CAREFUL BALANCE: Glycohemoglobin is an indicator for diabetes, but if its concentration falls to less than 5.5 percent, the risk of impairment grows
/ Staff writer, with CNA
Researchers at the National Health Research Institutes （NHRI） have found that a low level of glycated hemoglobin might accelerate aging.
A combination of high levels of blood sugar of glycated hemoglobin, also known as glycohemoglobin or hemoglobin A1c （HbA1c）, is known to heighten the risk of contracting diabetes.
Glycohemoglobin is a combination of hemoglobin and glucose formed nonenzymatically within a cell that reflects the average blood glucose level over the preceding 60 to 90 days. It is widely used to monitor diabetics through common health checks and clinical examinations.
A high level of glycohemoglobin increases inflammation in the body, leading to the degeneration of muscle function and a lack of physical strength, NHRI assistant investigator and attending physician Wu I-chien （吳易謙） told a news conference in Taipei yesterday.
A normal glycohemoglobin concentration level is 4.2 to 5.6 percent of red blood cells, he said, adding that the risk of developing diabetes increases when the level is at 5.7 to 6.4 percent, while above 6.5 percent is defined as diabetes.
However, “one cannot say a lower HbA1c is better,” Wu said, citing research by an NHRI team he was part of that traced the health of 2,565 initially fully functioning people aged 55 and older over a period of about five years.
In the “Healthy Aging Longitudinal Study in Taiwan,” baseline measurements were taken of each participant’s levels of glycohemoglobin and inflammation markers, and their physical health was repeatedly assessed over a mean follow-up period of 5.3 years.
The team found that compared with participants with glycohemoglobin concentration levels of 5.5 to 6 percent, those below or above that range experienced a greater annual increase in the likelihood of physical impairment.
When the glycohemoglobin level was less than 5.5 percent, even if it remained within normal levels, the risk of physical impairment was found to have increased by 1.25 times each year, Wu said.
“High and low HbA1c levels at baseline are associated with faster physical functioning decline, particularly among individuals with elevated circulating soluble interleukin-6 receptor, a sign of enhanced interleukin-6 trans-signaling,” said the study, which was published in June last year in the Journal of Gerontology: Medical Sciences, one of the main academic publications of the Gerontological Society of America.
Interleukin-6 is a cytokine that plays an important role in many chronic inflammatory diseases.
A high or low level of glycohemoglobin with an increase of certain inflammation-induced substances could be a sign of early aging, Wu said yesterday.
NHRI Institute of Population Health Sciences deputy director Hsu Chih-cheng （許志成） advised people aged 40 or older to receive regular health checkups to help detect early aging.
National Health Research Institutes assistant investigator and attending physician Wu I-chien points to a graph showing the results of research into glycated hemoglobin at a news conference in Taipei yesterday. Photo: Wu Liang-yi, Taipei Times