In a rapidly aging population, the physiological and psychological mechanisms underpinning successful aging are the focus of intense research. A key biological marker associated with aging at the cellular level is leukocyte telomere length (LTL) [1]. Telomeres cap the ends of chromosomes and serve to protect the chromosomes from deterioration and damage. With increasing cell divisions, telomeres shorten, until a critical length is reached, and the cell enters senescence. LTL is maintained by telomerase, which can add telomeric repeat sequences to the ends of chromosomes, hence elongating them to compensate for their attrition. Since the levels of telomerase are limited in most human tissues [2], over a lifetime of growing and physiological maintenance, the percentage of senescent cells builds up in all tissues, potentially impairing the body’s ability to repair itself. Ipso facto, LTL is widely-employed as a marker for cellular aging and disease [1, 3].
A growing body of research has demonstrated that in addition to chronological age, numerous factors exert effects on telomere length. Shorter telomeres are associated with various chronic illnesses such as cardiovascular diseases [4] and diabetes [5] as well as mental disorders such as major depression [6] and anxiety disorders [7]. More broadly, studies show that shorter LTL is associated with life stressors including urban living and poverty [8]. Shorter LTL has also been linked to impatience, as measured using behavioural economic tasks [9]. Conversely, healthy lifestyles such as exercise are correlated with longer telomeres [10]. Normal personality traits (e.g., the Big Five) have also been examined for correlation with LTL. For example, both neuroticism and hostility have been associated with shorter LTL [11, 12]. Beyond disease factors, lifestyle behaviors, and general personality traits, less work has examined the association between telomere length and putatively adaptive psychological traits, such as mindfulness and self-compassion.
Mindfulness, viz. paying attention to experiences in the present moment in an intentional and non-judgmental manner [13], can be conceptualized as a dispositional trait, and is associated with a variety of physical and psychological health outcomes including reduced depression, anxiety, and rumination, as well as improved quality of life and subjective health [14]. As highlighted in a recent review, there is increasing evidence that dispositional mindfulness is an individual trait that is conceptually distinct from other well-established personality traits, such as conscientiousness and neuroticism [15]. Moreover, dispositional mindfulness needs to be considered apart from state mindfulness, which refers to momentary, short term, or current expression of the quality of mindfulness. It is believed that dispositional mindfulness is a natural human capacity, and can be cultivated and strengthened over time through systematic practices such as meditation [16]. A widely-employed measure to operationalize dispositional mindfulness is the five facet mindfulness questionnaire (FFMQ), which describes mindfulness as consisting of five facets (observing, describing, acting with awareness, nonreactivity, nonjudging) [17]. With the exception of the observing facet [18], each of the other facets is consistently associated with psychological well-being [17, 19]. Specifically, it has been demonstrated that the observing facet as assessed in the FFMQ does not include items pertaining to awareness of emotions, which may be crucial to psychological well-being [18]. Taken together, existing research points to the value of examining the role of individual facets of mindfulness as predictors of psychological and physical health.
The positive relationship between mindfulness and psychological well-being suggests the notion that dispositional mindfulness can be pegged to biological markers of aging that correspond with favourable health trajectories [3]. Mindfulness meditation has been theorized to impact biological aging through lowering cognitive stress and stress-related arousal, as well as increasing positive states of mind [20]. Increased positive emotions and lowered stress arousal may result in greater vagal tone and growth hormone axis activity, and lower cortisol, insulin, and oxidative stress, which in turn promote telomere maintenance [3, 20]. In this vein, some investigations, and confirmed by meta-analysis, show that mindfulness training increases telomerase activity [21, 22]. However, there has not been much work examining the association between mindfulness and LTL. One study that examined only a single facet of dispositional mindfulness, mind wandering, found association with shorter LTL in a sample of predominantly Caucasian women [23]. As mindfulness is commonly viewed as a multidimensional construct [17], the involvement of other components of dispositional mindfulness (e.g., the nonreactivity and nonjudging components) crucially need to be evaluated for association with LTL towards a more panoptic understanding of the dynamics of telomere maintenance, dispositional mindfulness, and implications for psychological well-being. Therefore, a key aim of this study was to examine the association between different facets of dispositional mindfulness and LTL in a sample of Chinese adults. Based on prior research, we hypothesized that several attentional (i.e., describe and acting with awareness) and attitudinal (i.e., nonjudging and nonreactivity) facets of trait mindfulness would be associated with longer LTL.
Self-compassion is a personality trait that resonates with mindfulness, and has been associated with adaptive functioning. It refers to the tendency to relate to one’s experiences of pain and suffering with an attitude of kindness and compassion (Neff, 2016), and has been conceptualized as consisting of three aspects: 1) self-kindness, which refers to the ability to relate to oneself kindly; 2) common humanity, which refers to the tendency of perceiving suffering as a common human experience, as opposed to feeling isolated during times of failure; and 3) mindfulness, which refers to being aware of and accepting of one’s inner experiences, versus over-identifying with the experiences. Self-compassion is correlated with greater well-being in both adolescents and older adults [24] and conversely, a meta-analysis found a strong association between low self-compassion and psychopathological symptoms, particularly depression, anxiety, and stress [25]. In a study involving 20 Caucasian Zen meditators, the common humanity subscale of the Self Compassion Scale was found to correlate with improved telomere maintenance [26]. In a second small-scale investigation, also involving a predominantly Caucasian sample, practitioners of loving-kindness meditation, a form of practice that aims to cultivate self-compassion (in addition to compassion towards all living beings), have longer LTL compared to controls [27]. Despite the promising findings suggesting a potential positive association between LTL and compassion-related practices or traits, these studies are limited by small samples and a restricted range of demographics focusing on largely Caucasian participants who are experienced meditators. Further research with bigger and more diverse ethnic and gender cohorts is warranted to gain a fuller understanding of the relationship between facets of self-compassion and LTL.
Surprisingly, the important role of dispositional mindfulness and self-compassion in LTL has yet to be adequately evaluated in the great majority of people who are non-meditators, or do not meditate regularly. Hence, a main goal of the current study is to bridge this critical gap in understanding the dynamics of telomere maintenance, especially the relationship of LTL to psychological health and the personality traits of dispositional mindfulness and self-compassion in a sample of community adults with little or no regular meditation experience. Accordingly, we utilized a cross-sectional design to examine the association between dispositional mindfulness, self-compassion, and LTL in a cohort of Chinese adults of mixed gender. In our analyses, we assessed and controlled for the effects of confounding factors such as chronological age and psychological symptoms (i.e., depression, anxiety, and stress symptoms) on the association between LTL and these personality traits. We hypothesized that both dispositional mindfulness and self-compassion, along with their individual facets, would be associated with longer LTL.