Leukocyte telomere length in the Finnish Diabetes Prevention Study

Abstract

Leukocyte telomere length (TL) is considered a biomarker for biological aging. Shortened TL has been observed in many complex diseases, including type 2 diabetes (T2DM). Lifestyle intervention studies, e.g. the Diabetes Prevention Study (DPS), have shown a decrease in the incidence of T2DM by promoting healthy lifestyles in individuals with impaired glucose tolerance (IGT). Our aim was to study in the DPS the influence of the lifestyle intervention on TL. TL was measured by quantitative PCR-based method at two time points (N = 334 and 343) on average 4.5 years apart during the active intervention and post-intervention follow-up. TL inversely correlated with age. Our main finding was that TL increased in about two thirds of the individuals both in the intervention and in the control groups during follow-up; TL increased most in individuals with the shortest TL at the first measurement. TL was not associated with development of T2DM, nor did lifestyle intervention have an effect on TL. No association between insulin secretion or insulin resistance indices and TL was observed. We did not detect an association between TL and development of T2DM in the DPS participants. It could be due to all participants being overweight and having IGT at baseline, both of which have been found to be independently associated with shorter leukocyte TL in some earlier studies. TL had no substantial role in worsening of glucose tolerance in people with IGT. Our study confirms that leukocyte TL can increase with time even in obese people with impaired glucose metabolism.

Figure 1. Telomere length as a function of age.

Females are shown with red dots and males with blue dots, each dot representing one individual. Regression lines for both groups are shown with the same color coding. A) the first DNA sample; B) the second DNA sample.

Figure 2. Telomere length change between the 1^st and 2^nd DNA sampling.

Diabetes Prevention Study sample A) intervention cases and B) controls as a histogram with frequencies of telomere length difference between two time points.

Figure 3. Telomere length yearly change as a function of telomere length at the 1^st DNA sampling.

Diabetes Prevention Study sample intervention cases (N = 190) are shown with red dots and controls (N = 188) with blue dots, each dot representing one individual. Regression lines for both groups are shown with the same color coding. Relative telomere length is adjusted for age and sex.