Study Title and Description
Green tea and coffee consumption is inversely associated with depressive symptoms in a Japanese working population.
Key Questions Addressed
|1||For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on behavior*?|
Primary Publication Information
|Title||Green tea and coffee consumption is inversely associated with depressive symptoms in a Japanese working population.|
|Author||NM Pham,A Nanri,K Kurotani,K Kuwahara,A Kume,M Sato,H Hayabuchi,T Mizoue,|
Secondary Publication Information
There are currently no secondary publications defined for this study.
Extraction Form: Behavior - Design Details - INCLUDED Studies
No arms have been defined in this extraction form.
|Question... Follow Up||Answer||Follow-up Answer|
|What outcome is being evaluated in this paper?||Behavior|
|What is the objective of the study (as reported by the authors)?||To examine the association between the consumption of green tea, coffee and caffeine and depressive symptoms.|
|Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods)||Study procedure and participants In July and November 2009, a health survey was conducted among municipal employees in two workplaces in northeastern Kyushu, Japan. The overall objective of the survey was to examine the association of lifestyle including diet with mental and physical health. At the time of the routine health check-up, all full-time workers (n 605) except those who were on long-term sick or maternity leave were invited to participate. Of these, 567 (325 men and 242 women aged 20–68 years) consented (response rate 94 %). Participants were asked to fill out a survey questionnaire before the health check-up. The survey questionnaire was then checked by research staff for completeness and, where necessary, clarifications were made with the participant. We also obtained data that were routinely collected during the health examination, including anthropometric measurements and biochemical data, and information about medical history, smoking and alcohol drinking. We excluded participants who were pregnant (n=8) and those having missing data on confounding factors under study (n=22). After these exclusions, 537 individuals (319 men and 218 women) remained. Ascertainment of depressive symptoms Depressive symptoms were assessed with the Japanese version(21) of the Center for Epidemiologic Studies Depression (CES-D) scale(22). This scale comprises twenty questions addressing six symptoms of depression experienced by participants during the past week: depressed mood, feelings of guilt or worthlessness, helplessness or hopelessness, psychomotor retardation, loss of appetite and sleep disorders. Each question is scored on a scale of 0–3 according to the frequency of the symptom and the total score ranges from 0 to 60, with a higher score indicating worse depressive status. The criterion validity of the CES-D scale has been well established in both Western(22) and Japanese(21) subjects. The presence of depressive symptoms was defined as a CES-D score of 16 or higher. As a self-rating depression scale, CES-D was developed for epidemiological surveys among adults of all ages, whereas other instruments such as the Beck Depression Inventory, the Zung Self-Rating Depression Scale and the Geriatric Depression Scale were designed for clinical research or elderly populations(23). Dietary assessment Information about dietary intake during the preceding month was obtained using a validated brief self administered diet history questionnaire (BDHQ)(24), which ascertained consumption frequency of forty-six food and non-alcoholic beverage items, including vegetables, fruit, green tea and coffee. Consumptions of green tea and coffee were elicited by a closed-ended question, and the beverage consumption in terms of volume was estimated by assigning the following values (cups/week) to the frequency of consumption(24): 05none; 0?55,1 cup/week; 151 cup/week; 2?552–3 cups/week; 554–6 cups/week; 751 cup/d; 17?552–3 cups/d; 285$4 cups/d. A cup size of green tea or coffee was assumed as 150 ml for women and 171 ml (150 ml31?14) for men(24). Correlations between consumption of green tea and coffee according to the above-mentioned BDHQ and those from 16 d dietary records were high (Spearman’s r50?74 and 0?73 for green tea consumption in men and women, respectively; the corresponding data for coffee consumption were 0?85 in men and 0?87 in women)(24). Referring to the Food Composition Table in Japan(25), we estimated daily caffeine consumption from green tea and coffee consumption, using respectively 20 and 60mg of caffeine per 100 ml of each beverage. Statistical analysis The descriptive data are presented as means and standard deviations, medians and interquartile ranges, or percentages. Participants were divided into three groups: those consuming ≤1 cup, 2–3 cups and ≥4 cups of green tea daily; and those consuming ,1 cup, 1 cup and >2 cups of coffee daily. Caffeine consumption was estimated from caffeine contents in green tea and coffee, and was categorized into quartiles (≤100 mg/d, 101–165 mg/d, 166–291 mg/d and .291 mg/d). Participants’ characteristics according to green tea and coffee consumption, treated as ordinal variables with ordinal values from 1 to 3 assigned to the three consumption levels, were evaluated by using linear regression analysis for continuous variables and the Mantel–Haenszel test of trend for categorical variables.|
|How many outcome-specific endpoints are evaluated?||1|
|What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately)||depression|
|List additional health endpoints (separately).|
|List additional health endpoints (separately)|
|What is the study design?||Cross-sectional|
|Randomized or Non-Randomized?|
|What were the diagnostics or methods used to measure the outcome?||Subjective|
|Optional: Name of Method or short description||Depressive symptoms were assessed with the Japanese version(21) of the Center for Epidemiologic Studies Depression (CES-D) scale(22). This scale comprises twenty questions addressing six symptoms of depression experienced by participants during the past week: depressed mood, feelings of guilt or worthlessness, helplessness or hopelessness, psychomotor retardation, loss of appetite and sleep disorders. Each question is scored on a scale of 0–3 according to the frequency of the symptom and the total score ranges from 0 to 60, with a higher score indicating worse depressive status. The criterion validity of the CES-D scale has been well established in both Western(22) and Japanese(21) subjects. The presence of depressive symptoms was defined as a CES-D score of 16 or higher. As a self-rating depression scale, CES-D was developed for epidemiological surveys among adults of all ages, whereas other instruments such as the Beck Depression Inventory, the Zung Self-Rating Depression Scale and the Geriatric Depression Scale were designed for clinical research or elderly populations(23).|
|Caffeine (general)||Caffeine (general)|
|What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.)||quartiles of caffeine intake: </= 100 mg/day ; 101-165 mg/day ; 166-291 mg/day ; > 291 mg/day|
|What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models. Copy from methods)||Multiple logistic regression analysis was performed to calculate odds ratios and 95% confidence intervals for prevalence of depressive symptoms according to the above-described categories of green tea, coffee and caffeine consumption. The base model (model 1) included age (year, continuous), sex and workplace (survey in July or November 2009). We added covariates accumulatively to model 1 in subsequent models: history of cancer, CVD, diabetes mellitus or chronic hepatitis (yes or no), marital status (married or unmarried), living status (alone or not alone), overtime work (none, ,10 or $10 h/month), job position (low or middle and high), occupational physical activity (active or sedentary), nonoccupational physical activity (,5 or $5 MET-h/week), current smoking (yes or no), alcohol drinking (yes or no), BMI (kg/m2, continuous), n-3 PUFA intake (percentage of energy, continuous), log-transformed red meat intake (g/d, continuous), log-transformed vegetable and fruit consumption (g/d, continuous) and coffee consumption (,1, 1 or ≥2 cups/d; when calculating the OR for consumption of green tea) or green tea (≤1, 2–3 or $4 cups/d; when calculating the ORs for consumption of coffee) for model 2; log-transformed serum CRP concentrations (mg/l, continuous) for model 3; and log-transformed serum folate concentration (ng/ml, continuous) for model 4. Neither green tea nor coffee consumption was included in the multivariate models when examining the association between caffeine consumption and depressive symptoms. Trend tests were performed using multiple logistic regression analysis with ordinal numbers assigned to the category of green tea, coffee and caffeine consumption. We also examined effect modification by sex on the association of green tea, coffee and caffeine consumption with depressive symptoms, using the likelihood ratio test. We repeated all the above analyses after excluding participants who reported a history of psychological problems (n 6). Two-sided P values of less than 0.05 were considered statistically significant. All analyses were performed using the statistical software package STATA version 12.1.|
|Provide a general description of results (as reported by the authors).||Concerning caffeine consumption (Table 3), participants in the highest v. the lowest quartile of caffeine consumption had a 43% lower odds of having depressive symptoms in a fully adjusted model (OR=0.57; 95% CI 0.30- 1.05; P for trend = 0.02).|
|Did the authors perform a dose-response analysis (or trend/related analysis)?||Yes|
|What were the authors's observations re: trend analysis?||Concerning caffeine consumption (Table 3), participants in the highest v. the lowest quartile of caffeine consumption had a 43% lower odds of having depressive symptoms in a fully adjusted model (OR=0.57; 95% CI 0.30- 1.05; P for trend = 0.02).|
|What were the author's conclusions?||We found that higher consumption of green tea, coffee and caffeine was each associated with a lower prevalence of depressive symptoms in a Japanese working population. These findings add support for a protective role of green tea, coffee and caffeine against depression. Longitudinal studies including persons with a high intake of coffee and caffeine are required to confirm the present cross-sectional association.|
|What were the sources of funding?||This study was supported by a Grantin- Aid for Scientific Research (B) (21390213) from the Japan Society for the Promotion of Science; a Grant-in-Aid for Young Scientists (B) (21790598) from the Ministry of Education, Culture, Sports, Science and Technology; and a Grant of the National Center for Global Health and Medicine.|
|What conflicts of interest were reported?||The authors declare no conflict of interest.|
|Does the exposure (dose) need to be standardized to the SR?||No|
|Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).|
|List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot. Characterize value as LOAEL/NOAEL, etc. if possible.||depression - NOAEL = > 291 mg/day|
|Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot.||No adverse effects observed. Caffeine (as well as coffee and tea) consumption offered a protective effect against depressive symptoms.|
|What is the importance of the study with respect to the adverseness of the outcome?||Critcal|
No baseline characteristics have been defined for this extraction form.
Results & Comparisons
No Results found.
|Arm or Total||Title||Description||Comments|
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