Human Cytomegalovirus Increases the Risk of Future Hemorrhagic But Not Ischemic Stroke – A Nested Case-Control Study –

Human cytomegalovirus infection is associated with stroke in women: the US National Health and Nutrition Examination Survey 1999-2004

BACKGROUND

Increasing evidence indicated that infection factors play important roles in stroke development. Human cytomegalovirus (HCMV) infection was positively associated with atherosclerosis and hypertension which are stroke risk factors. Therefore, we aimed to explore the relationship between HCMV infection and stroke using the data of US National Health and Nutrition Examination Survey (NHANES).

METHODS

We analysed data on 2844 men and 3257 women in the NHANES 1999-2004. We included participants aged 20-49 years who had valid data on HCMV infection and stroke.

RESULTS

54.1% of participants had serological evidence of HCMV infection and 0.8% of them had a previous diagnosis of stroke. There were ethnic differences in the prevalence of HCMV seropositivity (p<0.001). There was no significant association between HCMV seropositivity and stroke in men in any of the models. In women, HCMV seropositivity was associated with stroke before adjustment (OR=3.45, 95% CI 1.09 to 10.95, p=0.036). After adjusting for race/ethnicity, the association remained significant (OR=4.40, 95% CI 1.37 to 14.09, p=0.014). After further adjustment for body mass index, diabetes, hypercholesterolaemia, hypertension, alcohol consumption, smoking and physical activity, the association still existed (OR=3.58, 95% CI 1.14 to 11.25, p=0.030). The association was significant consistently in adjusted model for age (OR=3.39, 95% CI 1.08 to 10.64, p=0.037).

CONCLUSIONS

We found a strong association between HCMV and stroke in women from the nationally representative population-based survey. This provide additional motivation for undertaking the difficult challenge to reduce the prevalence of stroke.

Infectious Causes of Stroke

Stroke is one of the primary causes of mortality and morbidity worldwide. It can be ischemic or hemorrhagic, and the former can be due to an in-situ thrombus or a distant embolus. Despite being a rare cause, stroke can also be caused in the setting of infection. Bacterial agents are the most common cause of stroke, among other infectious agents. Until the antibiotic era, rheumatic heart disease was a predisposing risk factor of infective endocarditis. VZV is the most common cause of strokes in pediatric and adult populations. Cryptococcus and Candida spp are the most common yeasts involved in CNS infections, especially in immunocompromised patients. In COVID-19 patients, ischemic strokes are more common than hemorrhagic strokes. In this review, we will discuss the most common infectious agents, with particular emphasis on COVID-19.

Infectious causes of stroke

PURPOSE OF REVIEW

Stroke continues to be a leading cause of debility in the world. Infections have been associated with stroke, but are not considered as directly causal, and so they are not often included in the traditional stroke workup and management. They are especially important in patients with stroke of undetermined etiology, and in certain patient populations, such as young patients without traditional risk factors, and immunocompromised patients.

RECENT FINDINGS

There has been strong evidence for infectious conditions, such as endocarditis, and pathogens, such as varicella zoster in stroke causation, and more supportive evidence is surfacing in recent years of several organisms increasing the stroke risk or being directly causal in stroke. The evidence also seems to be pointing to the role of inflammation in increasing the risk of stroke via accelerated atherosclerosis, vasculitis and vasculopathy.

SUMMARY

Infectious causes should be considered in the differential and work up of stroke in certain patient populations and appropriate treatments need to be initiated to minimize adverse stroke-related outcomes.

Sex difference in the incidence of stroke and its corresponding influence factors: results from a follow-up 8.4 years of rural China hypertensive prospective cohort study

Background

Few studies investigate sex difference in stroke incidence in rural China hypertensive population.

Methods

A total of 5097 hypertensive patients aged ≥35 years (mean age, 56.3 ± 11.2 years; 43.8% men) were included in our analysis with a median follow-up 8.4 years in Fuxin county of Liaoning province in China. Cox proportional hazard models were used to analyze the association between the potential factors and incident stroke.

Results

We observed 501 new strokes (310 ischemic, 186 hemorrhagic, and 5 unclassified stroke) during the follow-up. The overall incidence of stroke was 1235.21 per 100,000 person-years; for men, the rates were 1652.51 and 920.80 for women. This sex difference in all stroke can be explained by approximately 25% through age, systolic blood pressure, body mass index, low-density lipoprotein-cholesterol, current smoking, current drinking, antihypertensive drugs, education and physical activity. Subgroup analysis indicated that in hemorrhagic stroke this sex difference was more remarkable (63.89% can be explained).

Conclusions

The incidence of stroke was higher in men than that in women and this difference was partly explained by several traditional cardiovascular risk factors.

Non-traditional lipid profiles associated with ischemic stroke not hemorrhagic stroke in hypertensive patients: results from an 8.4 years follow-up study

BACKGROUND

Studies have shown that non-traditional lipid profiles have a better association with stroke than traditional blood lipids in clinical applications, other studies have drawn different conclusions.

METHODS

This study was a large-scale study with a median follow-up of 8.4 years. The hazard ratio (HR) and 95% Confidence interval (CI) of lipid variables for risk of incident stroke were analyzed by multivariable Cox proportional hazard models.

RESULTS

During the follow-up, 502 new strokes (310 ischemic, 187 hemorrhagic, and 5 unclassified strokes) occurred among the 5099 hypertensive patients. Comparing with the lowest quarter, the HR of future ischemic stroke (IS) in the highest were 1.41(95%CI, 1.03-1.92) for TC, 1.60 (95%CI, 1.15-2.22) for TG, 1.03 (95%CI, 0.75-1.42) for HDL-C, 1.77 (95%CI, 1.29-2.44) for LDL-C, 1.42 (95%CI, 1.03-1.94) for non-HDL, 2.09 (95%CI, 1.45-3.00) for TC/HDL, 2.08 (95%CI, 1.46-2.96) for LDL/HDL, 1.86 (95%CI 1.33-2.60) for TG/HDL, respectively. No significant association was observed between lipid-related indicators and hemorrhagic stroke. The results of statistical differences showed that the correlation between LDL/HDL and the risk of ischemic stroke in non-traditional lipids was higher than that of other traditional lipids (P < 0.001), except for LDL (P = 0.056).

CONCLUSIONS

We didn't find that HDL was associated with the risk of stroke and all the lipid parameters were not associated with the risk of hemorrhagic stroke. LDL/HDL was associated with a higher risk of ischemic stroke than other lipids and should be considered for clinical diagnosis and future disease prevention.

Association of herpesviruses and stroke: Systematic review and meta-analysis

BACKGROUND

Herpesviruses induce a range of inflammatory effects potentially contributing to an increased risk of stroke.

OBJECTIVES

To investigate whether patients with infection, or reactivation of, human herpesviruses are at increased stroke risk, compared to those without human herpesviruses.

DATA SOURCES

Six medical databases and grey literature sources from inception to January 2017.

STUDY ELIGIBILITY CRITERIA

Studies where the exposure was any human herpesvirus and the outcome was stroke. We included randomised controlled trials, cohort, case-control, case-crossover and self-controlled case series designs.

METHODS

Meta-analyses when sufficiently homogeneous studies were available. Quality of evidence across studies was assessed.

RESULTS

We identified 5012 publications; 41 met the eligibility criteria. Across cohort and self-controlled case series studies, there was moderate quality evidence that varicella infection in children was associated with a short-term increased stroke risk. Zoster was associated with a 1.5-fold increased stroke risk four weeks following onset (summary estimate: 1.55, 95%CI 1.46-1.65), which resolved after one year. Subgroup analyses suggested post-zoster stroke risk was greater among ophthalmic zoster patients, younger individuals and those not prescribed antivirals. Recent infection/reactivation of cytomegalovirus and herpes simplex viruses, but not past infection, was associated with increased stroke risk; however the evidence across studies was mainly derived from small, very low quality case-control studies.

CONCLUSIONS

Our review shows an increased stroke risk following zoster and suggests that recent infection or reactivation of other herpesviruses increases stroke risk, although better evidence is needed. Herpesviruses are common and potentially preventable; these findings may have implications for reducing stroke burden.

High anti-human cytomegalovirus antibody levels are associated with the progression of essential hypertension and target organ damage in Han Chinese population

Human cytomegalovirus (CMV) infection is associated with hypertension and has been linked with the pathogenesis of increased arterial blood pressure (BP). Currently, whether CMV infection is associated with the progression of hypertension and hypertensive target organ damage (TOD) remains to be identified. We aimed to examine the relationship between CMV infection and the progression of hypertension and hypertensive TOD, which could provide clues on the possible mediating mechanisms, in the Han Chinese population. A total of 372 patients with hypertension and 191 healthy controls (Han participants from Xinjiang, China) were included in the study. Enzyme-linked immunosorbent assay (ELISA) and qPCR were used to detect CMV infection. C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) titers were also analyzed using an ELISA kit. Moreover, cardiovascular disease markers were evaluated by echocardiography, carotid ultrasonography, and tomographic scans. Essential hypertension (EH) patients exhibited a marked increase in CMV IgG antibody, CRP, TNF-α, and IL-6 levels. Higher grade of hypertension and hypertensive TOD had higher CMV IgG antibody and CRP levels. The CMV IgG antibody titers were positively correlated with arterial BP, greater grade of hypertension and hypertensive TOD, and CRP and IL-6 levels. The higher quartile of CMV IgG titer and CRP level were associated with the incidence of hypertension and the progression of hypertension and hypertensive TOD. In the Han Chinese population, high CMV IgG titers are associated with the progression of hypertension and hypertensive TOD. CMV IgG titer >4.25 U could be an independent predictor of hypertension and progression of hypertension, while that >4.85 U could be an independent risk factor for hypertensive TOD. The underlying mechanism may be largely mediated by chronic inflammation.