Moreover, for the mental conditions the low hormone levels were linked to high levels of fat in the blood and metabolic syndrome.
“These results provide clues to better understand the high prevalence of cardiovascular diseases in people with recurrent depressions or bipolar disorder. The results may in the future contribute to better preventative treatments of cardiovascular diseases in these disorders,” said Swedish researcher Martin Maripuu of the Department of Clinical Sciences, Division of Psychiatry at Umeå University.
The study appears in the Journal of Affective Disorders.
Bipolar disorder and recurrent depressions are lifelong diseases that are associated with a 10-15 year reduction in life expectancy.
A strong contributing factor to the shortened life expectancy is the high prevalence of cardiovascular diseases. Stress, low physical activity, and high energy intake are lifestyle factors linked to increased risk of metabolic and cardiovascular diseases.
Over the last 25 years, researcher have discovered one of the most important stress systems in the body is called the hypothalamic–pituitary–adrenal axis or HPA axis. The HPA axis is a complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland, and the adrenal glands.
This system regulates the production and levels of the vital stress hormone cortisol. Cortisol is also important for metabolism.
High cortisol levels over a long period of time is considered to contribute to the accumulation of fat. Stress normally leads to HPA-axis over activity, which in turn leads to increased levels of cortisol. If the additional stress is prolonged, it may lead to underactivity in the stress system, with low levels of cortisol as a result.
In people with recurrent depressions and with bipolar disorder it has previously been shown that metabolic risk factors for cardiovascular diseases are common and that disturbances in the stress regulation system often occur.
Researchers studied the link between cortisol levels and metabolic diseases by designing an experiment in which 245 patients with bipolar disorder or recurrent depressions were analyzed, together with 258 people in a control group.
Researchers measured cortisol levels in participants after they had taken a so-called dexamethasone suppression test, which is used to discover early deviations in the stress system. They discovered patients with bipolar disorder or recurrent depressions with low levels of cortisol suffer from:
- obesity (34 percent in comparison to 11 percent among other patients);
- dyslipidaemia, i.e. high levels of fat in the blood (42 percent compared to 18 percent among other patients), and;
- metabolic syndrome (41 percent in comparison to 26 percent among other patients).
The good news is that there was no correlation between cortisol levels and high blood sugar levels or high blood pressure.
Nevertheless, “the results show that cortisol regulation is linked to worsened physical health in people with bipolar disorder or recurrent depressions. However, further studies are needed in order to better understand these associations,” said Maripuu.
Source: Umea University