Diabetes in the Elderly

Advances in medical science and improved social conditions during the past few decades have increased the life span of humans. This ageing of the population is also a product of demographic transition owing to a reduction in fertility and mortality.

This phenomenon of population ageing is universal. Almost 10% of the population in developed countries and 5 to 8% in the developing countries are over the age of 60 years. By 2020 more than 1000 million people aged 60 years and older will be living in the world, more than 700 million of them in developing countries 1. In 1970, only 3.7% of the population in Malaysia was 60 years and above. In the year 2020, this population would have increased to 7% and would comprise 2.1 million of the estimated population of 29.5 million.

The prevalence of diabetes mellitus (DM) increases with age and 20% of the elderly population has DM. In addition, over 25% of older persons have impaired glucose tolerance (IGT). Patients with pre-existing DM, either type 1 or type 2 often survive into old age, frequently with many complications of the disease. These form the major chunk of the elderly diabetic population. DM may also present in old age, when it is almost always type-2. Rarely, even type 1 DM may develop first time in old age.

Carbohydrate Metabolism in the Elderly

Most studies have revealed rises in glucose levels, especially post prandial blood glucose levels that directly correlate with age. Fasting blood glucose increases by 0.05 to 0.1 mmol/L per decade, with postprandial blood glucose levels increasing up to 0.8 mmol/L per decade.

The relative importance and mechanisms of deficient insulin secretion and action during ageing are still debated. The increased hyperglycemia may be due to delayed suppression of hepatic glucose output owing to impaired insulin release, and reduced rate of peripheral uptake. The predominant problem of lean elderly diabetics is insulin deficiency. Obese patients have both insulin resistance and relative insulin deficiency. Major contribution also comes from extrinsic factors like diet, medication, activity, chronic illness and stress, which reduce the muscle mass and alter other organ functions resulting in glucose intolerance.