Egg Consumption and Risk of Total and Cause-Specific Mortality: An Individual-Based Cohort Study and Pooling Prospective Studies on Behalf of the Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group

Egg Consumption and Mortality: A Prospective Cohort Study of Australian Community-Dwelling Older Adults

BACKGROUND/OBJECTIVES

Egg consumption in adults has been linked with a modestly increased risk of all-cause and CVD mortality. However, evidence on adults aged 65 y+ is limited. The objective of this study was to investigate the association between egg intake and mortality in community-dwelling older adults.

METHODS

In this prospective cohort study, 8756 adults aged 70+ years, participants in the ASPirin in Reducing Events in the Elderly (ASPREE) Longitudinal Study of Older Persons, self-reported the frequency of their total egg intake: never/infrequently (rarely/never, 1-2 times/month), weekly (1-6 times/week), and daily (daily/several times per day). All-cause and cause-specific (cardiovascular disease [CVD] and cancer) mortality was established from at least two sources: medical records, death notices, next of kin, or death registry linkage. The association between egg intake and mortality was assessed using Cox proportional hazards regression analysis, adjusted for socio-demographic, health-related, and clinical factors and overall dietary quality.

RESULTS

Over the median 5.9-year follow-up period, a total of 1034 all-cause deaths (11.8%) were documented. A 29% lower risk of CVD mortality (HR (95% CI): 0.71 [0.54-0.92]) and a 17% (HR (95% CI): 0.83 [0.71-0.96]) lower risk of all-cause mortality were observed among those who consumed eggs weekly, compared to those who consumed eggs never/infrequently; no statistically significant association was observed for weekly consumption and cancer mortality. In contrast, compared to those that never or infrequently consumed eggs, daily consumption had slightly higher odds of mortality, though these results did not reach statistical significance.

CONCLUSIONS

The consumption of eggs 1-6 times per week was associated with a lower risk of all-cause mortality and CVD mortality in community-dwelling adults aged 70 years and over. These findings may be important to inform the development of evidence-based guidelines for egg consumption.

Eggs - a scoping review for Nordic Nutrition Recommendations 2023

Cardiovascular diseases (CVD), type 2 diabetes (T2D), and cancer are a significant public health burden in the Nordic and Baltic countries. High intake of eggs, mainly due to its high cholesterol content, has been suggested to have adverse health effects. The purpose of this scoping review is to describe the evidence related to the impact of egg intake on health. A literature search identified 38 systematic reviews and meta-analyses on egg consumption in relation to health outcomes published between 2011 and 30 April 2022. Overall, current evidence from systematic reviews of randomized clinical trials indicates that higher egg intake may increase serum total cholesterol concentration and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol, but with substantial heterogeneity in the response. However, recent evidence from observational studies does not provide strong support for a detrimental role of moderate egg consumption (up to one egg/day) on the risk of CVD, especially in the European studies. The overall evidence from observational studies indicates that egg consumption is not associated with increased risk of mortality or T2D in European study populations. There is also little support for a role of egg consumption in cancer development, although a weak association with higher risk of certain cancers has been found in some studies, mainly case-control studies. Again, no associations with cancer risk have been observed in European studies. Systematic reviews and meta-analyses of egg consumption in relation to other health-related outcomes are scarce. There are also limited data available on the associations between the consumption of more than one egg/day and risk of diseases. Based on the available evidence, one egg/day is unlikely to adversely affect overall disease risk.

The Prospective Associations of Egg Consumption with the Risk of Total Cerebrovascular Disease Morbidity among Chinese Adults

BACKGROUND

Studies investigating the relationship between egg consumption and the risk of cerebrovascular disease (CED) have yielded inconsistent results. This study evaluated the association between egg consumption and the risk of CED among Chinese adults.

METHODS

Data were obtained from China Kadoorie Biobank, Qingdao. A computerised questionnaire was used to collect information regarding egg consumption frequency. CED events were tracked through linkage with the Disease Surveillance Point System and the new national health insurance databases. Cox proportional hazards regression analyses were used to evaluate associations between egg consumption and CED risk controlling for potential confounders.

RESULTS

After a median follow-up of 9.2 years, 865 and 1083 CED events among men and women, respectively, were documented. More than 50% of participants consumed eggs daily with an average age of 52.0 (10.4) years at baseline. No association between egg consumption and CED were identified in the whole cohort and women. However, a 28% lower risk of CED was observed in those who consumed eggs at a higher frequency (HR = 0.72, 95% CI: 0.55-0.95) and a significant trend for the association (p for trend = 0.012) in a multivariable model in men.

CONCLUSION

Higher frequency of egg consumption was associated with a lower risk of total CED events among men but not women in Chinese adults. The beneficial effect on women warrants further investigations.

Differences in all-cause mortality risk associated with animal and plant dietary protein sources consumption

The relationship between protein intake and mortality is still controversial. We prospectively examined the associations of dietary protein sources with all-cause mortality risk in the Isfahan cohort study (ICS). A total of 5431 participants, aged ≥ 35 years, were enrolled in the ICS, in 2001 and followed through 2013. The frequency of protein intakes from different sources was estimated through a validated food frequency questionnaire at baseline. Any new case of death was recorded over the follow-up duration. Hazard ratio (HR)s and 95% confidence interval (CI)s were estimated through Cox proportional hazards regression models. During a median follow-up of 11.3 years, 483 deaths were documented. Higher intakes of plant proteins (HR = 0.64, 95% CI 0.46, 0.91) and animal proteins (HR = 1.52, 95% CI 1.13, 2.05) were associated with a decreased and increased risk of mortality, respectively. Additional adjustment for some mediators did not considerably affect the associations for animal protein (HR = 1.55, 95% CI 1.15, 2.09), whereas led to a tendency towards lower risk for plant protein in the top quintile compared with the bottom one (HR = 0.67, 95% CI 0.48, 0.95; P trend = 0.06). Among specific major sources, higher intakes of nuts and fish were associated with a 27% (95% CI 0.58, 0.93) and 21% (95% CI 0.62, 1.01) lower risk of mortality, respectively. The inverse association between plant protein and mortality risk might be mediated by some metabolic disorders. However, our results suggest an independent positive association for animal protein and all-cause mortality.

The association of egg consumption with blood pressure levels and glycated hemoglobin in Spanish adults according to body mass index

The objective of this study was to evaluate the association of egg consumption with blood pressure (BP) and glycated hemoglobin (HbA1c). In addition, it was assessed whether this association changes according to body weight status. This cross-sectional study is based on multicenter data from Spanish adult participants in the EVIDENT II trial. Egg consumption was assessed with a Food Frequency Questionnaire, and data on BP and HbA1c were collected using standardized procedures. Linear regression and ANCOVA models adjusted for the main confounders were performed. The analyses were stratified by body weight status. A total of 668 participants were analyzed (mean age 52.4 ± 11.8 years, 62.3% women). Compared with lower consumption, higher egg consumption was associated with lower systolic (ß =  - 6.15 ± 1.74; p-for-trend = 0.017), diastolic (ß =  - 4.41 ± 1.03; p-for-trend = 0.002), and mean arterial pressure (ß =  - 4.99 ± 1.17; p-for-trend = 0.003) and with lower HbA1c (ß =  - 0.19 ± 0.06; p-for-trend = 0.019) levels. These associations lost statistical significance in the adjusted analyses. The results did not vary by body weight status. In conclusion, consumption of up to 1 egg per day is not associated with BP or HbA1c, even in overweight or obese individuals. Our findings suggested that this frequency of egg consumption is safe as part of a healthy diet and lifestyle for cardiometabolic risk.

Association of Egg Consumption with Risk of All-Cause and Cardiovascular Disease Mortality: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies

BACKGROUND

Recent studies have reported conflicting associations between egg consumption and the risk of all-cause or cardiovascular disease (CVD) mortality, including ischemic heart disease (IHD) mortality and stroke mortality. With accumulating evidence, up-to-date evidence about the association should be synthesized.

OBJECTIVES

We aimed to assess the association of the risk of all-cause and CVD mortality with egg consumption.

METHODS

We searched the PubMed, Embase, and Web of Science databases through 3 November, 2021 for observational studies conducted in participants ≥18 y of age and which provided ORs, RRs, or HRs and 95% CIs for ≥3 egg consumption categories or for increased intake of egg addressing the associations of interest. A random-effects model was used to pool the reported risk estimates. Restricted cubic splines were used to examine the dose-response association.

RESULTS

Twenty-four articles with 48 reports (25 for all-cause mortality, 11 for CVD mortality, 6 for IHD mortality, and 6 for stroke mortality) involving 11,890,695 participants were included. Intake of each 1-egg/d increment was associated with increased risk of all-cause mortality (RR: 1.06; 95% CI: 1.02, 1.10; P = 0.008), but the association was restricted to women, Americans, and studies with adjustments for hyperlipidemia. Egg consumption was linearly associated with CVD mortality only in participants >60 y of age, Americans, studies with follow-up duration ≥15 y, and studies with adjustments for hyperlipidemia (P ≤ 0.018). No significant association was found between egg consumption and IHD or stroke mortality (P ≥ 0.080).

CONCLUSIONS

Egg consumption was linearly associated with a modestly increased risk of all-cause mortality and, in older participants, Americans, and studies with longer follow-up or adjustments for hyperlipidemia, CVD mortality. These findings suggest that it may be prudent to avoid high egg consumption.

Egg and Dietary Cholesterol Intake and Risk of All-Cause, Cardiovascular, and Cancer Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Objective

This systematic review and meta-analysis of prospective cohort studies examined the associations between egg and dietary cholesterol intake and the risk of mortality from all causes, including cardiovascular disease (CVD) and cancer.

Methods

We searched PubMed, Scopus, ISI Web of Knowledge, and Google Scholar until April 2021, as well as references to the relevant articles retrieved. Random-effects models were used to calculate summary relative risk (RR) and 95% confidence intervals (CIs) for the highest vs. lowest categories of egg and dietary cholesterol intake. Also, linear and non-linear dose–response analyses were conducted to examine the dose-response relationships.

Results

We included 55 studies, comprising data from 2,772,486 individuals with 228,425, 71,745, and 67,211 cases of all-cause, CVD, and cancer mortality, respectively. Intake of each additional egg per day was associated with a 7% higher risk of all-cause (1.07, 95% CI: 1.02–1.12, I² = 84.8%) and a 13% higher risk of cancer mortality (1.13, 95% CI: 1.06–1.20, I² = 54.2%), but was not associated with CVD mortality (1.00, 95% CI: 0.92–1.09, I² = 81.5%). Non-linear analyses showed increased risks for egg consumption of more than 1.5 and 0.5 eggs/day, respectively. Each 100 mg/day increment in dietary cholesterol intake was associated with a 6% higher risk of all-cause mortality (1.06, 95% CI: 1.03–1.08, I² = 34.5%) and a 6% higher risk of cancer mortality (1.06, 95% CI: 1.05–1.07, I² = 0%), but was not associated with CVD mortality (1.04, 95% CI: 0.99–1.10, I² = 85.9%). Non-linear analyses demonstrated elevated risks of CVD and cancer mortality for intakes more than 450 and 250 mg/day, respectively.

Conclusions and Relevance

High-dietary intake of eggs and cholesterol was associated with all-cause and cancer mortality. Little evidence for elevated risks was seen for intakes below 0.5 egg/day or 250 mg/day of dietary cholesterol. Our findings should be considered with caution because of small risk estimates and moderate between-study heterogeneity.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=252564, PROSPERO, identifier: CRD42021252564.

Role of diet in stroke incidence: an umbrella review of meta-analyses of prospective observational studies

BACKGROUND

Stroke is one of the major challenges for the global healthcare system, which makes it necessary to explore the relationship between various modifiable factors and stroke risk. Recently, numerous meta-analyses of prospective observational studies have reported that dietary factors played a key role in the occurrence of stroke. However, the conclusions of previous studies have remained controversial and unclear. Accordingly, we conducted an umbrella review synthesizing and recalculating available evidence to assess the certainty of the associations between dietary factors and stroke.

METHODS

Relevant meta-analyses examining the associations between dietary factors and stroke were searched in PubMed and Embase databases up to September 1, 2021. For each eligible meta-analysis, two independent reviewers appraised the methodologic quality using the AMSTAR 2 criteria and estimated the summary effect size, 95% confidence intervals, 95% prediction intervals, heterogeneity between studies, and small-study effects. Moreover, we further assessed the associations between dietary factors and ischemic stroke as well as hemorrhagic stroke. Lastly, a set of pre-specified criteria was applied to qualitatively evaluate the epidemiological credibility of each dietary factor.

RESULTS

Overall, our umbrella review included 122 qualified meta-analyses for qualitative synthesis, involving 71 dietary factors related to food groups, foods, macronutrients, and micronutrients. Using the AMSTAR 2 criteria, 5 studies were assessed as high quality, 4 studies as moderate quality, and 113 studies as low or critically low quality. We identified 34 dietary factors associated with stroke occurrence, 25 dietary factors related to ischemic stroke, and 11 factors related to hemorrhagic stroke. Among them, high/moderate certainty epidemiological evidence demonstrated an inverse association between intake of fruits (RR: 0.90) and vegetables (RR: 0.92) and stroke incidence, but a detrimental association between red meat (RR: 1.12), especially processed red meat consumption (RR:1.17), and stroke incidence. Besides, the evidence of high/moderate certainty suggested that the intake of processed meat, fruits, coffee, tea, magnesium, and dietary fiber was associated with ischemic stroke risk, while consumption of tea, fruits, and vegetables was relevant to hemorrhagic stroke susceptibility.

CONCLUSIONS

Our study has reported that several dietary factors have a significant impact on stroke risk and offered a new insight into the relationship between dietary modification and stroke occurrence. Our results may provide an effective strategy for stroke prevention.

Does eating eggs matter?

Dietary cholesterol is absorbed in proportion to the amount ingested, blocking its hepatic synthesis, increasing its biliary excretion, only slightly increasing production of bile acids while potentially raising the serum concentration of the atherogenic low-density lipoprotein. Humans lie midway between rats and rabbits that respond to dietary cholesterol, respectively, with high and low capacity to produce bile acids, and low or high capacity to raise blood cholesterol. There are regular studies exonerating as well as blaming dietary cholesterol as a cardiovascular risk factor, particularly in genetic hypercholesterolemic individuals. We then resorted at reviewing all meta-analyses on the subject but failed to reach at a clear conclusion useful in medical practice. Nevertheless, ingestion of the same amount of cholesterol results in wide variation in the amounts absorbed and in plasma lipoprotein profiles depending on poorly understood genetic factors. Several genetic conditions are capable of interfering with the absorption and synthesis of cholesterol. Hyperabsorption of dietary cholesterol elicits the accumulation of cholesterol in the liver and in plasma. In this regard, most cases of familial hypercholesterolemia that have a case of intestinal hyperabsorption of cholesterol also demonstrate the same defect. A practical useful suggestion is to measure for a few weeks the total serum cholesterol and its fractions at least three times before and during the intake of eggs that the candidate wishes to maintain in his usual dietary practice as an efficient procedure to identify those who respond with undesirable increases in serum cholesterol.

Egg Consumption and Risk of All-Cause and Cause-Specific Mortality: A Systematic Review and Dose-Response Meta-analysis of Prospective Studies

The association between egg consumption and mortality is extremely debatable. This study aimed to investigate the potential dose-response association of egg consumption with risk of mortality from all causes and cause-specific in the general population. The primary comprehensive literature search was conducted in PubMed/Medline, Scopus, ISI Web of Science, and Embase up to March 2021, as well as reference lists of relevant original papers and key journals. We calculated summary RRs and their 95% CIs for the highest and lowest categories, as well as the linear trend estimation of egg intake, using the random-effects model. Thirty-three (32 publications) cohort studies were included. These studies enrolled 2,216,720 participants and recorded 232,408 deaths from all causes. Comparing highest versus lowest egg intake categories was not associated with the risk of mortality from all causes (RR: 1.02; 95% CI: 0.94, 1.11; n = 25), cardiovascular disease (CVD) (RR: 1.04; 95% CI: 0.87, 1.23, n = 11), coronary heart disease (CHD) (RR: 0.98; 95% CI: 0.84, 1.16; n = 10), stroke (RR: 0.81; 95% CI: 0.64, 1.02; n = 9), and respiratory disease (RR: 0.96; 95% CI: 0.53, 1.71; n = 3); however, it was associated with a higher risk of cancer mortality (RR: 1.20; 95% CI: 1.04, 1.39; n = 13). In the linear dose-response analysis, an additional intake of 1 egg per week was associated with a 2% and 4% increased risk of all-cause and cancer mortality, respectively, and a 4% decreased risk of stroke mortality. The certainty of the evidence was rated as low to moderate. Higher egg consumption was not associated with an increased risk of mortality from all causes, CVD, CHD, stroke, or respiratory disease, whereas an elevated risk was observed for cancer mortality. These findings suggest that eggs be consumed in low to moderate amounts (≤1 egg/d) as part of a healthy diet.

Dietary Choline Supplements, but Not Eggs, Raise Fasting TMAO Levels in Participants with Normal Renal Function: A Randomized Clinical Trial

BACKGROUND

Choline is a dietary precursor to the gut microbial generation of the prothrombotic and proatherogenic metabolite trimethylamine-N-oxide (TMAO). Eggs are rich in choline, yet the impact of habitual egg consumption on TMAO levels and platelet function in human subjects remains unclear.

METHODS

Healthy volunteers (41% male, 81% Caucasian, median age 28 years) with normal renal function (estimated glomerular filtration rate >60) were recruited and assigned to 1 of 5 daily interventions for 4 weeks: 1) hardboiled eggs (n = 18); 2) choline bitartrate supplements (n = 20); 3) hardboiled eggs + choline bitartrate supplements (n = 16); 4) egg whites + choline bitartrate supplements (n = 18); 5) phosphatidylcholine supplements (n = 10). Fasting blood and urine samples were collected for quantification of TMAO, its precursors, and platelet aggregometry.

RESULTS

Participants' plasma TMAO levels increased significantly in all 3 intervention arms containing choline bitartrate (all P < .0001), but daily ingestion of 4 large eggs (P = .28) or phosphatidylcholine supplements (P = .27) failed to increase plasma TMAO levels. Platelet reactivity also significantly increased in the 3 intervention arms containing choline bitartrate (all P < .01), but not with eggs (P = .10) or phosphatidylcholine supplements (P = .79).

CONCLUSIONS

Despite high choline content in egg yolks, healthy participants consuming 4 eggs daily showed no significant increase in TMAO or platelet reactivity. However, choline bitartrate supplements providing comparable total choline raised both TMAO and platelet reactivity, demonstrating that the form and source of dietary choline differentially contributes to systemic TMAO levels and platelet responsiveness.

Association between egg consumption and arterial stiffness: a longitudinal study

BACKGROUND

Inconsistent associations between egg consumption and cardiovascular disease (CVD) risk have been observed in previous studies. This study aims to longitudinally investigate the association between egg consumption and altered risk of arterial stiffness, a major pre-clinical pathogenic change of CVD, which was assessed by brachial-ankle pulse wave velocity (baPWV).

METHODS

A total of 7315 Chinese participants from the Kailuan Study, free of CVD and cancer were included in this study. Egg consumption was assessed by a semi-quantitative validated food frequency questionnaire in 2014. baPWV was repeatedly measured at baseline and during follow-up (mean follow-up: 3.41 years). General linear regression was used to calculate means of baPWV change rate across different egg consumption groups, adjusting for age, sex, baseline baPWV, healthy eating index, total energy, social-economic status, blood pressure, obesity, smoking, lipid profiles, and fasting glucose concentrations.

RESULTS

Compared to the annual baPWV change rate in participants with 0-1.9 eggs/wk. (adjusted mean: 35.9 ± 11.2 cm/s/y), those consuming 3-3.9 eggs/wk. (adjusted mean: 0.2 ± 11.4 cm/s/y) had the lowest increase in baPWV during follow-up (P-difference = 0.002). Individuals with low (0-1.9 eggs/wk) vs. high (5+ eggs /wk) egg intake showed similar changes in baPWV.

CONCLUSIONS

In this large-scale longitudinal analysis, we did not find a significant difference in arterial stiffness, as assessed by baPWV level, between low and high egg consumption groups. However, moderate egg consumption (3-3.9 eggs/wk) appeared to have beneficial effects on arterial stiffness.

Association of food expenditure with life expectancy in the United States, 2001-2014

OBJECTIVES

A healthy diet is associated with reduced risk for premature death; however, data on the association between food expenditure and life expectancy are scarce. The aim of this study was to determine the association of expenditure on food groups with life expectancy in men and women.

METHODS

This study used data from 1548 counties, representing >90% of the population of the United States from 2001 through the end of 2014. Multivariable adjusted Bayesian generalized linear models were used to assess the association of county-level expenditure on nine groups of individual food and combined healthy and unhealthy foods, and a constructed healthy diet score with life expectancy at 40 y of age by sex.

RESULTS

A 1-unit increase in the healthy diet score based on food expenditure was associated with a 0.07 y (95% confidence interval [CI], 0.05-0.10), 0.04 y (95% CI, 0.02-0.07), and 0.06 y (95% CI, 0.04-0.08) increase in county-level life expectancy among men alone, women alone, and men and women combined, respectively. Increasing expenditure on whole grains (estimate of per 1% increase 0.07; 95% CI, 0.03-0.11), fresh fruit and vegetables (0.06; 95% CI, 0.02-0.09), and dairy products (0.05; 95% CI, 0.03-0.07), as well as reducing expenditure on sugar-sweetened beverages (-0.02; 95% CI, -0.04 to -0.01) and processed red meat (-0.05; 95% CI, -0.08 to -0.02) showed a positive association with increased county-level life expectancy.

CONCLUSIONS

These findings may inform a nutritional measure against premature death and stagnation of increase in life expectancy.

Nutritional Viewpoints on Eggs and Cholesterol

Although most current epidemiologic studies indicate no significant association between consuming one egg daily and blood cholesterol levels and cardiovascular risk, arguments still persist with a positive association. Since the diet is one of the most influential factors for this association, we illustrate characteristic features in Japanese people whose dietary pattern is distinct from that, for example, the US (United States) population. Available epidemiologic studies in healthy Japanese people show no association between consumption of one egg daily and blood cholesterol level, consistent with those observed in the US population. However, when consumption of major nutrients and food sources of cholesterol are compared to the US population, Japanese people may have an extra-reserve against the influence of eggs on cardiovascular risk markers, despite consuming relatively more eggs. Further discussion on the influence of nutrients contained in the egg and dietary pattern, including interaction with gut microbes, is necessary. In addition, special consideration at the personalized level is needed for judgment regarding dietary cholesterol not only for hypercholesterolemic patients but for hyper-responsive healthy persons. Although randomized controlled trials with long-term follow-up are required to evaluate the association between consumption of eggs and human health, available information, at least from the nutritional viewpoint, suggests that egg is a healthy and cost-efficient food worldwide.

Should we prescribe anticonvulsants for acute herpes zoster neuralgia and to prevent postherpetic neuralgia?: A protocol for meta-analysis and benefit-risk assessment

BACKGROUND

Herpes zoster-associated pain [i.e., acute herpes zoster neuralgia (AHN) and postherpetic neuralgia (PHN)] has the potential to cause significant patients' burden and heath resource expenditure. PHN is refractory to the existing treatments, and the consensus is preventing the transition of AHN to PHN is better than treating PHN. Anticonvulsants (e.g., gabapentin, pregabalin) have been recommended as one of the first-line therapies for PHN. In practice, anticonvulsants have also decreased the severity and duration of AHN and reduced the incidence of PHN. Nevertheless, its clinical application to AHN is hampered by inadequate evidence for its efficacy and safety. We performed this protocol for a systematic review to explore the efficacy and safety of anticonvulsants for AHN. Besides, a benefit-risk assessment of anticonvulsants for AHN would be performed to estimate the extent to which these drugs could relieve symptoms and whether the benefits outweigh harms.

METHODS

The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) was used to prepare our protocol and the results will be reported according to the PRISMA. We will search the China National Knowledge Infrastructure (CNKI), Chinese VIP Information (VIP), Cochrane Library, Embase, and PubMed databases, from inception to August 2019. Furthermore, Clinicaltrials (http://www.clinicaltrials.com) and Chinese Clinical Trial Registry (http://www.chictr.org.cn/abouten.aspx) will also be searched for relevant studies. Selection of eligible articles and data extraction will be independently performed by reviewers. We will record the characteristic information, pain outcomes, incidence of PHN and adverse effects. Data synthesis and other statistical analyses will be conducted using Review Manager Software 5.3 and STATA13.0. Furthermore, risk of bias assessment, meta-regression and subgroup analyses, publication bias assessment, grading of evidence will be performed for included studies.

ETHICS AND DISSEMINATION

As this systematic review will be performed based on published data, no ethical approval is needed. The findings will be submitted in peer-reviewed journals for publication.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019133449.

Egg and cholesterol consumption and mortality from cardiovascular and different causes in the United States: A population-based cohort study

BACKGROUND

Whether consumption of egg and cholesterol is detrimental to cardiovascular health and longevity is highly debated. Data from large-scale cohort studies are scarce. This study aimed to examine the associations of egg and cholesterol intakes with mortality from all causes, cardiovascular disease (CVD), and other causes in a US population.

METHODS AND FINDINGS

Overall, 521,120 participants (aged 50-71 years, mean age = 62.2 years, 41.2% women, and 91.8% non-Hispanic white) were recruited from 6 states and 2 additional cities in the US between 1995 and 1996 and prospectively followed up until the end of 2011. Intakes of whole eggs, egg whites/substitutes, and cholesterol were assessed by a validated food frequency questionnaire. Cause-specific hazard models considering competing risks were used, with the lowest quintile of energy-adjusted intake (per 2,000 kcal per day) as the reference. There were 129,328 deaths including 38,747 deaths from CVD during a median follow-up of 16 years. Whole egg and cholesterol intakes were both positively associated with all-cause, CVD, and cancer mortality. In multivariable-adjusted models, the hazard ratios (95% confidence intervals) associated with each intake of an additional half of a whole egg per day were 1.07 (1.06-1.08) for all-cause mortality, 1.07 (1.06-1.09) for CVD mortality, and 1.07 (1.06-1.09) for cancer mortality. Each intake of an additional 300 mg of dietary cholesterol per day was associated with 19%, 16%, and 24% higher all-cause, CVD, and cancer mortality, respectively. Mediation models estimated that cholesterol intake contributed to 63.2% (95% CI 49.6%-75.0%), 62.3% (95% CI 39.5%-80.7%), and 49.6% (95% CI 31.9%-67.4%) of all-cause, CVD, and cancer mortality associated with whole egg consumption, respectively. Egg white/substitute consumers had lower all-cause mortality and mortality from stroke, cancer, respiratory disease, and Alzheimer disease compared with non-consumers. Hypothetically, replacing half a whole egg with equivalent amounts of egg whites/substitutes, poultry, fish, dairy products, or nuts/legumes was related to lower all-cause, CVD, cancer, and respiratory disease mortality. Study limitations include its observational nature, reliance on participant self-report, and residual confounding despite extensive adjustment for acknowledged dietary and lifestyle risk factors.

CONCLUSIONS

In this study, intakes of eggs and cholesterol were associated with higher all-cause, CVD, and cancer mortality. The increased mortality associated with egg consumption was largely influenced by cholesterol intake. Our findings suggest limiting cholesterol intake and replacing whole eggs with egg whites/substitutes or other alternative protein sources for facilitating cardiovascular health and long-term survival.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00340015.

Egg Consumption and Stroke Risk: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

Background: The present study was performed to systematically quantify the association between egg consumption and stroke risk as inconsistent results have been produced.

Methods: Three electronic databases (PubMed, Embase, and Cochrane Library), previous reviews, meta-analyses, and bibliographies of relevant articles were retrieved from prospective cohort studies published before July 1, 2020. The random-effects model was employed to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). A dose-response analysis was also performed when data were available.

Results: Sixteen publications involving 24 prospective cohort studies were included in our final meta-analysis. No significant association between egg consumption and stroke risk was identified (RR = 0.92, 95% CI: 0.84–1.01) for the highest vs. the lowest quintiles of egg intake. Subgroup analysis indicated that geographic location significantly modified the effect of egg consumption on stroke risk. Higher egg consumption was attributed to a reduced probability of stroke in Asia (RR = 0.83, 95% CI: 0.73–0.94), but not in North America (RR = 0.95, 95% CI: 0.77–1.16) or Europe (RR = 1.02, 95% CI: 0.91–1.16). Dose-response analysis demonstrated a nearly J-shaped curve between egg consumption and risk of stroke. A decreased risk was observed for the intake of one to four eggs weekly and an increased risk for the intake of more than six eggs weekly. The results were significant at an intake of 10 eggs weekly.

Conclusions: The evidence from this meta-analysis showed that a J-shaped association exists between egg consumption and stroke risk.

Adverse impact of egg consumption on fatty liver is partially explained by cardiometabolic risk factors: A population-based study

BACKGROUND AND AIMS

We evaluated the association of egg consumption with liver tests (LTs) and non-alcoholic fatty liver disease (NAFLD). This relationship is poorly documented.

METHODS

The National Health and Nutrition Examination Survey (NHANES, 2005-2010) database was used. Analysis of covariance, adjusted linear and logistic regression models were used.

RESULTS

Of the 14,369 participants, 46.8% were men and 45.2% had NAFLD. After correction for several variables including: age, gender, race, education, poverty to income ratio, alcohol intake, energy intake, smoking, and physical activity - fatty liver index (FLI), serum aspartate aminotransferase (AST) alanine aminotransferase (ALT) were 36.9, 25.8 (U/L) and 23.9 (U/L), respectively, in the first tertile (T1) reaching 68.7, 34.9 and 36.5, respectively, in the third tertile (T3) (p < 0.001 for all comparisons). In the model with same covariates, there was significant positive linear relationship between FLI (standard β coefficient (β): 0.196), AST (β: 0.099) and ALT (β: 0.112) with egg consumption and participants in the highest tertile (T3) of egg consumption had 11% higher chance of NAFLD compared with T1 (odds ratio: 1.11 and 95% confidence interval: 1.07-1.17). Of note, after more correction for triglycerides, hypertension and diabetes, the significant link between egg consumption and LTs and/or NAFLD attenuated and disappeared.

CONCLUSION

Our findings highlight the adverse role of egg consumption on LTs and likelihood of NAFLD. These associations seem to be attributable to cardio-metabolic risk factors. These findings require confirmation to improve our understanding of the role of egg consumption in the pathogenesis of NAFLD.

Egg consumption and cardiovascular risk: a dose-response meta-analysis of prospective cohort studies

Purpose

Cardiovascular disease (CVD) is a leading cause of mortality globally and is strongly influenced by dietary risk factors. The aim was to assess the association between egg consumption and risk of CVD risk/mortality, including coronary heart disease (CHD), stroke, and heart failure.

Methods

MEDLINE, Embase, and Web of Science databases were searched through April 2020 for prospective studies. Two independent reviewers screened and extracted the data through standardized methods. Size effects were calculated as summary relative risks (SRRs) in a dose–response fashion through random-effects meta-analyses.

Results

Thirty-nine studies including nearly 2 million individuals and 85,053 CHD, 25,103 stroke, 7536 heart failure, and 147,124 CVD cases were included. The summary analysis including 17 datasets from 14 studies conducted on CVD (incidence and/or mortality) showed that intake of up to six eggs per week is inversely associated with CVD events, when compared to no consumption [for four eggs per week, SRR = 0.95 (95% CI: 0.90; 1.00)]; a decreased risk of CVD incidence was observed for consumption of up to one egg per day [SRR = 0.94 (95% CI: 0.89; 0.99)]. The summary analysis for CHD incidence/mortality including 24 datasets from 16 studies showed a decreased risk up to two eggs per week [(SRR = 0.96 (95% CI: 0.91; 1.00)]. No associations were retrieved with risk of stroke. The summary analysis for heart failure risk including six datasets from four studies showed that intake of one egg per day was associated with increased risk raising for higher intakes compared to no consumption [for 1 egg per day, SRR = 1.15 (95% CI:1.02; 1.30)]. After considering GRADE criteria for strength of the evidence, it was rated low for all outcomes but stroke, for which it was moderate (yet referring to no risk).

Conclusion

There is no conclusive evidence on the role of egg in CVD risk, despite the fact that higher quality studies are warranted to obtain stronger evidence for a possible protection of CVD associated with moderate weekly egg consumption compared to no intake; equally, future studies may strengthen the evidence for increased heart failure risk associated with high regular egg consumption.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02345-7) contains supplementary material, which is available to authorized users.

Cholesterol and Egg Intakes, and Risk of Hypertension in a Large Prospective Cohort of French Women

Purpose: The relationship between egg and cholesterol intakes, and cardiovascular disease is controversial. Meta-analyses indicate that egg consumption is associated with increased cardiovascular disease and mortality, but reduced incidence of hypertension, a major risk factor for cardiovascular disease. This study aims to investigate the associations between consumption of egg and cholesterol, and hypertension risk in a cohort of French women. Methods: We used data from the E3N cohort study, a French prospective population-based study initiated in 1990. From the women in the study, we included those who completed a detailed diet history questionnaire, and who did not have prevalent hypertension or cardiovascular disease at baseline, resulting in 46,424 women. Hypertension cases were self-reported. Egg and cholesterol intake was estimated from dietary history questionnaires. Cox proportional hazard models with time-updated exposures were used to calculate hazard ratios. Spline regression was used to determine any dose–respondent relationship. Results: During 885,321 person years, 13,161 cases of incident hypertension were identified. Higher cholesterol consumption was associated with an increased risk of hypertension: HR_Q1–Q5 = 1.22 [1.14:1.30], with associations similar regarding egg consumption up to seven eggs per week: HR_{4–7 eggs} = 1.14 [1.06:1.18]. Evidence for a non-linear relationship between hypertension and cholesterol intake was observed. Conclusions: Egg and cholesterol intakes were associated with a higher risk of hypertension in French women. These results merit further investigation in other populations.

Egg Consumption and Coronary Artery Disease: A Nice Knockdown Argument

To identify prospective cohort studies enrolling adults and investigating an association of egg consumption with incidence and mortality of coronary artery disease (CAD), PubMed and Web of Science were searched through June 2019. Adjusted hazard ratios (HRs) of CAD incidence/mortality for more versus the least frequent egg consumption were extracted from each study. Study-specific estimates were pooled in the random-effects model. Sixteen eligible studies with a total of 1 285 505 participants were identified and included in the present meta-analysis. The primary meta-analysis pooling all HRs for the most versus least frequent egg consumption demonstrated that egg consumption was associated with significantly low CAD incidence/mortality (pooled HR: 0.93; 95% confidence interval: 0.89-0.98; I ² = 9%). In the secondary meta-analyses (separately combining HRs for the third vs first tertile, the fourth vs first quartile, the third vs first quartile, the fifth vs first quintile, the fourth vs first quintile, and the third vs first quintile egg consumption), the fifth (vs first) quintile egg consumption was only associated with significantly low CAD incidence/mortality. In conclusion, egg consumption is independently associated with low incidence/mortality of CAD, which may be derived from the comparisons of the fifth versus first quintile egg consumption.

Deciphering the Riddles in Nutrition and Cardiovascular Disease

Cardiovascular disease is the leading global cause of death in Western countries, and its development is largely associated with unhealthy dietary patterns. A large body of scientific evidence has reported that nutrition might be the most preventive factor of cardiovascular disease death and could even reverse heart disease. Processes of chronic inflammation and oxidative distress share triggers that are modifiable by nutrition. This review aimed to identify potential targets (food patterns, single foods or individual nutrients) for cardiovascular disease prevention, and analyse the mechanisms implicated in their cardioprotective effects.