Statin use and risk of Parkinson’s disease: a meta-analysis of observational studies

Inconsistent results regarding the association between statin use and risk of Parkinson’s disease (PD) have been reported. We therefore examined the association between statin use and risk of PD by conducting a detailed meta-analysis of all observational studies published regarding this subject. A literature search in the PubMed database was undertaken through April 2012, looking for observational studies evaluating the association between statin use and risk of PD. Combined relative risk (RR) estimates and 95 % confidence intervals (CIs) were calculated using a random-effects model. Subgroup and sensitivity analyses were also performed. A total of eight (five case–control and three cohort) studies contributed to the analysis. There was heterogeneity and publication bias among the studies. Statin use significantly reduced the risk of PD by 23 % (RR 0.77, 95 % CI 0.64–0.92, p = 0.005). However, long-term statin use did not significantly affect the risk of PD (RR 0.72, 95 % CI 0.45–1.13, p = 0.15). Stratification of studies by age and smoking status significantly affected the final estimate (age-adjusted RR 0.61, 95 % CI 0.42–0.86, p = 0.005; age-not-adjusted RR 0.93, 95 % CI 0.83–1.05, p = 0.23 and smoking-adjusted RR 0.60, 95 % CI 0.42–0.87, p = 0.007; smoking-not-adjusted RR 0.92, 95 % CI 0.82–1.02, p = 0.10). Furthermore, sensitivity analysis confirmed the stability of results. Our meta-analysis supports the hypothesis that statin use reduced the risk of PD. Nevertheless, more randomized clinical trials and observational studies are required to confirm this association with underlying biological mechanisms in the future.     

Selective Serotonin 3 Receptor Antagonist Treatment for Schizophrenia: Meta-analysis and Systematic Review

Double-blinded, randomized, placebo-control trials of selective serotonin 3 receptor antagonists (5-HT₃R-ANTs) for schizophrenia have differed in outcome. This meta-analysis tests the hypothesis that 5-HT₃R-ANTs are effective for the treatment for schizophrenia. We searched PubMed, the Cochrane Library database, and PsycINFO up to June 15, 2013. We conducted a systematic review and meta-analysis of individual patient data from randomized controlled trials comparing 5-HT₃R-ANTs add-on therapy with placebo. The risk ratio (RR), 95 % confidence intervals (CI), and standardized mean difference (SMD) were calculated. A random-effects model was used. Six studies (total n = 311) were identified. These included one granisetron plus risperidone study, one ondansetron plus risperidone study, one ondansetron plus haloperidol, and three tropisetron plus risperidone studies. The statistically significant effects of 5-HT₃R-ANTs add-on therapy on Positive and Negative Syndrome Scale (PANSS) total scores were SMD = ?1.03, CI = ?1.70 to ?0.36, p = 0.003 (I ² = 82 %, 5 studies, n = 261); on negative scores were SMD = ?1.10, CI = ?1.82 to ?0.39, p = 0.002 (I ² = 84 %, 5 studies, n = 261); and on PANSS general scores were SMD = ?0.70, CI = ?1.23 to ?0.17, p = 0.01 (I ² = 73 %, 5 studies, n = 261). However, 5-HT₃R-ANTs add-on therapy was not superior to placebo in PANSS positive scores (SMD = ?0.12, p = 0.33). Dropout due to all cause (RR = 0.80, p = 0.50), inefficacy (RR = 0.76, p = 0.65), or adverse events (RR = 0.84, p = 0.75) was similar in both groups. Constipation occurred significantly more often with 5-HT₃R-ANTs than placebo (RR = 2.05, CI = 1.07–3.91, p = 0.03, NNH = 11, p = 0.02). 5-HT₃R-ANTs add-on therapy is more beneficial on the psychopathology (especially negative symptoms) than controls in patients with schizophrenia, and 5-HT₃R-ANTs seem to be well-tolerated treatments.     

Cigarette smoking and risk of completed suicide: A meta-analysis of prospective cohort studies

BackgroundEpidemiologic studies have reported conflicting results relating smoking to suicide risk. We conducted a meta-analysis of prospective cohort studies to evaluate the association of cigarette smoking with completed suicide.MethodsEligible prospective cohort studies were identified from PubMed and EMbase databases (from 1966 to May 2011) and the reference lists of retrieved articles. Two authors independently extracted data and assessed study quality using the Newcastle–Ottawa Scale. Study-specific risk estimates were pooled using random-effects model and generalized least squares trend estimation was used to assess dose–response relationship.ResultsFifteen prospective cohort studies involving 2395 cases among 1,369,807 participants were included in the meta-analysis. Our data suggested that cigarette smoking significantly increased the risk of completed suicide. Compared with never smokers, the pooled RR was 1.28 (95% CI: 1.001–1.641) for former smokers, and 1.81 (95% CI: 1.50–2.19) for current smokers, respectively. Subgroup analyses showed that the increased suicide risk among current smokers appeared to be consistent, although there was heterogeneity among studies of current smoking (p < 0.001). Significant dose–response relationship was found between smoking and suicide, and the risk of suicide was increased by 24% for each increment of 10 cigarettes smoked per day (RR, 1.24; 95% CI: 1.20–1.28).ConclusionsOur meta-analysis robustly demonstrates that cigarette smoking is associated with an increased risk of completed suicide, consistent with a dose–response relationship. This conclusion has an important public health message for countries with high smoking prevalence and high suicide rate such as China.     

Add-on fluvoxamine treatment for schizophrenia: an updated meta-analysis of randomized controlled trials

We performed an updated meta-analysis of fluvoxamine add-on therapy in patients with schizophrenia treated with antipsychotics based on two previous meta-analyses (Sepehry et al., in J Clin Psychiatry 68:604–610, 2007 and Singh et al., in Br J Psychiatry J Mental Sci 197:174–179, 2010). We searched PubMed, the Cochrane Library database, and PsycINFO up to January 2013. We conducted a systematic review and meta-analysis of individual patient data from randomized controlled trials comparing fluvoxamine add-on therapy with placebo. The risk ratio (RR), 95 % confidence intervals (CI), and standardized mean difference (SMD) were calculated. Seven studies (total n = 272) were identified. These included two clozapine studies, one olanzapine study, one second-generation antipsychotic (SGA) monotherapy study, and three first-generation antipsychotics (FGAs) monotherapy studies. There were significant effect of fluvoxamine add-on therapy on overall (SMD = ?0.46, CI = ?0.75 to ?0.16, p = 0.003, I ² = 0 %, 5 studies, n = 180) and negative symptoms (SMD = ?0.44, CI = ?0.74 to ?0.14, p = 0.004, I ² = 0 %, 5 studies, n = 180). However, fluvoxamine add-on therapy showed no significant effects on positive symptoms, depressive symptoms, and discontinuations from any cause or adverse events. Fluvoxamine add-on therapy in patients primarily treated with SGAs improved overall (p = 0.02) but not negative symptoms (p = 0.31). On the other hand, fluvoxamine add-on therapy in patients primarily treated with FGAs improved both overall (p = 0.04) and negative symptoms (p = 0.004) compared with control groups. Our results suggest that fluvoxamine add-on therapy is more beneficial on the psychopathology (especially negative symptoms) than controls in patients with schizophrenia who are primarily treated with FGAs. Given that a small number of studies were included in this meta-analysis, the results should be treated with caution.     

Anxiety and depression comorbidities in irritable bowel syndrome (IBS): a systematic review and meta-analysis

Irritable bowel syndrome (IBS) has been associated with high prevalence of psychological disorders. However, it remains unclear whether IBS and each of its subtypes (predominant diarrhea IBS-D, constipation IBS-C, mixed IBS-M) are associated with higher anxiety and depressive symptoms levels. This study aimed to determine the associations of IBS and each of its subtypes with anxiety and/or depression. We conducted a systematic review and meta-analysis using five electronic databases (PubMed, PsychINFO, BIOSIS, Science Direct, and Cochrane CENTRAL). We selected case–control studies comparing anxiety and depression levels of patients with IBS to healthy controls, using standardized rating scales. Outcomes were measured as random pooled standardized mean differences (SMD). Ten studies were included in our analysis (885 patients and 1,384 healthy controls). Patients with IBS had significant higher anxiety and depression levels than controls (respectively, SMD = 0.76, 95 % CI 0.47; 0.69, p < 0.01, I2 = 81.7 % and SMD = 0.80, 95 % CI 0.42; 1.19, p < 0.01, I2 = 90.7 %). This significant difference was confirmed for patients with IBS-C and -D subtypes for anxiety, and only in IBS-D patients for depression. However, other IBS subtypes had a statistical trend to be associated with both anxiety and depressive symptomatology, which suggests a lack of power due to the small number of studies included. Patients with IBS had significantly higher levels of anxiety and depression than healthy controls. Anxiety and depression symptomatology should be systematically checked and treated in IBS patients, as psychological factors are important moderators of symptom severity, symptom persistence, decisions to seek treatment, and response to treatment.     

Association between the IL7R T244I polymorphism and multiple sclerosis risk: a meta analysis

The aim of this study was to explore the association between the IL7R T244I polymorphism (rs6897932) and susceptibility of multiple sclerosis (MS). A comprehensive literature search for relevant studies was conducted on Google scholar, PubMed, the Chinese National Knowledge Infrastructure (CNKI) and the Chinese Biomedical Literature Database (CBM). This meta-analysis was performed using the STATA 11.0 software and the pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated. Seventeen case–control studies were included in this meta-analysis. In total, 17 articles provided data for 15,270 cases and 17,971 controls. The results showed significant association between the IL7R T244I polymorphism and susceptibility to MS (OR = 1.125, 95 % CI: 1.016–1.245, p = 0.024 for C vs. T; OR = 1.176, 95 % CI: 1.078–1.282, p < 0.001 for CC + CT vs. TT; OR = 1.243, 95 % CI: 1.088–1.421, p = 0.001 for CC vs. TT). Stratified analysis of ethnicities also showed significant association in Europeans. However, no association was found in Asians. This study suggested that the IL7R C allele was associated with an increased risk of MS and larger-scale studies of populations are needed to explore the roles played by the IL7R T244I polymorphism during the pathogenesis of MS.     

Risk factors for unprovoked epileptic seizures in multiple sclerosis: a systematic review and meta-analysis

The role of different factors in influencing the risk of seizures during multiple sclerosis (MS) is not known. To perform a systematic review and meta-analysis of risk factors for epilepsy during MS. Pubmed, Google scholar, and Scopus databases were searched. Articles published in English (1986–2016) were included. Nine studies were included (3 retrospective cohort and 6 case–control) enrolling 2845 MS patients (217 with epilepsy; 7.6%). MS patients with epilepsy had a younger age at onset compared to MS patients without seizures (difference in means = ?5.42 years, 95% CI ?7.19 to ?3.66, p < 0.001). Mean EDSS value at inclusion tended to be higher in patients with epilepsy, without reaching statistical significance (difference in means = 0.45, 95% CI ?0.01 to 0.91, p = 0.054). No differences were observed in sex distribution (OR = 0.94, 95% CI 0.51–1.72, p = 0.83) and clinical form (OR = 1.03, 95% CI 0.33–3.21, p = 0.96). Two studies evaluated presence and number of cortical lesions as a risk factor for epilepsy in MS using different MRI techniques: in one study, cortical lesions were more frequently observed in patients with epilepsy (OR = 7.06, 95% CI 2.39–20.8; p < 0.001). In the other, cortico-juxtacortical lesions were more frequently observed in patients with epilepsy (OR = 2.6, 95% CI 1.0–6.5; p = 0.047). Studies about risk factors for epilepsy during MS are heterogeneous. Compared to MS patients without seizures, patients with epilepsy have an earlier MS onset and a higher EDSS score after similar disease duration. Clinical form of MS and sex do not predict the appearance of seizures.     

Cigarette smoking and associated risk of multiple sclerosis in the Iranian population

Exposure to cigarette smoke is emerging as an environmental risk factor for multiple sclerosis (MS). We investigated the possible association between environmental tobacco smoke, its cumulative exposure, and MS risk. We used data from the Iranian Multiple Sclerosis Registry to identify a case-control of 662 patients who had MS and a comparison group of 394 patients. Information regarding current smoking status, including the number of cigarettes smoked per day, duration, and smoking pack-years indicative of cumulative dose of tobacco smoked was obtained. We analyzed the incidence of MS among ever–smokers who had been smokers during their disease course and prior to disease onset in comparison with never–smokers who had never been exposed by calculating the odds ratio (OR) with a 95% confidence interval (CI) employing logistic regression. Of the 662 MS patients, there were 523 women (79.0%) and 139 men (21.0%), with a mean age of 31 ± 10.0 years at disease onset. The risk for MS was increased among ever–smokers (OR = 1.78, 95% CI = 1.22–2.59, p = 0.03) compared to never–smokers. As compared with never smokers, the OR for patients with 6–10 pack years was 2.91 for men (95% CI = 1.11–9.47, p = 0.03) and 1.69 for women (95% CI = 1.02–6.45, p = 0.04). Our results demonstrate that cigarette smoking is significantly associated with an increased risk for MS. The risk effects of smoking were more noticeable in male patients and at higher tobacco doses.     

A double-blind randomized clinical trial of different doses of transdermal nicotine patch for smoking reduction and cessation in long-term hospitalized schizophrenic patients

There have been many studies of smoking cessation using nicotine replacement therapy (NRT) with schizophrenic patients, but none exploring the smoking-reduction effects of varying doses of NRT in long-stay patients with schizophrenia. This study aimed to examine the effect of different doses of the nicotine transdermal patch on smoking-reduction and cessation outcomes in long-term hospitalized schizophrenic patients. A total of 184 subjects participated in a randomized, controlled, double-blind 8-week clinical trial. Participants were randomized into two groups using two different doses of NRT: a high-dose NRT group (31.2 mg for the first 4 weeks, then 20.8 mg for 4 weeks, n = 92) or a low-dose NRT group (20.8 mg for 8 weeks, n = 92). The 7-day point prevalence of abstinence was 2.7 % (5/184). Participants in the low-dose NRT group reduced smoking by 3.1 more cigarettes on average than those in the high-dose group (p = 0.005). However, a repeated measures analysis of variance revealed that the main effect of changes in the number of cigarettes smoked, comparing the two types of treatment across periods, was not significant (p = 0.35, partial eta square = 0.018). In summary, among a cohort of chronic institutionalized schizophrenic patients, smoking cessation and reduction outcomes were not correlated with NRT dose, and the cessation rate was much lower than rates in similar studies. It indicates that long-term hospitalized schizophrenic patients have more difficulties with quitting smoking. More effective integrative smoking cessation programs should be addressed for these patients.     

Association of smoking with risk of multiple sclerosis: a population-based study

Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. Several studies have shown an association between smoking and MS risk. Here, in a population-based Canadian cohort, we investigate the relationship between personal and maternal smoking exposure and the risk of MS. Using the longitudinal Canadian database, 3,157 MS cases and 756 spouse controls were administered questionnaires on active and passive smoking history. Mothers of cases and controls were also asked about their smoking exposure during pregnancy. The MS cases were more likely to have smoked than spouse controls (odds ratio 1.32, 95 % confidence interval 1.10–1.60, p = 0.003). This association was driven by an excess of ever-smokers in male MS cases. No association was seen with maternal active or passive smoking exposure during pregnancy. Ever-smoking is associated with increased MS risk in males. Further work is needed to understand the mechanism underlying this association.     

Effectiveness of peer-delivered interventions for severe mental illness and depression on clinical and psychosocial outcomes: a systematic review and meta-analysis

Purpose

To evaluate the effectiveness of peer-delivered interventions in improving clinical and psychosocial outcomes among individuals with severe mental illness (SMI) or depression.

Methods

Systematic review and meta-analysis of randomised controlled trials comparing a peer-delivered intervention to treatment as usual or treatment delivered by a health professional. Random effect meta-analyses were performed separately for SMI and depression interventions.

Results

Fourteen studies (10 SMI studies, 4 depression studies), all from high-income countries, met the inclusion criteria. For SMI, evidence from three high-quality superiority trials showed small positive effects favouring peer-delivered interventions for quality of life (SMD 0.24, 95 % CI 0.08–0.40, p = 0.003, I ² = 0 %, n = 639) and hope (SMD 0.24, 95 % CI 0.02–0.46, p = 0.03, I ² = 65 %, n = 967). Results of two SMI equivalence trials indicated that peers may be equivalent to health professionals in improving clinical symptoms (SMD ?0.14, 95 % CI ?0.57 to 0.29, p = 0.51, I ² = 0 %, n = 84) and quality of life (SMD ?0.11, 95 % CI ?0.42 to 0.20, p = 0.56, I ² = 0 %, n = 164). No effect of peer-delivered interventions for depression was observed on any outcome.

Conclusions

The limited evidence base suggests that peers may have a small additional impact on patient’s outcomes, in comparison to standard psychiatric care in high-income settings. Future research should explore the use and applicability of peer-delivered interventions in resource poor settings where standard care is likely to be of lower quality and coverage. The positive findings of equivalence trials demand further research in this area to consolidate the relative value of peer-delivered vs. professional-delivered interventions.     

COMT Val158Met and PPARγ Pro12Ala polymorphisms and susceptibility to Alzheimer’s disease: a meta-analysis

The aim of this study was to explore whether the catechol-O-methyltransferase (COMT) Val158Met or the peroxisome proliferator-activated receptor-gamma (PPARγ) Pro12Ala polymorphisms are associated with susceptibility to Alzheimer’s disease (AD). We conducted a meta-analysis of the associations between the COMT Val158Met and the PPARγ Pro12Ala polymorphisms and AD in subjects. Meta-analysis showed no association between AD and the COMT G allele in any of the study subjects [odds ratio (OR) = 0.972, 95 % confidence intervals (95 % CI) = 0.893–1.059, p = 0.515]. Stratification by ethnicity indicated an association between the COMT GG+GA genotype and AD in an Asian group (OR = 0.702, 95 % CI = 0.517–0.953, p = 0.023), but not in Europeans (OR = 1.058, 95 % CI = 0.868–1.289, p = 0.579). Homozygote contrast analysis showed the same pattern for the COMT GG+GA genotype. Meta-analysis showed no association between AD and the PPARγ polymorphism (OR for the C allele = 0.963, 95 % CI = 0.818–1.134, p = 0.649). This meta-analysis identified an association between AD and the COMT Val158Met polymorphism in Asians but not in Europeans, but it revealed no association between AD and the PPARγ Pro12Ala polymorphism.     

Interleukin-18 −137 G/C and −607 C/A polymorphisms and Alzheimer’s disease risk: a meta-analysis

The ?137 G/C and ?607 C/A polymorphisms in interleukin-18 (IL-18) gene have been reported to be associated with Alzheimer’s disease (AD) risk, but the results are inconclusive. Considering a single study may lack the power to provide reliable conclusion, we performed a meta-analysis to investigate the association between the IL-18 ?137 G/C and ?607 C/A polymorphisms and AD susceptibility. A comprehensive literature search of PubMed, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang databases were conducted before September 1, 2015. The pooled odds ratio (OR) with 95 % confidence intervals (CIs) were calculated. Five eligible studies with a total of 1536 subjects were finally included in this meta-analysis. For the IL-18 ?137 G/C polymorphism, a significantly decreased risk was detected in patients carrying the C allele of ?137 G/C in all study subjects in allele model (C vs. G: OR = 0.816, 95 % CI = 0.680–0.980, p = 0.029). Moreover, stratification by ethnicity indicated markedly association between the ?137 G/C C allele and AD risk in Asians. For the IL-18 ?607 C/A polymorphism, a significantly decreased risk was found in patients carrying the A allele of ?607 C/A in all study subjects in dominant model (AA + CA vs. CC: OR = 0.696, 95 % CI = 0.529–0.915, p = 0.010). However, the results suggested no significant association between the ?607 C/A polymorphism and AD susceptibility when stratified by ethnicity. Our present meta-analysis suggests that the C allele carrier of IL-18 ?137 G/C was associated with decreased risk for AD in Asians. Further well-designed case–control studies with larger sample size and more ethnic groups are needed to confirm these conclusions.     

A Quantitative Assessment of the Association Between 1425G/A Polymorphism in PRKCH and Risk of Stroke

Previous studies suggested an association between 1425G/A polymorphism in PRKCH and stroke risk, but the results were inconsistent. To obtain a more precise estimation, we carried out a meta-analysis to analyze the effect of 1425G/A SNP in PRKCH on stroke risk. We searched PubMed, ISI Web of Science, Chinese Biomedical Database, China National Knowledge Infrastructure and WANFANG Data for all eligible case–control studies through April 2014. The odds ratios (ORs), together with the 95 % confidence intervals (CIs), were calculated to evaluate the strength of association between 1425G/A SNP and stroke risk. Overall, seven eligible studies involving a total of 4,574 cases and 5,471 controls were included in our meta-analysis. The results showed that the variant genotypes of 1425G/A polymorphism in PRKCH were significantly associated with a higher risk of stroke in all genetic models (GA vs. GG: OR 1.35, 95 % CI 1.24–1.47, P < 0.001; AA vs. GG: OR 1.50, 95 % CI 1.24–1.82, P < 0.001; GA/AA vs. GG: OR 1.37, 95 % CI 1.26–1.49, P < 0.001; AA vs. GA/GG: OR 1.35, 95 % CI 1.12–1.62, P = 0.002; A vs. G: OR 1.29, 95 % CI 1.21–1.39, P < 0.001). In the subgroup analysis, significantly increased risks were also observed for ischemic stroke, larger sample size (>1,000) and population-based studies. The result of our meta-analysis indicated that the 1425G/A SNP in PRKCH may contribute to susceptibility of stroke, especially for ischemic stroke.     

Comparative efficacy and safety of methylphenidate and atomoxetine for attention-deficit hyperactivity disorder in children and adolescents: Meta-analysis based on head-to-head trials

Introduction: Comparative efficacy and safety are important issues for appropriate drug selection for attention-deficit hyperactivity disorder (ADHD) treatment. Therefore we conducted a meta-analysis, where we compared atomoxetine (ATX) and methylphenidate (MPH) for ADHD treatment in children and adolescents. Method: Literature retrieval was conducted in relevant databases from their inception to April 2016 to select head-to-head trials that compared ATX and MPH in children and adolescents. Outcomes like response rate, ADHD Rating Scale (ADHD–RS) score, and adverse events were compared between ATX and MPH treatments. The standardized mean difference (SMD) and risk ratio (RR) with their corresponding 95% confidence intervals (CIs) were used as the effect size for continuous data or dichotomous data, respectively. Results: Eleven eligible randomized-controlled trials were included, and two of them were double-blind, while the remaining were open-label. Compared to ATX, MPH showed a higher response rate (RR = 1.14, 95% CI [1. 09, 1.20]), decreased inattention (SMD = ?0.13, 95% CI [?0.25, ?0.01]) and lower risk of adverse events (drowsiness: RR = 0.17, 95% CI [0.11, 0.26; nausea: RR = 0.49; 95% CI [0.29, 0.85; vomiting: RR = 0.41, 95% CI [0.27, 0.63]). However, MPH presented a higher risk of insomnia than ATX (RR = 2.27, 95% CI [1.63, 3.15], p < .01). Conclusion: Results of the meta-analysis add additional evidence of the effectiveness of both ATX and MPH and suggest that MPH should be a first treatment option in most patients with ADHD.     

A common biological basis of obesity and nicotine addiction

Smoking influences body weight such that smokers weigh less than non-smokers and smoking cessation often leads to weight increase. The relationship between body weight and smoking is partly explained by the effect of nicotine on appetite and metabolism. However, the brain reward system is involved in the control of the intake of both food and tobacco. We evaluated the effect of single-nucleotide polymorphisms (SNPs) affecting body mass index (BMI) on smoking behavior, and tested the 32 SNPs identified in a meta-analysis for association with two smoking phenotypes, smoking initiation (SI) and the number of cigarettes smoked per day (CPD) in an Icelandic sample (N=34 216 smokers). Combined according to their effect on BMI, the SNPs correlate with both SI (r=0.019, P=0.00054) and CPD (r=0.032, P=8.0 × 10⁻⁷). These findings replicate in a second large data set (N=127 274, thereof 76 242 smokers) for both SI (P=1.2 × 10⁻⁵) and CPD (P=9.3 × 10⁻⁵). Notably, the variant most strongly associated with BMI (rs1558902-A in FTO) did not associate with smoking behavior. The association with smoking behavior is not due to the effect of the SNPs on BMI. Our results strongly point to a common biological basis of the regulation of our appetite for tobacco and food, and thus the vulnerability to nicotine addiction and obesity.     

Hearing impairment and risk of Alzheimer’s disease: a meta-analysis of prospective cohort studies

Observational studies suggested an association between hearing impairment and cognitive disorders. However, whether hearing impairment is an independent risk factor or a harbinger of Alzheimer’s disease remains controversial. Our goal was to assess the association between hearing impairment (HI) and the risk of Alzheimer’s disease (AD) by conducting a meta-analysis of prospective cohort studies. We comprehensively searched the PubMed, Embase, Web of Science and Cochrane Library databases on January 19, 2016 to incorporate all the prospective cohort studies meeting the inclusion criteria to perform a systematic review and meta-analysis. Four prospective cohort studies with comparison between hearing impairment and normal hearing were incorporated, with 7461 participants. The outcomes of three studies were the incidence of Alzheimer’s disease and the outcome of the fourth study was the incidence of mild cognitive impairment. The overall combined relative risk of people with hearing impairment to develop Alzheimer’s disease was 4.87 (95% CI 0.90–26.35; p = 0.066), compared with the control group. Since both Alzheimer’s disease and mild cognitive impairment are cognitive disorders, we incorporated all the four studies and the overall combined relative risk was 2.82 (95% CI 1.47–5.42; p = 0.002), indicating that the difference was significant. This meta-analysis suggests that hearing impairment significantly increases the risk of cognitive disorders and future well-designed prospective cohort studies are awaited to confirm the association between hearing impairment and risk of Alzheimer’s disease.     

Sex-Specific Associations of Smoking with Spontaneous Subarachnoid Hemorrhage: Findings from Observational Studies

BackgroundSome studies have reported that women are at higher risk for spontaneous subarachnoid hemorrhage (SAH) compared with men, and smoking is the most important lifestyle risk factor for spontaneous SAH. However, it is still unknown whether the risk of SAH from smoking and smoking status is differential for women and men. We performed a meta-analysis to estimate the effect of smoking on SAH in women compared with men.MethodsPubMed (January 1, 1966 to February 19, 2020) and EMBASE (January 1, 1980 to February 19, 2020) were systematically searched. Studies that estimated sex-specific relative risks (RRs) of SAH were selected. We pooled sex-specific RRs, comparing women with men using random-effects meta-analysis.ResultsData from 20 observational studies that included 1,387,204 participants (563,898 women) and 7,838 SAHs (3,977 women) were analyzed. The combined women-to-men RRs of former smokers versus never smokers for SAH were 1.08 (95% confidence interval [CI] 0.62–1.89, p = 0.78). The pooled women-to-men RRs of current smokers versus never smokers were 1.39 (95% CI 1.05–1.83, p = 0.02). The combined women-to-men RRs of total smokers versus never smokers RRs were 1.15 (95% CI 0.88–1.52, p = 0.30).ConclusionsOur study shows there is not enough evidence to suggest that women who smoke have a greater risk for SAH than men; however, women who persistently smoke have a greater risk. Smoking seems to be more susceptible in the increased SAH risk in women.     

Association of midlife smoking status with change in processing speed and mental flexibility among HIV-seropositive and HIV-seronegative older men: the Multicenter AIDS Cohort Study

Smoking is a potential risk factor for age-related cognitive decline. To date, no study has examined the association between smoking and cognitive decline in men living with human immunodeficiency virus (HIV). The aim of this present study is to examine whether smoking status and severity in midlife is associated with a rate of decline in cognitive processing speed among older HIV-seropositive and HIV-seronegative men who have sex with men. Data from 591 older HIV-seropositive and HIV-seronegative men who have sex with men from the Multicenter AIDS Cohort Study were examined. All participants had information on smoking history collected before age 50 years and at least 5 years of follow-up after age 50. Smoking history was categorized as never smoker, former smoker, and current smoker and cumulative pack years was calculated. The raw scores of three neuropsychological tests (Trail Making A, Trail Making B, and Symbol Digit Modalities tests) were log transformed (Trail Making A and B) and used in linear mixed models to determine associations between smoking history and at least subsequent 5-year decline in cognitive processing speed. There were no significant differences in the rates of neurological decline among never smokers, former smokers, and current smokers. Findings were similar among HIV-seropositive participants. However, an increase of 5 pack-years was statistically significantly associated with a greater rate of decline in the Trail Making Test B score and Composite Score (β ?0.0250 [95% CI, ?0.0095 to ?0.0006] and ?0.0077 [95% CI, ?0.0153 to ?0.0002], respectively). We found no significant association between smoking treated as a categorical variable (never smoked, former smoker, or current smoker) and a small change in every increase of 5 pack-years on measures of psychomotor speed and cognitive flexibility. To optimize healthy aging, interventions for smoking cessation should be tailored to men who have sex with men.