Coffee Consumption and All-Cause and Cardiovascular Mortality - Three-Prefecture Cohort in Japan

Effect of Coffee Consumption on Risk of Coronary Heart Disease in a Systematic Review and Meta-Analysis of Prospective Cohort Studies

Previous prospective studies have reported inconsistent findings on the association between coffee consumption and the risk of coronary heart disease (CHD). This study aimed to investigate their association using a meta-analysis of prospective studies. We searched PubMed and EMBASE for prospective cohort studies of the association between coffee consumption and the risk of CHD in the general population. We conducted a random-effects meta-analysis and also subgroup meta-analyses by various factors. Of 870 studies searched from databases, 32 prospective cohort studies were included in the final analysis. In the main meta-analysis of all studies, no significant association between coffee consumption and the risk of CHD was observed (relative risk [RR] 1.05, 95% confidence interval [CI] 0.97 to 1.14, I² = 64.9%). In the subgroup meta-analyses by gender, coffee consumption significantly increased the risk of CHD in men (RR 1.19, 95% CI 1.05 to 1.35, n = 17), whereas a nonsignificantly decreased risk of CHD was observed in women (RR 0.91, 95% CI 0.77 to 1.08, n = 11). Also, in the subgroup meta-analyses by follow-up period, coffee consumption significantly increased the risk of CHD in the follow-up of 20 years or longer (RR 1.16, 95% CI 1.06 to 1.27, n = 4) regardless of gender. In conclusion, in the current meta-analysis of prospective studies, we found that, overall, no significant association between coffee consumption and the risk of CHD was observed. However, coffee consumption showed a differential effect by gender, with an increased risk of CHD in men and a potentially decreased risk in women.

Low-intensity cigarette smoking and mortality risks: a pooled analysis of prospective cohort studies in Japan

BACKGROUND

Increasing proportions of smokers in Japan smoke <10 cigarettes per day (CPD). Yet, the health risks of low-intensity smoking in Asia are poorly understood.

METHODS

We performed a pooled analysis of 410 294 adults from nine population-based prospective cohort studies participating in the Japan Cohort Consortium. Cigarette-use data were collected at each study baseline in 1983-1994. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality were calculated using multivariable-adjusted Cox regression by CPD among current smokers and by age at cessation among former smokers, with never smokers as the referent group. Pooled HRs and CIs were computed using a random-effect model.

RESULTS

The smoking prevalence was 54.5% in men and 7.4% in women. About 15.5% of male and 50.4% of female current smokers smoked 1-10 CPD (low-intensity). Both male and female low-intensity smokers had higher all-cause mortality risks than never smokers. Risks were further higher with increasing CPD in a dose-response manner. HRs (95% CIs) were 1.27 (0.97-1.66), 1.45 (1.33-1.59) and 1.49 (1.38-1.62) for 1-2, 3-5 and 6-10 CPD, respectively, in men; 1.28 (1.01-1.62), 1.49 (1.34-1.66) and 1.68 (1.55-1.81) for 1-2, 3-5 and 6-10 CPD, respectively, in women. Similar associations were observed for smoking-related causes of death. Among former low-intensity smokers, younger age at cessation was associated with lower mortality risk.

CONCLUSIONS

Smoking very low amounts was associated with increased mortality risks in Japan. All smokers should quit, even if they smoke very few CPD.

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.

Effect of dietary modification and antioxidant supplementation on intraocular pressure and open-angle glaucoma

Primary open-angle glaucoma (POAG) is an age-dependent, intraocular pressure (IOP)-related degeneration of the retinal ganglion cells (RGC). At present, IOP is the only modifiable factor that has been identified to prevent glaucomatous vision loss. Though the pathogenesis of glaucomatous optic neuropathy is still not well understood, increasing evidence suggests oxidative stress may contribute to the induction and progression of glaucoma. Furthermore, antioxidant use may be protective against glaucoma through various mechanisms, including reducing IOP, preserving vascular health, and preventing ganglion cell loss. This article provides a comprehensive review of the effect of oxidative stress, diet, and antioxidant therapy on IOP and open-angle glaucoma.

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.

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.