Chronic coffee consumption and respiratory disease: A systematic review

The Association Between Dietary Magnesium Intake with Chronic Obstructive Pulmonary Disease and Lung Function in US Population: a Cross-sectional Study

Chronic obstructive pulmonary disease (COPD) is now considered among the top three contributors to mortality globally. There is limited understanding surrounding the contribution of magnesium to the progression of COPD. This survey aims to evaluate the connection between dietary magnesium intake and both lung function and COPD prevalence among the US population. The research comprised 4865 participants in the National Health and Nutrition Examination Survey (NHANES) program conducted from 2007 to 2012. To evaluate the association between dietary magnesium intake and lung function as well as COPD, the study conducted multiple regression analyses, stratified analyses, and smoothed curves. In this study, we explored the relationship between higher magnesium intake and higher FEV1 [β = 0.21 (95% CI 0.12, 0.30)] and FVC [β = 0.25 (95% CI 0.14, 0.36)] after accounting for all potential confounding factors. We demonstrated a relationship between increased magnesium intake and reduced odds of developing COPD [OR = 0.9993 (95% CI 0.9987, 1.0000)]. The results of stratified analyses further indicated that the relationship between magnesium intake and the risk of COPD is more pronounced in the 40-60 age group and males. The study demonstrated positive associations between the intake of dietary magnesium and both FEV1 and FVC. Additionally, an adverse relationship between magnesium intake and the prevalence of COPD was also observed, suggesting that supplementation with magnesium may be a practical approach to preventing and managing COPD.

Nebulized caffeine alleviates airway hyperresponsiveness in a murine asthma model

The clinical definition of "difficult asthma" has expanded recently to include an ever-growing subset of patients with symptoms that cannot be controlled by conventional means, forcing the medical community to develop innovative therapeutics. Beneficial effects of coffee for subjects with asthma, primarily the effect of methylxanthine components, have long been described. Methylxanthines, including theophylline and caffeine, inhibit phosphodiesterases and downstream cAMP signaling to prevent mast cell degranulation while promoting immunomodulation (Peleman RA, Kips JC, Pauwels RA. Clin Exp Allergy 28: 53-56, 1998; Deshpande DA, Wang WCH, McIlmoyle EL, Robinett KS, Schillinger RM, An SS, Sham JSK, Liggett SB. Nat Med 16: 1299-1304, 2010). Caffeine is also a bitter taste receptor agonist, binding to taste-sensing type 2 receptors (TAS2R) before releasing calcium to hyperpolarize airway smooth muscle membranes, inducing bronchodilation (Workman AD, Palmer JN, Adappa ND, Cohen NA. Curr Allergy Asthma Rep 15: 72, 2015; Devillier P, Naline E, Grassin-Delyle S. Pharmacol Ther 155: 11-21, 2015). Theophylline is conventionally used to treat asthma, whereas, according to the literature, the dosage required for orally administered caffeine has yielded modest improvement (Alfaro TM, Monteiro RA, Cunha RA, Cordeiro CR. Clin Respir J 12: 1283-1294, 2018). We sought to determine whether aerosolization of ultrafine caffeine particles (2.5-4 μm) directly to the lungs of susceptible A/J mice challenged with methacholine would improve pulmonary function via forced oscillation technique. In addition, we assessed whether nebulization of caffeine leads to changes in lung pathophysiology and bronchoalveolar lavage cell profiles. We found that mice that received aerosolized caffeine had statistically significant decreases in maximum airway resistance [6.3 vs. 3.9 cmH2O·s/mL at 62.5 mg/mL caffeine; confidence interval (CI) = -4.3, -0.4; P = 0.02] and significant delays in the time required to reach maximum resistance compared with that of controls (64.7 vs. 172.1 sec at 62.5 mg/mL caffeine, CI = 96.0, 118.9; P < 0.0001). Nebulized caffeine yielded a consistent effect on airway hyperresponsiveness at a range of doses without evidence of significant pathology relative to vehicle control.NEW & NOTEWORTHY For decades, coffee has been shown to improve symptoms in patients with asthma. One component, theophylline, is conventionally used to treat asthma, whereas the dosage required for orally administered caffeine has yielded modest improvement. We sought to determine whether aerosolization of caffeine directly to the lungs of susceptible A/J mice challenged with methacholine would alter pulmonary function via forced oscillation technique. We found nebulized caffeine yielded a consistent improvement on murine AHR.

The Possible Role of Food and Diet in the Quality of Life in Patients with COPD-A State-of-the-Art Review

Diet has been described as a modifiable risk factor for the development and progression of chronic diseases, and emerging evidence increasingly points to its preventive and therapeutic role in chronic obstructive pulmonary disease (COPD). While the relationship between the underlying disease and diet is natural in conditions such as metabolic disorders, obesity, diabetes, etc., the direct effect is not so evident in chronic obstructive pulmonary disease. Poor diet quality and the development of nutrient deficiencies in respiratory diseases, including COPD, can be associated with disease-specific factors such as the exacerbation of respiratory symptoms. These symptoms can be improved by dietary interventions, leading to positive changes in the pathogenesis of the disease and the quality of life of patients. Therefore, our aim was to review the latest randomized controlled trials (RCTs) of dietary interventions in chronic respiratory patients and describe their effects on respiratory function, physical activity, systemic inflammatory parameters, and quality of life. We conducted a literature search on dietary interventions for COPD patients in the PubMed, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials (CENTRAL) databases, focusing on publications from 1 July 2018 to 1 July 2023. We used specific keywords and MESH terms, focusing on RCTs. A total of 26 articles and 1811 COPD patients were included in this review. On the basis of our findings, dietary interventions, in particular components of the Mediterranean diet such as protein, omega-3 polyunsaturated fatty acids, and vegetables, appear to have beneficial effects in patients with chronic respiratory diseases, and their application is beneficial. However, long-term follow-up studies are still needed to examine the effects of dietary interventions in this patient population.

Effects of coffee intake on airway hypersensitivity and immunomodulation: an in vivo murine study

BACKGROUND/OBJECTIVES

Coffee is a complex chemical mixture, with caffeine being the most well-known bioactive substance. The immunomodulatory and anti-inflammatory properties of coffee and caffeine impact health in various aspects, including the respiratory system. The objective is to investigate the effects of coffee and caffeine on airway hyperresponsiveness and allergic reactions, as well as to analyze and compare associated cytokine profiles.

MATERIALS/METHODS

BALB/c mice were intraperitoneally sensitized with ovalbumin (OVA) and given OVA inhalation to induce airway hypersensitivity. Two weeks after sensitization, they were intragastrically gavaged with coffee or caffeine, both containing 0.3125 mg caffeine, daily for 4 weeks. Control mice were fed with double-distilled water. Serum OVA-specific antibody levels were measured beforehand and 5 weeks after the first gavage. Airway hyperresponsiveness was detected by whole body plethysmography after gavage. Cytokine levels of bronchoalveolar lavage and cultured splenocytes were analyzed.

RESULTS

Coffee effectively suppressed T helper 2-mediated specific antibody response. Airway responsiveness was reduced in mice treated with either coffee or caffeine. Compared to the control, coffee significantly reduced OVA-specific immunoglobulin (Ig) G, IgG1 and IgE antibody responses (P < 0.05). Caffeine also attenuated specific IgG and IgG1 levels, though IgE level was unaffected. Coffee significantly reduced interleukin (IL)-4 and increased IL-10 concentration in spleen cells and bronchoalveolar lavage fluid (P < 0.05).

CONCLUSIONS

Coffee effectively attenuated airway hyperresponsiveness and systemic allergic responses induced by OVA food allergen in mice. As a complex composition of bioactive substances, coffee displayed enhanced immunomodulatory and anti-inflammatory effects than caffeine.

Synergistic Effects of Caffeine in Combination with Conventional Drugs: Perspectives of a Drug That Never Ages

Plants have been known since ancient times for their healing properties, being used as preparations against human diseases of different etiologies. More recently, natural products have been studied and characterized, isolating the phytochemicals responsible for their bioactivity. Most certainly, there are currently numerous active compounds extracted from plants and used as drugs, dietary supplements, or sources of bioactive molecules that are useful in modern drug discovery. Furthermore, phytotherapeutics can modulate the clinical effects of co-administered conventional drugs. In the last few decades, the interest has increased even more in studying the positive synergistic effects between plant-derived bioactives and conventional drugs. Indeed, synergism is a process where multiple compounds act together to exert a merged effect that is greater than that of each of them summed together. The synergistic effects between phytotherapeutics and conventional drugs have been described in different therapeutic areas, and many drugs are based on synergistic interactions with plant derivatives. Among them, caffeine has shown positive synergistic effects with different conventional drugs. Indeed, in addition to their multiple pharmacological activities, a growing body of evidence highlights the synergistic effects of caffeine with different conventional drugs in various therapeutic fields. This review aims to provide an overview of the synergistic therapeutic effects of caffeine and conventional drugs, summarizing the progress reported to date.

Association of Coffee and Tea Consumption with Cardiovascular Disease, Chronic Respiratory Disease, and their Comorbidity

SCOPE

Since associations between coffee and tea consumption with cardiovascular disease (CVD) and chronic respiratory disease (CRD) remain controversial. This study aims to investigate the separate and combined associations of coffee and tea consumption with CVD, CRD, and their comorbidity.

METHODS AND RESULTS

Within the UK Biobank, 390 039 participants (56.2 ± 8.1 years) free of CVD and CRD are included. Coffee and tea consumption are self-reported at baseline. During a median follow-up of 12.1 years, 31126 CVD, 34132 CRD, and 6071 CVD-CRD comorbidity cases are identified. J-shaped associations between coffee and tea consumption with CVD, CRD, and CVD-CRD comorbidity are observed (p for nonlinearity <0.001). Compared with neither coffee nor tea consumption, hazard ratios (HRs) and 95% confidence intervals (CIs) of combined consumption of moderate coffee and tea (each 2-3 cups per day) are 0.88 (0.81-0.96) for CVD, 0.78 (0.72-0.84) for CRD, and 0.74 (0.61-0.91) for CVD-CRD comorbidity.

CONCLUSION

Moderate consumption of coffee and tea separately or in combination are associated with lower risks of CVD, CRD, and their comorbidity.

Association of Coffee and Tea Consumption with the Risk of Asthma: A Prospective Cohort Study from the UK Biobank

Background: Previous observational studies investigated the relationship between coffee and tea intake and the risk of asthma, however, the conclusions were inconsistent. Further, the combined effect of coffee and tea consumption on asthma has rarely been studied. Methods: We examined associations between the self-reported intake of tea and coffee and the risk of incident asthma in a total of 424,725 participants aged from 39 to 73 years old from the UK Biobank. Cox proportional hazards models were used to estimate the associations between coffee/tea consumption and incident adult-onset asthma, adjusting for age, sex, race, smoking status, body mass index (BMI), education, and Townsend deprivation index. Results: Cox models with penalized splines showed J-shaped associations of coffee, tea, caffeinated coffee, and caffeine intake from coffee and tea with the risk of adult-onset asthma (p for nonlinear <0.01). Coffee intake of 2 to 3 cups/d (hazard ratio [HR] 0.877, 95% confidence interval [CI] 0.826−0.931) or tea intake of 0.5 to 1 cups/d (HR 0.889, 95% CI 0.816−0.968) or caffeinated coffee intake of 2 to 3 cups/d (HR 0.858, 95% CI 0.806−0.915) or combination caffeine intake from tea and coffee of 160.0 to 235.0 mg per day (HR 0.899, 95% CI 0.842−0.961) were linked with the lowest hazard ratio of incident asthma after adjustment for age, sex, race, smoking status, BMI, qualification, and Townsend deprivation index. Conclusions: Collectively, the study showed light-to-moderate coffee and tea consumption was associated with a reduced risk of adult-onset asthma and controlling total caffeine intake from coffee and tea for a moderate caffeine dose of 160.0 to 305.0 mg/day may be protective against adult-onset asthma. Further investigation on the possible preventive role of caffeine in asthma is warranted.

Hormonal regulation of health-promoting compounds in tea (Camellia sinensis L.)

Tea is the most frequently consumed natural beverage across the world produced with the young leaves and shoots of the evergreen perennial plant Camellia sinensis (L.) O. Kuntze. The expanding global appeal of tea is partly attributed to its health-promoting benefits such as anti-inflammation, anti-cancer, anti-allergy, anti-hypertension, anti-obesity, and anti- SARS-CoV-2 activity. The many advantages of healthy tea intake are linked to its bioactive substances such as tea polyphenols, flavonoids (catechins), amino acids (theanine), alkaloids (caffeine), anthocyanins, proanthocyanidins, etc. that are produced through secondary metabolic pathways. Phytohormones regulate secondary metabolite biosynthesis in a variety of plants, including tea. There is a strong hormonal response in the biosynthesis of polyphenols, catechins, theanine and caffeine in tea under control and perturbed environmental conditions. In addition to the impact of preharvest plant hormone manipulation on green tea quality, changes in hormones of postharvest tea also regulate quality-related metabolites in tea. In this review, we discuss the health benefits of major tea constituents and the role of various plant hormones in improving the endogenous levels of these compounds for human health benefits. The fact that the ratio of tea polyphenols to amino acids and the concentrations of tea components are changed by environmental conditions, most notably by climate change-associated variables, the selection and usage of optimal hormone combinations may aid in sustaining tea quality, and thus can be beneficial to both consumers and producers.

Diet and Respiratory Infections: Specific or Generalized Associations?

Background: Based on our recently reported associations between specific dietary behaviors and the risk of COVID-19 infection in the UK Biobank (UKB) cohort, we further investigate whether these associations are specific to COVID-19 or extend to other respiratory infections. Methods: Pneumonia and influenza diagnoses were retrieved from hospital and death record data linked to the UKB. Baseline, self-reported (2006−2010) dietary behaviors included being breastfed as a baby and intakes of coffee, tea, oily fish, processed meat, red meat (unprocessed), fruit, and vegetables. Logistic regression estimated the odds of pneumonia/influenza from baseline to 31 December 2019 with each dietary component, adjusting for baseline socio-demographic factors, medical history, and other lifestyle behaviors. We considered effect modification by sex and genetic factors related to pneumonia, COVID-19, and caffeine metabolism. Results: Of 470,853 UKB participants, 4.0% had pneumonia and 0.2% had influenza during follow up. Increased consumption of coffee, tea, oily fish, and fruit at baseline were significantly and independently associated with a lower risk of future pneumonia events. Increased consumption of red meat was associated with a significantly higher risk. After multivariable adjustment, the odds of pneumonia (p ≤ 0.001 for all) were lower by 6−9% when consuming 1−3 cups of coffee/day (vs. <1 cup/day), 8−11% when consuming 1+ cups of tea/day (vs. <1 cup/day), 10−12% when consuming oily fish in higher quartiles (vs. the lowest quartile—Q1), and 9−14% when consuming fruit in higher quartiles (vs. Q1); it was 9% higher when consuming red meat in the fourth quartile (vs. Q1). Similar patterns of associations were observed for influenza but only associations with tea and oily fish met statistical significance. The association between fruit and pneumonia risk was stronger in women than in men (p = 0.001 for interaction). Conclusions: In the UKB, consumption of coffee, tea, oily fish, and fruit were favorably associated with incident pneumonia/influenza and red meat was adversely associated. Findings for coffee parallel those we reported previously for COVID-19 infection, while other findings are specific to these more common respiratory infections.

Association of coffee drinking with all-cause and cause-specific mortality in over 190,000 individuals: data from two prospective studies

We examined the association of coffee drinking with all-cause and cause-specific mortality in a pooled analysis of two Korean prospective cohort studies: The Korea National Health and Nutrition Examination Survey and the Korean Genome and Epidemiology Study. We included 192,222 participants, and a total of 6057 deaths were documented. Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs), and the HRs were combined using a random-effects model. Coffee drinking was associated with a lower risk of all-cause mortality [HR (95% CI) = 0.84 (0.77-0.92), for ≥3 cups/day of coffee drinking versus non-drinkers; p for trend = 0.004]. We observed the potential benefit of coffee drinking for mortality due to cardiovascular disease, respiratory disease, and diabetes, but not for cancer mortality. Overall, we found that moderate coffee drinking was associated with a lower risk of death in population-based cohort analysis of Korean adults.

The Medicinal Chemistry of Caffeine

The purine alkaloid caffeine is the most widely consumed psychostimulant drug in the world and has multiple beneficial pharmacological activities, for example, in neurodegenerative diseases. However, despite being an extensively studied bioactive natural product, the mechanistic understanding of caffeine's pharmacological effects is incomplete. While several molecular targets of caffeine such as adenosine receptors and phosphodiesterases have been known for decades and inspired numerous medicinal chemistry programs, new protein interactions of the xanthine are continuously discovered providing potentially improved pharmacological understanding and a molecular basis for future medicinal chemistry. In this Perspective, we gather knowledge on the confirmed protein interactions, structure activity relationship, and chemical biology of caffeine on well-known and upcoming targets. The diversity of caffeine's molecular activities on receptors and enzymes, many of which are abundant in the CNS, indicates a complex interplay of several mechanisms contributing to neuroprotective effects and highlights new targets as attractive subjects for drug discovery.

Residence, Clinical Features, and Genetic Risk Factors Associated with Symptoms of COVID-19 in a Cohort of Older People in Madrid

BACKGROUND

The older population has been especially affected by the severe acute respiratory syndrome coronavirus 2 pandemic (COVID-19).

OBJECTIVE

The aim of the study was to explore the incidence, severity, mortality rate, clinical features, and risk factors of symptoms of COVID-19 in home-dwelling older people, and its association with type of residence, cognitive deterioration, and neurodegenerative diseases.

METHODS

Data about symptoms of COVID-19 were collected through a telephone survey in the cohort of 913 older volunteers of the Vallecas Project, aged 75-90 years, most of them (902) home-dwelling, in Madrid, Spain. The association of demographic and anthropometric measures, genetic polymorphisms, comorbidities, life habits, type of residence, and frailty surrogates were explored as potential risk factors for the incidence, severity, and mortality of COVID-19 in the older population.

FINDINGS

Sixty-two cases reported symptoms compatible with COVID-19; 6 of them had died, 4 in their home and 2 in the nursing home. Moderate/severe cases were significantly older and more frequently males. The APOE ε4 allele was associated with the presence of symptoms of COVID-19. Higher systolic blood pressure, more intense smoking habit, more alcohol intake, lower consumption of coffee and tea, and cognitive impairment were associated with disease severity.

CONCLUSIONS

The estimated incidence of symptomatic COVID-19 in this older cohort of Madrid was 6.8%, with an overall mortality rate of 0.7% (18.2% in those living in a nursing home) and a fatality rate of 9.9%. Our exploratory study indicates that life habits, other clinical conditions and, the ε4 variant of the APOE gene are associated with the presence and clinical severity of coronavirus infection.

Energy-drink consumption is associated with asthma, allergic rhinitis, and atopic dermatitis in Korean adolescents

BACKGROUND/OBJECTIVES

Few studies have evaluated the effects of energy drinks on allergic diseases. The purpose of this investigation was to evaluate the association between energy drinks and various allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis, in a large representative Korean adolescent population.

SUBJECTS/METHODS

This cross-sectional study used data from the Korea Youth Risk Behavior Web-based Survey collected from 2015 to 2016. A total of 129,809 participants (n = 67,056 for males; n = 62,753 for females) aged 12-18 years were included and were asked about their frequency of consumption of energy drinks such as Hot6^®, Redbull^®, and Bacchus^®. Their history of asthma, allergic rhinitis, and atopic dermatitis throughout life and in the last 12 months were obtained. The association between the frequency of energy-drink consumption and allergic diseases was analyzed using multiple logistic regression with adjustment for various covariates.

RESULTS

Age, sex, physical activity, obesity, region of residence, economic level, paternal and maternal educational level, smoking, and alcohol consumption differed significantly according to the frequency of energy-drink consumption (each P < 0.001). Frequent energy-drink consumption (≥7 times a week) was significantly associated with asthma throughout life (odds ratio [OR] = 1.30, 95% confidence interval (CI) = 1.03-1.64, P = 0.025), asthma within the last 12 months (OR = 1.65, 95% CI = 1.16-2.35, P = 0.006), allergic rhinitis within the last 12 months (OR = 1.21, 95% CI = 1.02-1.44, P = 0.030), and atopic dermatitis within the last 12 months (OR = 1.49, 95% CI = 1.17-1.90, P = 0.001) compared to no energy-drink consumption in the full-adjusted model.

CONCLUSIONS

Frequent energy-drink consumption is associated with allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis, in Korean adolescents.

Analysis of the Relationship between Asthma and Coffee/Green Tea/Soda Intake

This study aimed to evaluate the association between asthma and the intake of coffee/green tea/soda. We used Health Examinee data from the Korean Genome and Epidemiology Study (2004–2016). The participants (n = 3146 with asthma; n = 158,902 non-asthma) were asked about the frequency and amount of their coffee/green tea/soda intake. Multiple logistic regression analyses were used to calculate the adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for asthma according to the frequency and amount of coffee/green tea/soda intake. Compared to the group consuming no coffee, the aORs for asthma were 0.82 (95% CI = 0.73–0.93, p = 0.002) in the group consuming coffee 1–2 times/day and 0.87 (95% CI = 0.78–0.97, p = 0.011) in the group consuming coffee in quantities of 1 cup, respectively. However, the frequency and amount of green tea and soda consumption were not significantly associated with asthma after adjusting for coffee consumption (all p > 0.05). These findings were consistent in the female subgroup (1–2 times/day: aOR = 0.76, 95% CI = 0.66–0.87, p < 0.001, and 1 cup each time: aOR = 0.79, 95% CI = 0.70–0.90, p < 0.001) but not in the male subgroup. Drinking 1 cup of coffee each time and 1–2 times per day may have protective effects against asthma in a Korean population. However, the associations between asthma and green tea/soda cannot be clearly established.

The Joint Effects of Some Beverages Intake and Smoking on Chronic Obstructive Pulmonary Disease in Korean Adults: Data Analysis of the Korea National Health and Nutrition Examination Survey (KNHANES), 2008-2015

Some beverages and smoking cause an inflammatory response in the lungs and airways in a similar way, ultimately affecting chronic obstructive pulmonary disease (COPD) occurrence. Using a nationally representative health survey database, this study investigates the individual and joint effects of consumption of different beverages and smoking on COPD. This study is a cross-sectional analysis of 15,961 Korean adults in the Korea National Health and Nutritional Examination Survey of 2008–2015. COPD was defined as forced expiratory volume in 1 s (FEV₁) divided by forced vital capacity (FVC) <0.70. We used multiple linear and logistic regression models to examine the association of beverage consumption and smoking with an FEV₁/FVC ratio and odds ratio (OR) for COPD. The mean FEV₁/FVC ratio decreased with increasing soda intake (p = 0.016), coffee intake (p = 0.031), and smoking status; however, the mean FEV₁/FVC ratio increased with increasing green tea intake frequency (p = 0.029). When soda intake increased to 10 times/month, the OR of having COPD increased to 1.04 times (95% CI: 1.01, 1.07). The positive joint effect of soda intake and smoking on COPD was marginally significant (p = 0.058). We found that soda intake, coffee intake, and smoking increased airflow limitation while green tea intake decreased it. In addition, soda intake and smoking had a positive joint effect on COPD in the Korean population.

Role of Diet in Chronic Obstructive Pulmonary Disease Prevention and Treatment

Chronic obstructive pulmonary disease is one of the leading causes of morbidity and mortality worldwide and a growing healthcare problem. Identification of modifiable risk factors for prevention and treatment of COPD is urgent, and the scientific community has begun to pay close attention to diet as an integral part of COPD management, from prevention to treatment. This review summarizes the evidence from observational and clinical studies regarding the impact of nutrients and dietary patterns on lung function and COPD development, progression, and outcomes, with highlights on potential mechanisms of action. Several dietary options can be considered in terms of COPD prevention and/or progression. Although definitive data are lacking, the available scientific evidence indicates that some foods and nutrients, especially those nutraceuticals endowed with antioxidant and anti-inflammatory properties and when consumed in combinations in the form of balanced dietary patterns, are associated with better pulmonary function, less lung function decline, and reduced risk of COPD. Knowledge of dietary influences on COPD may provide health professionals with an evidence-based lifestyle approach to better counsel patients toward improved pulmonary health.

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.

How to recognize caffeine overdose

Caffeine is the most widely consumed stimulant in the world and can offer a variety of benefits when consumed in moderation. But consuming caffeine in extremely high amounts can lead to an overdose. This article examines how nurses can recognize the signs and symptoms of caffeine overdose and educate patients on how to prevent this common problem.

Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes

Objectives To evaluate the existing evidence for associations between coffee consumption and multiple health outcomes.Design Umbrella review of the evidence across meta-analyses of observational and interventional studies of coffee consumption and any health outcome.Data sources PubMed, Embase, CINAHL, Cochrane Database of Systematic Reviews, and screening of references.Eligibility criteria for selecting studies Meta-analyses of both observational and interventional studies that examined the associations between coffee consumption and any health outcome in any adult population in all countries and all settings. Studies of genetic polymorphisms for coffee metabolism were excluded.Results The umbrella review identified 201 meta-analyses of observational research with 67 unique health outcomes and 17 meta-analyses of interventional research with nine unique outcomes. Coffee consumption was more often associated with benefit than harm for a range of health outcomes across exposures including high versus low, any versus none, and one extra cup a day. There was evidence of a non-linear association between consumption and some outcomes, with summary estimates indicating largest relative risk reduction at intakes of three to four cups a day versus none, including all cause mortality (relative risk 0.83 (95% confidence interval 0.79 to 0.88), cardiovascular mortality (0.81, 0.72 to 0.90), and cardiovascular disease (0.85, 0.80 to 0.90). High versus low consumption was associated with an 18% lower risk of incident cancer (0.82, 0.74 to 0.89). Consumption was also associated with a lower risk of several specific cancers and neurological, metabolic, and liver conditions. Harmful associations were largely nullified by adequate adjustment for smoking, except in pregnancy, where high versus low/no consumption was associated with low birth weight (odds ratio 1.31, 95% confidence interval 1.03 to 1.67), preterm birth in the first (1.22, 1.00 to 1.49) and second (1.12, 1.02 to 1.22) trimester, and pregnancy loss (1.46, 1.06 to 1.99). There was also an association between coffee drinking and risk of fracture in women but not in men.Conclusion Coffee consumption seems generally safe within usual levels of intake, with summary estimates indicating largest risk reduction for various health outcomes at three to four cups a day, and more likely to benefit health than harm. Robust randomised controlled trials are needed to understand whether the observed associations are causal. Importantly, outside of pregnancy, existing evidence suggests that coffee could be tested as an intervention without significant risk of causing harm. Women at increased risk of fracture should possibly be excluded.