Coffee consumption and mortality in three Eastern European countries: results from the HAPIEE (Health, Alcohol and Psychosocial factors In Eastern Europe) study

Edge based metric dimension of various coffee compounds

An important dietary source of physiologically active compounds, coffee also contains phenolic acids, diterpenes, and caffeine. According to a certain study, some coffee secondary metabolites may advantageously modify a number of anti-cancer defense systems. This research looked at a few coffee chemical structures in terms of edge locating numbers or edge metric size to better understand the mechanics of coffee molecules. Additionally, this research includes graph theoretical properties of coffee chemical structures. The chemicals found in coffee, such as caffeine, diterpene or cafestol, kahweol, chlorogenic, caffeic, gallotannins, and ellagitannins, are especially examined in these publications.

Dietary Intake of (Poly)phenols and Risk of All-Cause and Cause-Specific Mortality in the Mexican Teachers' Cohort Study

BACKGROUND

Observational studies have reported that total (poly)phenol intake is associated with a reduction in all-cause and cardiovascular mortality, but mainly from high-income countries, where (poly)phenol intake may differ from that of low- and middle-income countries.

OBJECTIVES

Our objective was to evaluate the association between the intake of total, all classes, and subclasses of (poly)phenols and risk of all-cause and cause-specific mortality in a Mexican cohort.

METHODS

We used data from the Mexican Teachers' Cohort, which included 95,313 adult females. After a median follow-up of 11.2 y, 1725 deaths were reported, including 674 from cancer and 282 from cardiovascular diseases. (Poly)phenol intake was estimated using a validated food frequency questionnaire and the Phenol-Explorer database. Multivariable Cox models were applied to estimate the association between (poly)phenol intake and all-cause mortality and competitive risk models for cause-specific mortality.

RESULTS

Comparing extreme quartiles, total (poly)phenol intake was associated with lower risk of all-cause [hazard ratio (HR)Q4vs.Q1: 0.88; 95% CI: 0.76, 0.99; P-trend = 0.01] and cancer mortality (HRQ4vs.Q1: 0.81; 95% CI: 0.64, 0.99; P-trend = 0.02). Among (poly)phenol classes, phenolic acids, particularly hydroxycinnamic acids from coffee, showed an inverse association with all-cause (HRQ4vs.Q1: 0.79; 95% CI: 0.69, 0.91; P-trend = 0.002) and cancer mortality (HRQ4vs.Q1: 0.75; 95% CI: 0.61, 0.94; P-trend = 0.03). No associations were observed with flavonoids or with cardiovascular mortality.

CONCLUSION

Our study suggests that high (poly)phenol intake, primarily consisting of phenolic acids such as hydroxycinnamic acids, may have a protective effect on overall and cancer mortality. Null associations for flavonoid intake might be due to the potential underestimation of their intake in this population.

Caffeine Consumption in a Group of Adolescents from South East Poland-A Cross Sectional Study

Caffeine is the most common psychoactive substance available to adults, as well as to children and adolescents. The safety of its use in younger age groups requires further research. The aim of this study was to evaluate caffeine intake, to identify products and drinks that are the main sources of caffeine intake in the diet of the subjects and the risk of excessive caffeine intake with the diet of adolescents, stratified by gender. A cross-sectional study was conducted among 508 adolescents aged 16–18 years from southern Poland. Black tea, cola-based soft drinks and milk chocolate were the most frequently consumed products containing caffeine in the diet of the examined persons. The average caffeine intake was 95.54 mg/day (1.54 mg/kg b.w.). In 12.2% of the subjects the dose of 3 mg/kg b.w./day was exceeded, and in over 41.3% the dose causing sleep disorders was exceeded. The dose causing anxiety was also exceeded in 18.1% of the respondents, significantly more often in girls than boys (p = 0.0487).

The relationship of coffee consumption and CVD risk factors in elderly patients with T2DM

Objective

Clinical studies suggest increasing prevalence of cardiovascular disease (CVD) risk factors and diabetes among the elderly. Meanwhile, some food compounds, such as coffee, can also have beneficial effects on CVD risk factors. The aim of the present study was to examine the relationship between coffee consumption and CVD risk factors in the elderly with type 2 diabetes mellitus (T2DM).

Methods

This cross-sectional study was performed during 2017 on 300 elderly people above 60 years of age with T2DM in Isfahan, Iran. Dietary assessment was performed using a food frequency questionnaire. Coffee consumption was classified into three groups including < 1, 1–3, and > 3 cups/day. Partial correlation test was used to investigate the relationship between CVD risk factors and usual coffee consumption.

Results

The mean age and body mass index of participants were 70.04 ± 4.87 years and 24.74 ± 3.34 kg/m² respectively. Coffee consumption had a significant inverse relationship with fasting plasma glucose (FPG) and diastolic blood pressure (DBP) in the elderly with T2DM (r: − 0.117, 0.134; p: 0.046, 0.022). Triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) had a significant positive relationship with coffee consumption levels (r: 0.636, 0.128; p: 0.028, 0.029). These results were obtained after controlling for potential confounders.

Conclusion

Increasing coffee consumption was linked to improved status of some CVD risk factors including FPG, HDL-C, and DBP in the elderly with T2DM. Nevertheless, increasing coffee consumption was also associated with higher TG level and had no significant effect on other risk factors. Further studies are required to confirm these results.

Coffee Consumption and All-Cause, Cardiovascular, and Cancer Mortality in an Adult Mediterranean Population

We assessed the association between usual coffee consumption and all-cause, cardiovascular (CV), and cancer mortality in an adult population in Spain, taking into account both the amount and type of coffee consumed. We used baseline data on coffee consumption and other personal variables, and the number of deaths during an 18-year follow-up period, for 1567 participants aged 20 years and older from the Valencia Nutrition Study in Spain. Total, caffeinated, and decaffeinated coffee consumption was assessed using a validated food frequency questionnaire. Cox regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). During the 18-year follow-up period, 317 died; 115 due to CV disease and 82 due to cancer. Compared with no-consumption, the consumption of ≤1 cup per day and >1 cup per day of coffee was associated with a lower risk of all-cause mortality, HR = 0.73 (95% CI: 0.56–0.97) and HR 0.56 (95% CI: 0.41–0.77), respectively. A lower cancer mortality was observed among drinkers of more than 1 cup per day compared with nondrinkers, HR 0.41 (95% CI 0.20–0.86). Regarding the type of coffee, only the overall consumption of caffeinated coffee was associated with lower all-cause mortality at 12 and 18 years of follow-up, HR = 0.66 (95% CI:0.46–0.94) and HR = 0.59 (95% CI: 0.44–0.79), respectively. In conclusion, this study suggests that the moderate consumption of coffee, particularly caffeinated coffee (range 1–6.5 cups per day), is associated with a lower all-cause and cancer mortality after a long follow-up period. No significant association was found between coffee consumption and CVD mortality.

Coffee consumption and mortality in Japan with 18 years of follow-up: the Jichi Medical School Cohort Study

OBJECTIVE

Coffee consumption can be expected to reduce mortality due to cardiovascular diseases and cancer. This study tested the hypothesis of an inverse association between coffee intake and all-cause mortality and mortality due to cancer, coronary heart disease, or stroke.

STUDY DESIGN

Prospective cohort study.

METHODS

We analyzed data from the Jichi Medical School Cohort Study, Japan, enrolling 9946 subjects (men/women: 3870/6,076, age: 19-93 years) from 12 communities. A food frequency questionnaire assessing the subjects' daily coffee consumption was used.

RESULTS

During an average follow-up of 18.4 years, the total number of deaths was 2024, including 677 for cancer, 238 for coronary heart disease, and 244 for stroke. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause mortality and cause-specific mortality due to cancer, coronary heart disease, and stroke. Overall, no significant association was shown between coffee consumption and all-cause mortality. In the cause-specific mortality analyses, stroke mortality was significantly lower in those who consumed 1-2 cups of coffee daily (HR [95% CI]: 0.63 [0.42-0.95]) than in those who do not consume coffee, and this association occurred only in men.

CONCLUSION

This study showed no significant association between coffee consumption and all-cause mortality. A U-shaped association between coffee consumption and stroke mortality with a 37% lower stroke mortality, only significant in men who consume 1-2 cups of coffee daily was observed. It is necessary to examine the possibility of intervention studies to reduce stroke mortality through coffee consumption.

Associations of Coffee and Tea Consumption With Survival to Age 90 Years Among Older Women

BACKGROUND

Coffee and tea are two of the most widely consumed beverages worldwide and have been associated with reduced risk of mortality in some studies. However, it is unknown whether consumption of these beverages is associated with survival to an advanced age.

OBJECTIVE

To examine associations of coffee and tea consumption with survival to age 90 years.

DESIGN

Prospective cohort study among participants from the Women's Health Initiative, recruited during 1993 to 1998 and followed up until March 31, 2018.

SETTING

The setting included 40 US clinical centers.

PARTICIPANTS

A racially and ethnically diverse cohort of 27,480 older women, aged 65 to 81 years at baseline.

MEASUREMENTS

Women were classified as having either survived to age 90 years or died before this age. Consumption of caffeinated and decaffeinated coffee and caffeinated tea was assessed at baseline and categorized as 0, 1, 2 to 3, or 4 or more cups/day. Associations of coffee and tea consumption with survival to age 90 years were examined using logistic regression models adjusted for sociodemographic characteristics, lifestyle behaviors, dietary quality, and chronic disease history.

RESULTS

A total of 14,659 (53.3%) women survived to age 90 years during follow-up. Caffeinated coffee, decaffeinated coffee, or caffeinated tea consumption was not significantly associated with survival to age 90 years after adjusting for confounders. Findings did not significantly vary by smoking, body mass index, or race/ethnicity.

CONCLUSION

No amount of coffee or tea consumption was associated with late-age survival among older women. These findings may be reassuring to older women who consume coffee and tea as part of their daily diets but do not support drinking these beverages to achieve longevity.

Coffee consumption and overall and cause-specific mortality: the Norwegian Women and Cancer Study (NOWAC)

Coffee consumption has previously been reported to reduce overall and cause-specific mortality. We aimed to further investigate this association by coffee brewing methods and in a population with heavy coffee consumers. The information on total, filtered, instant, and boiled coffee consumption from self-administered questionnaires was available from 117,228 women in the Norwegian Women and Cancer (NOWAC) Study. We used flexible parametric survival models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for all-cause, cardiovascular, and cancer mortality by total coffee consumption and brewing methods, and adjusted for smoking status, number of pack-years, age at smoking initiation, alcohol consumption, body mass index, physical activity, and duration of education. During 3.2 million person-years of follow-up, a total of 16,106 deaths occurred. Compared to light coffee consumers (≤ 1 cup/day), we found a statistically significant inverse association with high-moderate total coffee consumption (more than 4 and up to 6 cups/day, HR 0.89; 95% CI 0.83–0.94) and all-cause mortality. The adverse association between heavy filtered coffee consumption (> 6 cups/day) and all-cause mortality observed in the entire sample (HR 1.09; 95% CI 1.01–1.17) was not found in never smokers (HR 0.85; 95% CI 0.70–1.05). During the follow-up, both high-moderate total and filtered coffee consumption were inversely associated with the risk of cardiovascular mortality (HR 0.79; 95% CI 0.67–0.94; HR 0.80; 95% CI 0.67–0.94, respectively). The association was stronger in the analyses of never smokers (> 6 cups of filtered coffee/day HR 0.20; 95% CI 0.08–0.56). The consumption of more than 6 cups/day of filtered, instant, and coffee overall was found to increase the risk of cancer deaths during the follow-up. However, these associations were not statistically significant in the subgroup analyses of never smokers. The data from the NOWAC study indicate that the consumption of filtered coffee reduces the risk of cardiovascular deaths. The observed adverse association between coffee consumption and cancer mortality is most likely due to residual confounding by smoking.

Dietary Research on Coffee: Improving Adjustment for Confounding

Meta-analyses have reported higher levels of coffee consumption to be associated with lower mortality. In contrast, some systematic reviews have linked coffee consumption to increased risks for lung cancer and hypertension. Given these inconsistencies, this narrative review critically evaluated the methods and analyses of cohort studies investigating coffee and mortality. A specific focus was adjustment for confounding related to smoking, healthy and unhealthy foods, and alcohol. Assessment of 36 cohort samples showed that many did not adequately adjust for smoking. Consuming 1-5 cups of coffee per day was related to lower mortality among never smokers, in studies that adjusted for pack-years of smoking, and in studies adjusting for healthy and unhealthy foods. Possible reduced health benefits for coffee with added sugar have not been adequately investigated. Research on coffee and health should report separate analyses for never smokers, adjust for consumption of healthy and unhealthy foods, and for sugar added to coffee.

Associations between coffee consumption and all-cause and cause-specific mortality in a Japanese city: the Takayama study

OBJECTIVE

Epidemiological studies suggest that coffee consumption is inversely associated with all-cause and cause-specific mortality. Evidence from studies targeting non-white, non-Western populations is still sparse, although coffee is popular and widely consumed in Asian countries.

DESIGN

Population-based, prospective cohort study. We used Cox proportional hazards models with adjustment for dietary and lifestyle factors to estimate associations between coffee consumption and all-cause and cause-specific mortality. Dietary intake including coffee consumption was assessed only at baseline using a validated FFQ.

SETTING

A Japanese city.

PARTICIPANTS

Individuals aged 35 years or older without cancer, CHD and stroke at baseline (n 29 079) and followed from 1992 to 2008.

RESULTS

From 410 352 person-years, 5339 deaths were identified (mean follow-up = 14·1 years). Coffee consumption was inversely associated with mortality from all causes and CVD among all participants, but not from cancer. Compared with the category of 'none', the multivariate hazard ratio (95 % CI) for all-cause mortality was 0·93 (0·86, 1·00) for <1 cup/d, 0·84 (0·76, 0·93) for 1 cup/d and 0·81 (0·71, 0·92) for 2-3 cups/d. The multivariate hazard ratio (95 % CI) for cardiovascular mortality were 0·87 (0·77, 0·99) for <1 cup/d, 0·76 (0·63, 0·92) for 1 cup/d and 0·67 (0·50, 0·89) for 2-3 cups/d. Inverse associations were also observed for mortality from other causes, specifically infectious and digestive diseases.

CONCLUSION

Drinking coffee, even 1 cup/d, was inversely associated with all-cause mortality and mortality from cardiovascular, infectious and digestive diseases.

Coffee consumption and all-cause and cause-specific mortality: a meta-analysis by potential modifiers

Coffee consumption has been associated with decreased mortality in previous studies. As aging, obesity, and lifestyle factors affect the risk of mortality, the association between coffee and mortality needs to be examined in various subpopulations by characteristics of subjects. To quantitatively assess this association, we conducted an updated meta-analysis including stratified analyses by potential modifiers. We searched in the PubMed and Web of Science databases through March 8, 2019, and conducted meta-analysis including linear and non-linear dose-response analyses. We identified 40 studies including 3,852,651 subjects and 450,256 all-cause and cause-specific deaths. Non-linear inverse associations between coffee consumption and mortality from all-causes, cardiovascular disease (CVD), and cancers were found. The lowest relative risk (RR) was at intakes of 3.5 cups/day for all-cause mortality (RR = 0.85, 95% CI 0.82-0.89), 2.5 cups/day for CVD mortality (RR = 0.83, 95% CI 0.80-0.87), and 2 cups/day for cancer mortality (RR = 0.96, 95% CI 0.94-0.99), while additional intakes were not associated with further lower mortality. An inverse association between coffee consumption and all-cause mortality was maintained irrespective of age, overweight status, alcohol drinking, smoking status, and caffeine content of coffee. By region, Europe and Asia showed stronger inverse associations than US. A non-linear inverse association was found for mortality from respiratory disease and diabetes, while linear inverse association was found for mortality from non-CVD, non-cancer causes. Moderate coffee consumption (e.g. 2-4 cups/day) was associated with reduced all-cause and cause-specific mortality, compared to no coffee consumption. The inverse association between coffee and all-cause mortality was consistent by potential modifiers except region.

The association of coffee consumption and oxygen desaturation index during sleep among Japanese male workers

BACKGROUND AND OBJECTIVE

Coffee is a major caffeine-containing food source that can be used for treatment of apnea in prematurity. However, few studies have examined the association between coffee consumption and sleep-disordered breathing (SDB). We investigated whether coffee consumption is associated with the oxygen desaturation index (ODI) as a marker of SDB among middle-aged Japanese male workers.

METHODS

The subjects were 1126 male local government workers aged 22-59 who participated in SDB screening in 2011-2012. Daily coffee consumption was assessed by a self-administered questionnaire. We measured 3% oxygen desaturation (3%ODI) during a night's sleep using a pulse oximeter. A general linear model was used to calculate the multivariate-adjusted means of 3%ODI per quartile of coffee consumption. We further analyzed the data after stratifying by overweight and current smoking status.

RESULTS

A inverse association between coffee consumption and 3%ODI was found. The multivariate-adjusted mean of 3%ODI for the lowest and highest coffee consumption groups were 11.9 times/h and 10.6 times/h (p for trend = 0.06), respectively; 14.6 and 11.5 times/h (p for trend = 0.01) in overweight participants; and 12.7 and 11.0 times/h (p for trend = 0.06) in non-smokers. No associations were found in non-overweight and smoking workers.

CONCLUSIONS

Our results suggest that higher coffee consumption was associated with lower 3% ODI as a marker of SDB in overweight and non-smoking workers.

Caffeinated and decaffeinated coffee consumption and risk of all-cause mortality: a dose-response meta-analysis of cohort studies

BACKGROUND

Previous meta-analysis showed an inverse association between coffee consumption and all-cause mortality. However, the relationship between caffeinated and decaffeinated coffee consumption and all-cause mortality is inconsistent. We aimed to identify and review the published evidence updating the association between coffee consumption and all-cause mortality and, furthermore, to investigate the association of caffeinated and decaffeinated coffee consumption and all-cause mortality.

METHODS

We systematically searched PubMed and Web of Science for studies published up to 9 November 2017. Cohort studies in which authors reported relative risks (RRs) of all-cause mortality for at least three levels of coffee consumption were eligible. Random-effects models were used to estimate the pooled RR of all-cause mortality with coffee consumption. Restricted cubic splines were used to model the dose-response association.

RESULTS

We included 21 cohort study articles (10 103 115 study participants and 240 303 deaths). We found a nonlinear association between coffee consumption and all-cause mortality (P_nonlinearity  < 0.001). Compared with no or rare coffee consumption, with a consumption of 3 cups day^-1 , the risk of all-cause mortality might reduce 13% (RR = 0.87; 95% confidence interval = 0.84-0.89).

CONCLUSIONS

The findings of the present study provide quantitative data suggesting that coffee consumption plays a role in reducing the risk of all-cause mortality. Similar inverse associations are found for caffeinated coffee and decaffeinated coffee.

Impact of Alcohol and Coffee Intake on the Risk of Advanced Liver Fibrosis: A Longitudinal Analysis in HIV-HCV Coinfected Patients (ANRS HEPAVIH CO-13 Cohort)

Background: Coffee intake has been shown to modulate both the effect of ethanol on serum GGT activities in some alcohol consumers and the risk of alcoholic cirrhosis in some patients with chronic diseases. This study aimed to analyze the impact of coffee intake and alcohol consumption on advanced liver fibrosis (ALF) in HIV-HCV co-infected patients. Methods: ANRS CO13-HEPAVIH is a French, nationwide, multicenter cohort of HIV-HCV-co-infected patients. Sociodemographic, behavioral, and clinical data including alcohol and coffee consumption were prospectively collected using annual self-administered questionnaires during five years of follow-up. Mixed logistic regression models were performed, relating coffee intake and alcohol consumption to ALF. Results: 1019 patients were included. At the last available visit, 5.8% reported high-risk alcohol consumption, 27.4% reported high coffee intake and 14.5% had ALF. Compared with patients with low coffee intake and high-risk alcohol consumption, patients with low coffee intake and low-risk alcohol consumption had a lower risk of ALF (aOR (95% CI) 0.24 (0.12–0.50)). In addition, patients with high coffee intake had a lower risk of ALF than the reference group (0.14 (0.03–0.64) in high-risk alcohol drinkers and 0.11 (0.05–0.25) in low-risk alcohol drinkers). Conclusions: High coffee intake was associated with a low risk of liver fibrosis even in HIV-HCV co-infected patients with high-risk alcohol consumption.

Association of Coffee Consumption With Total and Cause-Specific Mortality Among Nonwhite Populations

BACKGROUND

Coffee consumption has been associated with reduced risk for death in prospective cohort studies; however, data in nonwhites are sparse.

OBJECTIVE

To examine the association of coffee consumption with risk for total and cause-specific death.

DESIGN

The MEC (Multiethnic Cohort), a prospective population-based cohort study established between 1993 and 1996.

SETTING

Hawaii and Los Angeles, California.

PARTICIPANTS

185 855 African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites aged 45 to 75 years at recruitment.

MEASUREMENTS

Outcomes were total and cause-specific mortality between 1993 and 2012. Coffee intake was assessed at baseline by means of a validated food-frequency questionnaire.

RESULTS

58 397 participants died during 3 195 484 person-years of follow-up (average follow-up, 16.2 years). Compared with drinking no coffee, coffee consumption was associated with lower total mortality after adjustment for smoking and other potential confounders (1 cup per day: hazard ratio [HR], 0.88 [95% CI, 0.85 to 0.91]; 2 to 3 cups per day: HR, 0.82 [CI, 0.79 to 0.86]; ≥4 cups per day: HR, 0.82 [CI, 0.78 to 0.87]; P for trend < 0.001). Trends were similar between caffeinated and decaffeinated coffee. Significant inverse associations were observed in 4 ethnic groups; the association in Native Hawaiians did not reach statistical significance. Inverse associations were also seen in never-smokers, younger participants (<55 years), and those who had not previously reported a chronic disease. Among examined end points, inverse associations were observed for deaths due to heart disease, cancer, respiratory disease, stroke, diabetes, and kidney disease.

LIMITATION

Unmeasured confounding and measurement error, although sensitivity analysis suggested that neither was likely to affect results.

CONCLUSION

Higher consumption of coffee was associated with lower risk for death in African Americans, Japanese Americans, Latinos, and whites.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Dietary Polyphenol Intake, but Not the Dietary Total Antioxidant Capacity, Is Inversely Related to Cardiovascular Disease in Postmenopausal Polish Women: Results of WOBASZ and WOBASZ II Studies

The aim of the study was to assess the relationship between the dietary polyphenol intake (DPI) and the dietary total antioxidant capacity (DTAC) and the prevalence of cardiovascular disease (CVD) in postmenopausal women. Participants were 916 postmenopausal women diagnosed with CVD and 1683 postmenopausal women without history of CVD, who took part in the population-based studies carried out in Poland: WOBASZ (2003–2005) and WOBASZ II (2013-2014). Nutritional data were collected using a single 24-hour dietary recall. DPI and DTAC in the CVD women were significantly lower and accounted for 1766.39 mg/d and 10.84 mmol/d, respectively, versus 1920.57 mg/d and 11.85 mmol/d in the women without CVD, but these differences disappeared after the standardization for energy input. Also, in the multiple-adjustment model, higher DPI, but not DTAC, was associated with the reduced odds ratio for the prevalence of CVD. Beverages, mainly coffee and tea, contributed in more than 40% to DPI and in more than a half to DTAC. In this study, higher dietary polyphenol intake, but not the dietary total antioxidant capacity, was inversely associated with CVD in postmenopausal women, which points to the health benefits of increased polyphenol intake from food sources for these women.

Coffee Consumption and the Risk of Thyroid Cancer: A Systematic Review and Meta-Analysis

An inverse association has been reported between coffee consumption and the risk of several cancers. However, the association between coffee and thyroid cancer is controversial. Thus, this study aimed to evaluate the association between coffee consumption and the risk of thyroid cancer through a systematic review and meta-analysis. Published studies were examined from PubMed, Embase, Cochrane Central, and the reference lists of the retrieved articles. The summary odds ratio (OR) for the association between coffee consumption was categorized as highest versus lowest consumption, and thyroid cancer risk was calculated using a fixed effects model. Subgroup analyses by study design, geographic location, source of controls, and adjusted variables were performed. A total of 1039 thyroid cancer cases and 220,816 controls were identified from five case-control studies and two cohort studies. The summary OR for the association between coffee consumption and thyroid cancer risk was 0.88 (95% confidence interval (CI) = 0.71-1.07). There was no significant heterogeneity among the study results (I² = 0%, p = 0.79). However, the beneficial effect of coffee consumption on thyroid cancer was found only in hospital-based case-control studies (OR= 0.59, 95% CI= 0.37-0.93). There was no significant association between coffee consumption and thyroid cancer risk according to our meta-analysis results. These findings should be interpreted with caution because of potential biases and confounding variables. Further prospective studies with a larger number of cases are encouraged to confirm these results.

Coffee consumption and risk of all-cause, cardiovascular, and cancer mortality in smokers and non-smokers: a dose-response meta-analysis

Coffee consumption has been associated with several benefits toward human health. However, its association with mortality risk has yielded contrasting results, including a non-linear relation to all-cause and cardiovascular disease (CVD) mortality and no association with cancer mortality. As smoking habits may affect the association between coffee and health outcomes, the aim of the present study was to update the latest dose-response meta-analysis of prospective cohort studies on the association between coffee consumption and mortality risk and conduct stratified analyses by smoking status and other potential confounders. A systematic search was conducted in electronic databases to identify relevant studies, risk estimates were retrieved from the studies, and dose-response analysis was modeled by using restricted cubic splines. A total of 31 studies comprising 1610,543 individuals and 183,991 cases of all-cause, 34,574 of CVD, and 40,991 of cancer deaths were selected. Analysis showed decreased all-cause [relative risk (RR) = 0.86, 95 % confidence interval (CI) = 0.82, 0.89)] and CVD mortality risk (RR = 0.85, 95 % CI = 0.77, 0.93) for consumption of up to 4 cups/day of coffee, while higher intakes were associated with no further lower risk. When analyses were restricted only to non-smokers, a linear decreased risk of all-cause (RR = 0.94, 95 % CI = 0.93, 0.96), CVD (RR = 0.94, 95 % CI = 0.91, 0.97), and cancer mortality (RR = 0.98, 95 % CI = 0.96, 1.00) for 1 cup/day increase was found. The search for other potential confounders, including dose-response analyses in subgroups by gender, geographical area, year of publication, and type of coffee, showed no relevant differences between strata. In conclusion, coffee consumption is associated with decreased risk of mortality from all-cause, CVD, and cancer; however, smoking modifies the observed risk when studying the role of coffee on human health.