Sex differences in the associations of water, coffee and tea consumption with cardiovascular diseases: a prospective cohort study

Background

Water, coffee and tea are the primary sources of daily hydration. However, the sex-specific relationship between these beverages and cardiovascular disease (CVD) among remains unclear.

Methods

In total, 210,239 men and 251,383 women from the UK Biobank were included. The consumption of water, coffee and tea were self-reported. CVDs, including coronary heart disease (CHD), stroke and heart failure (HF) were followed till March 1st, 2023. Sex-specific Cox models were utilized to evaluate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations.

Results

During a median follow-up of 8.7 years, 11,098 (2.40%) participants developed new-onset HF, 33,426 (7.24%) participants developed new-onset CHD, and 9,706 (2.10%) participants developed new-onset stroke. After adjustments, higher water consumption was generally associated with reduced risk of CVDs among both men and women. In contrast, heavy coffee consumption (particularly ≥6 cups/day) was associated with a greater risk of HF [1.16 (1.03-1.31) in men vs. 1.25 (1.12-1.40) in women], a greater risk of CHD [1.27 (1.18-1.36) in men vs. 1.21 (1.14-1.29) in women] and a greater risk of stroke [1.13 (0.99-1.29) in men vs. 1.20 (1.03-1.31) in women]. Similarly, heavy tea consumption was associated with an increased risk of HF (men: HR 1.19 [1.08-1.31]; women: HR 1.12 [1.02-1.23]) and CHD (men: HR 1.12 [1.05-1.18]; women: HR 1.18 [1.12-1.24]).

Conclusion

Our study revealed that water consumption was associated with a lower risk of CVDs, with a lower risk of CVDs, while heavy coffee or tea consumption was linked to a higher risk. Notably, coffee and tea consumption partially attenuated the protective association of water intake with CVDs. Furthermore, significant sex differences were observed in the associations between coffee or tea consumption and CHD incidence.

Association of Retinal Vein Occlusion With Serum Osmolality and Hydration Status

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate serum osmolality and hydration status in patients with retinal vein occlusion (RVO).

PATIENTS AND METHODS

This cross-sectional study consisted of 79 patients with RVO and 81 age- and sex-matched peers without ocular disease. Data were collected from patient records and included a comprehensive ophthalmological examination, laboratory data of fasting blood test results, and internal medicine outpatient examination. Complete blood count and levels of fasting glucose, sodium, blood urea nitrogen (BUN), creatinine, triglyceride, low-density lipoprotein, high-density lipoprotein, HbA1c, and serum osmolality were evaluated. BUN/creatinine ratios were calculated.

RESULTS

Mean serum sodium and serum osmolality levels were 142.53 ± 2.13 and 139.74 ± 2.16 mEq/L and 286.58 ± 4.40 and 280.57 ± 4.39 mOsmol/kg H2O in the RVO and control groups, respectively. Serum osmolality and serum sodium levels, and BUN/creatinine ratio were significantly higher in the RVO group than in controls (P < 0.05 for all).

CONCLUSIONS

We found that serum osmolality, sodium levels, and the BUN/creatinine ratio increased significantly in the RVO group. The results suggest dehydration status may affect the genesis of vessel occlusion in RVO. [Ophthalmic Surg Lasers Imaging Retina 2024;55:130-135.].

Association of serum osmolality with all-cause and cardiovascular mortality in US adults: A prospective cohort study

BACKGROUND AND AIMS

The association between serum osmolality, an effective indicator of body hydration status, and long-term mortality in the general population remains undetermined. The present study aimed to investigate the association of serum osmolality with long-term all-cause and cardiovascular mortality among adults in the United States.

METHODS AND RESULTS

This cohort study used data from the National Health and Nutrition Examination Survey (NHANES) 2007-2014. Participants were linked to National Death Index mortality data from the survey date through December 31, 2019. Cox proportional hazards regression model was used to calculate hazard ratios (HRs) and 95% CIs, and restricted cubic spline (RCS) regression was conducted. A total of 18312 US adults were included. During a median follow-up of 8.7 years, 1353 total deaths occurred, including 379 cardiovascular deaths. After multivariable adjustments, compared with the 3rd quartile (Q3) of serum osmolality, participants in the 1st (Q1) and 4th (Q4) quartiles were at a significantly higher risk of all-cause mortality (HR 1.41 [95% CI, 1.14-1.75] and 1.29 [95% CI, 1.04-1.61], respectively). RCS revealed a nonlinear relationship of serum osmolality to all-cause and cardiovascular mortality, with an inflection point of 278 mmol/kg.

CONCLUSION

In the nationally representative cohort of US adults, serum osmolality was nonlinearly associated with all-cause and cardiovascular mortality. The risk of mortality was lowest around an osmolality of 278 mmol/kg. These findings suggest the importance of serum osmolality management for long-term health outcomes.

Association between iron status and incident coronary artery disease: a population based-cohort study

Disorders of iron metabolism has been implicated in cardiovascular disease. However, the association of serum iron stores and coronary artery disease (CAD) remains inconsistent. Here, we investigated the associations of serum iron metabolism with the incidence of CAD, the severity of coronary artery stenosis, metabolic biomarkers, and the risk of major adverse cardiovascular event (MACE). A total of 643 CAD patients and 643 healthy controls were enrolled to assess the associations of serum iron status with the presence of CAD, the severity of CAD, and the risk of MACE. Serum iron metabolism and other metabolic markers were measured in all subjects. All statistical analyses were analyzed using SPSS22.0 software and STATA statistical package. Serum level of iron metabolism markers, including serum iron, unsaturated transferrin iron binding capacity (UIBC), Total iron binding capacity (TIBC) levels, in CAD groups was significantly lower than the control group (P < 0.001). UIBC and TIBC were negatively correlated with ferritin in both sexes. Each unit increase of serum iron and TIBC were found to have a protective role for CAD in women (iron: OR 0.794, 95% CI (0.647-0.973), TIBC: OR 0.891, 95% CI (0.795-0.999), P < 0.05). However, high ferritin level was significant associated the CAD incident in both sexes (OR 1.029, 95% CI (1.002-1.058) in men, OR 1.013, 95% CI (1.0-1.025) in women, P < 0.05). Serum iron metabolism markers exhibited no significant association with the severity of CAD. Increased serum level of iron and TIBC levels were found to have a protective role for CAD in women, but not in men. Elevated serum ferritin is independently and positively associated with CAD in men and women.

Exploration of Blood Lipoprotein and Lipid Fraction Profiles in Healthy Subjects through Integrated Univariate, Multivariate, and Network Analysis Reveals Association of Lipase Activity and Cholesterol Esterification with Sex and Age

In this study, we investigated blood lipoprotein and lipid fraction profiles, quantified using nuclear magnetic resonance, in a cohort of 844 healthy blood donors, integrating standard univariate and multivariate analysis with predictive modeling and network analysis. We observed a strong association of lipoprotein and lipid main fraction profiles with sex and age. Our results suggest an age-dependent remodulation of lipase lipoprotein activity in men and a change in the mechanisms controlling the ratio between esterified and non-esterified cholesterol in both men and women.

Effect of calculated plasma osmolality and atherogenic index of plasma on carotid artery blood flow velocities

OBJECTIVES

The increase in carotid artery blood flow velocity is a measure of the severity of the carotid artery stenosis caused by atherosclerosis. Carotid artery stenosis is progressive and is of great importance due to the risk of stroke it creates. As an alternative to radiological examinations in these patients, patient follow-up can be facilitated by associating novel laboratory parameters with the severity of stenosis. In this study, we aimed to investigate the effect of the calculated plasma osmolality and atherogenic index of plasma on carotid artery blood flow velocities in patients with carotid artery stenosis.

METHODS

A total of 161 patients diagnosed with carotid artery stenosis who admitted to our clinic between May 2018 and May 2020 were retrospectively analyzed. According to the carotid artery blood flow velocities measured with the Doppler ultrasonography, the patients were divided into two groups as "Normal flow velocity group" (n = 62) and "Increased flow velocity group" (n = 99).

RESULTS

The calculated plasma osmolality, atherogenic index of plasma, and mean platelet volume were significantly associated with increased carotid artery blood flow velocity (p < 0.001, p < 0.001, p = 0.006; respectively). Calculated plasma osmolality and atherogenic index of plasma were identified as independent predictors of increase in carotid artery blood flow velocity (p < 0.001, p < 0.001; respectively). In the Receiver Operating Characteristic curve analysis, the plasma osmolality cut-off value, which predicts the increase in carotid artery blood flow velocity was found to be 291.45 mOsm/kg (Area Under the Curve: 0.746, p < 0.001, 65.7% sensitivity, and 67.7% specificity), and atherogenic index of plasma cut-off value was 0.20 (Area Under the Curve: 0.735, p < 0.001, 65.7% sensitivity, and 66.1% specificity).

CONCLUSION

There was a significant relationship between the increase in carotid artery blood flow velocity and the increase in plasma osmolality and atherogenic index of plasma values. As a result, we can predict the increase in carotid artery blood flow velocity, that is, the increase in the severity of the carotid artery stenosis, with plasma osmolality and atherogenic index of plasma values that can be calculated simply from routine biochemical tests.

A Simple Predictive Factor for Mortality in Fontan Surgery: Serum Hypo-Osmolality

OBJECTIVE

Close follow-up is important after the Fontan procedure, which is a palliative surgical method for a single ventricle. In this period, serum osmolality is an important parameter with the advantages of easy to obtain and poor outcome prediction.

METHODS

Patients who had undergone Fontan operation between May 2011 and February 2017 were retrospectively evaluated. Patients were divided into three groups based on their serum osmolality values: hypoosmolar (Group 1), isosmolar (Group 2), and hyperosmolar (Group 3). Demographics, clinical information and postoperative data of the groups were compared.

RESULTS

Forty-three patients had undergone extracardiac Fontan operation in the study period. There were 8, 19 and 16 patients in Groups 1, 2 and 3, respectively. Among the three groups, postoperative intubation and length of hospital stay, prolonged pleural effusion, need for inotropic support and mortality were statistically significantly higher in Group 1.

CONCLUSION

After the Fontan procedure, one of the determinants of cardiac output might be affected by serum osmolality. Decreased serum osmolality might be associated with poor prognosis after Fontan procedure. Serum osmolality monitoring may be beneficial to improve postoperative outcomes in these patients.

Iron hypothesis and coronary artery disease in geriatric patients

Context and aims: Iron is a pro-oxidant factor in the pathogenesis of CAD. The association of body iron status was investigated relative to the occurrence and severity of CAD.Design and methods: The subjects consisted of 110 males and 115 females who were classified as either a CAD case or a control according to the results of coronary angiography.Results: A new parameter, the "serum free iron index," was defined as the ratio of serum iron to UIBC. The level of ferritin showed significant increase [97.2 (67.0-171.2) µg/L vs. 85.6 (52.5-129.4), p = .034], whereas serum total iron, free iron index, transferrin, UIBC and iron saturation were unchanged in CAD patients relative to control group. Among the indices of body iron only serum ferritin had significant association with the likelihood (OR of 1.004 (1.000-1.007), p = .04) and severity of CAD [χ²(3)= 7.99, p = .01], but the correlation was lessened in the presence of classical risk factors. Serum ferritin had also the highest and significant efficiency to predict CAD (AUC = 0.61, p = .020).Conclusions: Serum ferritin as a marker of intracellular iron has significant association with CAD; nevertheless, the correlation is not independent. Since iron deficiency is prevalent in elderly patients, iron hypothesis needs to expand to the both sides of iron deficiency and toxicity.

Serum Creatinine and Occurrence and Severity of Coronary Artery Disease

Introduction:

The risk for cardiovascular disease is increased in all stages of the impairment of renal function. It is proposed that serum creatinine is a marker of diabetes and coronary artery disease (CAD) as well as the kidney function.

Aim:

to study the association of serum creatinine with the likelihood and severity of CAD. The study population consisted of 262 males and 266 females who were classified as CAD cases and controls according to the results of coronary angiography.

Results:

Patients with CAD compared with the controls had increased levels of serum urea and creatinine. Serum creatinine showed significant positive correlation with male sex, hypertension and negative correlation with total- and HDL-cholesterol and apoAI. Serum urea, uric acid and potassium were the major determinants of creatinine. All hematological parameters were strong negative correlates of creatinine. None of markers of inflammation had significant correlation with creatinine. Creatinine was associated significantly with the prevalence [odds ratio of 1.79 (1.47-2.20), p<0.001] and severity of CAD [F(3,528)= 3.0, p=0.03]. Serum creatinine was excluded from the regression equation after adjustment for major risk factors.

Conclusion:

Serum creatinine has significant association with CAD, but the correlation is not independent. Creatinine have significant association with markers of kidney function and body water status, but not with markers of inflammation and insulin function.

Mechanical Properties of Arterial Elastin With Water Loss

Elastin is a peculiar elastomer in that it requires water to maintain resilience, and its mechanical properties are closely associated with the immediate aqueous environment. The bulk, extra- and intrafibrillar water plays important roles in both elastic and viscoelastic properties of elastin. In this study, a two-stage liquid-vapor method was developed to investigate the effects of water loss on the mechanical properties of porcine aortic elastin. The tissue samples started in a phosphate-buffered saline (PBS) solution at their fully hydrated condition, with a gravimetric water content of 370±36%. The hydration level was reduced by enclosing the tissue in dialysis tubing and submerging it in polyethylene glycol (PEG) solution at concentrations of 10%, 20%, 30%, and 45% w/v, which reduced the water content of the samples to 258±34%, 224±20%, 109±9%, and 58±3%, respectively. The samples were then transferred to a humidity chamber to maintain the hydration level while the samples underwent equi-biaxial tensile and stress relaxation tests. The concentration of 10% PEG treatment induced insignificant changes in tissue dimensions and stiffness, indicating that the removal of bulk water has less effect on elastin. Significant increases in tangent modulus were observed after 20% and 30% PEG treatment due to the decreased presence of extrafibrillar water. Elastin treated with 45% PEG shows a very rigid behavior as most of the extrafibrillar water is eliminated. These results suggest that extrafibrillar water is crucial for elastin to maintain its elastic behavior. It was also observed that the anisotropy of elastin tends to decrease with water loss. An increase in stress relaxation was observed for elastin treated with 30% PEG, indicating a more viscous behavior of elastin when the amount of extrafibrillar water is significantly reduced. Results from this study shed light on the close association between the bulk, extra- and intrafibrillar water pools and the mechanics of elastin.

Association between heat stroke and ischemic heart disease: A national longitudinal cohort study in Taiwan

The purpose of this study is to determine the relationship between heat stroke and ischemic heart disease (IHD), in a nationwide population using a longitudinal approach. We retrospectively examined the data from the National Health Insurance Research Database (NHIRD) in Taiwan, for patients examined between 2000 and 2013. In total, 628 patients with a heat stroke episode were enrolled and matched with 1256 patients without any history of a heat stroke episode by propensity score matching at a ratio of 1:2. The mean follow-up years of the heat stroke group was 11.89 years and the mean follow up of the control group was 11.51 years. An association between heat stroke episodes and IHD (log-rank p < .001) was found in a univariate cox regression analysis. After multivariate adjustment, age, comorbidities (hypertension, diabetes, stroke), and lower insurance premiums were associated with IHD events in patients who had a heat stroke. IHD was independently associated with heat stroke following cox multivariate regression analysis and patients with a heat stroke episode had a higher incidence of IHD events compared to those without any heat stroke episode (2598.41/10⁵ person-years vs. 1286.14/10⁵ person-years, adjusted hazard ratio 3.527, 95% CI: 2.078-4.032, p < .001). The onset of IHD in patients who suffered a heat stroke was earlier than in those without a heat stroke episode (2.08 ± 3.45 vs. 3.61 ± 3.25 years, p < .001). In conclusion, clinicians should be aware about evaluating the IHD risk following a heat stroke episode in a patient.

Esterification of HDL-cholesterol is Decreased in Diabetes Mellitus and CAD and Enhanced Following Treatment with Statins

Background:

The main goal of using statins is to reduce the level of plasma cholesterol, meanwhile they have a wide spectrum of actions.

Objectives:

To identify the effect of statins on fractional cholesterol esterification (FCE) as well as the complete profile of lipids and (apo)lipoproteins.

Design and methods:

In an age and sex matched case-control study, 400 subjects who were referred for coronary angiography were divided into two groups according using statins.

Results:

Total cholesterol was decreased significantly following treatment with statins (165.6 ± 38.0 mg/dL vs. 205.3 ± 48.4, p≤0.001). About 90% of the reduction was occurred in nonHDL and 10% in HDL fraction. Reduction of nonHDL cholesterol (125.2 ± 35.2 mg/dL vs. 162.8 ± 45.2, p≤0.001) occurred on both unesterified (52.4 ± 21.5 mg/dL vs. 65.2 ± 25.5, p≤0.001) and esterified cholesterol (74.7 ± 27.3 mg/dL vs. 96.6 ± 34.1, p≤0.001). But the decrease in HDL cholesterol (40.4 ± 10.0 mg/dL vs. 42.3 ± 9.9, p≤0.079) happened exclusively in unesterified fraction (10.9 ± 3.4 vs. 15.2 ± 5.1, p≤0.001) and was counterbalanced with a significant increase in esterified portion (29.5 ± 8.2 mg/dL vs. 27.2 ± 9.5, p≤0.020). The ratio of esterified- per total- cholesterol in HDL was 67.5 ± 8.1% in the control group and was decreased to 58.0 ± 14.9% (p≤0.01) in diabetes and CAD and increased to 73.5 ± 6.9 (p≤0.01) after using statins.

Conclusions:

The results suggest that the percent of esterified cholesterol in HDL fraction is decreased in diabetes and CAD patients and increased by using statins.

The Ratio of Unesterified/esterified Cholesterol is the Major Determinant of Atherogenicity of Lipoprotein Fractions

Background

The hypothesis is proposed that the atherogenicity of lipoporotein fractions is correlated with the content of unesterified cholesterol.

Objectives

To evaluate the role and prognostic values of unesterified and esterified cholesterol in lipoprotein fractions for coronary artery disease (CAD).

Design and methods

The study population consisted of 400 patients who were divided to CAD controls and cases according to the data of coronary angiography. Fractional cholesterol esterification (FCE) as well as the complete profile of lipids and (apo)lipoproteins were determined.

Results

Total cholesterol was increased significantly in CAD patients (196.3 ± 52.3 mg/dL vs. 185.7 ± 48.0, p≤ 0.049) and the increment occurred totally in unesterified portion (77.2 ± 28.4 mg/dL vs. 71.1 ± 24.4, p≤ 0.031). HDL cholesterol showed a significant decrease in CAD group (39.9 ± 9.5 mg/dL vs. 44.6 ± 10.5, p≤ 0.001), but the decrement occurred wholly in the esterified portion (26.2 ± 9.2 mg/dL vs. 31.1 ± 8.1, p≤ 0.001). NonHDL cholesterol was increased significantly in CAD group (156.8 ± 48.3 mg/dL vs. 140.3 ± 43.6, p≤ 0.001), and the changes occurred in both un- and esterified portions. FCE in HDL was diminished significantly in CAD patients (64.8 ± 13.9% vs. 69.3 ± 7.9, p≤ 0.01). In multivariate logistic regression analysis, unesterified cholesterol in NonHDL (UeNonHDLc) and esterified cholesterol in HDL (EsHDLc) excluded total cholesterol and HDLc respectively from the regression equation. In ROC analysis, the ratio of UeNonHDLc/EsHDLc was the strongest predictor for CAD among cholesterol subfractions.

Conclusions

The results confirm that UeNonHDLc is atherogenic and EsHDLc is antiatherogenic and are independent risk factors for CAD.

Life Psychosocial Stresses and Coronary Artery Disease

Background:

It is hypothesized that the impacts of life events accumulate and can trigger and promote atherosclerosis in susceptible individuals. In the current study, the correlation of total life stressors during 1 year was investigated relative to coronary artery disease (CAD).

Methods:

The study population consisted of 148 males and 152 females aged 35–76 years. The subjects were classified as CAD cases and controls according to the results of coronary angiography. The severity of CAD was scored on the basis of the number and the extent of lesions at coronary arteries. The stressful events of life were assessed using Holmes-Rahe Questionnaire and was presented as total psychological stress scores per year (TPSS).

Results:

The frequency of cigarette smoking, diabetes mellitus, and hypertension was more prevalent in CAD cases than control subjects. The levels of TPSS were increased in patients with CAD compared to the controls (160.3 ± 71.3 vs. 139.8 ± 66.5, P = 0.020). TPSS was also associated positively with the levels of uric acid, erythrocytes counts, erythrocyte sedimentation rate, aspirin consumption, and negatively with high-density lipoprotein-cholesterol and apo-AI. In logistic regression analysis, TPSS correlated with the occurrence of CAD by the odds ratio of 1.773 (1.073–2.930), P = 0.025, but the association was weakened after adjustment for classical risk factors, especially hypertension. TPSS exhibited significant association with the severity of CAD [F (3,274) = 2.6, P = 0.051].

Conclusions:

The results suggest that TPSS are associated with the occurrence and severity of CAD significantly, but the association is not independent.

Association between fluid intake and kidney function, and survival outcomes analysis: a nationwide population-based study

OBJECTIVES

Fluid intake, one of the most common daily activities, has not been well studied in chronic kidney disease (CKD) populations, and clinical outcomes are rarely addressed. The aim of this nationwide study is to explore the influence of daily fluid intake on cardiovascular and all-cause mortality and its association with renal function.

DESIGN

Observational cohort study.

PARTICIPANTS

In all, 2182 participants aged more than 20 years participated in the Third National Health and Nutrition Examination Survey (1988-1994).

MAIN OUTCOME MEASURES

Survival outcomes in patients with or without CKD, using multiple variable adjusted Cox proportional hazard models.

RESULTS

In a longitudinal survey with a median follow-up length of 15.4 years, 1080 participants died and 473 cardiovascular deaths were recorded. For all-cause mortality in the CKD group, individuals in the highest quartile of fluid intake (≧3.576 L/day) had better survival outcomes than those in the lowest quartile of fluid intake (≤2.147 L/day) (p=0.029) after adjustment of several pertinent variables.

CONCLUSIONS

Although the interpretation of this observational study was limited by the failure to identify the compositions of ingested fluids, adequate hydration may offer some advantages in patients with CKD. However, the underlying pathophysiological mechanisms of the responses of normal and injured kidneys to chronic changes in fluid consumption warrant further investigation.

Association between fluid intake and kidney function, and survival outcomes analysis: a nationwide population-based study

OBJECTIVES

Fluid intake, one of the most common daily activities, has not been well studied in chronic kidney disease (CKD) populations, and clinical outcomes are rarely addressed. The aim of this nationwide study is to explore the influence of daily fluid intake on cardiovascular and all-cause mortality and its association with renal function.

DESIGN

Observational cohort study.

PARTICIPANTS

In all, 2182 participants aged more than 20 years participated in the Third National Health and Nutrition Examination Survey (1988-1994).

MAIN OUTCOME MEASURES

Survival outcomes in patients with or without CKD, using multiple variable adjusted Cox proportional hazard models.

RESULTS

In a longitudinal survey with a median follow-up length of 15.4 years, 1080 participants died and 473 cardiovascular deaths were recorded. For all-cause mortality in the CKD group, individuals in the highest quartile of fluid intake (≧3.576 L/day) had better survival outcomes than those in the lowest quartile of fluid intake (≤2.147 L/day) (p=0.029) after adjustment of several pertinent variables.

CONCLUSIONS

Although the interpretation of this observational study was limited by the failure to identify the compositions of ingested fluids, adequate hydration may offer some advantages in patients with CKD. However, the underlying pathophysiological mechanisms of the responses of normal and injured kidneys to chronic changes in fluid consumption warrant further investigation.

A retrospective study investigating the incidence and predisposing factors of hospital-acquired anemia

Hospitalized patients frequently have considerable volumes of blood removed for diagnostic testing which could lead to the development of hospital-acquired anemia. Low hemoglobin levels during hospitalization may result in significant morbidity for patients with underlying cardiorespiratory and other illnesses. We performed a retrospective study and data was collected using a chart review facilitated through an electronic medical record. A total of 479 patients who were not anemic during admission were included in analysis. In our study, we investigated the incidence of HAA and found that, between admission and discharge, 65% of patients dropped their hemoglobin by 1.0 g/dL or more, and 49% of patients developed anemia. We also found that the decrease in hemoglobin between admission and discharge did not differ significantly with smaller phlebotomy tubes. In multivariate analysis, we found that patients with longer hospitalization and those with lower BMI are at higher risk of developing HAA. In conclusion, our study confirms that hospital-acquired anemia is common. More aggressive strategies such as reducing the frequency of blood draws and expanding the use of smaller volume tubes for other laboratory panels may be helpful in reducing the incidence of HAA during hospitalization.

Fluid intake and all-cause mortality, cardiovascular mortality and kidney function: a population-based longitudinal cohort study

BACKGROUND

Drinking eight glasses of fluid or water each day is widely believed to improve health, but evidence is sparse and conflicting. We aimed to investigate the association between fluid consumption and long-term mortality and kidney function.

METHODS

We conducted a longitudinal analysis within a prospective, population-based cohort study of 3858 men and women aged 49 years or older residing in Australia. Daily fluid intake from food and beverages not including water was measured using a food frequency questionnaire. We did multivariable adjusted Cox proportional hazard models for all-cause and cardiovascular mortality and a boot-strapping procedure for estimated glomerular filtration rate (eGFR).

RESULTS

Upper and lower quartiles of daily fluid intake corresponded to >3 L and <2 L, respectively. During a median follow-up of 13.1 years (total 43 093 years at risk), 1127 deaths (26.1 per 1000 years at risk) including 580 cardiovascular deaths (13.5 per 1000 years at risk) occurred. Daily fluid intake (per 250 mL increase) was not associated with all-cause [adjusted hazard ratio (HR) 0.99 (95% CI 0.98-1.01)] or cardiovascular mortality [HR 0.98 (95% CI 0.95-1.01)]. Overall, eGFR reduced by 2.2 mL/min per 1.73 m(2) (SD 10.9) in the 1207 (31%) participants who had repeat creatinine measurements and this was not associated with fluid intake [adjusted regression coefficient 0.06 mL/min/1.73 m(2) per 250 mL increase (95% CI -0.03 to 0.14)].

CONCLUSIONS

Fluid intake from food and beverages excluding water is not associated with improved kidney function or reduced mortality.