form of diabetes by the year 2050.