The association of cigarette smoking and alcohol drinking with body mass index: a cross-sectional, population-based study among Chinese adult male twins

Exploring the Enigmatic Link: Unraveling the Relationship Between Obesity and Cigarette Smoking Among Diverse College Students at Imam Mohammed Ibn Saud Islamic University in Riyadh, Saudi Arabia

BACKGROUND

Obesity is defined as an excess of body fat. This medical condition frequently results in a high BMI and an increased risk of a variety of health problems, including diabetes, cardiovascular disease, and certain types of cancer. Cigarette smoking includes inhaling smoke created by the combustion of tobacco. It is linked to a variety of health issues, including lung cancer, heart disease, and respiratory ailments, and is a primary cause of preventable disease and premature death worldwide. The association between obesity and cigarette smoking is complex and incompletely understood. This study aims to investigate the intriguing association between obesity and cigarette smoking among diverse college students at Imam Mohammed Ibn Saud Islamic University in Riyadh, Saudi Arabia.

METHODOLOGY

The study was conducted as an observational study, specifically an analytical cross-sectional study, to measure the prevalence of cigarette smoking and obesity and their association. This type of study is chosen because of its advantages including targeting a large sample in a short time and inexpensive way, with no loss to follow-up, unlike some other study designs.

RESULTS

In this study, we were able to collect data from 603 participants, of which 57.4% were male and 67.8% of them aged between 20 and 24 years old. Moreover, we found that 39.6% had normal weight; however, the prevalence of obesity, overweight, and underweight were 24%, 28.1%, and 8.3%, respectively. Considering the prevalence of smoking, we found that 22.6% of the participants reported being current smokers, while 5.3% were former smokers. There is a significant difference between participants with different BMIs (P=0.001). The prevalence of smoking was significantly higher in obese and overweighted participants (35.1% and 31.3%, respectively) compared with 28.4% in normal-weighted participants.

CONCLUSION

The prevalence of smoking and obesity in this study was significantly higher than reported in different studies. Moreover, we found a significant relationship between smoking and obesity; however, further investigation should be conducted to determine the cause of this relationship.

The Association between Oxidative Balance Score and Urinary Levels of 8-Hydroxydeoxyguanosine among Japanese Adults

The oxidative balance score (OBS), wherein higher OBSs indicate lower oxidative stress, was designed to assess a composite measure of multiple pro-oxidant and antioxidant effects on an individual's oxidative stress status. This study aimed to evaluate whether OBSs were inversely associated with urinary levels of 8-hydroxydeoxyguanosine (8-OHdG)-an oxidative stress marker-among Japanese adults. This cross-sectional study was based on data obtained during 2010-2012. Overall, 7552 participants from the J-MICC Study Saga who answered a self-administered food frequency questionnaire were recruited for the final analysis. OBSs were calculated from 11 pro-oxidant and antioxidant lifestyle factors, including dietary intake, physical activity, and alcohol and smoking status. Urinary 8-OHdG values were corrected by creatinine level (ng/mg creatinine). Our findings revealed a higher total OBS was significantly associated with lower urinary 8-OHdG/creatinine levels after adjustment for covariates in men and women (p for trend < 0.01 in both sexes). We performed a multiple regression analysis of the association between OBSs and urinary 8-OHdG/creatinine levels stratified by age, body mass index (BMI), and menopausal status and found consistent negative associations in most groups for both sexes. No significant differences in the 60-64 age group for women (standardized β = -0.09, p = 0.13) or BMI < 18.5 kg/m2 for men (standardized β = -0.18, p = 0.17) were observed. A higher OBS had a strong inverse association with urinary 8-OHdG/creatinine levels in men and women among Japanese adults. The OBS might be a useful tool for evaluating the roles of oxidative stress-related lifestyle factors, including diet.

Modifiable lifestyle-related risk factors for tinnitus in the general population: An overview of smoking, alcohol, body mass index and caffeine intake

INTRODUCTION

Tinnitus is a symptom and not a disease in its own right. A number of medical conditions are known to increase the risk of developing tinnitus. Most known risk factors are otological or neurological, but general health and lifestyle can also precipitate the condition. Understanding these modifiable risk factors can help to identify vulnerable groups and can inform preventive actions to reduce likelihood of developing tinnitus. Smoking, alcohol consumption, body mass index (BMI) and caffeine intake are all lifestyle risk factors hypothesized to be related to tinnitus. Nonetheless, research findings in support of those relationships are somewhat mixed.

METHODS

A systematic review was conducted to identify all relevant studies on the specific risk factors. Findings were summarized using a narrative synthesis and meta-analysis, where possible.

RESULTS

Overall 384 studies were included, mostly using cross-sectional designs. Findings indicated significantly increased risk of tinnitus among current (based on 26 studies) and ever smokers (based on 16 studies) and among obese people (based on seven studies), but no effect of alcohol consumption (based on 11 studies). With respect to caffeine intake or coffee drinking, only three studies examined this risk factor and so we were unable to draw conclusions.

CONCLUSION

Our results contribute to quantifying the relationship between tinnitus and specific lifestyle-related risk factors, and we highlight some of the gaps and inconsistencies across published studies.

Associations between lifestyle and amyotrophic lateral sclerosis stratified by C9orf72 genotype: a longitudinal, population-based, case-control study

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is considered to be caused by both genetic and environmental factors. The causal cascade is, however, not known. We aimed to assess lifestyle during the presymptomatic phase of ALS, stratified by C9orf72 mutation, and examine evidence supporting causality of lifestyle factors.

METHODS

This study was a longitudinal, population-based, case-control study that used data from the Prospective ALS study the Netherlands. We included patients with a C9orf72 mutation (C9+ group), patients without a C9orf72 mutation (C9- group), and controls. Patients fulfilled the revised El Escorial criteria and were recruited through neurologists and rehabilitation physicians in the Netherlands as well as the Dutch Neuromuscular Patient Association and ALS Centrum website. 1322 population-based controls, matched for age and sex, were enrolled via the patients' general practitioners. Blood relatives or spouses of patients were not eligible as controls. We studied the relationship between ALS risk and smoking, alcohol, physical activity, body-mass index (BMI), and energy intake by the use of structured questionnaires. Smoking, physical activity, and BMI were longitudinally assessed up to 50 years before onset (defined as the period before onset of muscle weakness or bulbar symptoms for cases, or age at completing the questionnaire for controls). We calculated posterior probabilities (P(θ|x)) for causal effects of smoking, alcohol, and BMI, using Bayesian instrumental variable analyses.

FINDINGS

Between Jan 1, 2006 and Jan 27, 2016, we included 143 patients in the C9+ group, 1322 patients in the C9- group, and 1322 controls. Compared with controls, cigarette pack-years (C9+ group mean difference from control 3·15, 95% CI 0·36 to 5·93, p=0·027; C9- group 3·20, 2·02 to 4·39, p<0·0001) and daily energy intake at symptom onset (C9+ group 712 kJ, 95% CI 212 to 1213, p=0·0053; C9- group 497, 295 to 700, p<0·0001) were higher in the C9+ and C9- groups, whereas current BMI (C9+ group -2·01 kg/m², 95% CI -2·73 to -1·29, p<0·0001; C9- group -1·35, -1·64 to -1·06, p<0·0001) and lifetime alcohol consumption (C9+ group -5388 units, 95% CI -9113 to -1663, p=0·0046; C9- group -2185, -3748 to -622, p=0·0062) were lower in the C9+ and C9- groups. Median BMI during the presymptomatic phase for the C9+ group was lower (-0·69 kg/m², 95% CI -1·24 to -0·13, p=0·015) and physical activity was similar (-348 metabolic equivalent of task [MET], 95% CI -966 to 270, p=0·27) to controls, whereas both the median BMI during the presymptomatic phase (0·27 kg/m², 95% CI 0·04 to 0·50, p=0·022) and physical activity (585 MET, 291 to 878, p=0·0001) were higher in the C9- group than controls. Longitudinal analyses showed more cigarette pack-years in the C9- (starting 47 years pre-onset) and C9+ (starting 24 years pre-onset) groups, and higher physical activity over time in the C9- group (starting >30 years pre-onset). BMI of the C9+ group increased more slowly and was significantly lower (starting at 36 years pre-onset) than in controls, whereas the BMI of the C9- group was higher than controls (23-49 years pre-onset, becoming lower 10 years pre-onset). Instrumental variable analyses supported causal effects of alcohol consumption (P(θ|x)=0·9347) and smoking (P(θ|x)=0·9859) on ALS in the C9- group. We found evidence supporting a causal effect of increased BMI at younger age (mean 33·8 years, SD 11·7) in the C9- group (P[θ|x]=0·9272), but not at older ages.

INTERPRETATION

Lifestyle during the presymptomatic phase differs between patients with ALS and controls decades before onset, depends on C9- status, and is probably part of the presymptomatic causal cascade. Identification of modifiable disease-causing lifestyle factors offers opportunities to lower risk of developing neurodegenerative disease.

FUNDING

Netherlands ALS Foundation.

Relevance of obstructive sleep apnea and smoking: Obstructive sleep apnea and smoking

BACKGROUND

The data concerning the association of smoking and obstructive sleep apnea (OSA) are limited. The effects of cigarette smoking on OSA still remain obscure.

OBJECTIVES

To reveal the impact of smoking on obstructive sleep apnea.

METHODS

About 384 patients with the diagnosis of OSA through full night polysomnographic (PSG) examination were included to the study. The demographic data (age, sex and BMI), complaints and medical history, status of smoking as non-smokers and smokers, smoking frequency (cigarettes/day), polysomnograhic data comprising apnea hypopnea index (AHI), non-REM sleep AHI (NREM AHI), REM sleep AHI (REM AHI), minimum oxygen saturation (min SaO2) were recorded for all the subjects. Non-smokers and smokers were compared in terms of severity of OSA.

RESULTS

The study population consisted of 384 subjects, 253 males and 131 females. Smoking frequency was not found correlated with OSA severity. Among smokers, males had higher severe OSA rate (P = 0.002, P < 0.05). In subjects with BMI < 30, severe OSA rate was higher in smokers (34.44% versus 21%) (P = 0.027, P < 0.05).

CONCLUSIONS

Our study detected higher rate of severe OSA in male smokers and smokers with BMI < 30. PSG data did not yield statistically significant difference in non-smokers and smokers. OSA severity was not found correlated with smoking frequency. Along with the study results, the impact of smoking on OSA is still controversial. Prospective studies with larger sample size may be contributive to further evaluation of the association of OSA with smoking.

Short-term impact of the COVID-19 confinement measures on health behaviours and weight gain among adults in Belgium

BACKGROUND

In Belgium, confinement measures were introduced on the 13th of March 2020 to curb the spread of the coronavirus disease (COVID-19). These measures may affect health behaviours of the population such as eating habits, physical activity and alcohol consumption, which in turn can lead to weight gain resulting in overweight and obesity, increasing the risk of several chronic diseases, but also of severe COVID-19. The purpose of this study is to assess the impact of confinement measures on health behaviours and their associations with weight gain.

METHODS

Data were derived from the second national COVID-19 health survey. Data were collected between the 16th and the 23rd of April 2020. The recruitment of participants was based on snowball sampling via Sciensano's website, invitations via e-mail and social media. The study sample includes participants aged 18 years and over with no missing data on the variables of interest (n = 28,029). The association between self-reported weight gain and health behaviour changes, adjusted for gender, age group and household composition was assessed through OR's (95% CI) calculated with logistic regression models, using post-stratification weights.

RESULTS

Overall, 28.6% reported weight gain after 6 weeks of confinement. Higher odds of weight gain were observed among participants who increased or decreased their consumption of sugar-sweetened beverages (OR = 1.39 (1.15-1.68) and 1.29 (1.04-1.60), respectively), among those who increased their consumption of sweet or salty snacks (OR = 3.65 (3.27-4.07)), among those who became less physically active (OR = 1.91 (1.71-2.13)), and among those who increased their alcohol consumption (OR = 1.86 (1.66-2.08)).

CONCLUSIONS

The most important correlates of weight gain during confinement were an increased consumption of sweet or salty snacks and being less physically active. These findings confirm the impact of diet and exercise on short term weight gain and plead to take more action, in supporting people to achieve healthier behaviours in order to tackle overweight and obesity, especially during the COVID-19 pandemic.

Early high-fat feeding improves histone modifications of skeletal muscle at middle-age in mice

The purpose of the present study was to investigate how the effects of high-fat diet feeding on the skeletal muscle persisted during aging using mice. Post-weaned male mice were fed a high-fat diet between 1- and 3-mo-old followed by return to supply a normal diet until 13-mo-old. Monthly physical tests demonstrated that age-related glucose intolerance that was generally developed after 10-mo-old in the control mice was significantly improved in mice fed a high-fat diet. Interestingly, mRNA expressions of Pdk4, Ucp3, and Zmynd17 were up-regulated by high-fat feeding and persisted in the tibialis anterior muscle until 13-mo-old. At Pdk4 and Ucp3 loci, enhanced distributions of active histone modifications were noted in the high-fat-fed mice at 13-mo-old. In contrast, age-related accumulation of histone variant H3.3 at these loci was suppressed. These results indicated that epigenetic modifications caused by early nutrition mediated the changes in skeletal muscle gene expression during aging.

Nutritional status and the associated factors among people living with HIV: an evidence from cross-sectional survey in hospital based antiretroviral therapy site in Kathmandu, Nepal

BACKGROUND

Nutritional status is the key concern among the people living with HIV but this issue has been failed to be prioritized in HIV strategic plan of Nepal. This study aims to assess the nutritional status among people living with HIV and determine their associated factors.

METHODS

A hospital based cross-sectional study was conducted where 350 people living with HIV attending the ART clinic were selected using systematic random sampling technique. Nutritional status among people living with HIV was assessed through anthropometry, body mass index; Underweight (body mass index < 18.5 kg/m2) and overweight/obesity (body mass index > 23 kg/m2). HIV related clinical factors such CD4 count, WHO stage, opportunistic infection, antiretroviral therapy regimen etc. were collected from the medical records. Socio-demographic data were collected using pretested structured questionnaire through interview technique. Multiple linear regression method was employed to determine the association between different independent factors and body mass index score.

RESULTS

The prevalence of underweight was found to be 18.3% (95% CI: 14.3-22.6). Most of the study participants were overweight/obese (39.1%). After subjection to multiple linear regression analysis, it was found that age, being male, being married, being in business occupation, smoking, hemoglobin level and antiretroviral therapy duration were significantly associated with body mass index score. Majority of the participants in our study lacked diversified food (62.3%).

CONCLUSION

Overweight/obesity is an emerging problem among people living with HIV. This group of participants should be screened for the presence of non-communicable disease. This study also highlights the importance of nutritional program being an integral part of HIV/AIDS continuum of care. Therefore, an effort should be made to address the burden of malnutrition by addressing the identified determinants.

Serum free thiols predict cardiovascular events and all-cause mortality in the general population: a prospective cohort study

BACKGROUND

Serum free thiols (R-SH, sulfhydryl groups) reliably reflect systemic oxidative stress. Since serum free thiols are rapidly oxidized by reactive species, systemic oxidative stress is generally associated with reduced serum free thiol levels. Free thiols associate with favorable disease outcomes in many patient cohorts, and the current hypothesis is that oxidative stress might also play an important role in cardiovascular disease. In this study, we aimed to establish the role of serum free thiols in the general population by investigating their relationship with the risk of cardiovascular (CV) events and all-cause mortality.

METHODS

Participants (n = 5955) of the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) cohort study from the general population were included. At baseline, serum levels of free thiols were quantified and adjusted to total protein levels. Protein-adjusted serum free thiol levels were studied for their associations with clinical and biochemical parameters, as well as with the risk of CV events and all-cause mortality.

RESULTS

The mean protein-adjusted serum free thiol level was 5.05 ± 1.02 μmol/g of protein. Protein-adjusted serum free thiols significantly predicted the risk of CV events, even after adjustment for potential confounding factors (hazard ratio [HR] per doubling 0.68 [95% confidence interval [CI] 0.47-1.00], P = 0.048). Similarly, protein-adjusted serum free thiols were significantly predictive of the risk of all-cause mortality (HR per doubling 0.66 [95% CI 0.44-1.00], P = 0.050). Stratified analyses revealed lower HRs for subjects with a lower body mass index (BMI), without hypertension, and without diabetes. Conversely, HRs were lower in subjects with albuminuria.

CONCLUSIONS

In this large population-based cohort study, serum free thiols significantly predicted the risk of CV events and all-cause mortality. Our results highlight the potential significance and clinical applicability of serum free thiols since they are amendable to therapeutic intervention.

A unified method for rare variant analysis of gene-environment interactions

Advanced technology in whole-genome sequencing has offered the opportunity to comprehensively investigate the genetic contribution, particularly rare variants, to complex traits. Several region-based tests have been developed to jointly model the marginal effect of rare variants, but methods to detect gene-environment (GE) interactions are underdeveloped. Identifying the modification effects of environmental factors on genetic risk poses a considerable challenge. To tackle this challenge, we develop a method to detect GE interactions for rare variants using generalized linear mixed effect model. The proposed method can accommodate either binary or continuous traits in related or unrelated samples. Under this model, genetic main effects, GE interactions, and sample relatedness are modeled as random effects. We adopt a kernel-based method to leverage the joint information across rare variants and implement variance component score tests to reduce the computational burden. Our simulation studies of continuous and binary traits show that the proposed method maintains correct type I error rates and appropriate power under various scenarios, such as genotype main effects and GE interaction effects in opposite directions and varying the proportion of causal variants in the model. We apply our method in the Framingham Heart Study to test GE interaction of smoking on body mass index or overweight status and replicate the Cholinergic Receptor Nicotinic Beta 4 gene association reported in previous large consortium meta-analysis of single nucleotide polymorphism-smoking interaction. Our proposed set-based GE test is computationally efficient and is applicable to both binary and continuous phenotypes, while appropriately accounting for familial or cryptic relatedness.

Association between overweight, obesity and incidence of advanced dental caries in South Korean adults: A 10-year nationwide population-based observational study

The objective of this study was to evaluate the association between overweight, obesity and the incidence of advanced dental caries in South Korean adults, using alternate measures. The participants included 376,077 people aged 20 years and older who had health examination at least one time between 2005 and 2008. This evaluation is based on a change of body mass index (BMI) category, for 10 years, using a nationally representative data resource available from the National Health Insurance System. Instead of using decayed, missing, and filled teeth (DMFT), the diagnostic codes which indicate dental caries, pulpal disease and visiting frequency at dental health professionals were used in this case. A multivariate adjusted Cox regression analysis was performed to examine the association between advanced dental caries and BMI. In addition to the BMI, a multivariate analysis of gender, age, lifestyle behaviors and systemic disease information was included. To this end, the hazard ratio (HR) and 95% confidence interval (CI) were calculated. Chiefly, it is noted that the overweight and obese people were more likely to develop advanced dental caries independent of the noted variables. The positive association between high BMI and incidence of advanced dental caries was more prominent in the population's characteristic of people who were in a classification of the elderly and women. Among the health and lifecycle behaviors, smoking or not was found to be one of the factors affecting the results. The alternate method used in this study showed that being overweight and obesity had a direct association with the incidence of advanced dental caries in Korean adults.

The Chinese National Twin Registry: a 'gold mine' for scientific research

The Chinese National Twin Registry (CNTR) currently includes data from 61 566 twin pair from 11 provinces or cities in China. Of these, 31 705, 15 060 and 13 531 pairs are monozygotic, same-sex dizygotic and opposite-sex dizygotic pairs, respectively, determined by opposite sex or intrapair similarity. Since its establishment in 2001, the CNTR has provided an important resource for analysing genetic and environmental influences on chronic diseases especially cardiovascular diseases. Recently, the CNTR has focused on collecting biologic specimens from disease-concordant or disease-discordant twin pairs or from twin pairs reared apart. More than 8000 pairs of these twins have been registered, and blood samples have been collected from more than 1500 pairs. In this review, we summarize the main findings from univariate and multivariate genetic effects analyses, gene-environment interaction studies, omics studies exploring DNA methylation and metabolomic markers associated with phenotypes. There remains further scope for CNTR research and data mining. The plan for future development of the CNTR is described. The CNTR welcomes worldwide collaboration.

Association of current and former smoking with body mass index: A study of smoking discordant twin pairs from 21 twin cohorts

Background

Smokers tend to weigh less than never smokers, while successful quitting leads to an increase in body weight. Because smokers and non-smokers may differ in genetic and environmental family background, we analysed data from twin pairs in which the co-twins differed by their smoking behaviour to evaluate if the association between smoking and body mass index (BMI) remains after controlling for family background.

Methods and findings

The international CODATwins database includes information on smoking and BMI measured between 1960 and 2012 from 156,593 twin individuals 18–69 years of age. Individual-based data (230,378 measurements) and data of smoking discordant twin pairs (altogether 30,014 pairwise measurements, 36% from monozygotic [MZ] pairs) were analysed with linear fixed-effects regression models by 10-year periods. In MZ pairs, the smoking co-twin had, on average, 0.57 kg/m² lower BMI in men (95% confidence interval (CI): 0.49, 0.70) and 0.65 kg/m² lower BMI in women (95% CI: 0.52, 0.79) than the never smoking co-twin. Former smokers had 0.70 kg/m² higher BMI among men (95% CI: 0.63, 0.78) and 0.62 kg/m² higher BMI among women (95% CI: 0.51, 0.73) than their currently smoking MZ co-twins. Little difference in BMI was observed when comparing former smoking co-twins with their never smoking MZ co-twins (0.13 kg/m², 95% CI 0.04, 0.23 among men; -0.04 kg/m², 95% CI -0.16, 0.09 among women). The associations were similar within dizygotic pairs and when analysing twins as individuals. The observed series of cross-sectional associations were independent of sex, age, and measurement decade.

Conclusions

Smoking is associated with lower BMI and smoking cessation with higher BMI. However, the net effect of smoking and subsequent cessation on weight development appears to be minimal, i.e. never more than an average of 0.7 kg/m².

Sense of Coherence, Smoking Status, Biochemical Cardiovascular Risk Factors and Body Mass in Blue Collar Workers-Short Report

The crucial cause of cardiovascular disorders is atherosclerosis developed by abnormal cholesterols levels or disorders affecting blood glucose. One of the best-known cardiovascular risk factors is also tobacco smoking. Simultaneously, sense of coherence (SoC) as a personal resource motivating to managing one's own health behaviors, such as avoiding tobacco smoking, was reported to be protective against coronary heart disease. Such association was observed in white-collar workers but not in blue-collar workers. According to the above, the present article aims to establish relationships between SoC, smoking behaviors, biochemical markers (BM): lipids and glucose levels and body mass index (BMI) in blue-collar workers. Sense of Coherence Questionnaire (SOC-29), fasting blood test, and BMI were used to assess such relationships. The study group consisted of 304 Polish males working 8-hr shifts in a 4-brigade rotating system. The analysis revealed that SoC level did not differ depending on smoking behavior. The analysis also showed no differences in BMI and BM depending on SoC. Concerning smoking status, the study group was divided into three subgroups which differed regarding triglycerides and glucose levels. The present findings considering SoC indicate that any psychological construct should not be studied separately because probably only some sets of different features may influence one's behavior and BM as well.

If you drink, don't smoke: Joint associations between risky health behaviors and labor market outcomes

This paper examines the links between risky health behaviors and labor market success. We provide new evidence on the joint relationships between the most prominent forms of risky health behavior - alcohol consumption, smoking and physical inactivity - and long-term labor market outcomes. We use twin data for Finnish men and women linked to register-based individual information on earnings and labor market attachment. The twin data allow us to account for shared family and environmental factors and to measure risky health behaviors in 1975 and 1981. The long-term labor market outcomes were measured in adulthood as an average over the period 1990-2009. The sample sizes are 2156 and 2498 twins, for men and women, respectively. We find that being both a smoker and a heavy drinker in early adulthood is negatively related to long-term earnings and employment later in life, especially for men. We conclude that how and why risky health behaviors cluster and how that affects individual level outcomes call for more attention.

Running training experience attenuates disuse atrophy in fast-twitch skeletal muscles of rats

Responsiveness to physiological stimuli, such as exercise and muscular inactivation, differs in individuals. However, the mechanisms responsible for these individual differences remain poorly understood. We tested whether a prior experience of exercise training affects the responses of skeletal muscles to unloading. Young rats were assigned to perform daily running training with a treadmill for 8 wk. After an additional 8 wk of normal habitation, the rats were hindlimb unloaded by tail suspension for 1 wk. Fast-twitch plantaris, gastrocnemius, and tibialis anterior muscles did not atrophy after unloading in rats with training experience, although soleus muscle lost weight similar to sedentary rats. We also analyzed the transcriptome in plantaris muscle with RNA sequencing followed by hierarchical clustering analysis and found that a subset of genes that were generally upregulated in sedentary rats after unloading were less responsive in rats with training experience. The distribution of histone 3 was diminished at the loci of these genes during the training period. Although the deposition of histone 3 was restored after an additional period of normal habitation, the incorporation of H3.3 variant was promoted in rats with training experience. This remodeling of nucleosomes closely correlated to the conformational changes of chromatin and suppressed gene expression in response to unloading. These results suggest that exercise training stimulated the early turnover of histone components, which may alter the responsiveness of gene transcription to physiological stimuli.NEW & NOTEWORTHY The present study demonstrates that disuse atrophy was suppressed in fast-twitch skeletal muscles of rats with training experience in early life. We also found a subset of genes that were less responsive to unloading in the muscle of rats with training experience. It was further determined that exercise training caused an early turnover of nucleosome components, which may alter the responsiveness of genes to stimulus in later life.

Limited common origins of multiple adult health-related behaviors: Evidence from U.S. twins

Health-related behaviors are significant contributors to morbidity and mortality in the United States, yet evidence on the underlying causes of the vast within-population variation in behaviors is mixed. While many potential causes of health-related behaviors have been identified-such as schooling, genetics, and environments-little is known on how much of the variation across multiple behaviors is due to a common set of causes. We use three separate datasets on U.S. twins to investigate the degree to which multiple health-related behaviors correlate and can be explained by a common set of factors. We find that aside from smoking and drinking, most behaviors are not strongly correlated among individuals. Based on the results of both within-identical-twins regressions and multivariate behavioral genetics models, we find some evidence that schooling may be related to smoking but not to the covariation between multiple behaviors. Similarly, we find that a large fraction of the variance in each of the behaviors is consistent with genetic factors; however, we do not find strong evidence that a single common set of genes explains variation in multiple behaviors. We find, however, that a large portion of the correlation between smoking and heavy drinking is consistent with common, mostly childhood, environments. This suggests that the initiation and patterns of these two behaviors might arise from a common childhood origin. Research and policy to identify and modify this source may provide a strong way to reduce the population health burden of smoking and heavy drinking.