Tobacco Consumption and High-Sensitivity Cardiac Troponin I in the General Population: The HUNT Study

Comparison of smokers' mortality with non-smokers following out-of-hospital cardiac arrests: a systematic review and meta-analysis

OBJECTIVE

Although some studies have linked smoking to mortality after out-of-hospital cardiac arrests (OHCAs), data regarding smoking and mortality after OHCAs have not yet been discussed in a meta-analysis. Thus, this study conducted this systematic review to clarify the association.

METHODS

The study searched Medline-PubMed, Web of Science, Embase and Cochrane libraries between January 1972 and July 2022 for studies that evaluated the association between smoking and mortality after OHCAs. Studies that reportedly showed relative risk estimates with 95% confidence intervals (CIs) were included.

RESULTS

Incorporating a collective of five studies comprising 2477 participants, the analysis revealed a lower mortality risk among smokers in the aftermath of OHCAs compared with non-smokers (odds ratio: 0.77; 95% CI 0.61-0.96; P < 0.05). Egger's test showed no publication bias in the relationship between smoking and mortality after OHCAs.

CONCLUSIONS

After experiencing OHCAs, smokers had lower mortality than non-smokers. However, due to the lack of data, this 'smoker's paradox' still needs other covariate effects and further studies to be considered valid.

Physical activity and diet associations with the gut microbiota in the Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND

Gut microbiota may influence metabolic pathways related to chronic health conditions. Evidence for physical activity and diet influences on gut microbial composition exists, but data from diverse population-based cohort studies are limited.

OBJECTIVES

We hypothesized that gut microbial diversity and genera are associated with physical activity and diet quality.

METHODS

Data were from 537 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a prospective cohort, who attended the year 30 follow-up examination (2015-2016; aged 47-61 y; 45% Black race/55% White race; 45% men/55% women). The 16S ribosomal RNA marker gene was sequenced from stool DNA, and genus-level taxonomy was assigned. Within-person microbial diversity (α-diversity) was assessed with Shannon diversity index and richness scores; between-person diversity (β-diversity) measures were generated with principal coordinates analysis (PCoA). Current and long-term physical activity and diet quality measures were derived from data collected over 30 y of follow-up. Multivariable-adjusted regression analysis controlled for: sociodemographic variables (age, race, sex, education, and field center), other health behaviors (smoking, alcohol consumption, and medication use), and adjusted for multiple comparisons with the false discovery rate (<0.20).

RESULTS

Based on PCoA β-diversity, participants' microbial community compositions differed significantly (P < 0.001), with respect to both current and long-term physical activity and diet quality. α-Diversity was associated only with current physical activity (positively) in multivariable-adjusted analysis. Multiple genera (n = 45) were associated with physical activity and fewer with diet (n = 5), including positive associations with Lachnospiraceae UCG-001 and Ruminococcaceae IncertaeSedis with both behaviors.

CONCLUSIONS

Physical activity and diet quality were associated with gut microbial composition among 537 participants in the CARDIA study. Multiple genera were associated with physical activity. Physical activity and diet quality were associated with genera consistent with pathways related to inflammation and short-chain fatty acid production.

Influence of cigarettes on myocardial injury in healthy population after exposure to high altitude over 5000 m

BACKGROUND

Myocardial injury (MI) is a severe complication once subjected to hypoxic condition at high altitude. Little evidence exists about the association of cigarettes and MI at high altitude, especially over 5000 m. In the present study, we intend to explore the influence of cigarettes on MI in healthy population after travelling to this extreme environment.

METHODS

Physical examination was performed in population at Pamirs plateau during November and December 2020. All participants were divided into cigarette group or control group. MI was diagnosed based on lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase isoenzymes (CK-MB) and aspartate amino transferase (AST).

RESULTS

311 people were included, 58 of whom developed MI, accounting for 18.6 %. Participants in cigarette group were all male, and younger than those in control group. There was longer exposure time in cigarette group. Compared with control group, red blood cell counting, hemoglobin (HGB) and hematocrit in cigarette group were significantly increased, while heart rate was significantly decreased. Cigarettes were found to significantly upregulate the level of CK-MB and LDH. After adjustment with age, sex, body mass index, altitude and exposure time as covariables, 108 male participants remained in each group, showing that none of clinical indexes had significant difference between the two groups. Logistic regression analysis revealed that female sex and oxygen saturation (SO₂) were independent risk factors for MI in non-smokers while HGB was independent risk factor in smokers. By using Spearman correlation analysis, four myocardial enzymes were not relevant with the level of SO₂ in non-smokers. For smokers, HGB was found to be in significant positive correlation with LDH.

CONCLUSION

Our study suggested that exposure to high altitude over 5000 m could abrogate the impact of cigarettes on MI in healthy population. The independent factors affecting the occurrence of MI were distinctive depending on current smoking status.