Influence of BDNF Val66Met genetic polymorphism in Major Depressive Disorder and Body Mass Index: Evidence from a meta-analysis of 6481 individuals

BACKGROUND

Major depressive disorder (MDD) and obesity are global health problems that frequently co-occur. Among shared etiological factors, genetic variation at the brain-derived neurotrophic factor (BDNF) gene is interesting since its implication in energy balance regulation, food intake and synaptic function. Thus, the aim of this study was to investigate the influence of the BDNF Val66Met polymorphism in relation to MDD and body mass index (BMI) in two large independent cohorts.

METHODS

The sample consisted of 2646 individuals with MDD and 3835 controls from the PISMA-ep and Radiant studies. Linear regressions were performed to test the association between the polymorphism and BMI and the interaction between the polymorphism and MDD on BMI. A meta-analysis across cohorts was conducted.

RESULTS

No association was found between the polymorphism and BMI. However, we found an association with MDD, showing these individuals higher BMI than controls in both cohorts. No differences were found in BMI depending on Val66Met genotype and no interaction between this polymorphism and MDD in relation to BMI was found. Although a tendency towards an interaction was found in the Radiant sample, the results of the meta-analysis did not support this finding.

LIMITATIONS

The use of self-reported height and weight measures to calculate BMI values.

CONCLUSIONS

We provide evidence for an association between BMI and MDD confirming previous results. Our meta-analysis including two large cohorts showed no interaction between BDNF, BMI and MDD. Future studies will be needed to confirm the role of this polymorphism in the relationship between BMI and MDD.

Unexplained pain complaints and depression in older people in primary care

OBJECTIVE

Chronic pain and depression are frequent conditions in primary care patients. Depression is frequently overlooked in the presence of pain of uncertain origin. The aim is to measure the prevalence and clinical correlates of unrecognized comorbid mood disorders and chronic pain of uncertain origin in older primary care patients, and to elucidate the differences with younger adults with the same conditions.

DESIGN

Cross-sectional study.

SETTING

Primary care centres in Spain.

PARTICIPANTS

Patients (n= 2720) with persistent pain of uncertain origin.

MEASUREMENTS

Pain characteristics, sites and intensity (Visual Analogical Scales), depression (PRIME-MD interview), clinical characteristics and health services use.

RESULTS

We observed a similarly high (80.5%) prevalence of undiagnosed mood disorders (especially major depressive disorders) among older and younger adult patients with comorbid chronic pain complaints of uncertain origin. Older patients suffered pain that was more intense, longer lasting and located in a higher number of different areas, when compared to younger patients. Pain intensity was a factor associated with suffering from mood disorders among patients above 65 years, whilst the number of pain sites was a more important factor among younger patients.

CONCLUSIONS

Depression is highly associated with pain of uncertain origin in older patients with differences in pain characteristics when compared to younger patients. The robust comorbid relationship between both conditions should alert clinicians to specifically look for depression in the presence of poorly explained painful symptoms.

Predicting the onset of major depression in primary care: international validation of a risk prediction algorithm from Spain

BACKGROUND

The different incidence rates of, and risk factors for, depression in different countries argue for the need to have a specific risk algorithm for each country or a supranational risk algorithm. We aimed to develop and validate a predictD-Spain risk algorithm (PSRA) for the onset of major depression and to compare the performance of the PSRA with the predictD-Europe risk algorithm (PERA) in Spanish primary care.

METHOD

A prospective cohort study with evaluations at baseline, 6 and 12 months. We measured 39 known risk factors and used multi-level logistic regression and inverse probability weighting to build the PSRA. In Spain (4574), Chile (2133) and another five European countries (5184), 11 891 non-depressed adult primary care attendees formed our at-risk population. The main outcome was DSM-IV major depression (CIDI).

RESULTS

Six variables were patient characteristics or past events (sex, age, sex×age interaction, education, physical child abuse, and lifetime depression) and six were current status [Short Form 12 (SF-12) physical score, SF-12 mental score, dissatisfaction with unpaid work, number of serious problems in very close persons, dissatisfaction with living together at home, and taking medication for stress, anxiety or depression]. The C-index of the PSRA was 0.82 [95% confidence interval (CI) 0.79-0.84]. The Integrated Discrimination Improvement (IDI) was 0.0558 [standard error (s.e.)=0.0071, Zexp=7.88, p<0.0001] mainly due to the increase in sensitivity. Both the IDI and calibration plots showed that the PSRA functioned better than the PERA in Spain.

CONCLUSIONS

The PSRA included new variables and afforded an improved performance over the PERA for predicting the onset of major depression in Spain. However, the PERA is still the best option in other European countries.

The risk for depression conferred by stressful life events is modified by variation at the serotonin transporter 5HTTLPR genotype: evidence from the Spanish PREDICT-Gene cohort

We report results from the PREDICT-Gene case-control study nested in a prospective cohort designed to identify predictors of the onset of depression among adult primary-care attendees. We tested the potential gene-by-environment interaction between 5HTTLPR genotype at the serotonin transporter gene and previous exposure to threatening life events (TLEs) in depression. A total of 737 consecutively recruited participants were genotyped. Additional information was gathered on exposure to TLEs over a 6-month period, socio-demographic data and family history of psychological problems among first-degree relatives. Diagnoses of depression were ascertained using the Composite International Diagnostic Interview (CIDI) by trained interviewers. Two different depressive outcomes were used (ICD-10 depressive episode and ICD-10 severe depressive episode). Both the s/s genotype and exposure to increasing number of TLEs were significantly associated with depression. Moreover, the 5HTTLPR s/s genotype significantly modified the risk conferred by TLEs for both depressive outcomes. Thus, s/s homozygous participants required minimal exposure to TLE (1 TLE) to acquire a level of risk for depression that was only found among l/s or l/l individuals after significantly higher exposure to TLEs (two or more TLEs). The interaction was more apparent when applied to the diagnosis of ICD-10 severe depressive episode and after adjusting for gender, age and family history of psychological problems. Likelihood ratios tests for the interaction were statistically significant for both depressive outcomes (ICD-10 depressive episode: LR X(2)=4.7, P=0.09 (crude), LR-X(2)=6.4, P=0.04 (adjusted); ICD-10 severe depressive episode: LR X(2)=6.9, P=0.032 (crude), LR-X(2)=8.1, P=0.017 (adjusted)).

Does depression predict cognitive outcome 9 to 12 years later? Evidence from a prospective study of elderly hypertensives

BACKGROUND

Previous longitudinal studies of the association between depression and cognitive dysfunction have had relatively short follow-up periods. This report presents a long-term study of the association between baseline syndromal depression and cognitive outcome measured 9 to 12 years later.

METHODS

Self-CARE (D) depression, cognitive function and pre-morbid intelligence were recorded on 1083 subjects on entry to the Medical Research Council trial of treatment of hypertension in older adults in 1983-5. In 1994-5, we aimed to re-interview all survivors to assess cognitive function using the MMSE. We used multivariate analysis to explore whether baseline depression predicted cognitive outcome after this long follow-up period.

RESULTS

Baseline depression was crudely associated with poorer cognitive outcome at time 2. However, this long-term prospective association was no longer apparent after adjusting for baseline cognitive performance, which was associated with baseline depression and robustly predicted cognitive outcome at time 2. We found that gender modified the association between depression and poorer cognitive outcome, so that the association was statistically significant only among men.

CONCLUSION

Propensity for depression and failing cognition may have common determinants that still need to be established by future neurobiological investigations in conjunction with further long-term prospective epidemiological research.

Long-term predictors of cognitive outcome in a cohort of older people with hypertension

BACKGROUND

Deteriorating cognitive function in late life substantially increases the risk for dementia, for other non-cognitive morbidity, for dependency, and early death.

AIMS

To identify early predictors of late-life cognitive outcome.

METHOD

Cognitive function, premorbid IQ, and cardiovascular risk exposure were recorded on 1083 subjects on entry to a hypertension treatment trial in 1983-1984. We followed up this cohort 9-12 years later to assess cognitive function with the Mini-Mental State Examination (MMSE), to update exposure status, and to obtain genomic material. Multivariate analysis was used to identify independent baseline predictors of cognitive outcome 9-12 years later.

RESULTS

We followed up 387 subjects (58.6% of survivors). After adjusting for baseline cognition, poorer cognitive outcome was found to be independently associated with a family history of dementia, increasing age, less decline in systolic blood-pressure, lower premorbid IQ (rather than limited education), and abstinence from alcohol.

CONCLUSIONS

Reduction in systolic blood pressure (among hypertensives) and moderate alcohol intake could protect against cognitive deterioration in late life.

Smoking, drinking, and incident cognitive impairment: a cohort community based study included in the Gospel Oak project

OBJECTIVES

Recent longitudinal studies have reported that smoking increases risk for cognitive impairment and that moderate alcohol intake could be preventive. The association between both cigarette smoking and alcohol drinking and incident cognitive impairment was studied in a representative population.

METHODS

This is a 1 year prospective population based cohort study of all residents aged 65 or over in the electoral ward of Gospel Oak in London, UK (n=889). Cognitive impairment was assessed at baseline and 1 year later using the organic brain syndrome (OBS) cognitive impairment scale from the short CARE structured assessment. Subjects who were cognitively impaired at baseline were excluded from this analysis.

RESULTS

The prevalence of OBS cognitive impairment was 10.4% at index assessment and the 1 year cumulative incidence of cognitive impairment was 5.7%. Cognitive impairment was not associated with use of alcohol, although there was a non-significant association in the direction of a protective effect against onset of cognitive impairment for moderate drinkers compared with non-drinkers and heavy drinkers. Current smoking status predicted cognitive impairment (risk ratio (RR) 3.7; (95% confidence interval (95% CI)=1.1-12.3) independently from sex, age, alcohol, occupational class, education, handicap, depression, and baseline cognitive function.

CONCLUSIONS

Smoking seems to be a prospective risk factor for incident cognitive impairment; thus encouragement of older people to stop smoking could be considered as part of a strategy to reduce the incidence of cognitive impairment.

CYP2D6 polymorphisms in Alzheimer's disease, with and without extrapyramidal signs, showing no apolipoprotein E epsilon 4 effect modification

BACKGROUND

Allelic variation at the CYP2D6 gene has been reported to be associated with Parkinsons' disease (PD) and Lewy body dementia (LBD), but not with Alzheimer's disease (AD). AD has been associated with apolipoprotein E (apoE) epsilon 4 allele loading.

METHODS

We examined CYP2D6 and apoE polimorphisms in a sample of 259 patients with dementia, 210 of whom had a diagnosis of AD, and 107 healthy controls.

RESULTS

We found that the allelic frequency in our AD sample did not vary from that in the controls. The debrisoquine hydroxylase poor metabolize phenotype was not more prevalent among AD cases than among controls in contrast to that reported for PD and LBD. We also found that CYP2D6 status does not modify the risk effect for AD conferred by apoE epsilon 4 alleles.

CONCLUSIONS

These findings provide some support to the notion that, at a genetic level, at least at this locus, AD could be distinct from PD and LBD.

Munchausen's syndrome

Munchausen's syndrome has been acknowledged for many years, receiving the name in 1951. In this article, the prevalence, patient characteristics, clinical presentations, possible concurrent conditions, aetiological factors, differential diagnosis, management and cost (to the patients and NHS) will be discussed.

Cognitive impairment and social distress as different pathways to depression in the elderly: a cross-sectional study

BACKGROUND

This study investigates the recent suggestion that some putative aetiological factors for depression, such as cerebral deterioration and social distress, may act differentially in the aetiology of depression in old age.

METHOD

In a cross-sectional study, a community sample of 654 elderly subjects were interviewed with Short-CARE to assess the prevalence of depression and cognitive impairment. Information was collected for a variety of potential risk factors for depression such as exposure to social support deficit, threatening life events, impairment, disability and handicap.

RESULTS

The prevalence of depression was 17% and that of a broad concept of cognitive impairment 23.9%. This analysis found associations between depression and exposure to social support deficits and threatening life events in the year prior to interview. These associations were considerably stronger for those subjects with no cognitive impairment than for those with cognitive impairment. We also found a progressive lowering in the strength of these associations the higher the chance of cognitive impairment measured as a longitudinal variable using both the Dementia Diagnostic Scale (DDS) and the Organic Brain Syndrome Scale (OBS) included in Short-CARE.

CONCLUSIONS

The results of this theory-driven analysis lend some support to the notion of at least two differential pathways to depression in the elderly, one via social distress factors and another mediated by cerebral deterioration clinically expressed as cognitive impairment.

[Depression and cognitive deterioration: a transversal study of comorbidity]

This cross-sectional study investigates the relation between a broad category of cognitive impairment and depression in a sample of 654 subjects aged 65 or over. This sample represents 74% of all subjects of that age living in a defined electoral district in North London, UK. The presence of depression and cognitive impairment was ascertained by interviewing all subjects with Short-CARE. Information was collected also for a variety of socto-demographic factors, level of social support and variables of functional limitation (i.e., impairment, disability and handicap). We found a cross-sectional association between depression and cognitive impairment (OR = 3.3; 95% CI: 2.1-3.1). However, when the analysis was adjusted for potential confounders using stratified analysis and logistic regression, we found that variables of functional limitation (especially disability and handicap) acted as confounders of the above association. This confounding effect did not differ significantly across sexes in our study.