A systematic review of the epidemiology of suicide in Iraq and Kurdistan region

OBJECTIVES

The suicide rate has increased in Iraq in recent years, making it a major public health concern. This systematic review examines the prevalence of suicidal behaviours in the Iraq and Kurdistan region.

MATERIALS AND METHODS

This study adhered to the PRISMA guidelines, conducting searches on PubMed, MEDLINE, Web of Science, and Google Scholar. Out of 153 initially identified publications, only 18 full articles met the inclusion criteria, with 135 articles excluded due to reasons such as eligibility criteria, duplication, predatory publications and lack of relevance and lack of quality data.

RESULTS

The suicide crude rate in Iraq (excluding Kurdistan) rose from 1.09 to 1.31 per 100,000 between 2015 and 2016, while Kurdistan had an estimated rate of 3.83 per 100,000 during the same period. Limited data on reference group sizes and population figures make specific rate calculations challenging. Suicide is more prevalent among women, those aged 15-40, and individuals with mental disorders. Contributing factors include domestic violence, mental health issues, and traditional norms. Urban residents generally have higher suicide rates than rural residents. Common suicide behaviours include self-immolation, hanging, firearms, jumping from heights, and self-poisoning with pesticides.

CONCLUSION

The prevalence of suicide in Iraq, as indicated by this systematic review, requires urgent attention and effective public health initiatives. The interplay of social, economic, cultural, and psychological factors emphasizes the need for comprehensive prevention programs. Additionally, a crucial requirement is the implementation of a standardised method for collecting suicide data to improve epidemiological understanding.

The prevalence of psychiatric disorders among Yazidi people results from ISIS invasion and consecutive trauma: A systematic review

BACKGROUND

The Yazidi community is a Kurdish minority of the population that lives mainly in Iraq. In history, they suffered from many problems and disasters, including the most recent brutal invasion by ISIS, which significantly impacted their mental health.

AIMS

Our objective is to examine the prevalence of psychiatric disorders among Yazidi people resulting from the invasion of ISIS in 2014.

METHODS

A systematic review was performed using the PRISMA protocol. 252 publications were initially identified in PubMed, EMBASE, Scopus, and Google Scholar using relevant keywords. Finally, 23 full articles were included for data extraction. The inclusion criteria were English papers that investigated Yazidi's psychiatric problems, regardless of gender, or age. However, letters to editors, systematic reviews, and studies that examine general physical health were excluded.

RESULTS

A total of 252 publications were identified; 217 were assessed for eligibility, of which 23 studies met eligibility criteria and were included in the present systematic review. According to the findings, the Yazidi people were severely affected by persecution, forced migration, massacres, and ISIS violence in the recent period and suffered from a variety of mental and psychiatric problems. The most prevalent mental disorders among Yazidi people of all ages and sexes are PTSD, depression, and anxiety disorders.

CONCLUSION

This study indicates that the Yazidi minority is a traumatized population. According to the results of the current systematic review, the Yazidi have suffered from a variety of mental and psychological disorders, most commonly PTSD, depression, and anxiety. Eventually, addressing these challenges should be prioritized to improve the quality of life of Yazidis through implications for intervention.

The Epistasis Project: A Multi-Cohort Study of the Effects of BDNF, DBH, and SORT1 Epistasis on Alzheimer's Disease Risk

Pre-synaptic secretion of brain-derived neurotrophic factor (BDNF) from noradrenergic neurons may protect the Alzheimer's disease (AD) brain from amyloid pathology. While the BDNF polymorphism (rs6265) is associated with faster cognitive decline and increased hippocampal atrophy, a replicable genetic association of BDNF with AD risk has yet to be demonstrated. This could be due to masking by underlying epistatic interactions between BDNF and other loci that encode proteins involved in moderating BDNF secretion (DBH and Sortilin). We performed a multi-cohort case-control association study of the BDNF, DBH, and SORT1 loci comprising 5,682 controls and 2,454 AD patients from Northern Europe (87% of samples) and Spain (13%). The BDNF locus was associated with increased AD risk (odds ratios; OR = 1.1-1.2, p = 0.005-0.3), an effect size that was consistent in the Northern European (OR = 1.1-1.2, p = 0.002-0.8) but not the smaller Spanish (OR = 0.8-1.6, p = 0.4-1.0) subset. A synergistic interaction between BDNF and sex (synergy factor; SF = 1.3-1.5 p = 0.002-0.02) translated to a greater risk of AD associated with BDNF in women (OR = 1.2-1.3, p = 0.007-0.00008) than men (OR = 0.9-1.0, p = 0.3-0.6). While the DBH polymorphism (rs1611115) was also associated with increased AD risk (OR = 1.1, p = 0.04) the synergistic interaction (SF = 2.2, p = 0.007) between BDNF (rs6265) and DBH (rs1611115) contributed greater AD risk than either gene alone, an effect that was greater in women (SF = 2.4, p = 0.04) than men (SF = 2.0, p = 0.2). These data support a complex genetic interaction at loci encoding proteins implicated in the DBH-BDNF inflammatory pathway that modifies AD risk, particularly in women.

PLCG2 protective variant p.P522R modulates tau pathology and disease progression in patients with mild cognitive impairment

A rare coding variant (rs72824905, p.P522R) conferring protection against Alzheimer’s disease (AD) was identified in the gene encoding the enzyme phospholipase-C-γ2 (PLCG2) that is highly expressed in microglia. To explore the protective nature of this variant, we employed latent process linear mixed models to examine the association of p.P522R with longitudinal cognitive decline in 3595 MCI patients, and in 10,097 individuals from population-based studies. Furthermore, association with CSF levels of pTau₁₈₁, total tau, and Aβ_1-42 was assessed in 1261 MCI patients. We found that MCI patients who carried the p.P522R variant showed a slower rate of cognitive decline compared to non-carriers and that this effect was mediated by lower pTau₁₈₁ levels in CSF. The effect size of the association of p.P522R with the cognitive decline and pTau₁₈₁ was similar to that of APOE-ε4, the strongest genetic risk factor for AD. Interestingly, the protective effect of p.P522R was more pronounced in MCI patients with low Aβ_1-42 levels suggesting a role of PLCG2 in the response to amyloid pathology. In line with this hypothesis, we observed no protective effect of the PLCG2 variant on the cognitive decline in population-based studies probably due to the lower prevalence of amyloid positivity in these samples compared to MCI patients. Concerning the potential biological underpinnings, we identified a network of co-expressed proteins connecting PLCG2 to APOE and TREM2 using unsupervised co-regulatory network analysis. The network was highly enriched for the complement cascade and genes differentially expressed in disease-associated microglia. Our data show that p.P522R in PLCG2 reduces AD disease progression by mitigating tau pathology in the presence of amyloid pathology and, as a consequence, maintains cognitive function. Targeting the enzyme PLCG2 might provide a new therapeutic approach for treating AD.

Seasonal distribution of births in patients with Alzheimer’s disease and elderly depressive patients

Winter births have been associated with a higher risk of Alzheimer’s disease (AD) and other psychiatric disorders. In the present investigation, this putative association was examined in a sample of gerontopsychiatric patients. An analysis of the quarterly birth rates of 83 patients with AD, 78 elderly depressive patients with an early onset and 74 patients with a late onset of the depressive disorder, 48 patients with both AD and depression (co-morbid patients) and 107 healthy control subjects, revealed no particular seasonal distribution for any of the diagnostic groups. In AD and co-morbid patients, controlling for the ApoE genotype did not change this finding. Logistic regression analysis revealed the expected findings that increasing age and the presence of the ApoE4 allele were associated with a higher risk of dementia. Younger age and female gender were identified as risk factors for a depressive disorder. A winter birth (birth in the first three months of the year) was not associated with any of the diagnostic subgroups.

We concluded that in our sample a seasonal distribution of births was not found to increase the risk for AD or geriatric depression.

Suicidality in ADHD: A review

Introduction

Both Attention Deficit Hyperactivity Disorder (ADHD) and suicidal behaviour are common psychiatric conditions with significant social and emotional morbidity. Although completed suicide in ADHD has been assessed in a previous meta-analysis, other domains of suicidal behaviour such as attempts and ideation have been documented only in individual studies. This review provides a summary of these studies in order to examine the relationship between attention deficit and risk to self.

Method

Electronic and manual literature search of MEDLINE, EMBASE and PSYCHINFO, using a range of search terms around suicidality, attention-deficit and hyperactivity. Articles included both those looking at diagnosis of ADHD in suicidal populations, and those looking at suicidality in pre-diagnosed ADHD populations.

Results

Wide variation was seen in all dimensions, with the main determining factor being co-morbid diagnoses.

Suicidal populations

In populations completing suicide, ADHD was present in 4 to 25.9%. In suicide attempt and ideation populations, 1.6 to 65% and 10.5–31.8% respectively had ADHD. Attention deficit disorders were diagnosed more frequently in suicidal males than females. Age and location differences were not consistent across groups.

ADHD populations

In those with diagnosed ADHD, 9.1–70% had attempted suicide and 15.8–66.3% described suicidal ideation. Higher rates were seen in prison inmates and drug dependent subjects.

Discussion

Although there is a positive relationship between ADHD and risk to self, the magnitude can vary greatly between different populations. Further research on larger samples is necessary to firmly establish this. The process of risk assessment in ADHD needs to take into account the possibility of intentional self-injury and provide management strategies.

Familial aggregation of depression, but no familial aggregation of individual depressive symptoms

Background

Familial aggregation of major depression might indicate a genetic liability for the disorder. The complete disorder or, alternatively, only some individual symptoms might be inherited. Under the latter condition, an increased frequency of inherited symptoms might consecutively increase the likelihood to reach the threshold for depression in relatives and, thus, might cause the familial aggregation of depression. Up to now, no study investigated the possibility of a relationship between individual depressive symptoms and the familial aggregation of depression.

Methods

The familial aggregation of early-onset depression (age-at-onset < 60 years, EOD) but less so of late-onset depression (LOD) has been shown in this sample. To assess the hypothesis of an inheritance of individual depressive symptoms as a possible cause of the familial aggregation of depression, frequencies of symptoms were compared in relatives of depressed patients and of controls using forward logistic regression analyses.

Results

Some individual depressive symptoms showed clustering in relatives of patients with depression, but the pattern of inheritance was inconsistent, i.e. the clustering of symptoms was different between non-depressed and depressed relatives of patients with EOD and LOD, respectively. No intra-familial clustering of specific depressive symptoms within families of depressed subjects could be observed.

Conclusions

Due to the inconsistencies in the clustering of individual symptoms in non-depressed and depressed relatives and the lack of intra-familial clustering, the familial aggregation of depression is unlikely to be caused by the aggregation of individual depressive symptoms. An inheritance of the vulnerability for complete depressive disorders influenced by environmental factors is more likely.

CYP46A1 variants influence Alzheimer’s disease risk and brain cholesterol metabolism

Background

Cholesterol 24S-hydroxylase (CYP46) catalyzes the conversion of cholesterol to 24S-hydroxycholesterol, the primary cerebral cholesterol elimination product. Only few gene variations in CYP46 gene (CYP46A1) have been investigated for their relevance as genetic risk factors of Alzheimer’s disease (AD) and results are contradictory.

Methods

We performed a gene variability screening in CYP46A1 and investigated the effect of gene variants on the risk of AD and on CSF levels of cholesterol and 24S-hydroxycholesterol.

Results

Two of the identified 16 SNPs in CYP46A1 influenced AD risk in our study (rs7157609: p = 0.016; rs4900442: p = 0.019). The interaction term of both SNPs was also associated with an increased risk of AD (p = 0.006). Haplotypes including both SNPs were calculated and haplotype G–C was identified to influence the risk of AD (p = 0.005). AD patients and non-demented controls, who were carriers of the G–C haplotype, presented with reduced CSF levels of 24S-hydroxycholesterol (p = 0.001) and cholesterol (p < 0.001).

Conclusion

Our results suggest that CYP46A1 gene variations might act as risk factor for AD via an influence on brain cholesterol metabolism.

Risk factors of major depression in the elderly

Background

Several risk factors of depression have been identified in retrospective as well as some prospective studies in the elderly. Confirmation in independent samples is needed. The present follow-up study prospectively investigated risk factors of depression in an elderly German sample.

Methods

One thousand four hundred and thirty-one subjects from a family study were re-investigated after 4.7 ± 2.5 years. Bivariate and multivariate forward logistic regression analyses were used to identify risk factors of the development of new depression in the elderly.

Results

Risk factors of a new depressive episode in 1408 elderly without current depression were age, female gender, a previous depression, subjective memory impairment, previous anxiety and somatoform disorders. The presence of dementia or mild cognitive impairment were significant risk factors in bivariate, but not multivariate analysis controlling for possible confounding. Risk factors of a first geriatric depressive episode were age, gender and subjective memory impairment; age remained the only significant risk factor in multivariate analysis.

Conclusions

This investigation confirms previous studies from other countries concerning the relevance of risk factors for depression in the elderly. The knowledge of risk factors might help identify subjects at increased risk of depression for early intervention approaches. Elderly with a history of previous depression carry the highest risk.

Alcohol dependence and physical comorbidity: Increased prevalence but reduced relevance of individual comorbidities for hospital-based mortality during a 12.5-year observation period in general hospital admissions in urban North-West England

Purpose:

Alcohol dependence (AD) is associated with an increase in physical comorbidities. The effects of these diseases on general hospital-based mortality are unclear. Consequently, we conducted a mortality study in which we investigated if the burden of physical comorbidities and their relevance on general hospital-based mortality differs between individuals with and without AD during a 12.5-year observation period in general hospital admissions.

Methods:

During 1 January 2000 and 30 June 2012, 23,371 individuals with AD were admitted at least once to seven General Manchester Hospitals. Their physical comorbidities with a prevalence ≥ 1% were compared to those of 233,710 randomly selected hospital controls, group-matched for age and gender (regardless of primary admission diagnosis or specialized treatments). Physical comorbidities that increased the risk of hospital-based mortality (but not outside of the hospital) during the observation period were identified using multiple logistic regression analyses.

Results:

Hospital-based mortality rates were 20.4% in the AD sample and 8.3% in the control sample. Individuals with AD compared to controls had a higher burden of physical comorbidities, i.e. alcoholic liver and pancreatic diseases, diseases of the conducting airways, neurological and circulatory diseases, diseases of the upper gastrointestinal tract, renal diseases, cellulitis, iron deficiency anemia, fracture neck of femur, and peripheral vascular disease. In contrast, coronary heart related diseases, risk factors of cardiovascular disease, diverticular disease and cataracts were less frequent in individuals with AD than in controls. Thirty-two individual physical comorbidities contributed to the prediction of hospital-based mortality in univariate analyses in the AD sample; alcoholic liver disease (33.7%), hypertension (16.9%), chronic obstructive pulmonary disease (14.1%), and pneumonia (13.3%) were the most frequent diagnoses in deceased individuals with AD. Multiple forward logistic regression analysis, accounting for possible associations of diseases, identified twenty-three physical comorbidities contributing to hospital-based mortality in individuals with AD. However, all these comorbidities had an equal or even lower impact on hospital-based mortality than in the comparison sample.

Conclusion:

The excess of in-hospital deaths in general hospitals in individuals with AD is due to an increase of multiple physical comorbidities, even though individual diseases have an equal or even reduced impact on general hospital-based mortality in individuals with AD compared to controls.

Gene-based analysis in HRC imputed genome wide association data identifies three novel genes for Alzheimer's disease

Late onset Alzheimer's disease is the most common form of dementia for which about 30 susceptibility loci have been reported. The aim of the current study is to identify novel genes associated with Alzheimer's disease using the largest up-to-date reference single nucleotide polymorphism (SNP) panel, the most accurate imputation software and a novel gene-based analysis approach which tests for patterns of association within genes, in the powerful genome-wide association dataset of the International Genomics of Alzheimer's Project Consortium, comprising over 7 million genotypes from 17,008 Alzheimer's cases and 37,154 controls. In addition to earlier reported genes, we detected three novel gene-wide significant loci PPARGC1A (p = 2.2 × 10-6), RORA (p = 7.4 × 10-7) and ZNF423 (p = 2.1 × 10-6). PPARGC1A and RORA are involved in circadian rhythm; circadian disturbances are one of the earliest symptoms of Alzheimer's disease. PPARGC1A is additionally linked to energy metabolism and the generation of amyloid beta plaques. RORA is involved in a variety of functions apart from circadian rhythm, such as cholesterol metabolism and inflammation. The ZNF423 gene resides in an Alzheimer's disease-specific protein network and is likely involved with centrosomes and DNA damage repair.

Genetic meta-analysis of diagnosed Alzheimer's disease identifies new risk loci and implicates Aβ, tau, immunity and lipid processing

Risk for late-onset Alzheimer's disease (LOAD), the most prevalent dementia, is partially driven by genetics. To identify LOAD risk loci, we performed a large genome-wide association meta-analysis of clinically diagnosed LOAD (94,437 individuals). We confirm 20 previous LOAD risk loci and identify five new genome-wide loci (IQCK, ACE, ADAM10, ADAMTS1, and WWOX), two of which (ADAM10, ACE) were identified in a recent genome-wide association (GWAS)-by-familial-proxy of Alzheimer's or dementia. Fine-mapping of the human leukocyte antigen (HLA) region confirms the neurological and immune-mediated disease haplotype HLA-DR15 as a risk factor for LOAD. Pathway analysis implicates immunity, lipid metabolism, tau binding proteins, and amyloid precursor protein (APP) metabolism, showing that genetic variants affecting APP and Aβ processing are associated not only with early-onset autosomal dominant Alzheimer's disease but also with LOAD. Analyses of risk genes and pathways show enrichment for rare variants (P = 1.32 × 10-7), indicating that additional rare variants remain to be identified. We also identify important genetic correlations between LOAD and traits such as family history of dementia and education.

Effect of agomelatine 25-50 mg on functional outcomes in patients with major depressive disorder

PURPOSE

The purpose of this work is to investigate the effect of agomelatine on functioning compared with placebo in patients suffering from Major Depressive Disorder (MDD).

METHODS

Data from two randomized, parallel, double-blind, placebo-controlled short-term agomelatine trials conducted by the manufacturer, one in adult and one in older patients, that evaluated the effect on social functioning, were pooled. The short term effect of agomelatine on social functioning was assessed using the Sheehan Disability Scale (SDS), according to SDS total and sub-item scores, as well as on functional response and remission rates. The Hamilton Depression rating scale was used to quantify severity of depression symptoms. A meta-analytic method using a random effect model was used to assess differences in treatment.

RESULTS

In total, 633 patients (422 on agomelatine; 211 on placebo) were included in the analyses. At endpoint, there was a significant difference in favor of agomelatine vs placebo of 3.47 (0.62) (95% confidence interval: [2.26; 4.67]; P < 0.001) on the SDS total score. Rates of symptomatic response and remission according to HAM-D₁₇ total score were significantly higher in patients taking agomelatine (54.3% and 18.3% respectively) than in those taking placebo (29.4% and 9.5% respectively) with respective differences of 24.9%, p < 0.001 and 9.3%, p < 0.001. The functional response rates were 52.9% on agomelatine and 34.5% on placebo, with a significant placebo-agomelatine difference in favor of agomelatine of 18.30 ± 4.39% (95% CI: [9.69; 26.91], p < 0.001). The functional remission rates were 22.3% with agomelatine and 10.2% with placebo, with a significant difference in favor of agomelatine of 11.7 ± 3.11% (95% CI: [5.61; 17.79], p < 0.001). Combined symptomatic and functional response rates were 42.1% on agomelatine and 23.2% on placebo (p < 0.001), and the combined symptomatic and functional remission rates were 13.9% on agomelatine and 6.8% on placebo (p < 0.005).

CONCLUSION

This study confirms the efficacy of agomelatine in improving social functioning in MDD patients.

Risk of cardiovascular malformations after exposure to paroxetine in pregnancy: meta-analysis

Aims and method

To examine the association between the use of paroxetine during pregnancy and the risk of cardiovascular defects in the newborn. A systematic review of nine electronic databases was carried out and bibliographies were hand-searched for other relevant articles. Inclusion criteria for studies were the use of selective serotonin reuptake inhibitors in the first trimester of pregnancy, with separate data available for paroxetine and cardiovascular defects in newborn babies. A random-effect model was used to combine the data.

Results

A total of 11 studies were included in the analysis, concerning 4515 offspring who were exposed to paroxetine in the first trimester and 1 469 302 controls. In pooled analysis, paroxetine in the first trimester of pregnancy was slightly, but significantly, associated with a risk of cardiovascular malformations in the offspring (relative risk= 1.25, 95% CI 1.01–1.54). Separate analyses of case-control and cohort studies made this difference non-significant.

Clinical implications

This meta-analysis supports current guidelines advising not to use paroxetine in early pregnancy.

Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

We identified rare coding variants associated with Alzheimer's disease in a three-stage case-control study of 85,133 subjects. In stage 1, we genotyped 34,174 samples using a whole-exome microarray. In stage 2, we tested associated variants (P < 1 × 10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, we used an additional 14,997 samples to test the most significant stage 2 associations (P < 5 × 10-8) using imputed genotypes. We observed three new genome-wide significant nonsynonymous variants associated with Alzheimer's disease: a protective variant in PLCG2 (rs72824905: p.Pro522Arg, P = 5.38 × 10-10, odds ratio (OR) = 0.68, minor allele frequency (MAF)cases = 0.0059, MAFcontrols = 0.0093), a risk variant in ABI3 (rs616338: p.Ser209Phe, P = 4.56 × 10-10, OR = 1.43, MAFcases = 0.011, MAFcontrols = 0.008), and a new genome-wide significant variant in TREM2 (rs143332484: p.Arg62His, P = 1.55 × 10-14, OR = 1.67, MAFcases = 0.0143, MAFcontrols = 0.0089), a known susceptibility gene for Alzheimer's disease. These protein-altering changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified risk genes in Alzheimer's disease. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to the development of Alzheimer's disease.

Little evidence for community treatment orders - a battle fought with heavy weapons

This editorial discusses the pros and cons of community treatment orders (CTOs) from the perspective of community general adult psychiatry. There is little scientific evidence supporting the application of CTOs. Preconditions of a CTO to work are likely to be met by few patients. The time for the application of a CTO may be better spent for patient-centred care until there is sufficient new and robust evidence that identifies the patients that might profit.

Suicidal events due to overdose and medical comorbidities in psychiatric disorders of ICD-10 classes F1–F4: A comparative overview of five studies in general hospital admissions

Introduction

General hospital-based studies may help towards improving the treatment of psychiatric disorders.

Objectives and aims

Based on five representative studies in general hospital admissions, we will represent a comparative overview of suicidal events due to overdose and of the most common medical comorbidities in psychiatric disorders of ICD-10 classes F1–F4.

Methods

In secondary analysis one-way Anova and Tukey HSD test were used for comparisons of interval variables. Suicidal events and medical comorbidities with prevalences > 10% were compared between studies using the OR and the 95% CI.

Results

Individuals with psychiatric disorders of ICD-10 classes F1–F4 were young (44.7–50.0 years), had an extended length of hospital stay at initial hospitalization (3.8–8.1 vs. 2.9–3.4 days), and significantly more likely suffered of suicidal events due to overdose than controls, contributing from 4.1% (OR = 4,1) to 11,6% (OR = 25.2) to general hospital admissions. Additionally, individuals with schizophrenia (SCH) significantly more likely suffered of type-2 diabetes mellitus (OR = 2.3, 95% CI 1.5–3.6) than individuals with major depressive disorder (MDD), anxiety disorder (ANX), and alcohol dependence (AD), but equal likely as individuals with bipolar disorder (BD). Asthma and hypertension contributed significantly more to hospitalizations in the MDD and ANX samples compared to the SCH, BD, and AD samples. In the AD sample, alcoholic liver disease was more prevalent than in all other samples.

Conclusions

In psychiatric disorders, the frequency of suicidal events due to overdose in general hospitals is significantly determined by the diagnostic class. Additionally, different medical comorbidities contribute more than other medical comorbidities to general hospital admissions in various psychiatric disorders.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Physical comorbidity and consequences for mortality and treatment

Introduction

Ageing is related to an increase rate of physical comorbidity. However, the interaction between physical comorbidity and the development of depression in the elderly is not yet clear. Depression may be the cause or consequence of physical morbidity. Both may increase mortality.

Methods

A total of 9604 patients with depression and a control sample of 96040 patients who attended a general hospital were followed-up for up to 12 years. Physical comorbidity and mortality was assessed.

Results

Twenty-nine physical disorders were more prevalent in subjects with depression, but the effect of individual disorders on mortality did not differ significantly in the depressed and control sample.

Conclusions

Patients with depression suffer more physical health problems than control patients that lead to death. The implications for early treatment will be discussed, a preventative approach may be most relevant.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Bipolar disorder and comorbidity: increased prevalence and increased relevance of comorbidity for hospital-based mortality during a 12.5-year observation period in general hospital admissions

BACKGROUND

Bipolar disorder (BD) is associated with an increase of psychiatric and physical comorbidities, but the effects of these disorders on general hospital-based mortality are unclear. Consequently, we investigated whether the burden of comorbidity and its relevance on hospital-based mortality differed between individuals with and without BD during a 12.5-year observation period in general hospital admissions.

METHODS

During 1 January 2000 and 30 June 2012, 621 individuals with BD were admitted to three General Manchester Hospitals. All comorbidities with a prevalence ≥1% were compared with those of 6210 randomly selected and group-matched hospital controls of the same age and gender, regardless of priority of diagnoses. Comorbidities that increased the risk for hospital-based mortality (but not mortality outside of the hospitals) were identified using multivariate logistic regression analyses.

RESULTS

Individuals with BD had a more severe course of disease than controls that was associated with a higher total number of in-hospital deaths. Individuals with BD compared to controls had a substantial higher burden of comorbidities, the most frequent comorbidities included asthma, type-2 diabetes mellitus (T2DM), and alcohol dependence. 18 other diseases with a surplus of diabetes related complications were also increased. Fourteen comorbidities contributed to the prediction of hospital-based mortality in univariate analyses. Risk factors for hospital-based mortality in multivariate analyses were ischemic stroke, pneumonia, bronchitis, chronic obstructive pulmonary disease, T2DM, and hypertension. The impact of T2DM on hospital-based mortality was higher in individuals with BD than in controls.

LIMITATIONS

The study design was not assigned to assess the type of BD, the current bipolar status, and if individuals with BD were treated with medication. It was neither possible to compare drug effects, nor to compare the adherence to treatment between samples.

CONCLUSION

In one of the largest samples of individuals with BD in general hospitals, the excess comorbity in individuals with BD compared to controls is in particular caused by asthma and T2DM. T2DM and its complications cause significant excess hospital-based mortality in individuals with BD.

Comorbidity and its relevance on general hospital based mortality in major depressive disorder: a naturalistic 12-year follow-up in general hospital admissions

Major depressive disorder (MDD) is associated with physical comorbidity, but the risk factors of general hospital-based mortality are unclear. Consequently, we investigated whether the burden of comorbidity and its relevance on in-hospital death differs between patients with and without MDD in a 12-year follow-up in general hospital admissions. During 1 January 2000 and 30 June 2012, 9604 MDD patients were admitted to three General Manchester Hospitals. All comorbidities with a prevalence ≥1% were compared with those of 96,040 age-gender matched hospital controls. Risk factors of in-hospital death were identified using multivariate logistic regression analyses. Crude hospital-based mortality rates within the period under observation were 997/9604 (10.4%) in MDD patients and 8495/96,040 (8.8%) in controls. MDD patients compared to controls had a substantial higher burden of comorbidity. The highest comorbidities included hypertension, asthma, and anxiety disorders. Subsequently, twenty-six other diseases were disproportionally increased, many of them linked to chronic lung diseases and to diabetes. In deceased MDD patients, chronic obstructive pulmonary disease and type-2 diabetes mellitus were the most common comorbidities, contributing to 18.6% and 17.1% of deaths. Furthermore, fifteen physical diseases contributed to in-hospital death in the MDD population. However, there were no significant differences in their impact on mortality compared to controls in multivariate logistic regression analyses. Thus in one of the largest samples of MDD patients in general hospitals, MDD patients have a substantial higher burden of comorbidity compared to controls, but they succumb to the same physical diseases as their age-gender matched peers without MDD.

EPA Guidance on Building Trust in Mental Health Services

Purpose

To advance mental health care use by developing recommendations to increase trust from the general public and patients, those who have been in contact with services, those who have never been in contact and those who care for their families in the mental health care system.

Methods

We performed a systematic literature search and the retrieved documents were evaluated by two independent reviewers. Evidence tables were generated and recommendations were developed in an expert and stakeholder consensus process.

Results

We developed five recommendations which may increase trust in mental health care services and advance mental health care service utilization.

Discussion

Trust is a mutual, complex, multidimensional and dynamic interrelationship of a multitude of factors. Its components may vary between individuals and over time. They may include, among others, age, place of residence, ethnicity, culture, experiences as a service user, and type of disorder. For mental health care services, issues of knowledge about mental health services, confidentiality, continuity of treatment, dignity, safety and avoidance of stigma and coercion are central elements to increase trust.

Conclusion

Evidence-based recommendations to increase mutual trust of service users and psychiatrists have been developed and may help to increase mental health care service utilization.

Physical comorbidity and its relevance on mortality in schizophrenia: a naturalistic 12-year follow-up in general hospital admissions

Schizophrenia is a major psychotic disorder with significant comorbidity and mortality. Patients with schizophrenia are said to suffer more type-2 diabetes mellitus (T2DM) and diabetogenic complications. However, there is little consistent evidence that comorbidity with physical diseases leads to excess mortality in schizophrenic patients. Consequently, we investigated whether the burden of physical comorbidity and its relevance on hospital mortality differed between patients with and without schizophrenia in a 12-year follow-up in general hospital admissions. During 1 January 2000 and 31 June 2012, 1418 adult patients with schizophrenia were admitted to three General Manchester NHS Hospitals. All comorbid diseases with a prevalemce ≥1% were compared with those of 14,180 age- and gender-matched hospital controls. Risk factors, i.e. comorbid diseases that were predictors for general hospital mortality were identified using multivariate logistic regression analyses. Compared with controls, schizophrenic patients had a higher proportion of emergency admissions (69.8 vs. 43.0%), an extended average length of stay at index hospitalization (8.1 vs. 3.4 days), a higher number of hospital admissions (11.5 vs. 6.3), a shorter length of survival (1895 vs. 2161 days), and a nearly twofold increased mortality rate (18.0 vs. 9.7%). Schizophrenic patients suffered more depression, T2DM, alcohol abuse, asthma, COPD, and twenty-three more diseases, many of them diabetic-related complications or other environmentally influenced conditions. In contrast, hypertension, cataract, angina, and hyperlipidaemia were less prevalent in the schizophrenia population compared to the control population. In deceased schizophrenic patients, T2DM was the most frequently recorded comorbidity, contributing to 31.4% of hospital deaths (only 14.4% of schizophrenic patients with comorbid T2DM survived the study period). Further predictors of general hospital mortality in schizophrenia were found to be alcoholic liver disease (OR = 10.3), parkinsonism (OR = 5.0), T1DM (OR = 3.8), non-specific renal failure (OR = 3.5), ischaemic stroke (OR = 3.3), pneumonia (OR = 3.0), iron-deficiency anaemia (OR = 2.8), COPD (OR = 2.8), and bronchitis (OR = 2.6). There were no significant differences in their impact on hospital mortality compared to control subjects with the same diseases except parkinsonism which was associated with higher mortality in the schizophrenia population compared with the control population. The prevalence of parkinsonism was significantly elevated in the 255 deceased schizophrenic patients (5.5 %) than in those 1,163 surviving the study period (0.8 %, OR = 5.0) and deceased schizophrenic patients had significantly more suffered extrapyramidal symptoms than deceased control subjects (5.5 vs. 1.5 %). Therefore patients with schizophrenia have a higher burden of physical comorbidity that is associated with a worse outcome in a 12-year follow-up of mortality in general hospitals compared with hospital controls. However, schizophrenic patients die of the same physical diseases as their peers without schizophrenia. The most relevant physical risk factors of general hospital mortality are T2DM, COPD and infectious respiratory complications, iron-deficiency anaemia, T1DM, unspecific renal failure, ischaemic stroke, and alcoholic liver disease. Additionally, parkinsonism is a major risk factor for general hospital mortality in schizophrenia. Thus, optimal monitoring and management of acute T2DM and COPD with its infectious respiratory complications, as well as the accurate detection and management of iron-deficiency anaemia, of diabetic-related long-term micro- and macrovascular complications, of alcoholic liver disease, and of extrapyramidal symptoms are of utmost relevance in schizophrenia.

The efficacy of agomelatine in elderly patients with recurrent major depressive disorder: a placebo-controlled study

OBJECTIVE

The present placebo-controlled study evaluated the efficacy, tolerability, and safety of 8-week treatment with agomelatine (25-50 mg/d by mouth) in elderly patients with major depressive disorder (MDD).

METHOD

Elderly outpatients aged ≥ 65 years with a primary diagnosis of moderate to severe episode of recurrent MDD (DSM-IV-TR) were recruited in 27 clinical centers in Argentina, Finland, Mexico, Portugal, and Romania from November 2009 to October 2011. The primary outcome measure was the 17-item Hamilton Depression Rating Scale (HDRS17) total score.

RESULTS

A total of 222 elderly patients entered the study (151 in the agomelatine group, 71 in the placebo group), including 69 patients aged 75 years and older. Agomelatine improved depressive symptoms in the elderly population, as evaluated by the HDRS17 total score, in terms of last postbaseline value (agomelatine-placebo difference: mean estimate [standard error] = 2.67 [1.06] points; P = .013) and response to treatment (agomelatine, 59.5%; placebo, 38.6%; P = .004). The agomelatine-placebo difference according to the Clinical Global Impressions-Severity of Illness scale (CGI-S) score was 0.48 (0.19). The agomelatine-placebo difference (estimate [standard error]) for remission on the HDRS17 was 6.9% (4.7%) and did not achieve statistical significance (P = .179, post hoc analysis). Clinically relevant effects of agomelatine were confirmed on all end points in the subset of severely depressed patients (HDRS17 total score ≥ 25 and CGI-S score ≥ 5 at baseline). Agomelatine was well tolerated by patients, with only minimal distinctions from placebo.

CONCLUSIONS

The present study provides the first evidence that an 8-week treatment with agomelatine 25-50 mg/d efficiently relieves depressive symptoms and is well tolerated in elderly depressed patients older than 65 years.

TRIAL REGISTRATION

Controlled-Trials.com identifier: ISRCTN57507360.

Cardiovascular Risk Profiles amongst Women in a Multiethnic Population in Inner City Britain: A Potential Impact of Anaemia

The risk of diabetes is markedly reduced in men with iron deficiency anaemia (IDA). The nature of this relationship in women is not clear, nor is there information about the influence of ethnicity, given the increased susceptibility of diabetes amongst South Asians and Afro-Caribbeans. We reviewed 3563 patients with a diagnosis of anaemia from 2000 to 2007. The age-adjusted prevalence of vitamin B12 deficiency and IDA was calculated, together with cardiovascular comorbidities amongst Caucasians, South Asians, and Afro-Caribbeans. The prevalence of vitamin B12 deficiency (women only) or IDA was markedly higher in South Asians compared to Caucasians and Afro-Caribbeans. Among women with IDA, diabetes was more prevalent among South Asians (45%, 95% CI 39.0-51.0) compared to Caucasians (3.0%, 2.1-4.0); P < 0.001. Among South Asian women with vitamin B12 deficiency, the prevalence of diabetes was reduced 8.5% (5.2-12.0). South Asian women with vitamin B12 deficiency had a higher prevalence of myocardial infarction (MI) and ischemic heart disease (IHD), but this relationship was reversed in IDA. IDA is associated with a greater prevalence of diabetes in South Asian women, but it is not coordinated by a greater risk of macrovascular complications. Given the cardiovascular impact of diabetes in South Asians, this association merits further study in relation to its pathophysiological implication.

Discovery by the Epistasis Project of an epistatic interaction between the GSTM3 gene and the HHEX/IDE/KIF11 locus in the risk of Alzheimer's disease

Despite recent discoveries in the genetics of sporadic Alzheimer's disease, there remains substantial "hidden heritability." It is thought that some of this missing heritability may be because of gene-gene, i.e., epistatic, interactions. We examined potential epistasis between 110 candidate polymorphisms in 1757 cases of Alzheimer's disease and 6294 control subjects of the Epistasis Project, divided between a discovery and a replication dataset. We found an epistatic interaction, between rs7483 in GSTM3 and rs1111875 in the HHEX/IDE/KIF11 gene cluster, with a closely similar, significant result in both datasets. The synergy factor (SF) in the combined dataset was 1.79, 95% confidence interval [CI], 1.35-2.36; p = 0.00004. Consistent interaction was also found in 7 out of the 8 additional subsets that we examined post hoc: i.e., it was shown in both North Europe and North Spain, in both men and women, in both those with and without the ε4 allele of apolipoprotein E, and in people older than 75 years (SF, 2.27; 95% CI, 1.60-3.20; p < 0.00001), but not in those younger than 75 years (SF, 1.06; 95% CI, 0.59-1.91; p = 0.84). The association with Alzheimer's disease was purely epistatic with neither polymorphism showing an independent effect: odds ratio, 1.0; p ≥ 0.7. Indeed, each factor was associated with protection in the absence of the other factor, but with risk in its presence. In conclusion, this epistatic interaction showed a high degree of consistency when stratifying by sex, the ε4 allele of apolipoprotein E genotype, and geographic region.

The role of variation at AβPP, PSEN1, PSEN2, and MAPT in late onset Alzheimer's disease

Rare mutations in AβPP, PSEN1, and PSEN2 cause uncommon early onset forms of Alzheimer's disease (AD), and common variants in MAPT are associated with risk of other neurodegenerative disorders. We sought to establish whether common genetic variation in these genes confer risk to the common form of AD which occurs later in life (>65 years). We therefore tested single-nucleotide polymorphisms at these loci for association with late-onset AD (LOAD) in a large case-control sample consisting of 3,940 cases and 13,373 controls. Single-marker analysis did not identify any variants that reached genome-wide significance, a result which is supported by other recent genome-wide association studies. However, we did observe a significant association at the MAPT locus using a gene-wide approach (p = 0.009). We also observed suggestive association between AD and the marker rs9468, which defines the H1 haplotype, an extended haplotype that spans the MAPT gene and has previously been implicated in other neurodegenerative disorders including Parkinson's disease, progressive supranuclear palsy, and corticobasal degeneration. In summary common variants at AβPP, PSEN1, and PSEN2 and MAPT are unlikely to make strong contributions to susceptibility for LOAD. However, the gene-wide effect observed at MAPT indicates a possible contribution to disease risk which requires further study.

Interactions between PPAR-α and inflammation-related cytokine genes on the development of Alzheimer's disease, observed by the Epistasis Project

OBJECTIVE

Neuroinflammation contributes to the pathogenesis of sporadic Alzheimer's disease (AD). Variations in genes relevant to inflammation may be candidate genes for AD risk. Whole-genome association studies have identified relevant new and known genes. Their combined effects do not explain 100% of the risk, genetic interactions may contribute. We investigated whether genes involved in inflammation, i.e. PPAR-α, interleukins (IL) IL- 1α, IL-1β, IL-6, and IL-10 may interact to increase AD risk.

METHODS

The Epistasis Project identifies interactions that affect the risk of AD. Genotyping of single nucleotide polymorphisms (SNPs) in PPARA, IL1A, IL1B, IL6 and IL10 was performed. Possible associations were analyzed by fitting logistic regression models with AD as outcome, controlling for centre, age, sex and presence of apolipoprotein ε4 allele (APOEε4). Adjusted synergy factors were derived from interaction terms (p<0.05 two-sided).

RESULTS

We observed four significant interactions between different SNPs in PPARA and in interleukins IL1A, IL1B, IL10 that may affect AD risk. There were no significant interactions between PPARA and IL6.

CONCLUSIONS

In addition to an association of the PPARA L162V polymorphism with the AD risk, we observed four significant interactions between SNPs in PPARA and SNPs in IL1A, IL1B and IL10 affecting AD risk. We prove that gene-gene interactions explain part of the heritability of AD and are to be considered when assessing the genetic risk. Necessary replications will require between 1450 and 2950 of both cases and controls, depending on the prevalence of the SNP, to have 80% power to detect the observed synergy factors.

Completed suicide, ideation and attempt in attention deficit hyperactivity disorder

OBJECTIVE

  Attention deficit hyperactivity disorder (ADHD) and suicidal behaviour are common conditions with significant social and emotional morbidity. Although completed suicide in ADHD has been assessed in a previous meta-analysis, other domains of suicidal behaviour such as attempts and ideation have been documented only in individual studies. This review provides a comprehensive summary of the relationship between attention-deficit and suicidality.

METHOD

  Electronic and manual literature search of MEDLINE, EMBASE and PSYCHINFO, using a range of search terms around suicidality, attention-deficit and hyperactivity.

RESULTS

  Twenty five papers were identified describing a relationship between ADHD and suicide. ADHD occurred more frequently in suicidal groups than controls, with most differences being statistically significant. The direction of results was consistent, with only one sample showing equivocal findings and one showing a reverse pattern. Attempts and ideation were more common in prediagnosed ADHD samples than controls. Three studies showed significant results only for men. Comorbidity had a large influence including delinquency and substance misuse.

CONCLUSION

  There is a positive relationship between ADHD and risk to self. More focussed research needs to take place on younger populations and those without comorbidity. This review highlights the importance of thorough risk assessment in the attention-deficit population.

Genome-wide association study of vascular dementia

BACKGROUND AND PURPOSE

Most studies investigating the genetics of dementia have focused on Alzheimer disease, but little is known about the genetics of vascular dementia. The aim of our study was to identify new loci associated with vascular dementia.

METHODS

We performed a genome-wide association study in the Rotterdam Study, a large prospective population-based cohort study in the Netherlands. We sought to replicate genome-wide significant loci in 2 independent replication samples.

RESULTS

In the discovery analysis of 5700 dementia-free individuals, 67 patients developed incident vascular dementia over a mean follow-up time of 9.3 ± 3.2 years. We showed genome-wide significance for rs12007229, which is located on the X chromosome near the androgen receptor gene (OR, 3.7; 95% CI, 2.3-5.8, per copy of the minor allele; P=1.3 × 10(-8)). This association was further confirmed in 2 independent populations (probability value of combined replication samples=0.024).

CONCLUSIONS

Our study shows a novel genetic locus for vascular dementia on the X chromosome. Further replication of this finding is required.

Interaction of insulin and PPAR-α genes in Alzheimer's disease: the Epistasis Project

Altered glucose metabolism has been described in Alzheimer's disease (AD). We re-investigated the interaction of the insulin (INS) and the peroxisome proliferator-activated receptor alpha (PPARA) genes in AD risk in the Epistasis Project, including 1,757 AD cases and 6,294 controls. Allele frequencies of both SNPs (PPARA L162V, INS intron 0 A/T) differed between Northern Europeans and Northern Spanish. The PPARA 162LL genotype increased AD risk in Northern Europeans (p = 0.04), but not in Northern Spanish (p = 0.2). There was no association of the INS intron 0 TT genotype with AD. We observed an interaction on AD risk between PPARA 162LL and INS intron 0 TT genotypes in Northern Europeans (Synergy factor 2.5, p = 0.016), but not in Northern Spanish. We suggest that dysregulation of glucose metabolism contributes to the development of AD and might be due in part to genetic variations in INS and PPARA and their interaction especially in Northern Europeans.

Alzheimer's disease and co-morbidity: increased prevalence and possible risk factors of excess mortality in a naturalistic 7-year follow-up

BACKGROUND

Subjects with late-onset Alzheimer's disease (AD) have to be sufficiently healthy to live long enough to experience and to be diagnosed with dementia in later life. In contrast, neurodegeneration and cognitive deficits in AD may increase the frequency of co-morbid disorders and their possible influence on mortality. Consequently, we investigated whether the pattern of co-morbidity and its relevance for later death differed between hospitalized AD and age-matched controls subjects.

METHODS

Co-morbid diseases with a prevalence of more than 1% at hospital admission were compared between 634 hospitalized AD and 72,244 control subjects aged above 70 years admitted to the University of Birmingham NHS Trust between 1 January 2000 to 31 December 2007. Risk factors, i.e. co-morbid diseases that were predictors of mortality within the 7-year follow-up, were identified and compared.

RESULTS

Subjects with AD suffer more eating disorders, infections, brain diseases and neck of femur fractures than other hospitalized elderly patients. In contrast, some cardiovascular diseases and diabetes mellitus were less prevalent in AD subjects in comparison with hospitalized controls. Diseases that might have contributed to later mortality in AD were pneumonia, ischemic heart disease and gastroenteritis, but there were no significant differences in their impact on mortality compared to other hospitalized elderly subjects with the same co-morbidities in multivariate logistic regression analyses.

CONCLUSION

Patients with AD have a different pattern of co-morbidity, but die from the same diseases as other hospitalized patients. Infections including pneumonia and diseases that may occur secondary to neurodegeneration and cognitive decline may need special attention in patients with AD who may not be able to identify or report the early symptoms. Preventive measures may be helpful to reduce the high risk and fatal consequences of undetected disease in AD.

Functional neuroanatomy of sustained memory encoding performance in healthy aging and in Alzheimer's disease

The aim of our study was to examine brain networks involved with sustaining memory encoding performance in healthy aging and in Alzheimer's disease (AD). Since different brain regions are affected by degradation in these two conditions, it might be conceivable that different compensation mechanisms occur to keep up memory performance in aging and in AD. Using an event-related functional magnetic resonance imaging (FMRI) design and a correlation analysis, 8 patients suffering from AD and 29 elderly control subjects were scanned while they studied a list of words for a subsequent memory test. Individual performance was assessed on the basis of a subsequent recognition test, and brain regions were identified where functional activations during study correlated with memory performance. In both groups, successful memory encoding performance was significantly correlated with the activation of the right frontal cortex. Furthermore, in healthy controls, there was a significant correlation of memory performance and the activation of the left medial and lateral temporal lobe. In contrast, in AD patients, increasing memory performance goes along with increasing activation of the hippocampus and a bilateral brain network including the frontal and temporal cortices. Our data show that in healthy aging and in AD, common and distinct compensatory mechanisms are employed to keep up a certain level of memory performance. Both in healthy aging and in patients with AD, an increased level of monitoring and control processes mediated by the (right) frontal lobe seems to be necessary to maintain a certain level of memory performance. In addition, memory performance in healthy older subjects seems to rely on an increased effort in encoding item-specific semantic and contextual information in lateral areas of the (left) temporal lobe. In AD patients, on the other hand, the maintenance of memory performance is related to an increase of activation of the (left) hippocampus in conjunction with a bilateral network of cortical areas that might be involved with phonological and visual rehearsal of the incoming information.

A multi-center study of ACE and the risk of late-onset Alzheimer's disease

A key pathological feature of late-onset Alzheimer's disease (LOAD) is the abnormal extracellular accumulation of the amyloid-β (Aβ) peptide. Thus, altered Aβ degradation could be a major contributor to the development of LOAD. Variants in the gene encoding the Aβ-degrading enzyme, angiotensin-1 converting enzyme (ACE) therefore represent plausible candidates for association with LOAD pathology and risk. Following Alzgene meta-analyses of all published case-control studies, the ACE variants rs4291 and rs1800764 showed significant association with LOAD risk. Furthermore ACE haplotypes are associated with both plasma ACE levels and LOAD risk. We tested three ACE variants (rs4291, rs4343, and rs1800764) for association with LOAD in ten Caucasian case-control populations (n = 8,212). No association was found using multiple logistic models (all p > 0.09). We found no population heterogeneity (all p > 0.38) or evidence for association with LOAD risk following meta-analysis of the ten populations for rs4343 (OR = 1.00), rs4291 (OR = 0.97), or rs1800764 (OR = 0.99). Although we found no haplotypic association in our complete dataset (p = 0.51), a significant global haplotypic p-value was observed in one population (p = 0.007) due to an association of the H3 haplotype (OR = 0.72, p = 0.02) and a trend towards an association of H4 (OR = 1.38, p = 0.09) and H7 (OR = 2.07, p = 0.08) although these did not survive Bonferroni correction. Previously reported associations of ACE variants with LOAD will be diminished following this study. At best, ACE variants have modest effect sizes, which are likely part of a complex interaction between genetic, phenotypic and pharmacological effects that would be undetected in traditional case-control studies.

Transferrin and HFE genes interact in Alzheimer's disease risk: the Epistasis Project

Iron overload may contribute to the risk of Alzheimer's disease (AD). In the Epistasis Project, with 1757 cases of AD and 6295 controls, we studied 4 variants in 2 genes of iron metabolism: hemochromatosis (HFE) C282Y and H63D, and transferrin (TF) C2 and -2G/A. We replicated the reported interaction between HFE 282Y and TF C2 in the risk of AD: synergy factor, 1.75 (95% confidence interval, 1.1-2.8, p = 0.02) in Northern Europeans. The synergy factor was 3.1 (1.4-6.9; 0.007) in subjects with the APOEε4 allele. We found another interaction, between HFE 63HH and TF -2AA, markedly modified by age. Both interactions were found mainly or only in Northern Europeans. The interaction between HFE 282Y and TF C2 has now been replicated twice, in altogether 2313 cases of AD and 7065 controls, and has also been associated with increased iron load. We therefore suggest that iron overload may be a causative factor in the development of AD. Treatment for iron overload might thus be protective in some cases.

Concordant association of insulin degrading enzyme gene (IDE) variants with IDE mRNA, Abeta, and Alzheimer's disease

Background

The insulin-degrading enzyme gene (IDE) is a strong functional and positional candidate for late onset Alzheimer's disease (LOAD).

Methodology/Principal Findings

We examined conserved regions of IDE and its 10 kb flanks in 269 AD cases and 252 controls thereby identifying 17 putative functional polymorphisms. These variants formed eleven haplotypes that were tagged with ten variants. Four of these showed significant association with IDE transcript levels in samples from 194 LOAD cerebella. The strongest, rs6583817, which has not previously been reported, showed unequivocal association (p = 1.5×10⁻⁸, fold-increase = 2.12,); the eleven haplotypes were also significantly associated with transcript levels (global p = 0.003). Using an in vitro dual luciferase reporter assay, we found that rs6583817 increases reporter gene expression in Be(2)-C (p = 0.006) and HepG2 (p = 0.02) cell lines. Furthermore, using data from a recent genome-wide association study of two Croatian isolated populations (n = 1,879), we identified a proxy for rs6583817 that associated significantly with decreased plasma Aβ40 levels (ß = −0.124, p = 0.011) and total measured plasma Aβ levels (b = −0.130, p = 0.009). Finally, rs6583817 was associated with decreased risk of LOAD in 3,891 AD cases and 3,605 controls. (OR = 0.87, p = 0.03), and the eleven IDE haplotypes (global p = 0.02) also showed significant association.

Conclusions

Thus, a previously unreported variant unequivocally associated with increased IDE expression was also associated with reduced plasma Aß40 and decreased LOAD susceptibility. Genetic association between LOAD and IDE has been difficult to replicate. Our findings suggest that targeted testing of expression SNPs (eSNPs) strongly associated with altered transcript levels in autopsy brain samples may be a powerful way to identify genetic associations with LOAD that would otherwise be difficult to detect.