Telomere length and type 2 diabetes: Mendelian randomization study and polygenic risk score analysis

Area of Science:

• Genetics
• Epidemiology
• Metabolic Diseases

Background:

• Observational studies suggest shorter telomere length is linked to increased type 2 diabetes (T2D) risk.
• Confounding factors and reverse causation in observational studies limit conclusions on causality.
• The causal relationship between telomere length and T2D requires robust investigation.

Purpose of the Study:

• To evaluate the causal effect of telomere length on T2D risk in the Chinese Han population.
• To utilize Mendelian randomization (MR) and polygenic risk score (PRS) approaches for causal inference.
• To clarify the association between genetically predicted telomere length and T2D susceptibility.

Main Methods:

• Employed Mendelian randomization (MR) using 8 telomere-length associated genetic variants as instrumental variables.
• Analyzed T2D genome-wide association study (GWAS) data from 2632 individuals (1318 cases, 1314 controls).
• Applied polygenic risk score (PRS) analysis with Chinese GWAS data to assess genetic overlap.

Main Results:

• Multiple MR methods (IVW, MR-Egger, median) showed no significant association between genetically predicted longer telomere length and T2D risk.
• Specific results indicated no evidence of increased T2D risk with longer telomeres (e.g., OR = 0.78, P = 0.522).
• PRS analysis did not reveal consistent genetic overlap between telomere length and T2D.

Conclusions:

• This study found no evidence to support a causal association between telomere length and type 2 diabetes.
• The findings suggest that the observed association in epidemiological studies may not be causal.
• Larger cohort studies are recommended for more definitive conclusions on telomere length and T2D causality.