Metabolic syndrome and stress
LONDON, UNITED KINGDOM. The incidence of metabolic syndrome (syndrome X, insulin resistance
syndrome) is growing rapidly in the Western world. The syndrome is increasingly viewed as an important
precursor of atherosclerosis and coronary disease. The syndrome consists of a cluster of common
symptoms including insulin resistance, abdominal obesity, hypertension (high blood pressure), high
triglyceride levels, and low levels of "good" cholesterol (HDL cholesterol).
British researchers have discovered that there is a strong connection between a dysfunctional autonomic
nervous system, stress hormone levels, and the metabolic syndrome (MS). Their study involved 30 working
men between the ages of 45 and 63 years who had been diagnosed with MS and 153 matched, healthy
controls. The researchers found that the men with MS had significantly higher levels of cortisol (urinary
metabolites) and normetanephrine (a metabolite of norepinephrine). They also had a higher heart rate,
lower heart rate variability, and an autonomic nervous system balance that was significantly tilted towards
sympathetic (adrenergic) predominance. The MS patients also had significantly higher levels of the
inflammation markers interleukin-6 and C-reactive protein. The viscosity of their blood plasma was also
significantly higher than that of the controls and their level of urinary epiandrosterone (a metabolite of
dehydroepiandrosterone [DHEA]) tended to be lower than that of the controls.
The researchers conclude that their findings point to a clear association between metabolic syndrome and
long-term stress. They estimate that about 37% of the risk of developing MS can be attributed to high
norepinephrine level (excessive sympathetic activity). Their findings, they believe, may go a long way
towards explaining why men at a low socioeconomic level (more stress) have a much higher risk of coronary
heart disease than do men in a more "comfortable" socioeconomic position.
Dr. Paul Hjemdahl, MD, PhD of the Karolinska Hospital and Institute in Stockholm commented on the new
findings. He agrees that an autonomic nervous system imbalance plays a large part in the development of
MS and suggests that weight loss, exercise, and dietary modifications may help prevent it. He also
suggests that psychosocial intervention to reduce stress and improve working conditions (reduce
inappropriate demands and improve job satisfaction and control) and social support may help prevent MS.
Says Dr. Hjemdahl, "Society faces a tough challenge regarding the metabolic syndrome and its medical
consequences in the future."
Brunner, EJ, et al. Adrenocortical, autonomic, and inflammatory causes of the metabolic syndrome.
Circulation, Vol. 106, November 19, 2002, pp. 2659-65
Hjemdahl, P. Stress and the metabolic syndrome. Circulation, Vol. 106, November 19, 2002, pp. 2634-36