Coffee drinking is dose-dependently related to the risk of acute coronary events in middle-aged men

Coffee consumption and mortality in a 14-year follow-up of an elderly northern Finnish population

The present study assessed the relationship between coffee consumption and mortality in a home-dwelling elderly population. A population-based cohort of 817 men and women born in 1920 or earlier and living in northern Finland provided complete data on daily coffee consumption and other variables at the baseline examination in 1991-1992. Deaths were monitored through to the end of 2005 by national death certificates, resulting in 6960 person-years of follow-up. Hazard rate ratios for mortality by daily coffee intake were estimated by Poisson regression models adjusted for some known predictors of mortality. During 14.5 years of follow-up, 623 deaths occurred. The total mortality rate was inversely related to the number of cups (average volume, 125 ml) of coffee consumed daily. After adjustment for age, sub-period of follow-up, sex, marital status, basic educational level, previous occupational group, current smoking, BMI, history of myocardial infarction, self-rated health and presence of diabetes, cognitive impairment or physical disability, the estimated relative risk reduction of total mortality per an increment of one more cup of coffee per d reported at baseline was 4 (95% CI 0, 8) %. The observed associations between coffee consumption and mortality from CVD, cancer, and other or unknown causes, respectively, were qualitatively similar to that of total mortality but the estimates were less precise. The effect of coffee consumption at baseline appeared to attenuate after 10 years since the start of follow-up. The present study provides evidence for daily (caffeine-containing) coffee intake being inversely associated with mortality in the elderly.

Coffee consumption and risk of cardiovascular events after acute myocardial infarction: results from the GISSI (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico)-Prevenzione trial

BACKGROUND

The relation between coffee consumption and cardiovascular disease has been studied extensively, but results are still debated. In addition, little evidence is available on patients with established coronary heart disease.

METHODS AND RESULTS

Prospectively ascertained information among 11,231 Italian patients (9584 males and 1647 females) with recent (< or = 3 months) myocardial infarction enrolled in the GISSI (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico)-Prevenzione trial was used. Usual dietary habits were assessed at baseline and updated at 0.5 and 1.5 years. Coffee consumption was categorized as never/almost never, < 2 cups per day, 2 to 4 cups per day, and > 4 cups per day. Medication use and fasting glucose were assessed at 0.5, 1, 1.5, 2.5, and 3.5 years. Risk was evaluated with Cox proportional hazards with time-varying covariates. The main outcome measure was the cumulative incidence of cardiovascular events (cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke). A total of 1167 cardiovascular events occurred during 36,961 person-years of follow-up. After multivariable adjustment for potential confounders in the time-dependent analysis, the relative risk of cardiovascular events across categories of coffee consumption was 1.02 (95% CI 0.87 to 1.20) for < 2 cups per day, 0.91 (95% CI 0.75 to 1.09) for 2 to 4 cups per day, and 0.88 (95% CI 0.64 to 1.20) for > 4 cups per day compared with abstainers (P for trend=0.18). Ultimately, coffee consumption did not change the risk of coronary heart disease events, stroke, and sudden death.

CONCLUSIONS

No association between moderate coffee intake and cardiovascular events was observed in post-myocardial infarction patients.

Coffee, caffeine, and coronary heart disease

PURPOSE OF REVIEW

This review summarizes and highlights recent advances in current knowledge of the relationship between coffee and caffeine consumption and risk of coronary heart disease. Potential mechanisms and genetic modifiers of this relationship are also discussed.

RECENT FINDINGS

Studies examining the association between coffee consumption and coronary heart disease have been inconclusive. Coffee is a complex mixture of compounds that may have either beneficial or harmful effects on the cardiovascular system. Randomized controlled trials have confirmed the cholesterol-raising effect of diterpenes present in boiled coffee, which may contribute to the risk of coronary heart disease associated with unfiltered coffee consumption. A recent study examining the relationship between coffee and risk of myocardial infarction incorporated a genetic polymorphism associated with a slower rate of caffeine metabolism and provides strong evidence that caffeine also affects risk of coronary heart disease. Several studies have reported a protective effect of moderate coffee consumption, which suggests that coffee contains other compounds that may be beneficial.

SUMMARY

Diterpenes present in unfiltered coffee and caffeine each appear to increase risk of coronary heart disease. A lower risk of coronary heart disease among moderate coffee drinkers might be due to antioxidants found in coffee.

Coffee drinking induces incorporation of phenolic acids into LDL and increases the resistance of LDL to ex vivo oxidation in humans

BACKGROUND

Epidemiologic and intervention studies indicate that both diet as a whole and single dietary components are involved in the risk of atherosclerosis. The resistance of LDL to oxidative modification is an ex vivo indicator of risk, which is modulated by dietary components. Coffee contains phenolic compounds with antioxidant activity. These molecules are found in plasma after the consumption of coffee, and it has been shown that, in vitro, they are able to decrease the susceptibility of LDL to oxidation.

OBJECTIVE

The aim of this study was to evaluate the effect of coffee consumption on the redox status of LDL as modulated by the possible incorporation of phenolic acids into LDL.

DESIGN

Ten healthy volunteers, after an overnight fast, drank 200 mL filtered coffee. Blood was drawn before and 30 and 60 min after drinking. Changes in LDL redox status were evaluated by the measure of LDL resistance to oxidative modification and the concentration of LDL(-), a mildly modified, electronegative LDL subfraction. Chlorogenic and phenolic acids concentration in LDL were measured by electrochemical HPLC.

RESULTS

The resistance of LDL to oxidative modification increased significantly after coffee drinking, but the LDL(-) concentration did not increase. The concentration into LDL of conjugated forms of caffeic, p-coumaric, and ferulic acids increased significantly after coffee drinking.

CONCLUSION

Drinking 200 mL (1 cup) coffee induces an increase in the resistance of LDL to oxidative modification, probably as a result of the incorporation of coffee's phenolic acids into LDL.

Long-term, moderate coffee consumption is associated with lower prevalence of diabetes mellitus among elderly non-tea drinkers from the Mediterranean Islands (MEDIS Study)

BACKGROUND

We evaluated the association between coffee drinking and the prevalence of type 2 diabetes mellitus in elderly people from the Mediterranean islands.

METHODS

During 2005-2007, 500 men and 437 women (aged 65 to 100 years) from the islands of Cyprus (n = 300), Mitilini (n = 142), Samothraki (n = 100), Cephalonia (n = 104), Corfu (n = 160) and Crete (n = 131) participated in the survey. Cardiovascular disease (CVD) risk factors (i.e. hypertension, diabetes, hypercholesterolemia and obesity), as well as behavioral, lifestyle and dietary characteristics were assessed using face-to-face interviews and standard procedures. Among various factors, fasting blood glucose was measured and prevalence of type 2 diabetes mellitus was estimated, according to the established American Diabetes Association (ADA) criteria, while all participants were asked about the frequency of any type of coffee consumption over the last year.

RESULTS

Coffee drinking was reported by 84% of the participants, the majority of whom drank boiled coffee. The participants reported that they had consumed coffee for at least 30 years of their life. Data analysis adjusted for various potential confounders, revealed that, compared to non-consumption, the multi-adjusted odds ratio for having diabetes was 0.47 (95%, CI 0.32 to 0.69) for 1-2 cups/day, while it was 1.05 (95%, CI 0.70 to 1.55) for >3 cups/day, after adjusting for various potential confounders. The association of coffee drinking with diabetes was significant only among non-tea drinkers. Increased coffee intake was not associated with diabetes prevalence.

CONCLUSION

The data presented suggest that moderate coffee drinking is associated with a lower likelihood of having diabetes, after adjusting for various potential confounders.

Health behaviours as explanations for educational level differences in cardiovascular and all-cause mortality: a follow-up of 60 000 men and women over 23 years

BACKGROUND

Health behaviours are potential explanatory factors for socioeconomic differences in mortality. We examined the extent to which seven health behaviours covering dietary habits, smoking and physical activity, can account for relative differences in cardiovascular and all-cause mortality by educational level.

METHODS

Health behaviour data derived from nationwide Finnish health behaviour surveys from the years 1979 to 2001. These annually repeated cross-sectional surveys were linked to register-based information on educational level and subsequent mortality from the year of the survey until the end of 2001 (average follow-up time 11.9 years). The analyses included 29 065 men and 31 543 women of whom 4263 died. Cardiovascular disease (CVD), coronary heart disease (CHD), stroke and all-cause mortality was studied.

RESULTS

Educational level showed a graded association with all mortality outcomes. Health behaviours explained 54% of the relative difference between primary and higher educational level in CVD mortality among in men and 22% among in women. For all-cause mortality the corresponding figures were 45 and 38%. Smoking, vegetable use and physical activity were the most important health behaviours explaining educational level differences in all mortality outcomes, while the effects of type of fat used on bread, coffee drinking, relative weight and alcohol use were small.

CONCLUSIONS

Smoking, low vegetable use and physical inactivity explained a substantial part of educational level differences in cardiovascular and all-cause mortality among men and women. Socioeconomic trends in these behaviours are of crucial importance in determining whether socioeconomic mortality differences will widen or narrow in the future.

Coffee consumption and risk of type 2 diabetes and heart disease

Coffee seems to have distinct acute and long-term effects on health, which can be modified by genetic background. Coffee consumption is potentially protective against the development of type 2 diabetes, but given the lack of a solid biological basis for this association, and the possible adverse cardiovascular effects of coffee, recommendations for optimal coffee intake are difficult to establish.

Is coffee a functional food?

Definitions of functional food vary but are essentially based on foods' ability to enhance the quality of life, or physical and mental performance, of regular consumers. The worldwide use of coffee for social engagement, leisure, enhancement of work performance and well-being is widely recognised. Depending on the quantities consumed, it can affect the intake of some minerals (K, Mg, Mn, Cr), niacin and antioxidant substances. Epidemiological and experimental studies have shown positive effects of regular coffee-drinking on various aspects of health, such as psychoactive responses (alertness, mood change), neurological (infant hyperactivity, Alzheimer's and Parkinson's diseases) and metabolic disorders (diabetes, gallstones, liver cirrhosis), and gonad and liver function. Despite this, most reviews do not mention coffee as fulfilling the criteria for a functional food. Unlike other functional foods that act on a defined population with a special effect, the wide use of coffee-drinking impacts a broad demographic (from children to the elderly), with a wide spectrum of health benefits. The present paper discusses coffee-drinking and health benefits that support the concept of coffee as a functional food.

Coffee consumption and risk of coronary heart disease: a meta-analysis

BACKGROUND AND AIMS

During the past three decades the relationship between habitual coffee drinking and coronary heart disease (CHD) has been assessed in numerous studies, with conflicting results. The aim of this study was to systematically examine the data published on the association between habitual coffee consumption and risk of CHD.

METHODS AND RESULTS

Thirteen case-control and 10 cohort studies were included. Case-control studies incorporated 9487 cases of CHD and 27,747 controls, and cohort studies included a total of 403,631 participants that were followed for between 3 and 44 years. The summary of odds ratios (OR) for the case-control studies showed statistically significant associations between coffee consumption and CHD for the highest intake group (>4 cups/day), OR 1.83 (95% CI 1.49-2.24; P<0.0001), and for the second highest category (3-4 cups/day), OR 1.33 (95% CI 1.04-1.71; P<0.0001), while no significant association emerged for low daily coffee intake (< or =2 cups/day), OR 1.03 (95% CI 0.87-1.21; P=0.45). The analysis of long-term follow-up cohort studies did not show any association between the consumption of coffee and CHD, with a relative risk (RR) of 1.16 (95% CI 0.95-1.41; P=0.14) for the highest category, and 1.05 (95% CI 0.90-1.22; P=0.57) and 1.04 (95% CI 0.90-1.19; P=0.60) for the second and third highest categories, respectively. These results did not differ substantially when controlling for region of origin, fatal and non-fatal events, year of publication, and number of years of follow-up.

CONCLUSIONS

Despite a significant association between high consumption of coffee and CHD reported among case-control studies, no significant association between daily coffee consumption and CHD emerged from long-term follow-up prospective cohort studies.

Coffee, caffeine, and coronary heart disease

PURPOSE OF REVIEW

This review summarizes and highlights recent advances in current knowledge of the relationship between coffee and caffeine consumption and risk of coronary heart disease. Potential mechanisms and genetic modifiers of this relationship are also discussed.

RECENT FINDINGS

Studies examining the association between coffee consumption and coronary heart disease have been inconclusive. Coffee is a complex mixture of compounds that may have either beneficial or harmful effects on the cardiovascular system. Randomized controlled trials have confirmed the cholesterol-raising effect of diterpenes present in boiled coffee, which may contribute to the risk of coronary heart disease associated with unfiltered coffee consumption. A recent study examining the relationship between coffee and risk of myocardial infarction incorporated a genetic polymorphism associated with a slower rate of caffeine metabolism and provides strong evidence that caffeine also affects risk of coronary heart disease. Several studies have reported a protective effect of moderate coffee consumption, which suggests that coffee contains other compounds that may be beneficial.

SUMMARY

Diterpenes present in unfiltered coffee and caffeine each appear to increase risk of coronary heart disease. A lower risk of coronary heart disease among moderate coffee drinkers might be due to antioxidants found in coffee.

Caffeinated beverage intake and the risk of heart disease mortality in the elderly: a prospective analysis

BACKGROUND

Motivated by the possibility that caffeine could ameliorate the effect of postprandial hypotension on a high risk of coronary events and mortality in aging, we hypothesized that caffeinated beverage consumption decreases the risk of cardiovascular disease (CVD) mortality in the elderly.

OBJECTIVE

The objective of the study was to use prospective cohort study data to test whether the consumption of caffeinated beverages exhibits this protective effect.

DESIGN

Cox regression analyses were conducted for 426 CVD deaths that occurred during an 8.8-y follow-up in the prospective first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. The analysis involved 6594 participants aged 32-86 y with no history of CVD at baseline.

RESULTS

Participants aged >or=65 y with higher caffeinated beverage intake exhibited lower relative risk of CVD and heart disease mortality than did participants with lower caffeinated beverage intake. It was a dose-response protective effect: the relative risk (95% CI) for heart disease mortality was 1.00 (referent), 0.77 (0.54, 1.10), 0.68 (0.49, 0.94), and 0.47 (0.32, 0.69) for <0.5, 0.5-2, 2-4, and >or=4 servings/d, respectively (P for trend = 0.003). A similar protective effect was found for caffeine intake in mg/d. The protective effective was found only in participants who were not severely hypertensive. No significant protective effect was found in participants aged <65 y or in cerebrovascular disease mortality for those aged >or=65 y.

CONCLUSION

Habitual intake of caffeinated beverages provided protection against the risk of heart disease mortality among elderly participants in this prospective epidemiologic analysis.

Catechol-o-methyltransferase gene polymorphism modifies the effect of coffee intake on incidence of acute coronary events

Background

The role of coffee intake as a risk factor for coronary heart disease (CHD) has been debated for decades. We examined whether the relationship between coffee intake and incidence of CHD events is dependent on the metabolism of circulating catecholamines, as determined by functional polymorphism of the catechol-O-methyltransferase (COMT) gene.

Methodology/Principal Findings

In a cohort of 773 men who were 42 to 60 years old and free of symptomatic CHD at baseline in 1984–89, 78 participants experienced an acute coronary event during an average follow-up of 13 years. In logistic regression adjusting for age, smoking, family history of CHD, vitamin C deficiency, blood pressure, plasma cholesterol concentration, and diabetes, the odds ratio (90% confidence interval) comparing heavy coffee drinkers with the low activity COMT genotype with those with the high activity or heterozygotic genotypes was 3.2 (1.2–8.4). Urinary adrenaline excretion increased with increasing coffee intake, being over two-fold in heavy drinkers compared with nondrinkers (p = 0.008 for trend).

Conclusions/Significance

Heavy coffee consumption increases the incidence of acute coronary events in men with low but not high COMT activity. Further studies are required to determine to which extent circulating catecholamines mediate the relationship between coffee intake and CHD.

Effect of chronic coffee consumption on aortic stiffness and wave reflections in hypertensive patients

OBJECTIVE

Aortic stiffness and wave reflections are important markers and prognosticators of cardiovascular risk. Caffeine increases acutely aortic stiffness and wave reflections. Furthermore, chronic coffee consumption is associated with increased aortic stiffness and wave reflections in normotensive subjects. In the present study, we aimed to assess the association between chronic coffee consumption, and aortic stiffness and wave reflections in hypertensive patients.

DESIGN

Epidemiological survey.

SETTING

Hypertension Unit, University Hospital. SUBJECTS-METHODS: We examined 259 never-treated hypertensives (age 50+/-12 years, 165 males) without diabetes mellitus, who were asked to describe in detail the type and amount of coffee they consumed. Carotid-femoral pulse wave velocity (PWV) and augmentation index (AIx) were measured non-invasively as indices of aortic stiffness and wave reflections, respectively.

RESULTS

When controlled for gender, age, height, smoking status, heart rate, mean pressure, HDL cholesterol and hsCRP, AIx was found to be higher with increasing daily coffee consumption. Post hoc analysis revealed that all groups of coffee consumption had higher AIx compared to no-consumption. PWV did not differ among groups of daily coffee consumption. Each participant had 35% higher relative risk of having high AIx for each cup (150 ml) of coffee per day, and 40% higher relative risk for each 10 cup-years.

CONCLUSIONS

Coffee consumption is associated with increased wave reflections, but not aortic stiffness in never-treated hypertensive patients. This finding may have important clinical implications for cardiovascular health in hypertensive subjects.

Transient exposure to coffee as a trigger of a first nonfatal myocardial infarction

BACKGROUND

The effects of coffee on myocardial infarction are uncertain. We hypothesize that coffee in the presence of predisposing factors can induce a cascade of events that, through sympathetic nervous activation, can induce the onset of myocardial infarction.

METHODS

We recruited 503 incident cases of nonfatal myocardial infarction between 1994 and 1998 in Costa Rica. We used a case-crossover design to calculate relative risks (RRs) and 95% confidence intervals (95% CIs).

RESULTS

The RR of myocardial infarction in the hour after coffee intake was 1.49 (95% CI = 1.17-1.89). Occasional coffee drinkers (< or =1 cup/day, n = 103) had a RR of myocardial infarction of 4.14 (2.03-8.42), moderate coffee drinkers (2-3 cups/day, n = 280) had a RR of 1.60 (1.16-2.21), and heavy coffee drinkers (> or =4 cups/d, n = 120) had a RR of 1.06 (0.69-1.63; P = 0.006, test of homogeneity). Patients with 3 or more risk factors (n = 101) had a RR of myocardial infarction of 2.10 (1.30-3.39), whereas patients with fewer than 3 risk factors (n = 396) had a RR of 1.39 (1.04-1.82; P = 0.15, test of homogeneity); and RR was 1.72 (1.30-2.30) among sedentary patients compared with 1.07 (0.66-1.72) among nonsedentary (P = 0.10, test of homogeneity).

CONCLUSIONS

The findings indicate that coffee intake may trigger myocardial infarction. The association is particularly strong among people with light/occasional intake of coffee (< or =1 cup/day), with sedentary lifestyle, or with 3 or more risk factors for coronary heart disease.

Effects of acute administration of caffeine on vascular function

Caffeine is the most widely used pharmacologic substance in the world. It is found in common nonessential grocery items (e.g., coffee, tea, cocoa, and chocolate). The effects of caffeine on cardiovascular diseases, including hypertension, remain controversial, and there is little information on its direct effect on vascular function. The purpose of this study was to determine the effect of caffeine on endothelial function in humans. This study was a double-blind, randomized placebo and active drug study. Forearm blood flow (FBF) responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and to sodium nitroprusside, an endothelium-independent vasodilator, were evaluated in healthy young men before and after the oral administration of caffeine 300 mg (n = 10) or placebo (n = 10). FBF was measured by using a strain-gauge plethysmograph. Caffeine significantly increased systolic and diastolic blood pressures by 6.0 +/- 6.0 and 2.6 +/- 3.1 mm Hg (p <0.05), respectively, but did not alter heart rate or baseline FBF. Caffeine augmented the FBF responses to ACh from 21.2 +/- 7.1 to 26.6 +/- 8.1 ml/min/100 ml tissue (p <0.05), whereas sodium nitroprusside-stimulated vasodilation was not altered by caffeine administration. The intra-arterial infusion of N(G)-monomethyl-L-arginine, a nitric oxide synthase inhibitor, abolished the caffeine-induced augmentation of FBF response to ACh. In the placebo group, the ACh- and sodium nitroprusside-stimulated vasodilation was similar before and after the follow-up period. In conclusion, these findings suggest that the acute administration of caffeine augments endothelium-dependent vasodilation in healthy young men through an increase in nitric oxide production.

Coffee consumption and risk of total and cardiovascular mortality among patients with type 2 diabetes

AIMS/HYPOTHESIS

Higher habitual coffee drinking has been associated with a lower risk of developing type 2 diabetes. The relation between coffee consumption and risk of cardiovascular disease (CVD) has been examined in many studies, but the issue remains controversial. This study was designed to assess the association between coffee consumption and CVD mortality among patients with type 2 diabetes.

METHODS

We prospectively followed 3,837 randomly ascertained Finnish patients with type 2 diabetes aged 25 to 74 years. Coffee consumption and other study parameters were determined at baseline. The International Classification of Diseases was used to identify CHD, CVD and stroke cases using computerised record linkage to the national Death Registry. The associations between coffee consumption at baseline and risk of total, CVD, CHD, and stroke mortality were analysed by using Cox proportional hazards models.

RESULTS

During the average follow-up of 20.8 years, 1,471 deaths were recorded, of which 909 were coded as CVD, 598 as CHD and 210 as stroke. The respective multivariate-adjusted hazard ratios in participants who drank 0-2, 3-4, 5-6, and > or =7 cups of coffee daily were 1.00, 0.77, 0.68 and 0.70 for total mortality (P<0.001 for trend), 1.00, 0.79, 0.70 and 0.71 for CVD mortality (P=0.006 for trend), 1.00, 0.78, 0.70 and 0.63 for CHD mortality (p=0.01 for trend), and 1.00, 0.77, 0.64 and 0.90 for stroke mortality (p=0.12 for trend).

CONCLUSIONS/INTERPRETATION

In this large prospective study we found that in type 2 diabetic patients coffee drinking is associated with reduced total, CVD and CHD mortality.

Coffee consumption and coronary heart disease in men and women: a prospective cohort study

BACKGROUND

We examined the association between long-term habitual coffee consumption and risk of coronary heart disease (CHD).

METHODS AND RESULTS

We performed a prospective cohort study with 44,005 men and 84,488 women without history of cardiovascular disease or cancer. Coffee consumption was first assessed in 1986 for men and in 1980 for women and then repeatedly every 2 to 4 years; the follow-up continued through 2000. We documented 2173 incident cases of coronary heart disease (1449 nonfatal myocardial infarctions and 724 fatal cases of CHD) among men and 2254 cases (1561 nonfatal myocardial infarctions and 693 fatal cases of CHD) among women. Among men, after adjustment for age, smoking, and other CHD risk factors, the relative risks (RRs) of CHD across categories of cumulative coffee consumption (<1 cup/mo, 1 cup/mo to 4 cups/wk, 5 to 7 cups/wk, 2 to 3 cups/d, 4 to 5 cups/d, and > or =6 cups/d) were 1.0, 1.04 (95% confidence interval 0.91 to 1.17), 1.02 (0.91 to 1.15), 0.97 (0.86 to 1.11), 1.07 (0.88 to 1.31), and 0.72 (0.49 to 1.07; P for trend=0.41); among women, the RRs were 1.0, 0.97 (0.83 to 1.14), 1.02 (0.90 to 1.17), 0.84 (0.74 to 0.97), 0.99 (0.83 to 1.17), and 0.87 (0.68 to 1.11; P for trend=0.08). Stratification by smoking status, alcohol consumption, history of type 2 diabetes mellitus, and body mass index gave similar results. Similarly, we found no effect when the most recent coffee consumption was examined. RRs for quintiles of caffeine intake varied from 0.97 (0.84 to 1.10) in the second quintile to 0.97 (0.84 to 1.11) in the highest quintile (P for trend=0.82) in men and from 1.02 (0.90 to 1.16) to 0.97 (0.85 to 1.11; P for trend=0.37) in women.

CONCLUSIONS

These data do not provide any evidence that coffee consumption increases the risk of CHD.

Shift Work Sleep Disorder

More than 6 million Americans work night shifts on a regular or rotating basis. The negative consequences of shift work have been established, and recent evidence suggests that patients with shift work sleep disorder (SWSD) are at increased risk of these consequences and co-morbidities. SWSD is a relatively common but under-recognised, and hence undertreated, condition with potentially serious medical, social, economic and quality-of-life consequences. In addition to increased risk of gastrointestinal and cardiovascular disease, patients with SWSD experience clinically significant excessive sleepiness or insomnia associated with work during normal sleep times, which has important safety implications. A number of studies have evaluated countermeasures or interventions in shift workers; proposed treatments include chronobiotic interventions, such as light exposure, melatonin, hypnotic agents, caffeine and CNS stimulants (amphetamine), and the wake-promoting agents modafinil and armodafinil. However, most studies evaluating pharmacological therapies and nonpharmacological interventions simulate night-shift work under conditions that may not accurately reflect real-world activities. Pharmacological and nonpharmacological countermeasures evaluated mostly in simulated laboratory conditions have been shown to improve alertness or sleep in shift workers but have not yet been evaluated in patients with SWSD. To date, three randomised, double-blind clinical studies have evaluated pharmacological therapies in patients with SWSD. These studies showed that modafinil and armodafinil significantly improve the ability to sustain wakefulness during waking activities (e.g. working, driving), overall clinical condition, and sustained attention or memory in patients with SWSD. In conclusion, SWSD is a common condition that remains under-recognised and undertreated. Further research is needed to evaluate different treatment approaches for this condition, to clarify the substantial health and economic consequences of SWSD, and to determine the potential for interventions or treatments to reduce the negative consequences of this condition.

Effect of coffee on endothelial function in healthy subjects: the role of caffeine

Coffee is one of the most widely used pharmacologically active beverages. The present study was designed to evaluate the acute effect of coffee ingestion on endothelial function in healthy individuals, and the potential role of caffeine. We studied 17 healthy young adults (28.9+/-3.0 years old; nine men), who were regular non-heavy coffee drinkers. The endothelial performance was estimated by endothelium-dependent FMD (flow-mediated dilatation) of the brachial artery before and 30, 60, 90 and 120 min after ingestion of a cup of caffeinated coffee (80 mg of caffeine) or the corresponding decaffeinated beverage (< 2 mg of caffeine) in two separate sessions, following a randomized single-blind cross-over design. There was no difference in baseline FMD values between the two sessions [7.78 compared with 7.07% after caffeinated and decaffeinated coffee respectively; P = NS (not significant)]. Caffeinated coffee led to a decline of FMD (7.78, 2.86, 2.12, 4.44 and 4.57% at baseline, 30, 60, 90 and 120 min respectively; P < 0.001). This adverse effect was focused at 30 (P = 0.004) and 60 min (P < 0.001). No significant effect on FMD was found with the decaffeinated coffee session (7.07, 6.24, 5.21, 7.41 and 5.20%; P = NS). The composite effect of the type of coffee consumed over time on FMD was significantly different (P = 0.021). In conclusion, coffee exerts an acute unfavourable effect on the endothelial function in healthy adults, lasting for at least 1 h after intake. This effect might be attributed to caffeine, given that decaffeinated coffee was not associated with any change in the endothelial performance.