Telomere length and periodontal attachment loss: a prospective cohort study

Reverse causal relationship between periodontitis and shortened telomere length: Bidirectional two-sample Mendelian random analysis

Background

Observational studies have demonstrated a link between shortened telomere lengths(TL) and chronic periodontitis. However, whether the shortened TL is the cause or the result of periodontitis is unknown.Therefore, our objective was to investigate a bidirectional causal relationship between periodontitis and TL using a two-sample Mendel randomized (MR) study.

Methods

A two-sample bidirectional MR analysis using publicly available genome-wide association study (GWAS) data was used. As the primary analysis, inverse variance weighting (IVW) was employed. To identify pleiotropy, we used leave-one-out analysis, MR-Egger, Weighted median, Simple mode, Weighted mode, and MR pleiotropy residual sum and outlier (MR-PRESSO).

Results

In reverse MR results, a genetic prediction of short TL was causally associated with a higher risk of periodontitis (IVW: odds ratio [OR]: 1.0601, 95% confidence interval [CI]: 1.0213 to 1.1002; P =0.0021) and other complementary MR methods. In the forward MR analysis, periodontitis was shown to have no significant effect on TL (IVW: p = 0.7242), with consistent results for the remaining complementary MR. No pleiotropy was detected in sensitivity analysis (all P>0.05).

Conclusion

Our MR studies showed a reverse causal relationship, with shorten TL being linked to a higher risk of periodontitis, rather than periodontitis shorten that TL. Future research is needed to investigate the relationship between cell senescence and the disease.

Association of periodontitis with leukocyte telomere length in US adults: A cross-sectional analysis of NHANES 1999 to 2002

BACKGROUND

This study examines the association of periodontitis with telomere length (TL) and effect modification by population characteristics.

METHODS

We analyzed data from 3,478 participants from the 1999 to 2002 National Health and Nutrition Examination Survey. Probing depth, attachment loss, and bleed on probing (BOP, available for 1,973 participants only) were examined on the distal, mesial, or mid-facial site of each tooth in two randomly selected quadrants. We defined periodontitis severity according to the Centers for Disease Control/American Academy of Periodontology guideline. TL from leukocytes was measured with qPCR. We used linear and logistic regression to examine the adjusted association of different severity of periodontitis and BOP with continuous TL (bp) and dichotomized short TL (<median), respectively. To assess effect modification, we stratified the analyses by a priori selected population characteristics including sex, age, body weight status, smoking, and cardiometabolic comorbidity.

RESULTS

Moderate BOP (<10% bleeding sites) was significantly associated with a shorter continuous TL (β = -89.0, SE = 37.8). Moderate to severe periodontitis was significantly associated with 47% (95% confidence interval [IL], 1.04 to 2.09) higher odds of shorter TL, compared with those with mild or no periodontitis. The association was stronger in those who were female (adjusted OR, 1.76; 95% CI, 1.10 to 2.83), overweight or obese (adjusted OR, 1.64; 95% CI, 1.12 to 2.41), or had cardiometabolic comorbidities (adjusted OR, 2.13; 95% CI, 1.38 to 3.29).

CONCLUSIONS

Periodontitis was associated with TL, a biomarker of cellular aging. The association was stronger in females, overweight or obese, or those with cardiometabolic diseases. Treatment on periodontitis could potentially protect individuals from aging-related diseases.

The Biology of Social Adversity Applied to Oral Health

Biological embodiment is a concept derived from Engel's biopsychosocial model to health, theorized as the process by which adverse social exposures trigger neuroendocrine and immune responses, leading to disease and/or increased disease susceptibility. This critical review discusses the biopsychosocial model as applied to oral health and its relevance to oral health policy while deciphering some of the pathobiological processes underlying social adversity. In periodontal disease, for example, such processes can occur via the activation of the hypothalamic-pituitary-adrenal axis and the consequent release of the chronic stress hormone cortisol. The latter contributes to a proinflammatory immune state that increases the risk for periodontal inflammation. Recent research shows that cortisol relates to an elevated oral inflammatory load, demonstrated as hyperactive neutrophils that are pivotal to periodontal tissue damage. Consistent with the biopsychosocial model, this relationship is amplified in those of lower income and higher financial stress. Similarly, among children from lower socioeconomic backgrounds, cortisol is linked to a higher cariogenic bacterial load. Such findings implicate the stress pathway as key in the oral pathogenic process, particularly under social/socioeconomic adversity. Collectively, this work emphasizes the importance of addressing social factors in alleviating oral disease burden and reducing the social gaps therein.

Smoking does not accelerate leucocyte telomere attrition: a meta-analysis of 18 longitudinal cohorts

Smoking is associated with shorter leucocyte telomere length (LTL), a biomarker of increased morbidity and reduced longevity. This association is widely interpreted as evidence that smoking causes accelerated LTL attrition in adulthood, but the evidence for this is inconsistent. We analysed the association between smoking and LTL dynamics in 18 longitudinal cohorts. The dataset included data from 12 579 adults (4678 current smokers and 7901 non-smokers) over a mean follow-up interval of 8.6 years. Meta-analysis confirmed a cross-sectional difference in LTL between smokers and non-smokers, with mean LTL 84.61 bp shorter in smokers (95% CI: 22.62 to 146.61). However, LTL attrition was only 0.51 bp yr-1 faster in smokers than in non-smokers (95% CI: -2.09 to 1.08), a difference that equates to only 1.32% of the estimated age-related loss of 38.33 bp yr-1. Assuming a linear effect of smoking, 167 years of smoking would be required to generate the observed cross-sectional difference in LTL. Therefore, the difference in LTL between smokers and non-smokers is extremely unlikely to be explained by a linear, causal effect of smoking. Selective adoption, whereby individuals with short telomeres are more likely to start smoking, needs to be considered as a more plausible explanation for the observed pattern of telomere dynamics.