436 CHAPTER 11
DIABETES Review the last paragraph, and it becomes obvious that weight problems
may also become associated with stress. One chronic illness sometimes associated with
excessive weight gain is diabetes, specifically Ty p e 2 d i a b e t e s (Type 1 diabetes is an
autoimmune disorder associated with failure of the pancreas to secrete enough insulin,
necessitating medication, and is usually diagnosed before the age of 40). Type 2 diabe-
tes is associated with excessive weight gain and occurs when pancreas insulin levels
become less efficient as the body size increases. Insulin resistance has been linked by
research to higher levels of the immune system’s cytokines. Stress, as mentioned ear-
lier, can increase the release of these cytokines (Tian et al., 2014). Type 2 diabetes can
respond favorably to proper diet, exercise, and weight loss but may also require med-
ication. Typically, it is associated with older adults, but with the rise in obesity among
children, more cases of Type 2 diabetes in children are now occurring.
While controllable, diabetes is a serious disorder that has now been associated with
an increased risk of Alzheimer’s disease, although memory loss appears to be slower for
diabetic Alzheimer patients than for nondiabetic Alzheimer’s patients (Sanz et al., 2009).
Several ongoing longitudinal studies strongly suggest that Type 2 diabetes not only is
associated with mental decline in middle-aged individuals (Nooyens et al., 2010), but
there is also indication that stress can compound the risk of that mental decline ( Reynolds
et al., 2010).
Research has continued to link high levels of stress with increased risk of diabetes.
A 35-year study in Sweden monitored the health and stress factors of 7,500 men who
began the study with no history of diabetes or coronary heart disease (Novak et al.,
2013). Those men who reported experiencing permanent stress, related to home life and/
or work life, had a 45 percent higher chance of developing diabetes compared to men
who reported no stress or only periodic stress. Another study found that high levels of
stress in the workplace can accurately predict who will develop diabetes, particularly in
those people who had low levels of social support (Toker et al., 2012).
CANCER Cancer is not one disease but rather a collection of diseases that can affect
any part of the body. Unlike normal cells, which divide and reproduce according to
genetic instructions and stop dividing according to those same instructions, cancer
cells divide without stopping. The resulting tumors affect the normal functioning of the
organs and systems they invade, causing them to fail, eventually killing the organism.
Although stress itself cannot directly give a person cancer, stress can have a sup-
pressing effect on the immune system, making the unchecked growth of cancer more
likely (Le et al., 2016). In particular, an immune-system cell called a natural killer (NK)
cell has as its main functions the suppression of viruses and the destruction of tumor
cells (Chan et al., 2014; Herberman & Ortaldo, 1981). Stress has been shown to depress
the release of natural killer cells, making it more difficult for the body’s systems to
fight cancerous growths (Chan et al., 2014; Zorilla et al., 2001). The hormone adrenaline
is released under stress and has been found to interfere with a protein that normally
would suppress the growth of cancer cells (Sastry et al., 2007). In other research, stress
has been linked to the release of hormones such as adrenaline and noradrenaline that,
over time, can cause mistakes (such as damage to the telomeres, structures at the ends of
chromosomes that control the number of times a cell can reproduce) in the instructions
given by the genes to the cells of the body. As these mistakes “pile up” over the years,
cells can begin to grow out of control, causing the growth of tumors and possibly cancer
(Kiecolt-Glaser et al., 2002).
Stress may impact the effectiveness of cancer treatments as well. In one study of
mice implanted with human prostate cancer cells, treatment with a drug to destroy the
cancer cells and prevent growth of tumors was effective when the mice were kept calm
and stress free but failed miserably when the mice were stressed (Hassan et al., 2013).
One possible bit of positive news: Unlike the research linking stress at work to heart
disease and diabetes, one study has found that work-related stress does not appear to beType 2 diabetes
disease typically occurring in mid-
dle adulthood when the body either
becomes resistant to the effects
of insulin or can no longer secrete
enough insulin to maintain normal
glucose levels.
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immune-system cell responsible for
suppressing viruses and destroying
tumor cells.