Xiangfei Meng

Education and Dementia in the Context of the Cognitive Reserve Hypothesis: A Systematic Review with Meta-Analyses and Qualitative Analyses

Background Cognitive reserve (CR) or brain reserve capacity explains why individuals with higher IQ, education, or occupational attainment have lower risks of developing dementia, Alzheimer’s disease (AD) or vascular dementia (VaD). The CR hypothesis postulates that CR reduces the prevalence and incidence of AD or VaD. It also hypothesizes that among those who have greater initial cognitive reserve (in contrast to those with less reserve) greater brain pathology occurs before the clinical symptoms of disease becomes manifest. Thus clinical disease onset triggers a faster decline in cognition and function, and increased mortality among those with initial greater cognitive reserve. Disease progression follows distinctly separate pathological and clinical paths. With education as a proxy we use meta-analyses and qualitative analyses to review the evidence for the CR hypothesis. Methodology/Principal Findings We searched PubMed, PsycoINFO, EMBASE, HealthStar, and Scopus databases from January 1980 to June 2011 for observational studies with clear criteria for dementia, AD or VaD and education. One hundred and thirty-three articles with a variety of study designs met the inclusion criteria. Prevalence and incidence studies with odds ratios (ORs), relative risks or original data were included in the meta-analyses. Other studies were reviewed qualitatively. The studies covered 437,477 subjects. Prevalence and incidence studies with pooled ORs of 2.61 (95%CI 2.21–3.07) and 1.88 (95%CI 1.51–2.34) respectively, showed low education increased the risk of dementia. Heterogeneity and sensitivity tests confirmed the evidence. Generally, study characteristics had no effect on conclusions. Qualitative analyses also showed the protective effects of higher education on developing dementia and with clinical disease onset hastening a decline in cognition and function, and greater brain pathology. Conclusion/Significance This systematic review and meta-analyses covering a wide range of observational studies and diverse settings provides robust support for the CR hypothesis. The CR hypothesis suggests several avenues for dementia prevention.

Maltreatment in childhood substantially increases the risk of adult depression and anxiety in prospective cohort studies: systematic review, meta-analysis, and proportional attributable fractions

BACKGROUND Literature supports a strong relationship between childhood maltreatment and mental illness but most studies reviewed are cross-sectional and/or use recall to assess maltreatment and are thus prone to temporality and recall bias. Research on the potential prospective impact of maltreatment reduction on the incidence of psychiatric disorders is scarce. METHOD Electronic databases and grey literature from 1990 to 2014 were searched for English-language cohort studies with criteria for depression and/or anxiety and non-recall measurement of childhood maltreatment. Systematic review with meta-analysis synthesized the results. Study quality, heterogeneity, and publication bias were examined. Initial screening of titles and abstracts resulted in 199 papers being reviewed. Eight high-quality articles met eligibility criteria. Population attributable fractions (PAFs) estimated potential preventive impact. RESULTS The pooled odds ratio (OR) between any type of maltreatment and depression was 2.03 [95% confidence interval (CI) 1.37-3.01] and 2.70 (95% CI 2.10-3.47) for anxiety. For specific types of maltreatment and depression or anxiety disorders, the ORs were: physical abuse (OR 2.00, 95% CI 1.25-3.19), sexual abuse (OR 2.66, 95% CI 1.88-3.75), and neglect (OR 1.74, 95% CI 1.35-2.23). PAFs suggest that over one-half of global depression and anxiety cases are potentially attributable to self-reported childhood maltreatment. A 10-25% reduction in maltreatment could potentially prevent 31.4-80.3 million depression and anxiety cases worldwide. CONCLUSION This review provides robust evidence of childhood maltreatment increasing the risk for depression and anxiety, and reinforces the need for effective programs and policies to reduce its occurrence.

Common and unique risk factors and comorbidity for 12-month mood and anxiety disorders among Canadians.

Objective: To explore the common and unique risk factors for mood and anxiety disorders. What sociodemographic, psychological, and physical risk factors are associated with mood and anxiety disorders and their comorbidities? What is the impact of multiple risk factors? Method: Data from the Canadian Community Health Survey: Mental Health and Well-Being were analyzed. Appropriate sampling weights and bootstrap variance estimation were employed. Multiple logistic regression was used to estimate odds ratios and confidence intervals. Results: The annual prevalence of any mood disorder was 5.2%, and of any anxiety disorder 4.7%. Major depressive episode was the most prevalent mood and anxiety disorder (4.8%), followed by social phobia, panic disorder, mania, and agoraphobia. Among people with mood and anxiety disorders, 22.4% had 2 or more disorders. Risk factors common to mood and anxiety disorders were being young, having lower household income, being unmarried, experiencing greater stress, having poorer mental health, and having a medical condition. Unique risk factors were found: major depressive episode and social phobia were associated with being born in Canada; panic disorder was associated with being Caucasian; lower education was associated with panic and agoraphobia; and poor physical health was associated with mania and agoraphobia. People who were young, unmarried, not fully employed, and had a medical condition, greater stress, poorer self-rated mental health, and dissatisfaction with life, were more likely to have a comorbid mood and (or) anxiety disorder. As the number of common risk factors increases, the probability of having mood and anxiety disorders also increases. Conclusions: Common and unique risk factors exist for mood and anxiety disorders. Risk factors are additive in increasing the likelihood of disease.

Successful Aging in Canada: Prevalence and Predictors from a Population-Based Sample of Older Adults

Background: Little research has been conducted to thoroughly explore the prevalence and predicators of successful aging (SA) from a national point of view. Objectives: The objectives of this study were (1) to estimate the prevalence of SA as defined by Rowe and Kahn using a large population-based dataset and (2) to determine the roles of sociodemographic, psychological, and lifestyle factors in SA among Canadian seniors. Methods: Data was from the Canadian Community Health Survey: Healthy Aging (CCHS-HA) (n = 25,864) conducted in 2008-2009. Rowe and Kahns concept was used to measure SA. Descriptive analyses were used to estimate the prevalence of SA in those aged 45+ living in private dwellings in the ten provinces of Canada. Multivariate logistic regression was used to assess predicators of SA among those aged 65+ and having complete data on cognition. Results: The prevalence of SA was 50.1% among those aged 50+, then decreased to 46.2% for those aged 55+, 42.0% for those aged 60+, and 37.2% among those aged 65+. Assuming those 65+ living in institutions as unsuccessful agers, then the prevalence of SA was 35.3% among Canadian seniors aged 65+. There were no differences in prevalence rate of SA between males and females. We did not find higher income associated with SA. Being younger, married, regular drinkers, exercisers, perceived better health, satisfied with life, and taking calcium in the past month were associated with SA. The predicted probability of being a successful ager was 41% for those aged 65-74 years, 33% for 75-84 years, and 22% for those 85+ years, while controlling for other covariates. Presence of disease led to a major decline in SA, levels of functioning and engagement in contrast remained relatively constant. Conclusion: Over one third of the seniors in Canada met the criteria for SA, largely because the operationalization of the definition only considered severe chronic diseases that may not be well managed and thus likely to result in functional impairment. The modifiable risk factors identified provide direction for prevention efforts to increase SA at a population level.

Apolipoprotein E gene, environmental risk factors, and their interactions in dementia among seniors

Little research has been conducted to explore the joint effect of apolipoprotein E (ApoE) genotypes and environmental risk factors on dementia. In this study, we examined the roles of ApoE alleles and genotypes in dementia and cognitively impaired not demented (CIND), assessed the risk of co‐existing or prior health conditions (i.e. depression), family history of diseases, and lifestyle factors on dementia, and explored the interactions between genetic and environmental risk factors and their joint effects on dementia and cognitive impairment.

Genetic association between BDNF gene polymorphisms and phobic disorders: A case–control study among mainland Han Chinese

INTRODUCTION Phobic disorders are a common group of syndromes comprising persistently recurring, irrational severe anxiety of specific objects, activities, or situations with avoidance behavior of the phobic stimulus. The present study investigated the association between whole region polymorphisms, (including the Val66Met variant), in the BDNF gene and phobic disorders among Han Chinese young adults. METHODS We conducted a case-control study to investigate the genetic association between BDNF polymorphisms and phobic disorders among mainland Chinese. One hundred and twenty young adults with phobic disorders and 267 matched controls were recruited. Three tag SNPs of BDNF were successfully genotyped by using PCR-based ligase detection reaction (PCR-LDR). RESULTS We found significant differences in allele distributions of SNP rs10835210 (P<0.001) between the experimental and the control groups. In the haplotype analysis based on linkage-disequilibrium across this gene locus, we demonstrated significant association between phobic disorders and BDNF haplotype CAC (P=0.004). Association was significant after 10(4) permutation tests (P<0.001). CONCLUSION To the best of our knowledge, this is the first study showing that the BDNF gene may play a significant role in the etiology of phobic disorders in the Han Chinese population.

Long-term trend in pediatric antidepressant use, 1983-2007: a population-based study.

Objective: Research is needed to clarify and improve our understanding of appropriateness and safety issues concerning antidepressant (AD) treatment. We explored the long-term trend in the dispensing of pediatric ADs using provincial, population-based data from Canada. Methods: Data covering 22 ADs were drawn from the Saskatchewan Ministry of Health administrative data files in outpatient settings. The data were for 9 triennial years from 1983 to 2007, a 24-year period, for those aged 0 to 19 in the general population. Descriptive analyses were used. Results: In 1983, 5.9 per 1000 population aged 0 to 19 were dispensed at least 1 AD; this decreased to 5.1 per 1000 population in 1989, and then increased to 15.4 per 1000 population in 2007, with a slower increase after 2004. Both sexes were dispensed more ADs from 1989 onwards, with females being the heavier users. The rate of AD use increased significantly with age, and this trend became more pronounced after 1998. Family physicians were the major prescribers and their prescriptions significantly increased from 1989 to 2004 and decreased in 2007. The use of selective serotonin reuptake inhibitors (SSRIs) was the major reason for the increase. The number of AD scripts per patient also increased. Conclusions: The growth in the prevalence of AD use among children and youth was largely caused by the use of SSRIs. The possibility of safety issues induced by AD use among children and adolescents, and different patterns of medication practice, suggest continuing education is warranted.

When social anxiety and depression go together: A population study of comorbidity and associated consequences

BACKGROUND Despite several studies suggesting higher depression severity and dysfunction occurring in individuals with major depressive disorder (MDD) comorbid with social anxiety disorder (SAD), a clear understanding of the specific risks associated with this comorbidity is lacking. In this study we compared the disease characteristics and level of disability of individuals with MDD-SAD with other comorbidities between depression and anxiety. METHODS Data from the Collaborative Psychiatric Epidemiology Surveys (CPES) (N=20,013) were used. Individuals were divided in four groups comparing MDD-SAD with MDD alone, as well as other comorbidities between MDD and one anxiety (MDD-1ANX) or more than two anxiety disorders (MDD≥2ANX), with respect to several clinical, demographic, and functional characteristics. RESULTS MDD-SAD comorbidity in the general population occurred in younger people, particularly men, and seemed to have an earlier onset of MDD. Occupational and social dysfunction was similar between individuals with MDD-SAD and those with MDD-1ANX. However, individuals with MDD≥2ANX had significantly higher severity as measured by suicidality as well as substance abuse and social and occupational dysfunction. SAD was the most prevalent comorbid anxiety in this group. LIMITATIONS The findings of this study were derived from the cross-sectional data. CONCLUSION Our results suggest that the particular risks associated with MDD-SAD are the early onset and likelihood of additional anxiety, leading to higher severity and disability levels. Clinicians should increase the screening and treatment of SAD and other anxiety disorders in individuals with MDD given the higher associated health risk and functional impairment.

Trends in psychotropic use in Saskatchewan from 1983 to 2007.

Objective: There has been little research reported on trends in the use of a full spectrum of psychotropics in a general population. We provide an overview of trends in psychotropic use over a 24-year period for Saskatchewan. Methods: Data were drawn from the Saskatchewan Ministry of Health administrative data files. It covers antidepressants (ADs), antipsychotics, mood stabilizers, anxiolytics, stimulants, and cholinesterase inhibitors in outpatient settings. We analyzed data from 9 triennial years from 1983 to 2007. Descriptive statistics were used. Results: Among the Saskatchewan population in our study, 8.38% were prescribed at least 1 psychotropic in 1983. The prevalence decreased to 7.44% in 1989, then gradually increased to 12.90% in 2007. We found a continuous increase in the number of psychotropic prescriptions for both males and females. The trend became more marked during the 1990s. Females used more psychotropics. Family physicians were the major prescribers, and their prescriptions dramatically increased over the period. There was an increase in the prescribing of all psychotropics except for anxiolytics. AD prescriptions dramatically increased, especially from 1995 onward. The proportion of patients with 8 to 11 and 12 or more prescriptions per year also gradually increased, whereas the proportion of patients with less than 3 prescriptions per year decreased. Conclusions: AD prescriptions are the major reason for the increasing trend of psychotropic use. Given the major role of family physicians in the use of psychotropics, the need for appropriate training and continuing education is reinforced.

Comorbidity Between Lifetime Eating Problems and Mood and Anxiety Disorders: Results from the Canadian Community Health Survey of Mental Health and Well-being

This study was to examine profiles of eating problems (EPs), mood and anxiety disorders and their comorbidities; explore risk patterns for these disorders; and document differences in health service utilization in a national population. Data were from the Canadian Community Health Survey of Mental Health and Well-being. The lifetime prevalence of EPs was 1.70% among Canadians, compared with 13.25% for mood disorder, 11.27% for anxiety disorder and 20.16% for any mood or anxiety disorder. Almost half of those with EPs also suffered with mood or anxiety disorders. A similar pattern in depressive symptoms was found among individuals with major depression and EPs, but individuals with EPs reported fewer symptoms. Factors associated with the comorbidity of EPs and mood and anxiety disorders were identified. Individuals with EPs reported more unmet needs. Patients with EPs should be concomitantly investigated for mood and anxiety disorders, as similar interventions may be effective for both.