Study: Metabolic Syndrome Risk Higher in Patients With Insomnia

People who have insomnia appear to be at a higher risk of developing a number of metabolic disorders, including hypertension, hyperglycemia, hyperlipidemia, and obesity, according to a new meta-analysis.

The findings were published in the Journal of Clinical Neuroscience.

Insomnia is a complicated disorder that has already been linked with a number of health issues, including depression, cardiovascular disease, and chronic obstructive pulmonary disease, noted corresponding author Yazhen Liu, PhD, of the Third Military Medical University in China. As many as 10% of adults globally are believed to suffer from insomnia, but Liu and colleagues said that rate can soar as high as 50% in elderly patients.

Metabolic syndrome (MetS), which is characterized by hypertension, hyperlipidemia, abdominal obesity, and insulin resistance, is also on the rise. In the United States, roughly one-third of adults have MetS, according to the CDC. In China, Liu said, the rate is about 15.5%.

The investigators sought to determine if they could identify links between insomnia and metabolic conditions.

“We believe that understanding whether the development of insomnia affects the possibility of the concurrence of metabolic syndrome can provide a theoretical basis for preventing the current public health problems dominated by chronic diseases,” Liu and colleagues wrote.

In order to uncover any links, the investigators analyzed existing literature to find observational studies that included data on insomnia and MetS-related symptoms. Their search yielded 12 studies, upon which the investigators conducted random effects modeling to develop aggregate risk estimates for metabolic disorders. Four of the studies occurred in China; 3 were in the United States; the rest took place in India, Japan, Spain, Mexico, and Brazil.

Their analysis found the odds ratio (OR) for hypertension among patients with insomnia was 1.41 (95% confidence interval [CI], 1.19-1.67). The OR for hyperglycemia was 1.29 (95% CI, 1.11-1.50), and for obesity was 1.31 (95% CI, 1.03-1.67). The lowest risk was for hyperlipidemia, with an OR of 1.12 (95%CI, 0.92-1.37).

Liu and colleagues wrote that the findings should prove helpful in terms of identifying strategies to fight MetS.

“This will provide a theoretical basis for controlling the risk of metabolic syndrome, and also play a guiding role in reducing the occurrence of insomnia,” they wrote.

They said their study aligns with earlier reporting, including research which found chronic insomnia tripled the risk of hypertension in adults and a separate study suggesting insomnia was a risk factor for hyperglycemia among middle-aged men.

The authors noted that the studies included in the meta-analysis tended to be skewed toward middle-aged and elderly patients, which could be due to the fact that insomnia tends to be more common in older patients.

The investigators added one limitation of their study is the subjective nature of insomnia, which makes it difficult to diagnose and track using diagnostic equipment. Also, they noted that patient self-reporting is the main way insomnia is diagnosed, which could have impacts on the correlations found.

Still, the authors said their meta-analysis makes a strong case that insomnia is correlated with metabolic diseases. They concluded future research should separately examine the association between insomnia and the 4 indicators of MetS.

Reference:

Zhang Y, Jiang X, Liu J, Lang Y, and Liu Y. The association between insomnia and the risk of metabolic syndrome: a systematic review and meta-analysis. J Clin Neurosci. Published online May 29, 2021. doi:10.1016/j.jocn.2021.05.039