While high or low hormone levels have been speculated as causing metabolic disease for long, a study has for the first time shown a clear link between low levels of a specific hormone and increased risk of metabolic diseases.
The study specifically focused to adropin is believed to play a critical role in regulating glucose levels and fatty acid metabolism. Scripps Research Associate Professor Andrew Butler had previously identified the hormone while studying obese and insulin resistant mice.
The Journal Obesity in its Feb. 2012 issue identifies adropin as:
Adropin is a secreted peptide that improves hepatic steatosis and glucose homeostasis when administered to diet-induced obese mice. It is not clear if adropin is a peptide hormone regulated by signals of metabolic state. Moreover, the significance of a decline in adropin expression with obesity with respect to metabolic disease is also not clear.
Andrew Butler led the new study with Peter J Havel, professor of molecular biosciences and nutrition at the University of California, Davis. According to Butler, “The results of this clinical study suggest that low levels of adropin may be a factor increasing risk for developing metabolic disorders associated with obesity and insulin resistance, which could then lead to diseases such as type 2 diabetes.”
According to the American College of Cardiology, about 47 million adults in the U.S suffer from metabolic syndrome, which is defined as a group of risk factors, especially obesity and insulin resistance, according to the National Institute of Health. Obesity and insulin resistance often occur together and increase the risk for coronary artery disease, stroke and type 2 diabetes.
This study that involved 85 women and 45 men conclusively shows obesity is associated with lower adropin levels. It is also observed in individuals with a higher metabolic syndrome risk factor score. This score is determined by measuring “triglycerides, LDL cholesterol, HDL, glucose, blood pressure, and waist circumference.”
In morbidly obese individuals, it was observed that circulating adropin concentrations increased significantly at three and six months following gastric bypass surgery. However, 12 months after surgery, the levels were found to return to pre-surgery levels.
Another interesting finding of the study is the difference between men and women in context of adropin levels. Women had lower plasma adropin level than men in people of normal weight and obesity had a bigger negative effect on adropin levels in men. Obesity in women could not be linked to lower plasma adropin levels. These differences are inexplicable at the moment.
However, “the link between low levels of adropin and increased metabolic risk was observed in both sexes,” irrespective of gender according to Butler.
It was found that adropin levels in general declined with age, but was more pronounced in men, while the decline was highest in those who are more than 30 years.
The study appears to be a positive step in therapeutics designed to fight obesity and metabolic disease by boosting the supply of adropin.