Diabetes : A rising menace

Introduction

Diabetes mellitus is a major health problem in all nations. This medical disorder is characterized by hyperglycemia and impaired metabolism of carbohydrates, fat and proteins and accompanied by absolute or relative insulin deficiency. Diabetes has diverse geographical distribution. The highest incidences have been reported from India, China, and the USA.

Diabetes is the single, most important metabolic disease, widely recognised as one of the leading causes of death and disability worldwide.2,3 This devastating disease can affect nearly every organ system in the body. It can cause blindness, lead to end stage renal disease, lower extremity amputations and increase the risk for stroke, ischemic heart disease, peripheral vascular disease, and neuropathy. Diabetes is not new to the medical world as it is known since antiquity (1500 BC), but now with its epidemic claws, diabetes has become a major health threat to the whole world.

The Global Scenario

The World Health Organisation (WHO) estimated that there are 135 million diabetic individuals in the year 1995 and it has projected that this number would increase to 300 million by the year 2025.4 It also declared that diabetes had reached epidemic proportions and predicts that most of the increase will be contributed by developing countries.4

Diabetes type1is accompanied with idiopathic or autoimmune insulin deficiency and constitutes 5-10% of all diabetic cases.5 Diabetes type 2 is characterized with insulin resistance and its relative deficiency and constitutes 90- 95% of cases.5,6 Gestational diabetes affects 3-5% of all pregnancies.5

In young people (less than 40 years), prevalence of diabetestype 1 is less than 0.3%. Type 2 has prevalence around 2-3% among people aged 40 or older. The prevalence increases with age.7 Annual incidence of type1 diabetes in the world is 0.8 to 50/100000. The rate shows an upward movement.

Prevalence rates are strikingly different among different ethnic groups. Highest prevalence has been reported from Pima tribe in Arizona, USA, where diabetes has affected nearly 35% of all individuals.8

Distributive pattern of diabetes shows higher rates among people of developing countries, and in lower socioeconomic groups of more developed countries.9 It is estimated that in year 2025, more than ¾ of diabetic patients will be inhabitants of developing countries.10

Diabetes in India

In India it is estimated that presently 19.4 million individuals are affected by this deadly disease, which is likely to go up to 57.2 million by the year 2025.11 The reasons for this escalation are due to changes in lifestyle, people living longer than before (aging) and low birth weight could lead to diabetes during adulthood. Diabetes related complications are coronary artery disease, peripheral vascular disease, neuropathy, retinopathy, nephropathy, etc. People with diabetes are 25 times more likely to develop blindness, 17 times more likely to develop kidney disease, 30-40 times more likely to undergo amputation, two to four times more likely to develop myocardial infarction and twice as likely to suffer a stroke than non-diabetics.

Prevalence of diabetes has increased globally. However, India has the maximum increase during the last few years. Type 2 diabetes mellitus is the commonest form of diabetes in India. The prevalence of type 2 diabetes mellitus is 2.4% in rural population and 11.6% in urban population. Prevalence of impaired glucose tolerance is also high in the urban population. Subjects under 40 years of age have a higher prevalence of impaired glucose tolerance than diabetes. The important risk factors for high prevalence of diabetes include: High familial aggregation, obesity specially central one, insulin resistance and lifestyle changes due to rapid urbanisation. A population study conducted in urban South India, at the Diabetes Research Centre, showed that there was a high prevalence of the clustering of cardiovascular risk factors namely, central adiposity, obesity, hyperinsulinemia, dyslipidemia, hypertension and glucose tolerance in the adults aged > 40 years.12 Isolated revalence of individual components was lower and combinations of one or more of them occurred more frequently (1.5 to 4 times) than expected by chance.

Conclusion

Prevalence of diabetes is increasing globally. India have the maximum increase during the last few years. Type 2 diabetes mellitus is the commonest form of diabetes.Prevalence of impaired glucose tolerance is also high in the urban population. The important risk factors for high prevalence of diabetes include: High familial aggregation, obesity specially central one, insulin resistance and lifestyle changes due to rapid urbanisation. Lifestyle modifications, inclusive of dietary modification, regular physical activity and weight reduction are indicated for prevention of diabetes.

References

Age- and Sex-specific Prevalence of
Diabetes in 11 Asian Cohorts

A study was conducted to report the age- and sex-specific prevalence of diabetes and impaired glucose regulation (IGR) according to revised World Health Organization criteria for diabetes in Asian populations. Eleven studies were performed across 4 countries, comprising 24,335 subjects (10,851 men and 13,484 women) aged 30-89 years who attended the 2-h oral glucose tolerance test and met the inclusion criteria for data analysis.

The results showed that the prevalence of diabetes increased with age and reached the peak at 70-89 years of age in Chinese and Japanese subjects but peaked at 60-69 years of age followed by a decline at the 70 years of age in Indian subjects. At 30-79 years of age, the 10- year age-specific prevalence of diabetes was higher in Indian than in Chinese and Japanese subjects. Indian subjects also had a higher prevalence of IGR in the younger age-groups (30-49 years) compared with that for Chinese and Japanese subjects. Impaired glucose tolerance was more prevalent than impaired fasting glycemia in all Asian populations studied for all age-groups.

The study concluded that Indians had the highest prevalence of diabetes among Asian countries. The age at which the peak prevalence of diabetes was reached was 10 years younger in Indian compared with Chinese and Japanese subjects.

Combination Therapy in Diabetes

Dr Jamal Ahmed,
MD, PhD (Medicine)Professor of Endocrinology,
Aligarh Muslim University, Aligarh

What is the disease burden of diabetes in India?

The exact figure is close to 10 percent of the population.

What is the rational for using the combination drugs for the management of Type 2 Diabetes?

Type 2 Diabetes is one disease where there are multiple defects and deficiencies. For example, every type 2 diabetic is insulin deficient and has a certain degree of insulin resistance. Thus, there is no justification for the treatment of type 2 diabetes by a
single drug.

To reiterate, in diabetes management, the clinician has to take care of insulin deficiency as well as insulin resistance.

What are the risk factors in diabetes that can be modified by the rational use of a combination?

The risk factors for diabetes are many and therefore the clinician has to look beyond glycemic control and make provisions for the control of hypertension, and of
lipid levels as well. In India, there is the issue of increased hypertriglyceridemia as compared to total cholesterol. We do have cases of increased LDL cholesterol also and perhaps, in the coming years the concept of lipid abnormality in type 2 diabetes will begin to emerge.

At present, diabetologists are talking about LDL and VLDL fractions. We are also talking about good and bad triglycerides. However, it does appear that with the change in perception, care will have to be provided for coagulation abnormalities also. Thus, rationally metformin is at least one of the drugs that has shown to have some improved metabolic profile as far as the lipids are concerned.

Does the combination of oral antidiabetic drugs help in preventing or delaying micro or macrovascular complications?

It has already been proved that there can be a definite reduction of microvascular complications with good glycemic control, but since there is no glycemic threshold for microvascular disease, the clinician has to delay the microvascular complication
by concentrating on the maintenance of blood pressure to less than 130/85, lipid levels, coagulation abnormalities and so on. It is also said that pioglitazone plays some role in preventing microvascular complications. At the time of diagnosis,
25 to 30 percent of the patients already have microvascular disease, the etiology of which is hyperinsulinemia.

Thus, theoretically pioglitazone is routinely prescribed even before diabetes develops. In this way, it is possible to delay microvascular complications by reducing insulin resistance.

Laugh a BIT

The surgeon told his patient who woke up after having been operated: "I'm afraid we're going to have to operate you again. Because, you see, I forgot my rubber gloves inside you." Patient: "Well, if it's just because of them, I'd rather pay for them if you just leave me alone."