Coffee and depression in Korea: the fifth Korean National Health and Nutrition Examination Survey

Risk and protective factors for severe mental disorders in Asia

Among 369 diseases and injuries, the years lived with disability (YLDs) and disability-adjusted life-years (DALYs) rates for severe mental illnesses (SMIs) are within the top 20 %. Research on risk and protective factors for SMIs is critically important, as acting on modifiable factors may reduce their incidence or postpone their onset, while early detection of new cases enables prompt treatment and improves prognosis. However, as most of the studies on these factors are from Western countries, the findings are not generalizable across ethnic groups. This led us to conduct a systematic review of the risk and protective factors for SMIs identified in Asian studies. There were common factors in Asian and Western studies and unique factors in Asian studies. In-depth knowledge of these factors could help reduce disability, and the economic and emotional burden of SMIs. We hope that this review will inform future research and policy-making on mental health in Asian countries.

Chlorogenic Acids, Acting via Calcineurin, Are the Main Compounds in Centella asiatica Extracts That Mediate Resilience to Chronic Stress in Drosophila melanogaster

Common symptoms of depressive disorders include anhedonia, sleep problems, and reduced physical activity. Drugs used to treat depression mostly aim to increase serotonin signaling but these can have unwanted side effects. Depression has also been treated by traditional medicine using plants like Centella asiatica (CA) and this has been found to be well tolerated. However, very few controlled studies have addressed CA's protective role in depression, nor have the active compounds or mechanisms that mediate this function been identified. To address this issue, we used Drosophila melanogaster to investigate whether CA can improve depression-associated symptoms like anhedonia and decreased climbing activity. We found that a water extract of CA provides resilience to stress induced phenotypes and that this effect is primarily due to mono-caffeoylquinic acids found in CA. Furthermore, we describe that the protective function of CA is due to a synergy between chlorogenic acid and one of its isomers also present in CA. However, increasing the concentration of chlorogenic acid can overcome the requirement for the second isomer. Lastly, we found that chlorogenic acid acts via calcineurin, a multifunctional phosphatase that can regulate synaptic transmission and plasticity and is also involved in neuronal maintenance.

Association between dietary caffeine, coffee, and tea consumption and depressive symptoms in adults: A systematic review and dose-response meta-analysis of observational studies

Background

Recent studies have reported an association between dietary caffeine intake (coffee and tea) and the presence of depressive symptoms. However, the findings are not conclusive.

Purpose

This study aimed to examine the correlation between the consumption of dietary caffeine (coffee and tea) and the presence of depressive symptoms in adults.

Methods

PubMed and Scopus databases were searched until December 2021. Two investigators analyzed data from identified studies and rated the quality of the evidence using the GRADE approach. Using the random-effects models, we estimated the relative risks (RRs) and 95% confidence intervals (CIs). We also modeled the dose-response associations through a one-stage, weighted mixed-effects meta-analysis.

Results

A total of 29 eligible studies included a total of 422,586 participants. On comparing the highest with the lowest category in cohort studies, we identified an inverse association between the intake of coffee and depressive symptoms (RR: 0.89, 95%CI: 0.82-0.95; I² = 63.7%, GRADE = low). There was a 4% reduction in the risk of depression associated with an increase in coffee intake of 240 ml/day (RR: 0.96, 95%CI: 0.95, 0.98; I² = 22.7%). By comparing the highest category with the lowest category in cohort studies, we discovered that caffeine intake was inversely associated with depressive symptoms (RR: 0.86, 95%CI: 0.79, 0.93; I² = 0.0%, GRADE = moderate). Based on our data analysis, no correlation exists between tea consumption and depressive symptoms.

Conclusion

According to our findings, coffee and dietary caffeine may have a protective effect against the development of depression. However, no evidence suggesting a link between tea consumption and reduced depressive symptoms has been found. Therefore, further longitudinal studies are needed to substantiate the causal relationship between coffee, tea, and caffeine and the risk of depression.

Dietary diversity, physical activity and depressive symptoms among middle-aged women: A cross-sectional study of 48,637 women in China

OBJECTIVE

Depression is the leading cause of mental health-related disease burden. This study aimed to investigate the relationship among dietary diversity, physical activity and depressive symptoms in middle-aged women.

METHOD

Based on the WHO guidelines on physical activity, subjects who meet moderate-intensity aerobic physical exercise of 150-300 min per week were qualified or otherwise unqualified. The dietary diversity scores (DDS) were developed according to the balanced diet pagoda and assessed the consumption of nine food groups. The total scores ranged from 0 to 9 and could divide into three levels: insufficient [DDS-1] (score of 1-5), moderate [DDS-2] (score of 6-7), and sufficient [DDS-3] (score of 8-9).

RESULTS

An age at menarche ≥12 years old (OR = 0.94; 95 % CI: 0.89-1.00; p < 0.05), a higher dietary diversity score [DDS-3] (OR = 0.59; 95 % CI: 0.55-0.63; p < 0.001), drinking coffee (OR = 0.88; 95 % CI: 0.84-0.92; p < 0.001), and qualified physical activity (OR = 0.69; 95 % CI: 0.66-0.72; p < 0.001) were protective factors for depressive symptoms, while an age at first birth ≤20 years old (OR = 1.23; 95 % CI: 1.12-1.36; p < 0.001) or ≥30 years old (OR = 1.18; 95 % CI: 1.11-1.26; p < 0.001), eating late-night snacks (OR = 1.44; 95 % CI: 1.36-1.52; p < 0.001), drinking sugar-sweetened beverages (OR = 1.15; 95 % CI: 1.06-1.24; p < 0.001), and overeating (OR = 2.30; 95 % CI: 2.069-2.56; p < 0.001) were risk factors.

CONCLUSION

This study suggested that dietary diversity and physical activity are associated with depressive symptoms in middle-aged women. To improve dietary diversity, attention should be given to dietary patterns and dietary habits, instead of simply increasing the amount of food.

Depression and Associated Factors Among the Elderly Population in an Urban Tertiary Geriatric Hospital in Bangladesh

Background: Geriatric depression becoming a serious concern worldwide, but no studies addressed depression among patients attending outpatient department of a tertiary geriatric care hospital in Bangladesh. Methods: This cross-sectional study was conducted in face-to-face interview using the Geriatric Depression Scale (GDS-15) to measure depression among 230 elderly outpatients (60-80 years old) who visited the hospital for medical reasons in Dhaka city; a variety of socio-demographic, behavioral, and psycho-social variables as well as history of chronic diseases were assessed to detect factors associated with depression. Results: The prevalence of depression was 81.7%; 52.6%, 25.2%, and 3.9% showed mild, moderate and severe depression (the GDS scores 5-8, 9-11, and 12-15), respectively. In logistic regression models, the associated factors included marital status, occupational status, educational status, physical activity, and history of cerebrovascular diseases or stroke. The prevalence of depression was generally higher than other reports elsewhere, and the reason behind this may include the use of the GDS-15 and the setting to carry out this study. Conclusion: Nationally representative investigations are warranted to further address depression among the elderly in Bangladesh; these findings would be helpful for future studies and intervention programs.

Higher dietary phytochemical index is associated with lower odds of knee osteoarthritis

Previous studies have shown that adherence to dietary patterns rich in plant-based foods may reduce the odds of osteoarthritis; however, limited data are available on the association of consumption of diets rich in phytochemicals and odds of knee osteoarthritis (KOA). In this case–control study conducted in Iran, we aimed to investigate whether a higher dietary phytochemical index (DPI) is associated with decreased odds of having KOA. A total of 124 cases aged 20–60 years diagnosed with bilateral primary KOA according to the American College of Rheumatology criteria and 124 controls frequency-matched on age, sex, and body mass index (BMI) were included in the study. A validated food frequency questionnaire (FFQ) was used to collect information on dietary intakes. To calculate DPI scores, the dietary energy derived from foods rich in phytochemicals (kcal) was divided by the participant’s total daily energy intake (kcal). Patients with KOA had lower intakes of dietary fiber (P = 0.004), vitamin A (P = 0.007), vitamin C (P = 0.001), and folate (P = 0.021) compared to controls. In the crude model, individuals in the third tertile of DPI had 65% lower odds of having KOA compared to those in the first tertile (OR 0.35, 95% CI 0.19 to 0.67, P-trend = 0.001). After adjustment for potential confounders, including age, sex, physical activity, smoking, and supplement use, this inverse association remained significant (OR 0.37, 95% CI 0.19 to 0.73, P-trend = 0.004). After further adjustment for BMI, this inverse association between DPI and odds of KOA also remained significant (OR 0.35, 95% CI 0.18 to 0.69, P-trend = 0.003). These findings suggest that adherence to a phytochemical-rich diet, as indicated by the increasing DPI score, is associated with lower odds of KOA.

Coffee and caffeine intake in relation to symptoms of psychological disorders among adults

OBJECTIVE

Given that there is an inconsistency in the findings related to the relationship between coffee and caffeine consumption and symptoms of psychological disorders, we performed a cross-sectional analysis to examine the association between coffee and caffeine intake and symptoms of psychological disorders among adults.

DESIGN

In this cross-sectional study, 3362 participants were included. We assessed the coffee and caffeine intakes using a self-completed food frequency questionnaire (FFQ). Symptoms of depression, anxiety, and psychological distress were assessed using HADS and GHQ screening tools.

RESULTS

The mean age of participants in this study was 36.2±7.8 years. After controlling for potential confounders, individuals who consumed coffee weekly or more had a significantly lower odds of symptoms of depression (OR: 0.67; 95% CI: 0.46-0.96) and symptoms of anxiety (OR: 0.57; 95% CI: 0.34-0.95) compared with those who did not consume coffee. However, no significant association was found between coffee intake and symptoms of psychological distress (OR: 0.98; 95%CI: 0.68-1.42). No significant relationship was found between caffeine intake and odds of symptoms of depression (OR: 0.94; 95% CI: 0.75-1.16), symptoms of anxiety (OR: 0.90; 95% CI: 0.67-1.20), and symptoms of psychological distress (OR: 1.13; 95% CI: 0.89-1.42).

CONCLUSION

Compared with lack of coffee intake, weekly or more coffee consumption might be correlated with symptoms of depression and anxiety.

Effects of black tea consumption and caffeine intake on depression risk in black tea consumers

BACKGROUND

The aim of this study was to compare black tea consumption and caffeine intake with depression status.

SUBJECTS AND METHODS

This study was conducted on 491 adults (M:169, F:322). The average daily caffeine intake of individuals was calculated using the amounts of caffeinated beverages they consumed daily and the caffeine contents of these beverages. The participants' depression status was determined using the Beck Depression Inventory (BDI). All of the research data were evaluated using STATA.

RESULTS

According to BDI scores, 30.1% of participants had depression. Black tea was consumed by all of the participants and also had the highest consumption level of 620.1±90.4mL and the mean caffeine intake of the participants was 629.5±418.8 mg. Multivariate regression analyses showed that consuming more than 1 cup was protective against depression up to 4 cups. Moreover, a 450-600 mg caffeine intake also reduces the risk of depression than lower or higher intake levels.

CONCLUSION

Our study suggests that black tea consumption up to 4 cups and caffeine intake between 450-600 mg can help protect against depression. Further studies are needed to better understand the protective effects of black tea and caffeine on depression.

Dietary phytochemical index in relation to risk of glioma: a case-control study in Iranian adults

BACKGROUND & AIM

No study is available that explores the association of dietary phytochemical index (DPI) with glioma. The objective of the current study was to assess this association in Iranian adults.

METHODS

This hospital-based case-control study included 128 newly-diagnosed cases of glioma and 256 age- and sex-matched controls. Data collection on dietary intakes was done using a 123-item validated food frequency questionnaire. Calculation of DPI was done as (dietary energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)) × 100. Logistic regression models were used to examine the association between DPI and glioma.

RESULTS

Individuals in the top tertile of DPI were more likely to be older and female. Before taking potential confounders into account, subjects in the top tertile of DPI tended to have a 40% reduced chance of glioma than those in the bottom tertile (OR: 0.60; 95% CI: 0.35-1.02, P = 0.06). After controlling for age, sex, energy intake, several demographic variables and dietary intakes, the association between DPI and glioma became strengthened (OR: 0.43; 95% CI: 0.19-0.97, P = 0.04).

CONCLUSION

High intakes of phytochemical-rich foods were associated with a lower risk of glioma in adults. High consumption of phytochemical-rich foods might be recommended to prevent glioma. However, further studies with a prospective design are needed to confirm our findings.

Complex effect of caffeine and dioxidine on behavioral responses in mice in Porsolt test

Relevance. In light of the popularization of the use of caffeine-containing products, the question of the combined use of caffeine with substances exhibiting a toxic effect remains open. The doses of caffeine, which have a pronounced antidepressant effect, are also insufficiently studied. The aim of the study was to study the effect of repeated administration of caffeine and dioxidine on the behavioral responses of mice in the Porsolt test. Materials and methods. The experiment was carried out on 36 outbred male mice, divided into 6 groups. Experimental groups for 15 days of the study received caffeine at a dose of 40 mg/kg (first) or 100 mg/kg (second), dioxidine at a dose of 200 mg/kg (third), together with caffeine 40 mg/kg or 100 mg/kg, and dioxidine (fourth and fifth groups, respectively). The animals of the control group were injected with saline. To study the behavior, the Porsolt test was carried out, evaluating the following indicators on the 1st, 8th and 15th days of the experiment: the total time of immobilization, active swimming, climb, the number of grooming and shaking off acts. Results . The administration of caffeine at a dose of 40 mg/kg caused an increase in the time of active swimming and a decrease in the duration of immobilization on the 8th and 15th days. When caffeine was used at a dose of 100 mg/kg, an increase in the time of active swimming was noted with a single exposure, with an experiment duration of 8-15 days, an increase in the duration of immobilization was observed. Dioxidine caused a significant decrease in the time of active swimming and an increase in the duration of immobilization during all days of the experiment. The combined use of caffeine (40 mg/kg and 100 mg/kg) and dioxidine on the 1st day led to a decrease in immobilization and the time of active swimming. In both groups, 100 % animal mortality was observed by the 15th day. Conclusion. The results of the study indicate the presence of an antidepressant effect in caffeine at a dose of 40 mg/kg on the 8th and 15th days of the experiment and the absence of this effect in caffeine at a dose of 100 mg/kg with a duration of administration of 8-15 days. The use of dioxidine led to the absence of antidepressant activity and the presence of the opposite effect. The combined administration of caffeine (40 mg/kg and 100 mg/kg) and dioxidine led to 100 % mortality in the experimental groups by the 15th day of the experiment

Associations of Non-Alcoholic Beverages with Major Depressive Disorder History and Depressive Symptoms Clusters in a Sample of Overweight Adults

BACKGROUND

Meta-analysis of observational studies concluded that soft drinks may increase the risk of depression, while high consumption of coffee and tea may reduce the risk. Objectives were to explore the associations between the consumption of soft drinks, coffee or tea and: (1) a history of major depressive disorder (MDD) and (2) the severity of depressive symptoms clusters (mood, cognitive and somatic/vegetative symptoms).

METHODS

Cross-sectional and longitudinal analysis based on baseline and 12-month-follow-up data collected from four countries participating in the European MooDFOOD prevention trial. In total, 941 overweight adults with subsyndromal depressive symptoms aged 18 to 75 years were analyzed. History of MDD, depressive symptoms and beverages intake were assessed.

RESULTS

Sugar-sweetened soft drinks were positively related to MDD history rates whereas soft drinks with non-nutritive sweeteners were inversely related for the high vs. low categories of intake. Longitudinal analysis showed no significant associations between beverages and mood, cognitive and somatic/vegetative clusters.

CONCLUSION

Our findings point toward a relationship between soft drinks and past MDD diagnoses depending on how they are sweetened while we found no association with coffee and tea. No significant effects were found between any studied beverages and the depressive symptoms clusters in a sample of overweight adults.

The combined effect of socioeconomic status and metabolic syndrome on depression: the Korean National Health and Nutrition Examination Survey (KNHANES)

Background

Depression shows different patterns depending on socioeconomic status (SES) and metabolic syndrome (MS). However, the nature of this association remains poorly understood. The aim of this study was to examine whether the combination of MS and lower SES was associated with the prevalence of depression, based on data from the Korea National Health and Nutrition Examination Survey (KNHANES).

Methods

Data were obtained from a cross-sectional study of 24,102 adults (> 19 years of age) who participated in the KNHANES during 2008–2013 and for whom MS and depression data were available. MS was defined using the diagnostic criteria of the modified National Cholesterol Education Program Adult Treatment Panel III. Measure of depression was ascertained from self-reports of physician diagnosis. Multiple logistic regression analysis was used to evaluate the association between depression and MS as well as SES (alone and in combination).

Results

Overall, 622 of the 24,102 subjects (2.6%) met the criteria for depression. The prevalence of depression was associated with MS, a lower high-density lipoprotein cholesterol level, an elevated triglyceride level, a lower education level, and a lower household income. Participants with MS and a low SES had a higher likelihood of depression than those without MS and a high SES (odds ratio [OR] = 4.180 for low education level and OR = 3.994 for low household income level).

Conclusions

This study suggests that the combination of SES and MS may play an important role in depression, which has implications for healthcare policy and depression management.

Intake of Coffee Associated With Decreased Depressive Symptoms Among Elderly Japanese Women: A Multi-Center Cross-Sectional Study

Background

Depression in elderly people is a major global concern around the world. Epidemiological evidence of the association of beverages with depressive symptoms has received research attention; however, epidemiological studies on the association of coffee and green tea consumption with depressive symptoms among the elderly population are limited. The objective of this study is to cross-sectionally examine the association of depressive symptoms with the intake of coffee, green tea, and caffeine and to verify the antidepressant effect of caffeine.

Methods

The subjects were 1,992 women aged 65–94 years. Intakes of coffee, green tea, and caffeine, as well as depressive symptoms, were assessed with a validated brief dietary history questionnaire (BDHQ) and the Center for Epidemiologic Studies Depression Scale (CES-D), respectively. Multiple logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for depressive symptoms with adjustments for potential confounders.

Results

Coffee intake was associated with a lower prevalence of depressive symptoms, the ORs of which for the 4th versus the 1st quartiles of intake was 0.64 (95% CI, 0.46–0.88, P for trend = 0.01) in a fully adjusted model. Caffeine intake was marginally associated with depressive symptoms, but the association was not statistically significant (OR 0.75; 95% CI, 0.55–1.02, P for trend = 0.058).

Conclusion

The result suggests that the inverse association of coffee intake with depressive symptoms might be associated with not only caffeine intake but also some other substances in coffee or factors related to coffee intake. Because of the cross-sectional design of the present study, longitudinal studies are required to confirm the present finding.

Socioeconomic status and depression as combined risk factors for acute myocardial infarction and stroke: A population-based study of 2.7 million Korean adults

OBJECTIVES

To evaluate the separate and combined associations of socioeconomic status (SES) and depression with the incidences of acute myocardial infarction (AMI) and stroke.

METHODS

We conducted a population-based cohort study using nationwide health insurance claims data collected from 2002 to 2016 in South Korea. A total of 2,705,090 subjects aged 20 years or older for whom had health screening data were collected between 2004 and 2005 were analyzed. The hazard ratios (HRs) for the incidences of AMI and stroke were calculated using Cox proportional regression analyses.

RESULTS

After adjusting for cardiovascular risk factors, a low SES was associated with increased risks of AMI (HR, 1.16; 95% confidence interval (CI), 1.14-1.19) and stroke (HR, 1.13; 95% CI, 1.11-1.14) incidence. Depression was also associated with an increased incidence of AMI (HR, 1.26; 95% CI, 1.21-1.31) and stroke (HR, 1.24; 95% CI, 1.21-1.27). Patients with depression who had a low SES exhibited significantly increased risks of AMI (HR, 1.47; 95% CI, 1.36-1.60) and stroke (HR, 1.37; 95% CI, 1.30-1.44) compared to patients with a high SES who were not diagnosed with depression. Depression showed a positive effect modification of low and medium SES compared to high SES on the association with AMI but not with stroke.

CONCLUSIONS

Subjects with both a low SES and depression displayed the highest risk. Both SES and depression should be considered in cardiovascular risk assessments, particularly in individuals with depression who have a low SES.

Coffee Consumption and the Risk of Depression in a Middle-Aged Cohort: The SUN Project

Coffee is one of the most widely consumed drinks around the world, while depression is considered the major contributor to the overall global burden of disease. However, the investigation on coffee consumption and depression is limited and results may be confounded by the overall dietary pattern. We assessed the relationship between coffee intake and the risk of depression, controlling for adherence to the Mediterranean diet. We studied 14,413 university graduates of the 'Seguimiento Universidad de Navarra' (SUN) cohort, initially free of depression. We evaluated coffee consumption using a validated food-frequency questionnaire (FFQ). Incident depression cases were adjudicated only if the participant met two criteria simultaneously: (a) validated physician-diagnosed depression together with (b) new onset of habitual antidepressant use. Both criteria were needed; participants meeting only one of them were not classified as cases. Participants who drank at least four cups of coffee per day showed a significantly lower risk of depression than participants who drank less than one cup of coffee per day (HR: 0.37 (95% CI 0.15⁻0.95)). However, overall, we did not observe an inverse linear dose⁻response association between coffee consumption and the incidence of depression (p for trend = 0.22).

Chlorogenic Acid and Mental Diseases: From Chemistry to Medicine

BACKGROUND

At present, much attention has been focused on the beneficial effects of natural products on the human health due to their high efficacy and low adverse effects. Among them, polyphenolic compounds are known as one of the most important and common classes of natural products, which possess multiple range of health-promotion effects including anti-inflammatory and antioxidant activities. A plethora of scientific evidence has shown that polyphenolic compounds possess beneficial effects on the central nervous system.

METHODS

Data were collected from Web of Science (ISI Web of Knowledge), Medline, Pubmed, Scopus, Embase, and BIOSIS Previews (from 1950 to 2015), through searching of these keywords: "chlorogenic acid and mental diseases" and "chlorogenic acid and neuroprotection".

RESULTS

Chlorogenic acid is known as one of the most common polyphenolic compounds, and is found in different types of fruits and vegetables, spices, wine, olive oil, as well as coffee. The potential neuroprotective effects of chlorogenic acid have been highlighted in several in vitro and in vivo studies. This review critically analyses the available scientific evidence regarding the neuroprotective effects of chlorogenic acid, and its neuropharmacological mechanisms of action. In addition, we also discuss its biosynthesis, sources, bioavailability and metabolism, to provide a broad perspective of the therapeutic implications of this compound in brain health and disease.

CONCLUSION

The present review showed that chlorogenic acid possesses neuroprotective effects under the both in vitro and in vivo models.

How does adenosine control neuronal dysfunction and neurodegeneration?

The adenosine modulation system mostly operates through inhibitory A₁ (A₁ R) and facilitatory A_2A receptors (A_2A R) in the brain. The activity-dependent release of adenosine acts as a brake of excitatory transmission through A₁ R, which are enriched in glutamatergic terminals. Adenosine sharpens salience of information encoding in neuronal circuits: high-frequency stimulation triggers ATP release in the 'activated' synapse, which is locally converted by ecto-nucleotidases into adenosine to selectively activate A_2A R; A_2A R switch off A₁ R and CB1 receptors, bolster glutamate release and NMDA receptors to assist increasing synaptic plasticity in the 'activated' synapse; the parallel engagement of the astrocytic syncytium releases adenosine further inhibiting neighboring synapses, thus sharpening the encoded plastic change. Brain insults trigger a large outflow of adenosine and ATP, as a danger signal. A₁ R are a hurdle for damage initiation, but they desensitize upon prolonged activation. However, if the insult is near-threshold and/or of short-duration, A₁ R trigger preconditioning, which may limit the spread of damage. Brain insults also up-regulate A_2A R, probably to bolster adaptive changes, but this heightens brain damage since A_2A R blockade affords neuroprotection in models of epilepsy, depression, Alzheimer's, or Parkinson's disease. This initially involves a control of synaptotoxicity by neuronal A_2A R, whereas astrocytic and microglia A_2A R might control the spread of damage. The A_2A R signaling mechanisms are largely unknown since A_2A R are pleiotropic, coupling to different G proteins and non-canonical pathways to control the viability of glutamatergic synapses, neuroinflammation, mitochondria function, and cytoskeleton dynamics. Thus, simultaneously bolstering A₁ R preconditioning and preventing excessive A_2A R function might afford maximal neuroprotection. The main physiological role of the adenosine modulation system is to sharp the salience of information encoding through a combined action of adenosine A_2A receptors (A_2A R) in the synapse undergoing an alteration of synaptic efficiency with an increased inhibitory action of A₁ R in all surrounding synapses. Brain insults trigger an up-regulation of A_2A R in an attempt to bolster adaptive plasticity together with adenosine release and A₁ R desensitization; this favors synaptotocity (increased A_2A R) and decreases the hurdle to undergo degeneration (decreased A₁ R). Maximal neuroprotection is expected to result from a combined A_2A R blockade and increased A₁ R activation. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".

Coffee and caffeine consumption and depression: A meta-analysis of observational studies

OBJECTIVE

The results from observation studies on the relationship between coffee intake and risk of depression and the relationship between caffeine consumption and depression remain controversial. We conducted a meta-analysis with a dose-response analysis to quantitatively summarize the evidence about the association between coffee and caffeine intakes and risk of depression.

METHOD

Relevant articles were identified by researching PubMed, Web of Science, China National Knowledge Infrastructure and WANFANG DATA in English or Chinese from 1 January 1980 to 1 May 2015. Case-control, cohort or cross-sectional studies evaluating coffee or caffeine consumption and depression were included. A random-effects model was used to combine study-specific relative risk and 95% confidence interval. Dose-response relationship was assessed by restricted cubic spline functions.

RESULTS

Data were obtained from 11 observation articles; 330,677 participants from seven studies in seven articles were included in the coffee-depression analysis, while 38,223 participants from eight studies in seven articles were involved in the caffeine-depression analysis. Compared with the lowest level consumption, the pooled relative risk (95% confidence interval) for coffee-depression and caffeine-depression was 0.757 [0.624, 0.917] and 0.721 [0.522, 0.997], respectively. For dose-response analysis, evidence of a linear association was found between coffee consumption and depression, and the risk of depression decreased by 8% (relative risk = 0.92, 95% confidence interval = [0.87, 0.97], p = 0.002) for each cup/day increment in coffee intake; a nonlinear association was found between caffeine consumption and depression, the risk of depression decreased faster and the association became significant when the caffeine consumption was above 68 mg/day and below 509 mg/day.

CONCLUSIONS

Coffee and caffeine consumption were significantly associated with decreased risk of depression.

Coffee, tea, caffeine and risk of depression: A systematic review and dose-response meta-analysis of observational studies

SCOPE

The aim of the study was to systematically review and analyze results from observational studies on coffee, caffeine, and tea consumption and association or risk of depression.

METHODS AND RESULTS

Embase and PubMed databases were searched from inception to June 2015 for observational studies reporting the odds ratios or relative risks (RRs) and 95% confidence intervals (CI) of depression by coffee/tea/caffeine consumption. Random effects models, subgroup analyses, and dose-response analyses were performed. Twelve studies with 23 datasets were included in the meta-analysis, accounting for a total of 346 913 individuals and 8146 cases of depression. Compared to individuals with lower coffee consumption, those with higher intakes had pooled RR of depression of 0.76 (95% CI: 0.64, 0.91). Dose-response effect suggests a nonlinear J-shaped relation between coffee consumption and risk of depression with a peak of protective effect for 400 mL/day. A borderline nonsignificant association between tea consumption and risk of depression was found (RR 0.70, 95% CI: 0.48, 1.01), while significant results were found only for analysis of prospective studies regarding caffeine consumption (RR = 0.84, 95% CI: 0.75, 0.93).

CONCLUSION

This study suggests a protective effect of coffee and, partially, of tea and caffeine on risk of depression.