Leucocyte Telomere Length and Glucose Tolerance Status in Mixed-Ancestry South Africans

Abstract

Telomeres are DNA-tandem repeats situated at the ends of chromosomes and are responsible for genome stabilization. They are eroded by increased cell division, age and oxidative stress with shortened leucocyte telomeres (LTL) being associated with inflammatory disorders, including Type II diabetes. We assessed LTL in 205 participants across glucose tolerance groups at baseline and after three years in the mixed ancestry population of South Africa which have been shown to have high rates of obesity and T2DM. Baseline and follow-up data included glucose tolerance status, anthropometric measurements, lipids, insulin, γ-glutamyl transferase (GGT), cotinine, and HbA1c. Telomere length was measured using the absolute telomere q-PCR method performed on a Bio-Rad MiniOpticon Detector. No significant difference was detected in LTL across glucose tolerance groups at both time points, including in subjects who showed a deterioration of their glucose tolerance status. There was, however, a significant negative correlation between LTL and age which was more pronounced in diabetes (r = −0.18, p = 0.04) and with GGT (r = −0.16, p = 0.027). This longitudinal study has demonstrated that LTL shortening is not evident within three years, nor is it associated with glycaemia. Further studies in a larger sample and over a longer time period is required to confirm these results.

Serum gamma-glutamyl transferase, a marker of alcohol intake, is associated with telomere length and cardiometabolic risk in young adulthood

“…Compared with our results, a recent study in 205 individuals in South Africa noted a significant negative correlation between leukocyte telomere length and GGT (r = − 0.16, p = 0.03) 34 . In contrast to our findings, no associations between telomere length and indicators of oxidative stress including GGT were observed in a study in 143 elderly Dutch men and 109 Greek elderly men 33 .…”

“…As telomere length, GGT is also strongly associated with risk of cardiovascular disease 28 , metabolic syndrome 29 , 30 , and mortality 31 , 32 . Although the association between GGT and telomere length is barely studied 33 , 34 . Advanced understanding of their interrelation already in young adulthood may be relevant to provide new insights on the underlying pathways of disease development.…”

Telomere shortening associates with elevated insulin and nuchal fat accumulation

“…The first study investigated participants from the multiethnic Women's Health Initiative and reported only limited clinical usability of RTL for diabetes risk stratification among postmenopausal women 40 . The second study analyzed RTL and glucose tolerance status in 205 mixed-ancestry South Africans and found no association of RTL with glycaemia 41 .…”

The importance of educating older adults with diabetes

“…It occurs after the age of 40. It accounts for 90-95% of all diabetes cases, although unfortunately it is also more common in young people, especially in developed countries (Weale et al, 2019). Sokolov (2012) explains that in this type of diabetes, the pancreas produces insulin, but in small amounts, or the body has developed a resistance to it.…”