Overview of diabetes mellitus
Diabetes mellitus (DM) is a metabolic disorder in which blood glucose levels become too high, as the body produces little or no insulin (a hormone produced by the pancreas that aids in the utilization of glucose for energy), or cannot use insulin properly. The disorder has been growing at an alarming pace not only in the developed countries but also in the developing countries where noncommunicable diseases are rapidly surpassing communicable diseases as the commonest cause of death.
The World Health Organization (WHO) has suggested that over the next two decades, DM in the developing countries will be seen more in the lesser age group ranging from 20 to 45 years.1 India, with a population over 1 billion has the largest number of diabetic patients in the world, (estimated over 32 million in the year 2000) and this figure is predicted to increase to nearly 80 million by the year 2030.1,2
Characterized by chronic hyperglycemia (high blood glucose), long-term DM is associated with damage to various organs such as the nerves (neuropathy), eyes (retinopathy), kidneys (nephropathy) and the heart (cardiovascular diseases). The cornerstone of therapy revolves around disease prevention, motivation toward healthy lifestyle choices and complication surveillance. Education of partner or caretakers is important in maintaining positive lifestyle changes in diabetic patients. Oral hypoglycemic agents (OHAs) are the primary treatment of type 2 DM. Intensive treatment with insulin has been shown to have significant benefits in both type 1 and type 2 diabetic patients.3
Types and Pathogenesis of Diabetes
Type 1 Diabetes Mellitus
Type 2 Diabetes Mellitus
Gestational Diabetes Mellitus
Other Specific Types
Symptoms of diabetes (Clinical Features)
Understanding of diabetes symptoms can lead to early diagnosis and treatment.
Risk Factors for diabetes
Certain groups of people are at a higher risk for T2DM, therefore, asymptomatic individuals with the following criteria should be screened for diabetes:9
- Age more than 45 years
- History of gestational diabetes mellitus
- Impaired glucose tolerance
- Excess body weight
- Sedentary lifestyle
- Family history of diabetes
- History of delivery of big baby weighing more than 3.5 kg
- High blood pressure (blood pressure ≥140/90 mmHg)
- Clinical cardiovascular diseases (myocardial infarction, angina and stroke) or peripheral vascular diseases.
Diagnosis of Diabetes
The diagnosis of diabetes can be made in one of the following three methods but each must be confirmed on a subsequent day:
Presence of symptoms of diabetes and a random blood glucose value of ≥200 mg/dL
Fasting plasma glucose ≥126 mg/dL
Two-hour plasma glucose ≥200 mg/dL during an oral glucose tolerance test (OGTT)
The OGTT is carried out after an overnight fast of 8–10 h following 3 days of adequate carbohydrate intake (>150 g/day). After taking an initial fasting blood sample, a 75g load of oral glucose dissolved in 250 mL of water is given and the blood sample is collected again 2 h after the drink.
In addition, the glycosylated hemoglobin (HbA1c) may be used to diagnose diabetes although it is not specifically recommended as a diagnostic test for DM. A HbA1c level of 1% above the upper range of normal reference value is suggestive of diabetes and has a specificity of 98%.10
Management of diabetes
Living with diabetes
Prevention of diabetes
Recommendations for diabetes treatment and prevention are the following:
- Maintain a healthy body weight (body mass index of 20–25 kg/m²).
- Be physically active.
- Eat a healthy and balanced diet—high fiber, whole meal products, more fruits and vegetables (at least 5 portions a day).
- Reduce intake of fatty and sugar-containing foods.
- Consume low-fat dairy foods such as skimmed or semi-skimmed milk.
- Avoid smoking and alcohol intake.
Micro- and Macrovascular Complications of Diabetes
Diabetes significantly increases an individual’s risk of developing multiple microvascular and cardiovascular complications.
Micro vascular complications
The long-term microvascular complications of diabetes include
- Diabetic retinopathy
- Diabetic nephropathy
- Diabetic neuropathy
Diabetic retinopathy can result in loss of vision, therefore early diagnosis of retinopathy is essential as early use of laser photocoagulation may delay and prevent visual loss. This early detection can only be achieved by a program of routine screening.
Diabetic nephropathy may lead to end-stage renal disease. The rate of decline in renal function is accelerated by the presence of hypertension. Peripheral neuropathy which is complicating diabetes most commonly affects the sensory and motor nerves of the lower limbs.
Diabetic neuropathy poses the risk of foot ulcers, limb amputation, neuropathic joint damage, sexual dysfunction and dysfunction of other internal organs such as the stomach, bowel and bladder.
The macrovascular complications of diabetes include atherosclerotic cardiovascular, peripheral vascular and cerebrovascular diseases. Diabetes is a major risk factor for the development of atherosclerosis of the major vessels especially coronary and aorto-ilio-femoral systems. These in turn are the major cause of premature death in people with T2DM. Prevention of the cardiovascular complications is a major goal of current therapeutic policy. Although reduction in macrovascular complications depends on tight glycemic control, modification of other risk factors such as smoking, hypertension and dyslipidemia is also equally important.
Diabetes complications can be avoided and even if they occur, their progress can be prevented through early surveillance and treated. The appropriate approach to treat the diabetic complications is first ensure appropriate implementation of the therapies that can avoid the complications and also to detect the complications at the earliest possible time so that treatment can be initiated.
You May Also Like To Read
1.Wild S, Roglic G, Green A, Sicree R, King H. Global prevalence of diabetes: estimates for the year 2000 and projections for 2030. Diabetes Care. 2004; 27: 1047–1053.
2.Pradeepa R, Mohan V. The changing scenario of the diabetes epidemic: implications for India. Indian Journal of Medical Research. 2002; 116: 121–132.
3.Wright A, Burden AC, Paisey RB, Cull CA, Holman RR. UK Prospective Diabetes Study Group. Sulfonylurea inadequacy: efficacy of addition of Insulin over 6 years in patients with type 2 diabetes in the UK Prospective Diabetes Study. (UKPDS 57). Diabetes Care. 2002; 25: 330–336.
4.Sparre T, Larsen MR, Heding PE, Karlsen AE, Jensen ON, Pociot F. Unraveling the pathogenesis of type 1 diabetes with proteomics: present and future directions. Mol Cell Proteomics. 2005; 4(4): 441–457.
5.Centers for Disease Control and Prevention. National diabetes fact sheet: general information and national estimates on diabetes in the United States, 2005. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2005.
6.Chiasson JL. Prevention of type 2 diabetes: fact or fiction? Expert Opin Pharmacother. 2007; 8(18): 3147–3158.
7.Marant C, Romon I, Fosse S, Weill A, Simon D, Eschwège E, et al. French medical practice in type 2 diabetes: The need for better control of cardiovascular risk factors. Diabetes Metab. 2007 Dec 6; (Epub ahead of print).
8.Boriboonhirunsarn D, Talungjit P, Sunsaneevithayakul P, Sirisomboon R. Adverse pregnancy outcomes in gestational diabetes mellitus. J Med Assoc Thai. 2006; 89 Suppl 4: S23–S28.
9.American Diabetes Association. Screening for type 2 diabetes. Diabetes Care. 2004; 27(Suppl 1): S11–S14.
10.Davidson MB, Peters AL, Schriger DL. An alternative approach to the diagnosis of diabetes with a review of the literature. Diabetes Care. 1995; 8:1065–1071.
11.Arnolds S, Heise T. Inhaled insulin. Best Pract Res Clin Endocrinol Metab. 2007; 21(4): 555–571.
12.Yki-Järvinen H. Combination therapies with insulin in type 2 diabetes. Diabetes Care. 2001; 24: 758–767.
Written by: Dr Vijay soni
Date last updated: January 15, 2015