The other face of the epidemiological studies


Dr.Almoutaz Alkhier Ahmed
Saudi Arabia, Gurayat North
Gurayat General Hospital / Diabetic center
P.O.Box 672


Since the beginning of human civilization the bottle between health and sickness is going on. Each side seeks for weapons to win the bottle.

Statistical measurements are among the precious weapons in this bottle.

When we look deeply  on the results of the epidemiological studies done on diabetes and its compilications,we will notice a wide variations on their results .sometime the variation can occur on the same location if the study repeated by different research group.

I think Lacks of national guidelines force the health care providers to practice on different bases.unfortunatly nonbased or malpractices are considerable problems among health care providers.

Also lack of specific medical knowledge about specific disease such as diabetes may affects the performance of health providers making them arranging their list of priorities in an appropriate manner so far from the best bases to manage that disease.

If we return back view years we will find that diabetes was the main issue. Matter had been changed; recently we start to talk about prediabetes and the importance of risk factors in developing the disease or its complications.

Rising prevalences not only indicate more spread of the disease, but it could also reflect our inability to neutralize the risk factors which lead to that disease or its complications.

I think the standards of providers and work should be flag in every epidemiological studies aim to calculate the prevalence of any disease or its complications generally or diabetes and its complications specifically.

Just let us review most of the studies done to estimate the prevalences of diabetes in different countries and let us focus on the methodology; unfortunately we will find nothings on those who collect or interpret the data. Most of the concentration is about the sample itself.

Again, man power is an important factor in the series of weapons used to defense against diabetes. Qualified man power will do great job on defending against the disease, at least they know what they do and have a capability to plan well and but parameters to follow their work. 

The Sine wave hypothesis:

This hypothesis tries to explain the variations in the results of the prevalances of a disease or its complications particularly diabetes mellitus.

The variation in the prevalences of diabetes or its complications depends on:

a) The man power that do the epidemiological works .in particularly, those who are in the field .many mistakes can be done on the field which can affect the result of those studies. Although some were given consideration for these mistakes on their statistical calculation but still it is a problem specially in studies with small size samples. For this reason some researchers prefer to do the work by them self and this create another problem which is the loss of team work soul. The accuracy of data collection depends to some extent to the degree of orientation and training given to those responsible from it, especially if the data contains information need skills to obtain it. So, some studies will be running by trained teams knowing what they are doing while others will be running by persons who may have no considerable levels of knowledges or skills about what is going and this will affect the results of the studies done.

b) The resources available for the work:

One of the commonest explanations for the variation on the results of the epidemiological studies is the cost. If you look for accuracy you should pay for, it is a valuable wisdom and logical one.

 The budget available for the work affects the result of the work by different means. Laboratory works or the clinical works may be affected due to lack of kits for investigations or equipments needed for clinical evaluation or workshops needed for training or video-visuals aids needed for learning. Not all members of the research teams should be professional on the area of the research but at least they should know what they are doing and how to do it properly to decrease the bias on the results.

If we look deeply on the figures of the prevalences of diabetes and its complications presented on the diabetes atlas produced by the IDF we will noticed tow points:

1) High prevalences where the previous factors are available
2) Low prevalence where there are shortage of the previous factors.

In some areas the size of the population participated in a study will affect the prevalences. for example in areas where their are shortage of the previous factors but there is a big size participants, the prevalences may be found to be high and on the other hand in areas where the participants are view and there is adequacy in the previous factors ,the prevalences may also be high. An example for this is the prevalence of diabetes in the Middle East and the prevalences of diabetes among certain population such as Pima Indian.

So, when ever there is adequacy of the previous factors the prevalence will found to be raised and when ever these factors are lack and the size of participants is small we the prevalences will be low.

The prevalence of any disease such as diabetes directly proportionate to the incidence of the disease and the incidence of the disease depends on the available risk factors for the occurrence of the disease.

Activate prophylaxis processes against the risk factors will trapped these factors and may delay  the occurrence of diabetes or even prevent it, so the incidence ,then the prevalence will be dropped.

This will be clear when we looks for the prevalences of the complications of diabetes.
In the areas where there is shortage of prophylaxis measurements against risk factors for certain health problem, the cummulatative effect of these factors will lead to the appearance of the problem or its complications in up stair manner.

Again, the manpower and the resources available for the health services are an important determinants for the prevalnces of the diseases or its compilications.Variation in the quality of  manpower and the budget available to keep the work in a standard level will affect the results of studies aim to calculate the prevalnces of the disease or its complications


When ever there is variation in prevalence of a disease (within a time and place) we should look for the quality of a manpower and the budget available for the work .Audiut studies looking to calculate the prevalences of diabetes or its complications should measure or describe the level of the services (manpower and budget) in the areas of these studies and put it clear in the methodology part. It is not only the description of the participants or the equipments participated or used or the type of software used to analyze the data, but it is also the description of those doing the work and their level of knowledge in the topic of the studies and the level of the skills needed to get the data.

The high prevalence of the disease or its complications does not means always high epedimicity of the disease but it can also means low standards of components of good health process..