By Debosree Pal, Jawaharlal Nehru Centre for Advanced Scientific Research, India
Dating back to around 1500 B.C, diabetes had found its first mention in Egyptian manuscripts. It was only much later, in the first century A.D. that the term diabetes meaning ‘siphon’ was coined by Aretaeus. Mellitus meaning ‘honey’ was coined by the British Surgeon-General John Rollo later in 1798 to refer to the high glucose content found in the urine of people with the condition. The rate of prevalence of diabetes and prediabetes across the world has doubled in the past three decades. The question is what has contributed to such an explosion?While type 1 diabetes is autoimmune-mediated or idiopathic in nature, type 2 diabetes is largely caused by lifestyle or genetic predisposition. According to studies by WHO and the Centers for Disease Control and Prevention, the rate of incidence of diabetes is much higher in Hispanics, African Americans, American Indians and natives of the South Pacific islands. But notably, type 2 diabetes is far more prevalent in developing than developed countries, with China, India, Pakistan, Bangladesh and Indonesia being amongst the 10 countries predicted to have the largest number of people with this condition by 2030. Furthermore, rapid urbanisation and associated lifestyle changes has increased the prevalence of type 2 diabetes in rural areas as well. With an estimated 642 million people being affected by diabetes by 2040 as per reports by the International Diabetes Federation and type 2 diabetes contributing to 90-95% of cases (as per studies by CDC), type 2 diabetes in particular has taken on the status of an epidemic.
Causes and risk factors
One of the major factors that increases the risk of developing type 2 diabetes is obesity. A study by FAIR Health based on claim lines (which refers to the services listed on an insurance claim) in the United States, it was found that in the period of 2011-2015, obesity and type 2 diabetes diagnosis were concomitant. Alongside type 2 diabetes, obesity is also predicted to rise from 33% in 2005 to 53.8% by 2030. But, interestingly, normal-weight individuals who are ‘metabolically obese’, meaning that they have a higher fat percentage at a given BMI, are more prone to developing type 2 diabetes than otherwise. This trend is, in fact, reflected in the Asian population when compared with Europeans.
Type 2 diabetes emergence in childhood and young adults
The prevalence of type 2 diabetes in children (age group 0-10 years) and young adults (age group 10-19 years) is indeed alarming. According to reports in 2011, the percentage of type 2 diabetes cases in children and adolescents increased from 3% to 45% over a span of only ten years. Although ethnicity and familial inheritance accounts for a proportion of such type 2 diabetes cases, it has been observed that 14.9% of diagnosed type 2 diabetes cases in the youth occur in non-Hispanic white individuals. This brings us to the same question of the major factor that is contributing to type 2 diabetes cases in children and youths. Studies have shown that obesity or overweight is again one of the leading causes.
Mechanism of obesity induced insulin resistance (Wang et al). CRTC2 can interact with either CREB to activate gluconeogenesis under fasting conditions or with ATF6α to upregulate stress-responsive genes during ER stress. However chronic ER stress targets ATF6α for proteasomal degradation, upon which chronic hyperglycemia sets in, ultimately leading to insulin resistance.
Diabetes, in general, has serious implications on quality of life, if not controlled. In the long term, it can lead to loss of vision, kidney failure, cardiovascular diseases and lower limb amputation. The modifiable factor contributing largely to type 2 diabetes i.e., obesity should be the foremost line of action. Increase in physical activity, reduced calorie intake, healthy diet and controlling smoking habits can keep prediabetic individuals from developing diabetes and diabetic individuals from keeping it in check. At the same time, policies at the national and international levels would help regulate this epidemic. The WHO’s Framework Convention on Tobacco Control, started in 2005, aims at reducing tobacco usage across the globe. Regulation of food products high in fat, sugar and salt has become necessary in the current scenario. It is also important to provide proper nutrition to expecting mothers and newborns to address the issues of childhood type 2 diabetes since gestational diabetes also contributes to type 2 diabetes in the young population.
Is type 2 diabetes preventable or can it be controlled?
Some countries have introduced tools like the Indian Diabetes Risk Score to assess the risk of undiagnosed patients for developing diabetes based on age, waist circumference family history and physical activity. The WHO has taken worldwide initiatives, such as in Senegal and Samoa, to create community awareness and better diagnosis and management of non-communicable disease like diabetes. The Diabetes Association of Thailand and the Thai Society of Diabetes Educators work on capacity-building for better diabetes management. Various other rehabilitation and medicinal outreach programs are also in place for regulating type 2 diabetes and diabetes in general around the globe.
Whilst national and international level policy implementations can help management of type 2 diabetes, awareness at the community and the individual level is also vitally important.
- Ritu Lakhtakia. The History of Diabetes Mellitus. Sultan Qaboos Univ Med J. 2013 Aug; 13(3): 368–370
- Chen L, Magliano DJ, Zimmet PZ. The worldwide epidemiology of type 2 diabetes mellitus–present and future perspectives. Nat Rev Endocrinol. 2011 Nov 8;8(4):228-36
- Wang Y, Vera L, Fischer WH, Montminy M. The CREB coactivator CRTC2 links hepatic ER stress and fasting gluconeogenesis. Nature. 2009 Jul 23;460(7254):534-7
I am 5th year PhD student at the Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, India. Designing problems and troubleshooting them to understand biological phenomena is what attracts me to the world of molecular biology.
You can find me on Twitter @crimson_deb.
This post is the first in our emerging diseases series. If you are interested in reading more on this topic, you can also check out the June issue of The Biochemist magazine.