If the number of so-called lymphocytes in your blood is very low, then this is an indication that you may become gravely ill over time. A Danish study published today has revealed these results in the CMAJ (Canadian Medical Association Journal). Thanks to this insight, doctors can now take preventive measures for people who have been diagnosed with such low levels of lymphocytes.

A lymphocyte is a type of white blood cell that forms in red bone marrow. Lymphocytes play an important role in the immune system. Lower levels of lymphocyte blood cells is a condition known as lymphopenia.

Lymphopenia often comes to light during routine blood tests. Until now, patients were usually not referred for further testing. The great potential of lymphopenia as a predictor of future health was previously unknown.

“Our research showed that participants with lymphopenia were at great risk of dying, from whatever cause. Regardless of any other risk factor for death from all causes, including age,” Dr. Stig Bojesen writes.

Increased risk of death

The scientists examined the medical data of 108,135 people of Danish descent aged 20 to 100 years old. Furthermore, they were all registered within the Danish healthcare system between 2003 and 2015. They found a link between a low lymphocyte count and an increased risk of death from an illness or a medical condition. That risk was even higher when it came to death from cancer, cardiovascular diseases, respiratory diseases, infections and other causes. A total of 10,372 people died during the study period.

Identifying people at increased risk

Lymphopenia may also be a more passive indication of the overall frailty of the human body. This invariably brings with it a higher risk of death from any cause. Aging has been linked to both the decreasing number of lymphocytes found in this research and to mortality in general. Although the reason for the age-related decline in lymphocyte counts is not yet known, it may have to do with the shrinkage of the thymus gland through the years. This in turn leads to a reduction in the amount of lymphocytes. Which results in a worsening of the general immune competence level.

Of course, participants may have had an as yet undetectable and potentially fatal disease on the examination day, which may have affected their lymphocyte count and mortality risk. “Nevertheless, given that the link between lymphopenia and high mortality remained for several years after the research into the participants, it is unlikely that this influenced our findings,” the scientists concluded.

The published article can be viewed via this link.