Association between Cigarette Smoking and Sarcopenia according to Obesity in the Middle-Aged and Elderly Korean Population: The Korea National Health and Nutrition Examination Survey (2008-2011)

Tissue-specific mitochondrial toxicity of cigarette smoke concentrate: consequence to oxidative phosphorylation

Cigarette smoke exposure is a well-known risk factor for developing numerous chronic health conditions, including pulmonary disease and cardiometabolic disorders. However, the cellular mechanisms mediating the toxicity of cigarette smoke in extrapulmonary tissues are still poorly understood. Therefore, the purpose of this study was to characterize the acute dose-dependent toxicity of cigarette smoke on mitochondrial metabolism by determining the susceptibility and sensitivity of mitochondrial respiration from murine skeletal (gastrocnemius and soleus) and cardiac muscles, as well as the aorta to cigarette smoke concentrate (CSC). In all tissues, exposure to CSC inhibited tissue-specific respiration capacity, measured by high-resolution respirometry, according to a biphasic pattern. With a break point of 451 ± 235 μg/mL, the aorta was the least susceptible to CSC-induced mitochondrial respiration inhibition compared with the gastrocnemius (151 ± 109 μg/mL; P = 0.008, d = 2.3), soleus (211 ± 107 μg/mL; P = 0.112; d = 1.7), and heart (94 ± 51 μg/mL; P < 0.001; d = 2.6) suggesting an intrinsic resistance of the vascular smooth muscle mitochondria to cigarette smoke toxicity. In contrast, the cardiac muscle was the most susceptible and sensitive to the effects of CSC, demonstrating the greatest decline in tissue-specific respiration with increasing CSC concentration (P < 0.001, except the soleus). However, when normalized to citrate synthase activity to account for differences in mitochondrial content, cardiac fibers' sensitivity to cigarette smoke inhibition was no longer significantly different from both fast-twitch gastrocnemius and slow-twitch soleus muscle fibers, thus suggesting similar mitochondrial phenotypes. Collectively, these findings established the acute dose-dependent toxicity of cigarette smoke on oxidative phosphorylation in permeabilized tissues involved in the development of smoke-related cardiometabolic diseases.NEW & NOTEWORTHY Despite numerous investigations into the mechanisms underlying cigarette smoke-induced mitochondrial dysfunction, no studies have investigated the tissue-specific mitochondrial toxicity to cigarette smoke. We demonstrate that, while aorta is least sensitive and susceptible to cigarette smoke-induced toxicity, the degree of cigarette smoke-induced toxicity in striated muscle depends on the tissue-specific mitochondrial content. We conclude that while the mitochondrial content influences cigarette smoke-induced toxicity in striated muscles, aorta is intrinsically protected against cigarette smoke-induced mitochondrial toxicity.

Relationship between DNA methylation changes and skeletal muscle mass

BACKGROUND

Sarcopenia is a disease diagnosed in the elderly. In patients with sarcopenia, the muscle mass decreases every year. The occurrence of sarcopenia is greatly affected by extrinsic factors such as eating habits, exercise, and lifestyle. The present study aimed to determine the relationship between muscle mass traits and genes affected by epigenetic factors with three different adjustment methods using Korean Genome and Epidemiology Study (KOGES) data.

RESULTS

We conducted a demographic study and DNA methylation profiling by three studies according to the muscle mass index (MMI) adjustment methods: appendicular skeletal muscle mass divided by body weight (MMI1); appendicular skeletal muscle mass divided by square of height (MMI2); appendicular skeletal muscle mass divided by BMI (MMI3). We analyzed differentially methylated regions (DMRs) for each group. We then restricted our subjects to be top 30% (T30) and bottom 30% (B30) based on each MMI adjustment method. Additionally, we performed enrichment analysis using PathfindR to evaluate the relationship between identified DMRs and sarcopenia. A total of 895 subjects were included in the demographic study. The values of BMI, waist, and hip showed a significant difference in all three groups. Among 446 participants, 44 subjects whose DNA methylation profiles were investigated were included for DNA methylation analysis. The results of enrichment analysis showed differences between groups. In the women group through MMI1 method, only the glutamatergic synapse pathway showed a significant result. In the men group through MMI2 method, the adherens junction pathway was the most significant. Women group through MMI2 method showed similar results, having an enriched Rap1 signaling pathway. In men group through MMI3 method, the Fc epsilon RI signaling pathway was the most enriched. Particularly, the notch signaling pathway was significantly enriched in women group through MMI3 method.

CONCLUSION

This study presents results about which factor should be concerned first in muscle mass index (MMI) adjustment. The present study suggested that GAB2 and JPH3 in MMI1 method, HLA-DQB1 and TBCD in MMI2 method, GAB2, NDUFB4 and ISPD in MMI3 method are potential genes that can have an impact on muscle mass. It could enable future epigenetic studies of genes based on annotation results. The present study is a nationwide study in Korea with the largest size up to date that compares adjustment indices for MMI in epigenetic research.

Association between systemic immune-inflammation index and low muscle mass in US adults: a cross-sectional study

BACKGROUND

Chronic inflammatory responses have been reported to be associated with low muscle mass and systemic immune-inflammation index(SII) is a novel indicator of inflammation. The purpose of our study was to clarify the relationship between SII and low muscle mass.

METHODS

This study was a cross-sectional study based on National Health and Nutrition Examination Survey (2011-2018). SII was calculated as the platelet count × neutrophil count/lymphocyte count. Appendicular skeletal muscle index was used to define low muscle mass. The individuals were divided into four groups by the quartile of SII (Q1-Q4). Multivariate weighted logistic regression analysis, smooth curve fitting and subgroup analysis were used to investigate the relationship between SII and sarcopenia. Subgroup analysis were based on demographic and clinical variables.

RESULTS

There were 10,367 individuals enrolled in our final analysis. The overall mean age was 39.39 years and 49.17% were males. The overall prevalence of low muscle mass in the study population was 8.77%. The smooth curve fitting analysis indicated a near-linear relationship between SII and low muscle mass. In multivariate weighted logistic regression analysis, the odds ratio (OR) of Q4 is 1.28 (95% CI, 1.16-1.40) for low muscle mass when compared to lowest quartile of the SII. In subgroup analysis, SII still increased the risk of low muscle mass independently.

CONCLUSION

The increased SII levels were associated with an increased risk of low muscle mass in a large population. Our study increased the understanding between inflammation and low muscle mass. Anti-inflammation therapy may be important for low muscle mass.

The Role of Smoking in the Mechanisms of Development of Chronic Obstructive Pulmonary Disease and Atherosclerosis

Tobacco smoking is a major cause of chronic obstructive pulmonary disease (COPD) and atherosclerotic cardiovascular disease (ASCVD). These diseases share common pathogenesis and significantly influence each other's clinical presentation and prognosis. There is increasing evidence that the mechanisms underlying the comorbidity of COPD and ASCVD are complex and multifactorial. Smoking-induced systemic inflammation, impaired endothelial function and oxidative stress may contribute to the development and progression of both diseases. The components present in tobacco smoke can have adverse effects on various cellular functions, including macrophages and endothelial cells. Smoking may also affect the innate immune system, impair apoptosis, and promote oxidative stress in the respiratory and vascular systems. The purpose of this review is to discuss the importance of smoking in the mechanisms underlying the comorbid course of COPD and ASCVD.

Gene polymorphisms associated with heterogeneity and senescence characteristics of sarcopenia in chronic obstructive pulmonary disease

BACKGROUND

Sarcopenia, or loss of skeletal muscle mass and decreased contractile strength, contributes to morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD). The severity of sarcopenia in COPD is variable, and there are limited data to explain phenotype heterogeneity. Others have shown that COPD patients with sarcopenia have several hallmarks of cellular senescence, a potential mechanism of primary (age-related) sarcopenia. We tested if genetic contributors explain the variability in sarcopenic phenotype and accelerated senescence in COPD.

METHODS

To identify gene variants [single nucleotide polymorphisms (SNPs)] associated with sarcopenia in COPD, we performed a genome-wide association study (GWAS) of fat free mass index (FFMI) in 32 426 non-Hispanic White (NHW) UK Biobank participants with COPD. Several SNPs within the fat mass and obesity-associated (FTO) gene were associated with sarcopenia that were validated in an independent COPDGene cohort (n = 3656). Leucocyte telomere length quantified in the UK Biobank cohort was used as a marker of senescence. Experimental validation was done by genetic depletion of FTO in murine skeletal myotubes exposed to prolonged intermittent hypoxia or chronic hypoxia because hypoxia contributes to sarcopenia in COPD. Molecular biomarkers for senescence were also quantified with FTO depletion in murine myotubes.

RESULTS

Multiple SNPs located in the FTO gene were associated with sarcopenia in addition to novel SNPs both within and in proximity to the gene AC090771.2, which transcribes long non-coding RNA (lncRNA). To replicate our findings, we performed a GWAS of FFMI in NHW subjects from COPDGene. The SNP most significantly associated with FFMI was on chromosome (chr) 16, rs1558902A > T in the FTO gene (β = 0.151, SE = 0.021, P = 1.40 × 10-12 for UK Biobank |β= 0.220, SE = 0.041, P = 9.99 × 10-8 for COPDGene) and chr 18 SNP rs11664369C > T nearest to the AC090771.2 gene (β = 0.129, SE = 0.024, P = 4.64 × 10-8 for UK Biobank |β = 0.203, SE = 0.045, P = 6.38 × 10-6 for COPDGene). Lower handgrip strength, a measure of muscle strength, but not FFMI was associated with reduced telomere length in the UK Biobank. Experimentally, in vitro knockdown of FTO lowered myotube diameter and induced a senescence-associated molecular phenotype, which was worsened by prolonged intermittent hypoxia and chronic hypoxia.

CONCLUSIONS

Genetic polymorphisms of FTO and AC090771.2 were associated with sarcopenia in COPD in independent cohorts. Knockdown of FTO in murine myotubes caused a molecular phenotype consistent with senescence that was exacerbated by hypoxia, a common condition in COPD. Genetic variation may interact with hypoxia and contribute to variable severity of sarcopenia and skeletal muscle molecular senescence phenotype in COPD.

Does the association between smoking and mortality differ due to frailty status? A secondary analysis from the Mexican Health and Aging Study

BACKGROUND

despite the well-known adverse health effects of smoking, evidence of these effects on frail individuals is still scarce.

AIMS

to assess whether frailty influences the association between smoking and mortality.

METHODS

individuals ≥50 years from the Mexican Health and Aging Study were analysed. Mortality rates from a 17-year follow-up were compared between smoking status groups (never, previous and current) and other smoking behaviour-related characteristics (pack-years, age commenced and cessation). Baseline variables were included to adjust the Cox regression models. First, models were adjusted for the whole sample, including an interaction term between the frailty index (FI) and smoking variables. A second set of models were stratified by FI levels: 0.00-0.10, 0.11-0.20, 0.21-0.30 and ≥ 0.31.

RESULTS

from a total 14,025 individuals, mean age was 62.4 (95% confidence interval [95% CI]: 62.1-62.8) and 53.9% were women (95% CI: 52.4-55.6). Main results from the survival analyses showed that when including FI interaction term with smoking status, comparing current to never smoking, the hazard ratio (HR) was 2.03 (95% CI: 1.07-3.85, P = 0.029), and comparing current to previous smoking, the HR was 2.13 (95% CI: 1.06-4.26, P = 0.032). Models stratified by FI levels showed a significant HR only for the two highest level groups. Similar results were found for the smoking behaviour-related characteristics.

DISCUSSION

our results suggest that frailty could modify smoking mortality risk. Other smoking characteristics were impacted by frailty, in particular, cessation. It was noteworthy that having ≥10 years of tobacco cessation was beneficial for frail individuals.

CONCLUSIONS

smoking has a higher toll on frail individuals, but ceasing is still beneficial for this group.

Sleep duration and sarcopenia in adults aged ≥ 65 years from low and middle-income countries

BACKGROUND

Sleep duration may influence risk for sarcopenia but studies on this topic are scarce, especially from low and- middle-income countries (LMICs). Thus, the aim of the present study was to investigate the association between sleep duration and sarcopenia among adults aged ≥ 65 years from five LMICs (China, Ghana, India, Russia, South Africa).

METHODS

Cross-sectional, community-based data from the WHO study on global ageing and adult health (SAGE) were analysed. Sarcopenia was defined as having low skeletal muscle mass (SMM) and weak handgrip strength, while severe sarcopenia was defined as having low SMM, weak handgrip strength, and slow gait speed. Self-reported sleep duration in the past two nights were averaged and classified as ≤ 6, > 6 to ≤ 9, and ≥ 9 h/day. Multivariable logistic regression analysis was conducted.

RESULTS

Data on 13,210 adults aged ≥ 65 years [mean (SD) age 72.6 (11.3) years; 55.0% females] were analyzed. In the overall sample, compared to > 6 to ≤ 9 h/day of sleep duration, > 9 h/day was associated with 1.70 (95% CI 1.15-2.51) and 1.75 (95% CI 1.08-2.84) times higher odds for sarcopenia and severe sarcopenia, respectively. No significant associations were observed among males, but associations were particularly pronounced among females [i.e., OR = 2.19 (95% CI 1.26-3.81) for sarcopenia, and OR = 2.26 (95% CI 1.20-4.23) for severe sarcopenia].

CONCLUSIONS

Long sleep duration was associated with an increased odds of sarcopenia and severe sarcopenia in LMICs, particularly in females. Future studies should investigate whether addressing long sleep duration among females can lead to lower risk for sarcopenia onset in LMICs.

Relationship between Sarcopenia and Cardiovascular Disease Risk among Taiwanese Older Adults

OBJECTIVE

Increasing evidence supports sarcopenia as an important parameter for predicting cardiometabolic risks. The objective of this study was to investigate the relationship between muscle mass, muscle strength, and physical performance, and cardiovascular risk among older community-dwelling adults.

DESIGN

The associations between dynapenia, sarcopenia, and Framingham risk score (FRS) were estimated by multivariate regression models.

SETTING

Muscle mass is estimated by skeletal muscle mass index using a bioelectrical impedance analysis. Muscle strength is measured by handgrip strength using an analog isometric dynamometer. Physical performance is measured by gait speed using a 6-meter walking distance. Dynapenia was defined as low muscle strength and/or slow gait speed presents with normal muscle mass. The diagnosis of presarcopenia and sarcopenia was based on criteria proposed by the Asian Working Group for Sarcopenia in 2014. The FRS was used for evaluating 10-year coronary heart disease risk.

PARTICIPANTS

Adults aged 65 years and older who attended health examinations from 2015 to 2017 were recruited.

RESULTS

There were totally 709 subjects enrolled in this study. Dynapenic men (n=47) had 17.70±5.08% FRS and sarcopenic women (n=74) had 7.74±6.06% FRS. Participants with presarcopenia had the lowest FRS (men: 15.41±5.35%; women: 5.25±3.70%). Men with dynapenia had higher FRS than the presarcopenia group with odds ratio (OR) of 2.52 (95% Confidence Interval [CI]: 1.03-6.14). Women with sarcopenia had significantly higher FRS than the presarcopenia group with OR of 2.81 (95%CI: 1.09-7.27).

CONCLUSION

Older dynapenic men and older sarcopenic women had higher risks of 10-year coronary heart disease. Presarcopenic older adults had the lowest coronary heart disease risk in both genders.

Skeletal System Biology and Smoke Damage: From Basic Science to Medical Clinic

Cigarette smoking has a negative impact on the skeletal system, as it reduces bone mass and increases fracture risk through its direct or indirect effects on bone remodeling. Recent evidence demonstrates that smoking causes an imbalance in bone turnover, making bone vulnerable to osteoporosis and fragility fractures. Moreover, cigarette smoking is known to have deleterious effects on fracture healing, as a positive correlation between the daily number of cigarettes smoked and years of exposure has been shown, even though the underlying mechanisms are not fully understood. It is also well known that smoking causes several medical/surgical complications responsible for longer hospital stays and a consequent increase in the consumption of resources. Smoking cessation is, therefore, highly advisable to prevent the onset of bone metabolic disease. However, even with cessation, some of the consequences appear to continue for decades afterwards. Based on this evidence, the aim of our review was to evaluate the impact of smoking on the skeletal system, especially on bone fractures, and to identify the pathophysiological mechanisms responsible for the impairment of fracture healing. Since smoking is a major public health concern, understanding the association between cigarette smoking and the occurrence of bone disease is necessary in order to identify potential new targets for intervention.

Relationship between smoking and the incidence of sarcopenia: The SarcoPhAge cohort

INTRODUCTION

The association of tobacco use and incidence of muscle impairments has not been extensively explored in research. In this study, the relationship between smoking and the incidence of sarcopenia is investigated.

METHODS

The present longitudinal study used data from the Sarcopenia and Physical Impairment with advancing Age (SarcoPhAge) cohort, which includes older adults aged ≥65 years. All individuals with follow-up data on muscle health were included in this post hoc analysis. A diagnosis of sarcopenia was established, at each year of follow-up, according to the European Working Group on Sarcopenia in older People 2 (EWGSOP2) criteria. A sensitivity analysis was performed using other diagnostic criteria for sarcopenia. The smoking status and the number of cigarettes smoked per day were self-reported. The relationship between smoking status or the number of cigarettes smoked per day and the incidence of sarcopenia/severe sarcopenia throughout the 5 years of follow-up was evaluated using the Cox proportional hazards model.

RESULTS

In total, the study population included 420 participants, with a median age of 71.7 years (P25-P75 = 67.7-76.9 years) and 59.8% were female. Over the 5 years of follow-up, 78 participants (18.6%) became sarcopenic as per the EWGSOP2 criteria and 41 individuals (9.8%) developed severe sarcopenia. There were significantly more smokers than non-smokers who developed sarcopenia (35.9% vs 16.8%, P-value = 0.003). A fully adjusted Cox model confirmed this observation, yielding a hazard ratio of 2.36 (95% confidence interval [CI]: 1.31-4.26), meaning that smokers have a 2.36-fold higher risk of developing sarcopenia. Furthermore, individuals who smoked had a 2.68 times increased risk of developing severe sarcopenia (95% CI: 1.21-5.93) than those who did not smoke. Sensitivity analyses globally confirmed these findings when applying other diagnostic criteria for sarcopenia.

DISCUSSION

Smoking seems to be an important predictor for the onset of sarcopenia, highlighting, once again, that tobacco use is a major public health problem.

[Association of Cigarette Smoking with Muscle Mass Reduction and Low Muscle Strength in Community-Dwelling Elderly Men]

OBJECTIVES

Recently, attention has been paid to the impact of cigarette smoking on skeletal muscles, as its underlying pathophysiological mechanism has been gradually elucidated. In this study, we aimed to examine whether cigarette smoking is associated with muscle mass reduction and low muscle strength in elderly men.

METHODS

The study participants comprised 417 community-dwelling elderly men (aged 73±6 years) without severe glucose intolerance, chronic kidney disease, or liver disease. Bioelectrical impedance analysis was performed to estimate appendicular skeletal muscle mass (ASM), which was normalized for height (ASM index, kg/m²). Handgrip strength (HGS) was measured using a Smedley grip dynamometer. Cumulative smoking exposure level during a lifetime was expressed in pack-years, which is a product of the average number of packs of cigarettes smoked per day and smoking duration in years.

RESULTS

When the participants were stratified on the basis of cumulative smoking exposure (<10 pack-years, 10-39 pack-years, ≥40 pack-years), the ASM index and HGS progressively decreased with increasing exposure level (P for trend <0.01). In multiple regression analysis, heavy smoking (defined as ≥40 pack-years) was found to be a significant determinant of the ASM index and HGS, independent of potential confounding factors. Among former smokers, the subgroup that quit smoking for ≥20 years had a significantly higher ASM index and HGS than the subgroup that quit smoking for <10 years. The duration of smoking cessation was significantly associated with the ASM index and HGS, even after adjusting for cumulative smoking exposure.

CONCLUSIONS

These findings suggest that cigarette smoking contributes to the loss of muscle mass and function in elderly men and that smoking cessation could reverse the impact of cigarette smoking on skeletal muscles.

Obesity, dynapenia, and their combination: Implications for bone mineral density in Brazilian adults-the Pró-Saúde study

OBJECTIVES

This study aimed to evaluate bone mineral density (BMD) in the presence or absence of dynapenia or obesity in Brazilian adults.

METHODS

This is a cross-sectional study conducted in 502 adults (age: 33-81 y; 51% women) participating in the Pró-Saúde study, a cohort of civil servants at the university campuses in Rio de Janeiro, Brazil. Body composition and BMD were determined by dual energy x-ray absorptiometry. Handgrip strength was measured using a dynamometer. According to measures of handgrip strength (≤19 kg for women; ≤32 kg for men) and fat mass (>30% for men; >40% for women), participants were classified into four groups: non-obese non-dynapenic, obese non-dynapenic, non-obese dynapenic, and obese dynapenic. The association between BMD at each specific bone site and obesity, dynapenia, and their interaction was evaluated using a general linear model.

RESULTS

The prevalence of dynapenic obesity was 14% in men and 15.2% in women. Dynapenia alone was not associated with BMD at any site in either men nor women. Obesity and dynapenia interacted to influence BMD in women (P < 0.05). Total body, lumbar spine, and femoral neck BMD were higher by 6.3%, 9.3%, and 10.4%, respectively, in dynapenic obese women compared with their non-obese counterparts (P < 0.05). In men, obesity, dynapenia, and their combination were not associated with BMD at any site.

CONCLUSIONS

Our results suggest that dynapenia, obesity, and their combination may affect BMD in a sex-dependent manner. In the presence of dynapenia, fat mass appears to exert a protective effect on BMD in women, but not in men.