Study Links Anxiety and Insomnia to Decrease in Immune Cells

Researchers in Saudi Arabia have studied the relationship between anxiety disorders, insomnia, and NK cell levels among young female students. Their findings were published in Frontiers in Immunology.

Dr. Renad Alhamawi, the first author and an assistant professor at Taibah University, stated, "We found that in students with insomnia symptoms, count and percentage of total NK cells and their sub-populations were declined. Students with general anxiety symptoms had a lower percentage and number of circulatory NK cells and their sub-populations compared to symptom-free students."

The study involved 60 female participants aged 17 to 23, who completed questionnaires assessing their sociodemographic data and symptoms of anxiety and insomnia. Approximately 53% reported sleep difficulties aligned with insomnia, while 75% exhibited anxiety symptoms, with 17% and 13% classifying their anxiety as moderate and severe.

Blood samples were collected to analyze different NK cell types. The primary subpopulations studied were CD16+CD56dim cells, predominantly found in the nervous system, and CD16+CD56high cells, which play a role in immunoregulation. Both are categorized as circulatory NK cells.

Results indicated that students reporting anxiety symptoms had a significantly lower percentage and number of circulatory NK cells compared to peers without symptoms. Severity of anxiety influenced these counts; those with moderate to severe anxiety demonstrated a notable reduction in circulatory NK cell percentages compared to those with minimal symptoms. In students with insomnia symptoms, higher anxiety scores correlated with lower total peripheral NK cell proportions.

A decline in NK cells can weaken immune defenses, increasing susceptibility to various health issues, such as infections, cancers, and mental health disorders. Alhamawi remarked, "Understanding how these psychological stressors influence the distribution and activity of immune cells may provide valuable insights into the mechanisms underlying inflammation and tumorigenesis."

The researchers acknowledged limitations in the study, noting that it only included young female participants, a demographic that has experienced rising rates of anxiety and sleep disturbances. They stressed the need for studies encompassing a wider age range, genders, and geographic locations to better understand the impact of anxiety and insomnia on NK cell levels and function.

Previous research suggests that healthy habits—like regular physical activity, reduced stress levels, and a balanced diet—may help maintain NK cell performance. Nevertheless, anxiety and insomnia can disrupt biological processes, including immune responses, contributing to chronic inflammatory diseases and overall health deterioration, according to Alhamawi.