Unidirectional and bidirectional causation between smoking and blood DNA methylation: evidence from twin-based Mendelian randomisation.

Cigarette smoking is associated with numerous differentially-methylated genomic loci in multiple human tissues. These associations are often assumed to reflect the causal effects of smoking on DNA methylation (DNAm), which may underpin some of the adverse health sequelae of smoking. However, prior causal analyses with Mendelian Randomisation (MR) have found limited support for such effects.

Linking the gut microbiome to host DNA methylation by a discovery and replication epigenome-wide association study.

Microbiome influences multiple human systems, but its effects on gene methylation is unknown. We investigated the relations between gene methylation in blood and the abundance of common gut bacteria profiled by 16s rRNA gene sequencing in two population-based Dutch cohorts: LifeLines-Deep (LLD, n = 616, discovery) and the Netherlands Twin Register (NTR, n = 296, replication). In LLD, we also explored microbial pathways using data generated by shotgun metagenomic sequencing (n = 683).

Ambulatory autonomic nervous system activity in relation to hearing impairment.

Previous research has demonstrated that hearing impairment is associated with heightened subjective experiences of listening effort, fatigue, and stress, impacting daily functioning. This study aimed to evaluate whether hearing impairment alters physiological stress systems and whether different aspects of hearing impairment could vary in predicting dysregulation in these systems. Hallmark measures of parasympathetic and sympathetic nervous system activity were derived from electrocardiography, impedance cardiography, and electrodermal activity recordings taken from 133 individuals, aged 37 to 73, over two 24-hr periods, including sleep.