The decline in telomere length with age is more pronounced in lymphocytes than in granulocytes.

Shown is the mean telomere length for both cell types extracted from several hundred measurements over the entire age range (Baerlocher and Lansdorp, unpublished). Not shown is the considerable variation in telomere length values between individuals at any given age.³⁵ The gray bar at the bottom represents nontelomeric DNA contributing to the telomere length measurements (flow fluorescence in situ hybridization [FISH] measurements were calibrated using Southern blot analysis in which on average 2-4 kb of subtelomeric DNA between restriction sites and start of telomere repeats is included in the measurement). Both granulocytes and lymphocytes show a highly significant decline in telomere length with age, which is best described by a cubic function.