On the line between patient and population health
BMJ 2018 ; 360 doi: https://doi.org/10.1136/bmj.k1408 (Published 29 March 2018)
Cite this as: BMJ 2018;360:k1408
Re: On the line between patient and population health
Neurology of Socioeconomic Status and Lifestyle Diseases.
In each and every countries socioeconomic status is one of the important factor which influences the health parameters.
Low socioeconomic status is associated with more communicable diseases malnutrition related disorders and chronic respiratory diseases . High socioeconomic status is associated with Non communicable diseases and life style diseases . Cancers stress psychiatric diseases and accidents are more in both socioeconomic levels.
In brain different areas are responsible for the response to stress. Some areas of brain detect social threats and other areas detect physiological threats. These areas of brain are responsible for activating neuronal pathways in the brain, among them, the hypothalamus and the periaqueductal gray area which then trigger a series of changes in different parameters such as heart rate, blood pressure, inflammation, glucose levels, and fight, flight, or freeze response.
These modified parameters then allow the human to cope up with the acute stress and ultimately allowing the survival of the body. Once the stress is extinguished, the stress response stops.
In humans, especially in modern era, the most common source of stress is socioeconomical conditions. The repeated or chronic activation of a response designed for acute stress can leads to modifications of parameters such as blood pressure, heart rate, sugar level in the blood, and fat deposit in blood vessels and the abdominal viscera. And these modifications then lead to high blood pressure, arrhythmias, diabetes, stroke heart attack and abdominal obesity.
This overuse of the stress response is one way in which chronic stress can lead to pathological conditions which will shorten life.
Another way by which chronic stress leads to diseases has to do with inflammation. It has become clear in the last twenty five years that inflammation plays a key role in most lifestyle diseases.
Neurological and Cardiovascular diseases would be due to inflammation of the arterial wall and cancers would be the consequence of long term inflammation of different tissues, and degenerative diseases of the central nervous system (such as Alzheimer’s disease) would be a consequence of inflammation of the brain.
A paradox arises however when trying to relate stress and inflammation: stress is anti-inflammatory! Stress activates the hypotahalamo-pituitary-adrenal axis leading to a rise in cortisol which is a potent anti-inflammatory hormone: the effect of cortisol on its receptor is to reduce inflammation. When cortisol is chronically elevated however, the cortisol receptors react by becoming "down regulated", i.e. less numerous and less sensitive. This down regulation compensates for the increase in cortisol levels. When the cortisol level (stress level) falls, even temporarily and relatively, the cortisol receptors remain down regulated for a period of time. This is when a problem arises. A relatively lower cortisol level in presence of down regulated cortisol receptors results in a reduced anti-inflammatory effect of the stress system and therefore to a pro-inflammatory situation. This pro-inflammatory state triggers the onset of inflammation which leads to inflammatory diseases.
Socioeconomic status a source of chronic stress. The chronic activation of systems designed for acute threats modifies their basal activity. This modification especially the one involving cortisol and its receptors can lead to a pro-inflammatory state responsible for most of lifestyle diseases of recent days.
This hypothesis allows us to postulate a causal chain from socioeconomical status to stress, from stress to inflammation, and from inflammation to diseases.
Competing interests: No competing interests
30 March 2018
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