Childhood obesity is associated with shorter leukocyte telomere length

Abstract

Context: Obesity in adults is associated with shorter mean leukocyte telomere length (LTL), a marker of biological age that is also associated with age-related conditions including cardiovascular disease and type 2 diabetes. However, studies of childhood obesity and LTL have proved inconclusive.

Objective: The objective of the study was to clarify the relationship between telomere length and childhood obesity by measuring the average LTL in a large case-control cohort.

Participants and methods: LTL was measured in 793 French children aged 2-17 yr (471 with early onset obesity and 322 nonobese controls) using multiplex quantitative real-time PCR. The average LTL in the two groups was compared, and the relationships between telomere length and selected anthropometric and biochemical measurements were examined.

Results: Obese children had a mean LTL that was 23.9% shorter than that of nonobese children (P < 0.0001). Telomere length was inversely associated with age (R = -0.17, P = 0.002 in controls; R = -0.15, P = 0.001 in cases), log weight (R= -0.13, P = 0.017 in controls; R = -0.16, P = 0.0004 in cases), and height (R = -0.15, P = 0.008 in controls; R = -0.17, P = 0.0002 in cases). The mean LTL of girls and boys was not significantly different in either the cases or controls or in the group overall.

Conclusion: Obese girls and boys have significantly shorter leukocyte telomeres than their nonobese counterparts, a finding that highlights a potentially deleterious impact of early onset obesity on future health.

Fig. 1.

Distribution of LTL for all samples (n = 793), expressed as log T/S values. Log T/S values are normally distributed (Shapiro-Wilk test for normality, P = 0.65).

Fig. 2.

Comparison of LTL distribution in nonobese and obese subjects (A) and in male and female subjects (B). The box plots indicate the maximum and minimum, the lower and upper quartiles, and the median log T/S ratio value in each group. The mean log T/S ratio values of each group are given below. A, LTL (expressed as log T/S ratio) is significantly shorter in obese compared with nonobese study subjects. The mean log T/S ratio in all nonobese samples is 0.191 (se 0.008), the mean log T/S ratio in all obese samples is 0.072 (se 0.006, P < 0.0001). B, LTL (expressed as the log T/S ratio) is not significantly different in male study subjects compared with female study subjects (the mean log T/S ratio of males = 0.113, se 0.007; the mean log T/S ratio of females = 0.126, se 0.007, P = 0.19).