Does Stress Lead to Increased Diabetes Risk?
By Jacob Gan, Ph D
It is believed that improperly unmanaged stress is a major determinant in almost all illness conditions. Does stress also leads to diabetes? Let us investigate.
There are two major types of diabetes: type 1 diabetes mellitus and type 2 diabetes mellitus.
Type 1 diabetes mellitus is also known as juvenile diabetes because it starts in children and young adults. It is due to insufficient amount of insulin being produced (known as insulin deficiency). Since it does not start
later in life, we can safely conclude that type 1 diabetes mellitus is unlikely
to be caused by stress.
Type 2 diabetes mellitus usually
occurs later in life, after the age of forty.
Type 2 diabetes mellitus is the most common form of diabetes. In type 2
diabetes mellitus, the problems arise because
1.
Either the body does not produce enough insulin,
or
2.
The insulin produced is ignored by the cells in
the body (known as insulin resistance), or both.
Discussion on what insulin
is and what the roles it plays is in order.
Insulin is a hormone that
regulates carbohydrate metabolism (and to some extent fat metabolism as
well). Insulin helps the body to use
sugar. Sugar is the basic source of energy for the cells in the body, and
insulin takes the sugar from the blood into the cells.
When we say blood sugar, we
refer to glucose in the blood because glucose is the main type of simple sugar in our blood.
Our body needs to have glucose level controlled to within a narrow range
(0.7-1.1 mg per ml). Below 0.7 mg per ml is termed "hypoglycemia", and above 1.8 mg per ml is termed
"hyperglycemia". Both can
result in problems as we shall see later.
When there is more glucose
in the blood, more insulin is secreted into the blood, resulting in cells
(muscle cells, red blood cells and fat cells) absorbing the glucose out of the
blood, thus reducing the blood glucose level.
When there is less glucose
in the blood, more glucagon (counter part of insulin) is secreted into the blood, stimulating liver to release the glucose it has
stored in its cells into the blood stream, thus increasing blood glucose. Glucagon also induces the liver and some of the muscle cells to produce glucose out of protein.
If the glucose does not go
into cells, instead it builds up in the blood, two problems arise. Firstly, if the cells do not get the glucose they need, they die. Secondly, prolong period
of high blood glucose levels may hurt your eyes, kidneys, nerves or heart. Insulin is used to treat this “hyperglycemia”
aspect of diabetes.
“Hypoglycemia” or low blood glucose level
condition can happen when more insulin is introduced than there is food in the
stomach to be acted on. This often
happens when a patient injects insulin in anticipation of food consumption, but
the food consumption is delayed or insufficient food is consumed. Symptoms of “hypoglycemia” include strange
behavior, clumsy or jerky movements, seizure, confusion, tingling sensations
around the mouth, dizziness, sweating, headache etc.
Now that we understand the mechanics of
diabetes, is there anything to suggest that stress can cause diabetes (type 2)?
The usual reason explaining where stress
lead to sickness is the weakening of our immunity system caused by stress. However, diabetes is not caused by weak
immunity system.
Psychological stress caused by the death
of a spouse, a financial crisis or other life-altering event has been
associated with higher risk of developing diabetes in middle age. Many studies
have shown that the abovementioned types of major life events were associated
with type 2 diabetes regardless of family history of the disease, exercise or
alcohol use. However, although such
circumstantial evidence seems to suggest a link between a higher proportion of
people under greater stress and diabetes, we cannot conclude that stress cause
diabetes.
There is a theory that says that
stressful life events increase the diabetes risk by increasing levels of the
hormone cortisol and decreasing levels of sex steroids such as testosterone, which have been shown to influence the action of
insulin.
Some researchers have tried to determine
whether stress, which can be measured using the ratio cortisol/testosterone, affects insulin resistance. In the prospective study by George Davey Smith and colleagues from the University of Bristol in the United Kingdom, cortisol/testoterone ratio was positively associated with IHD (ischemic heart disease) mortality and incidence. Adjustment for potential socioeconomic and behavioral confounding variables had little
influence on these associations, but they appeared to be mediated by
components of the insulin resistance syndrome (elevated blood
pressure, triglyceride levels, body mass index, total cholesterol,
HDL cholesterol, and impaired glucose tolerance). This suggests that methods of reducing the cortisol/testoterone ratio may improve insulin resistance and reduce the risk of ischemic heart disease (IHD). But, it does not suggest that reducing stress can reduce the risk of diabetes.
More conclusive research findings will be
needed before we can conclude that stress does indeed lead to diabetes.
Jacob Gan, PhD
Reference:
The Truth About Diabetes
Stress, the Silent Killer
The Power of Laughter
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