SCREENING FOR DIABETES, PREVENTION AND CARE

In the past, the commonest approach to diabetes screening was a preliminary, semi-quantitative test for glucose in a urine sample, followed by an oral glucose tolerance test for those found to have glycosuria. The underlying assumption is that early detection and effective control of hyperglycaemia in asymptomatic diabetics reduces morbidity.

Urine test for glucose, 2 hours after a meal, is commonly used in medical practice for detecting cases of diabetes. All those with glycosuria are considered diabetic, unless otherwise proved by a standard oral glucose tolerance test. Most studies now confirm that although glucose is found in urine in the most severe cases of diabetes, it is often absent in milder forms of the disease, and such cases are likely to be missed by urine test. 

This is known as lack of "sensitivity". To be more precise, the sensitivity of the test (i.e., proportion of people with disease who have a positive test) varies between 10-50 per cent. The lack of sensitivity means that many diabetics would have been missed if this had been the only test. That is, the test yields too many "false-negatives". 

Further, glycosuria may be found in perfectly normal people; this gives rise to "false-positives". Since the specificity of the test is over 90 per cent, the yield of false-positives is not very high. For these reasons, urine testing is not considered an appropriate tool for case-finding or epidemiological surveys of the population.

Because of the inadequacies of urine examination, "standard oral glucose test" remains the cornerstone of diagnosis of diabetes. Mass screening programmes have used glucose measurements of fasting, postprandial or random blood sample. The measurement of glucose levels in random blood samples is considered unsatisfactory for epidemiological use; at the most, it can give only a crude estimate of the frequency of diabetes in a population. 

The fasting value alone is considered less reliable since true fasting cannot be assured and spurious diagnosis of diabetes may more readily occur. Therefore, for epidemiological purposes, the 2-hour value after 75 g oral glucose may be used either alone or with the fasting value. Automated biochemistry has now made it possible to screen thousands of samples for glucose estimation. The criteria for the diagnosis of diabetes, proposed.

Two strategies for primary prevention have been suggested:

The scope for primary prevention of type 1 diabetes is limited on the basis of current knowledge and is probably not appropriate. However, the development of prevention programmes for type 2 diabetes based on elimination of environmental risk factors is possible. There is pressing need for primordial prevention that is, prevention of the emergence of risk factors in countries in which they have not yet appeared. 

The preventive measures comprise maintenance of normal body weight through adoption of healthy nutritional habits and physical exercise. The nutritional habits include an adequate protein intake, a high intake of dietary fibre and avoidance of sweet foods. Elimination of other less well defined factors such as protein deficiency and food toxins may be considered in some populations. These measures should be fully integrated into other community-based programmes for the prevention of non-communicable diseases (e.g., coronary heart disease).

high-risk strategy: There is no special high-risk strategy for type 1 diabetes. At present, there is no practical justification for genetic counselling as a method of prevention. Since NIDDM appears to be linked with sedentary life. style, over-nutrition and obesity, correction of these may reduce the risk of diabetes and its complications. 

Since alcohol can indirectly increase the risk of diabetes, it should like oral contraceptives. It is wise to reduce factors that promote atherosclerosis, e.g., smoking, high blood pressure, elevated cholesterol and high triglyceride levels. There programmes may most effectively be directed at target population groups.

When diabetes is detected, it must be adequately treated The aims of treatment are: (a) to maintain blood glucose levels as close within the normal limits as is practicable (se Table 3), and (b) to maintain ideal body weight. Treatment is based on (a) diet alone small balanced meals more or (c) diet frequently, (b) diet and oral antidiabetic drugs, and insulin Good control of blood glucose protects against the development of complications. 

Please see in chapter "Nutrition and health" under title "Nutritional factors in selected diseases" for details. Proper management of the diabetic is most important lo prevent complications. Routine checking of blood sugar, of urine for proteins and ketones, of blood pressure, visual acuity and weight should be done periodically. 

The feet should be examined for any defective blood circulation (Doppler ultrasound probes are advised), loss of sensation and the health of the skin. Primary health care is of great importance to diabetic patients since most care is obtained at this level.