Obesity is a multifactorial pathophysiological condition with an imbalance in biochemical, immunochemical, redox status and genetic parameters values. We aimed to estimate the connection between relative leucocyte telomere lengths (rLTL) – biomarker of cellular ageing with metabolic and redox status biomarkers values in a group of obese and lean children. The study includes 110 obese and 42 lean children and adolescents, both sexes. The results suggested that rLTL are significantly shorter in obese, compared with lean group (P < 0·01). Negative correlation of rLTL with total oxidant status (TOS) (Spearman’s ρ = –0·365, P < 0·001) as well as with C-reactive protein (Spearman’s ρ = –0·363, P < 0·001) were observed. Principal component analysis (PCA) extracted three distinct factors (i.e. principal components) entitled as: prooxidant factor with 35 % of total variability; antioxidant factor with 30 % of total variability and lipid antioxidant – biological ageing factor with 12 % of the total variability. The most important predictor of BMI > 30 kg/m2 according to logistic regression analysis was PCA-derived antioxidant factor’s score (OR: 1·66, 95th Cl 1·05–2·6, P = 0·029). PCA analysis confirmed that oxidative stress importance in biological ageing is caused by obesity and its multiple consequences related to prooxidants augmentation and antioxidants exhaustion and gave us clear signs of disturbed cellular homoeostasis deepness, even before any overt disease occurrence.

Telomeres are nucleoprotein complexes that form the ends of eukaryotic chromosomes where they protect DNA from genomic instability, prevent end-to-end fusion and limit cellular replicative capabilities. Increased telomere attrition rates, and relatively shorter telomere length, is associated with genomic instability and has been linked with several chronic diseases, malignancies and reduced longevity. Telomeric DNA is highly susceptible to oxidative damage and dietary habits may make an impact on telomere attrition rates through the mediation of oxidative stress and chronic inflammation. The aim of this study was to examine the association between leucocyte telomere length (LTL) with both the Dietary Inflammatory Index® 2014 (DII®) and the Alternative Healthy Eating Index 2010 (AHEI-2010). This is a cross-sectional analysis using baseline data from 263 postmenopausal women from the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial, in Calgary and Edmonton, Alberta, Canada. No statistically significant association was detected between LTL z-score and the AHEI-2010 (P = 0·20) or DII® (P = 0·91) in multivariable adjusted models. An exploratory analysis of AHEI-2010 and DII® parameters and LTL revealed anthocyanidin intake was associated with LTL (P < 0·01); however, this association was non-significant after a Bonferroni correction was applied (P = 0·27). No effect modification by age, smoking history, or recreational physical activity was detected for either relationship. Increased dietary antioxidant and decreased oxidant intake were not associated with LTL in this analysis.

There are limited data on the association between Fe overload and leucocyte telomere length (LTL), known as a useful biomarker of the replicative ageing of cells. The aim of the study was to evaluate associations between Fe-status biomarkers and LTL. A cross-sectional study included 1174 men and women aged 50–79 years who provided blood samples for assays of Fe-status biomarkers including ferritin, transferrin saturation (TSAT), total Fe-binding capacity (TIBC) and relative LTL. They were free of hepatitis, potential infection or Fe deficiency. In multiple linear regression analysis adjusted for potential confounding variables, log-transformed LTL was positively associated with TIBC (adjusted coefficient estimate for its highest quartile: 0·17 (se 0·03), P<0·001) and inversely associated with TSAT (adjusted coefficient estimate for its third and fourth quartiles: −0·09 (se 0·03), P<0·01). These associations were consistent after additional adjustment for serum concentrations of high-sensitivity C-reactive protein, alanine transaminase and aspartate transaminase. In particular, participants with not only abnormally high concentrations (>45 %) but also with high-normal concentrations (35–45 %) of TSAT had shorter LTL compared with those with low-normal concentrations (<30 %) (P<0·05). We also observed that less-active or obese persons with high TSAT concentrations had shorter LTL than others. Our findings that cellular ageing is influenced not only by Fe overload but also by high-normal concentrations of TSAT support the hypothesis regarding the detrimental effects of labile Fe, which has a potent pro-oxidant activity in the body.

A few studies have examined the association between vitamin D and telomere length, and fewer still have examined the relationship in black or male populations. We investigated the cross-sectional association between the vitamin D metabolite 25-hydroxyvitamin D (25(OH)D) concentration in plasma and relative leucocyte telomere length (LTL) in 1154 US radiologic technologists who were 48–93 years old (373 white females, 278 white males, 338 black females, 165 black males). Plasma 25(OH)D concentration was measured by the chemiluminescence immunoassay, and relative LTL was measured by quantitative PCR. Logistic regression was used to obtain OR and 95 % CI for long v. short (based on median) LTL in relation to continuous 25(OH)D, quartiles of 25(OH)D and 25(OH)D deficiency. We found no significant association between continuous 25(OH)D and long LTL in all participants (Ptrend=0·440), nor in white females (Ptrend=0·845), white males (Ptrend=0·636), black females (Ptrend=0·967) or black males (Ptrend=0·484). Vitamin D deficiency (defined as 25(OH)D<30 nmol/l), however, was significantly associated with short LTL in whites (P=0·024), but not in other groups. In this population, we found little evidence to support associations between 25(OH)D and long LTL over the entire range of 25(OH)D in the overall study population or by sex and race.