Genetically Determined Smoking Behavior and Risk of Nontraumatic Subarachnoid Hemorrhage

Aneurysmal Subarachnoid Hemorrhage and Sex Differences: Analysis of Epidemiology, Outcomes, and Risk Factors

BACKGROUND

The differences in outcomes after aneurysmal subarachnoid hemorrhage (aSAH) between the sexes have not been concretely determined. This study aimed to evaluate the differences in epidemiology, outcomes, and risk factors between male and female patients with aSAH.

METHODS

We performed a multicenter, retrospective study of patients with aSAH from 2017 to 2020. We investigated the epidemiological differences between the two sexes. Propensity score matching (PSM) was used to compare short-term outcomes between the sexes. Binary logarithmic regression was performed to investigate the odds ratio (OR) for dependent survival in patients of different sexes.

RESULTS

A total of 5,407 consecutive patients with aSAH were included in this study, and the female-to-male ratio was 1.8:1. The peak incidence of aSAH occurred in the 6th and 7th decades in males and females, respectively. There were more female patients with internal carotid artery or posterior communicating artery aneurysms (53.2%), and there were more male patients with anterior cerebral artery or anterior communicating artery aneurysms (43.2%). The incidence of multiple aneurysms was greater in female patients (21.5% vs. 14.2%, P < 0.001). There was no significant difference in outcomes before and after PSM at discharge. The dependent survival risk was related only to the clinical condition on admission in women. In addition, age > 50 years (OR 1.88, 95% confidence interval 1.17-3.02; P = 0.01) and hypertension (OR 1.81, 95% confidence interval 1.25-2.61; P = 0.002) were also risk factors for male patients.

CONCLUSIONS

There were more female patients with aneurysms than male patients in this study. Most aneurysm locations were different between the two groups. There was no significant difference in discharge outcomes before and after PSM. The risk factors for dependent survival were different between female and male patients.

Association of gut microbiome with risk of intracranial aneurysm: a mendelian randomization study

OBJECTIVE

To investigate the potential causal link between genetic variants associated with gut microbiome and risk of intracranial aneurysm (IA) using two-sample mendelian randomization (MR).

METHODS

We performed two sets of MR analyses. At first, we selected the genome-wide statistical significant(P < 5 × 10^-8) single nucleotide polymorphisms (SNPs) as instrumental variables (IVs). Then, we selected the locus-wide significant (P < 1 × 10^-5) SNPs as IVs for the other set of analyses to obtain more comprehensive conclusions. Gut microbiome genetic association estimates were derived from a genome-wide association study (GWAS) of 18,473 individuals. Summary-level statistics for IA were obtained from 79,429 individuals, which included 7,495 cases and 71,934 controls.

RESULTS

On the basis of locus-wide significance level, inverse variance weighted(IVW) showed that Clostridia [(odds ratio (OR): 2.60; 95% confidence interval (CI): 1.00-6.72, P = 0.049)], Adlercreutzia (OR: 1.81; 95% CI: 1.10-2.99, P = 0.021) and Victivallis (OR: 1.38; 95% CI: 1.01-1.88, P = 0.044) were positively related with the risk of unruptured intracranial aneurysm(UIA); Weighted median results of MR showed Oscillospira (OR: 0.37; 95% CI: 0.17-0.84, P = 0.018) was negatively with the risk of UIA and Sutterella (OR: 1.84; 95% CI: 1.04-3.23, P = 0.035) was positively related with the risk of UIA; MR-Egger method analysis indicated that Paraprevotella (OR: 0.32; 95% CI: 0.13-0.80, P = 0.035) was negatively with the risk of UIA and Rhodospirillaceae (OR: 13.39; 95% CI: 1.44-124.47, P = 0.048) was positively related with the risk of UIA. The results suggest that Streptococcus (OR: 5.19; 95% CI: 1.25-21.56; P = 0.024) and Peptostreptococcaceae (OR: 4.92; 95% CI: 1.32-18.32; P = 0.018) may increase the risk of UIA according to genome-wide statistical significance thresholds.

CONCLUSION

This MR analysis indicates that there exists a beneficial or detrimental causal effect of gut microbiota composition on IAs.

A two-sample Mendelian randomization analysis of modifiable risk factors and intracranial aneurysms

We aimed to investigate the causality between potentially modifiable risk factors and the risk of intracranial aneurysm. Genetic instruments for 51 modifiable factors and intracranial aneurysm data were obtained from recently published genome-wide association studies. We applied two-sample Mendelian randomization methods to investigate their causal relationships. Genetically predicted cigarettes per day, smoking initiation, systolic blood pressure, hypertension and body fat percentage were significantly associated with an increased risk of intracranial aneurysm [odds ratios (OR) 2.67, 95% confidence interval (CI) 1.75–4.07, p = 5.36 × 10^–6, OR 1.53, 95% CI 1.32–1.77, p = 9.58 × 10^–9, OR 1.05, 95% CI 1.02–1.08, p = 1.18 × 10^–3, OR 1.65, 95% CI 1.19–2.28, p = 2.56 × 10^–3 and OR 1.29, 95% CI 1.11–1.52, p = 1.33 × 10^–3, respectively]. Type 2 diabetes mellitus was significantly associated with a decreased risk of intracranial aneurysm (OR 0.89, 95% CI 0.83–0.95, p = 8.54 × 10^–4). Body fat percentage was significantly associated with subarachnoid haemorrhage (p = 5.70 × 10^–5). This study provided genetic evidence of causal effects of smoking, blood pressure, type 2 diabetes mellitus and obesity on the risk of intracranial aneurysm.

Mendelian Randomization in Stroke: A Powerful Approach to Causal Inference and Drug Target Validation

Stroke is a leading cause of death and disability worldwide. However, our understanding of its underlying biology and the number of available treatment options remain limited. Mendelian randomization (MR) offers a powerful approach to identify novel biological pathways and therapeutic targets for this disease. Around ~100 MR studies have been conducted so far to explore, confirm, and quantify causal relationships between several exposures and risk of stroke. In this review, we summarize the current evidence arising from these studies, including those investigating ischemic stroke, hemorrhagic stroke, or both. We highlight the different types of exposures that are currently under study, ranging from well-known cardiovascular risk factors to less established inflammation-related mechanisms. Finally, we provide an overview of future avenues of research and novel approaches, including drug target validation MR, which is poised to have a substantial impact on drug development and drug repurposing.