A good egg: An evaluation of a social and behavior change communication campaign to increase egg consumption among children in Rwanda

Childhood malnutrition, which is endemic in rural areas of low-income countries, leads to a host of deleterious outcomes such as poor cognitive development, low educational attainment and lower lifetime wages. Promoting the consumption of eggs among young children has emerged as a promising strategy to combat childhood malnutrition, though pathways to scale remain unclear. In this paper, we evaluate the impact of a social and behaviour change communication (SBCC) campaign combined with a program in which rural families purchased chickens on credit (poultry + SBCC; n = 769) relative to an arm in which families only received the poultry intervention (poultry only; n = 750), using a difference-in-difference estimation strategy with propensity score matching. The SBCC consisted of radio messages, in-person training, text message reminders and posters. We found a relatively modest but statistically significant increase in the number of times per week respondents in the poultry + SBCC arm reported feeding eggs to children of 0.28 (p = 0.02) compared to the poultry-only arm. The increase in egg feeding, however, was more pronounced for boys (0.42, p < 0.01) than for girls (0.14, p = 0.26). In addition, the campaign increased egg feeding more for those who were already feeding eggs to children (0.63, p < 0.01) than those who were not engaging in those practices at baseline (0.26, p < 0.01). However, the difference in these differences was not statistically significant. Future campaigns should ensure higher saturation of messaging and include specific messaging around the importance of feeding girls as well as boys. Campaigns seeking to scale up egg feeding quickly could potentially target the easier-to-reach segment of caregivers who already occasionally feed eggs to children though these might not be the neediest group.

The Longitudinal Association of Egg Consumption with Cognitive Function in Older Men and Women: The Rancho Bernardo Study

This study examines the prospective association of egg consumption with multiple domains of cognitive function in older, community-dwelling men and women followed for 16.3 years. Participants were 617 men and 898 women from the Rancho Bernardo Cohort aged 60 and older, who were surveyed about egg intake/week in 1972-1974, and attended a 1988-1991 research visit, where cognitive function was assessed with 12 tests. Analyses showed that egg intake ranged from 0-24/week (means: men = 4.2 ± 3.2; women = 3.5 ± 2.7; p < 0.0001). In men, covariate-adjusted regressions showed that egg intake was associated with better performance on Buschke total (p = 0.04), long-term (p = 0.02), and short-term (p = 0.05) recall. No significant associations were observed in women (p's > 0.05). Analyses showed that in those aged <60y in 1972-1974, egg intake was positively associated with scores on Heaton copying (p < 0.04) and the Mini-Mental Status Exam (MMSE; p < 0.02) in men and category fluency (p < 0.05) in women. Egg intake was not significantly associated with odds of poor performance on MMSE, Trails B, or category fluency in either sex. These reassuring findings suggest that there are no long-term detrimental effects of egg consumption on multiple cognitive function domains, and for men, there may be beneficial effects for verbal episodic memory. Egg consumption in middle age may also be related to better cognitive performance later in life.

Influence of Prolonged Whole Egg Supplementation on Insulin-like Growth Factor 1 and Short-Chain Fatty Acids Product: Implications for Human Health and Gut Microbiota

The gut microbiota exert a profound influence on human health and metabolism, with microbial metabolites playing a pivotal role in shaping host physiology. This study investigated the impact of prolonged egg supplementation on insulin-like growth factor 1 (IGF-1) and circulating short-chain fatty acids (SCFAs). In a subset of a cluster-randomized trial, participants aged 8-14 years were randomly assigned into three groups: (1) Whole Egg (WE)-consuming 10 additional eggs per week [n = 24], (2) Protein Substitute (PS)-consuming yolk-free egg substitute equivalent to 10 eggs per week [n = 25], and (3) Control Group (C) [n = 26]. At week 35, IGF-1 levels in WE significantly increased (66.6 ± 27.7 ng/mL, p < 0.05) compared to C, with positive SCFA correlations, except acetate. Acetate was stable in WE, increasing in PS and C. Significant propionate differences occurred between WE and PS (14.8 ± 5.6 μmol/L, p = 0.010). WE exhibited notable changes in the relative abundance of the Bifidobacterium and Prevotella genera. Strong positive SCFA correlations were observed with MAT-CR-H4-C10 and Libanicoccus, while Roseburia, Terrisporobacter, Clostridia_UCG-014, and Coprococcus showed negative correlations. In conclusion, whole egg supplementation improves growth factors that may be related to bone formation and growth; it may also promote benefits to gut microbiota but may not affect SCFAs.

Egg consumption and risk of coronary artery disease, potential amplification by high genetic susceptibility: a prospective cohort study

BACKGROUND

Remarkable heterogeneity has been observed among population-based studies on egg consumption and risk of coronary artery disease (CAD). Whether genetic susceptibility serves as a potential explanation for this inconsistency remains unknown.

OBJECTIVES

We performed a prospective cohort study to investigate the association of egg consumption with incident CAD at different genetic susceptibilities.

METHODS

We included 34,111 participants without CAD at baseline from the project of Prediction for Atherosclerotic Cardiovascular Disease Risk in China. Egg consumption was assessed with food frequency questionnaires. Genetic susceptibility was quantified by a predefined polygenic risk score (PRS) with 540 genetic variants. The hazard ratio (HR) and 95% confidence interval (95% CI) of incident CAD associated with egg consumption and PRS were estimated using the Cox proportional hazards models.

RESULTS

Over a median 11.7 y of follow-up, 1,128 incident cases of CAD were recorded. Both higher egg consumption and increased PRS were related to higher risk of CAD. When stratified by genetic risk, each increment of 3 eggs/wk was associated with a 5% higher risk of CAD for participants at low to intermediate genetic risk (HR: 1.05; 95% CI: 1.01, 1.09), whereas risk increased to HR 1.10 (95% CI: 1.05, 1.16) for those at high genetic risk; a significant synergistic interaction was also indicated at both multiplicative (Pinteraction = 0.007) and additive (relative excess risk: 0.73; 95% CI: 0.24, 1.22) scales. When the joint effect was examined, in comparison with those at low to intermediate genetic risk and consuming <1 egg/wk, the HR (95% CI) was 2.95 (2.41, 3.62) for participants with high genetic risk and consumption of ≥10 eggs/wk, and the corresponding standardized 10-y CAD rates increased from 1.37% to 4.24%.

CONCLUSIONS

Genetic predisposition may synergistically interact with egg consumption in relation to increased CAD risk. PRS-stratified recommendations on egg consumption may help formulate personalized nutrition policies.

[Egg consumption and non-alcoholic fatty liver disease: a prospective cohort study]

OBJECTIVE

To explore the association between egg consumption and the risk of non-alcoholic fatty liver disease(NAFLD), which will provide epidemiological evidence for NAFLD prevention.

METHODS

A total of 6734 non-NAFLD participants(5500 men and 1234 women, aged(45±14) years old)in the Kailuan cohort followed up in 2014-2015 were enrolled. Semi-quantitative food frequency questionnaires were used to collect the diet frequency, including the consumption of eggs, over the past years. Then the score of dietary approaches to stop hypertension(DASH) was calculated. Abdominal ultrasound was applied for fatty liver diagnosis. The Kaplan-Meier method was used to estimate the cumulative incidences of NAFLD for the three groups(0-4, 5-7 and &gt;7 eggs/week). Furthermore, Cox regression models under various adjusted factors were used to compare the risks of NAFLD.

RESULTS

During the median follow-up of 45 months, 1484 NAFLDs were identified among 6734 non-NAFLD participants. The 4-year cumulative incidence rates of NAFLD for the individuals consuming 0-4, 5-7, and &gt;7 eggs/week were 27.1%, 19.9% and 29.6%(P&lt;0.05). The DASH score was significantly higher in those who consumed 5-7 eggs/week than in the other two groups(P&lt;0.001). After adjusting confounders, including DASH score and dietary cholesterol, we found that compared with those consuming 5-7 eggs/week, the individuals with 0-4 and &gt;7 eggs/week had a higher NAFLD hazard, with hazard ratios(95% confidence interval) of 1.20(1.03, 1.41) and 1.25(1.06, 1.47), respectively. The association was more significant in the population with a higher DASH score(P_(interaction)=0.02).

CONCLUSION

Eating 5-7 eggs/week may have the lowest risk of NAFLD, suggesting taking a moderate amount of eggs to prevent NAFLD, even if the overall diet quality is relatively healthy.

Frequency of Egg Intake Associated with Mortality in Chinese Adults: An 8-Year Nationwide Cohort Study

Whether egg consumption plays a beneficial/detrimental role in affecting human health and longevity has been debated for decades. Large-scale cohort evidence from low- and middle-income populations are scarce. In this study, we aimed to assess the association of egg consumption with mortality in Chinese adults. A nationwide cohort of 30,835 participants ages 16-110 years were enrolled from 25 provincial regions in China's mainland. Dietary intake (e.g., egg, meat, vegetable) was assessed by a food-frequency questionnaire. Cox proportional hazards models were used to examine associations between egg consumption and mortality, adjusting for demographic characteristics, dietary factors and health status. Dose-response relationships were investigated using the smoothing function of restricted cubic splines. Several subgroup analyses were performed. A total of 1651 all-cause deaths occurred during a median follow-up of 8.1 years. Egg consumption was associated with lower risks of mortality, with the lowest risk occurring in the group of moderate egg intake (3-6 times/week). Compared with non-consumers, the hazard ratios (95% confidence intervals) for mortality were 0.84 (0.72-0.97) for 3-6 times/week and 0.82 (0.69-0.98) for ≥7 times/week, whereas no significant associations were observed among the lower egg intake group (1-2/week). An approximately inverted J-shaped association was observed in three models, while restricting our analysis in the multivariable model (model 3) did not identify a significant violation for the linear relationship (p for nonlinear = 0.122). There were no statistically significant effect modifications in the subgroup analyses. Egg consumption may be associated with lower risks of mortality in Chinese adults. Our findings found moderate-to-high egg consumption might be beneficial for improving long-term health and longevity.

Association of Egg Consumption Frequency and Quantity with Dyslipidemia in Chinese Rural Adults

OBJECTIVE

The aim was to estimate the association of egg consumption with dyslipidemia and its subtypes in Chinese adults.

METHODS

The cross-sectional health survey was conducted in Hanzhong city of Shaanxi province in 2010.Consumption of eggs (alone and mixed in foods) and nutrients were assessed using a semi-quantitative 81-item food frequency questionnaire (FFQ). Serum lipids and other physical measurements were measured by trained medical staff. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from multivariable logistic regressions. Restricted cubic spline was used to visualize the possible non-linear association.

RESULTS

A total of 2241 participants (mean age, 48.0 years; 34.5% men) were included. The age- and gender- standardization dyslipidemia prevalence was 21.1% in men and 18.4% in women, respectively. Approximately 42.1% of individuals never or rarely consumed egg, while 9.4% consumed ≥2 times/week. The mean egg intake was 21.5 g/d in men and 17.4 in women. In women, after adjustment for demographics and lifestyle factors, the ORs (95%CI) for dyslipidemia and hypertriglyceridemia were 0.57(0.32-1.05) and 0.38 (0.17-0.85) for individuals consuming egg ≥2 times/week, compared with never or rarely consumers. When further adjustment of BMI and dietary factors, the inverse relation persisted for hypertriglyceridemia but attenuated to margin of significance for dyslipidemia (P-trend = 0.050). Increment of 25 g/d was associated with 15% (OR: 0.85, (0.71-1.00)) lower risk of dyslipidemia. Results from restricted cubic splines showed a substantial reduction of the risk within lower range of consumption, which reached the minimum risk around 20-50 g/d (P-nonlinearity = 0.069). No associations were observed in men.

CONCLUSION

Egg consumption was associated with decreased risk of dyslipidemia among Chinese women but not men. Additionally, the beneficial effect tended to be stronger at 20-50 g egg per day. Further study is warranted to validate these findings and clarify the causality.

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.

Potential of Egg as Complementary Food to Improve Nutrient Intake and Dietary Diversity

The original aim was to determine the effect of egg consumption on infant growth in a low socioeconomic community in South Africa in a randomized controlled trial. Enrolment was, however, prematurely stopped due to COVID-19 lockdown regulations. The resultant small sample (egg group n = 70; control group n = 85) was followed up to assess the feasibility of egg consumption for eight months in terms of dietary intake, egg usage and perceived effects of lockdown on child feeding. Egg consumption remained low in the control group, <10% consumed egg ≥4 days/week at the follow-up points. In the egg group, egg was frequently consumed at midpoint (daily 87.1%, 4−6 days 8.1%) and endpoint (daily 53.1%, 4−6 days 21.9%). At endpoint, dietary intake of cholesterol and vitamin D was higher, and intake of niacin and vitamin B6 lower in the egg group compared to the control group. Dietary diversity was low, 36.2% of the egg group and 18.9% of the control group (p < 0.05) achieved minimum dietary diversity at endpoint. No babies developed egg allergy or sensitization, and adjusted regression analysis showed that frequency of egg intake was not related with the incidence or duration of allergy-related symptoms. This study showed that frequent egg consumption can contribute safely to complementary food for babies, especially in low- and middle-income countries.

Association of egg consumption, metabolic markers, and risk of cardiovascular diseases: A nested case-control study

Background

Few studies have assessed the role of individual plasma cholesterol levels in the association between egg consumption and the risk of cardiovascular diseases. This research aims to simultaneously explore the associations of self-reported egg consumption with plasma metabolic markers and these markers with the risk of cardiovascular disease (CVD).

Methods

Totally 4778 participants (3401 CVD cases subdivided into subtypes and 1377 controls) aged 30-79 were selected based on the China Kadoorie Biobank. Targeted nuclear magnetic resonance was used to quantify 225 metabolites in baseline plasma samples. Linear regression was conducted to assess associations between self-reported egg consumption and metabolic markers, which were further compared with associations between metabolic markers and CVD risk.

Results

Egg consumption was associated with 24 out of 225 markers, including positive associations for apolipoprotein A1, acetate, mean HDL diameter, and lipid profiles of very large and large HDL, and inverse associations for total cholesterol and cholesterol esters in small VLDL. Among these 24 markers, 14 were associated with CVD risk. In general, the associations of egg consumption with metabolic markers and of these markers with CVD risk showed opposite patterns.

Conclusions

In the Chinese population, egg consumption is associated with several metabolic markers, which may partially explain the protective effect of moderate egg consumption on CVD.

Funding

This work was supported by the National Natural Science Foundation of China (81973125, 81941018, 91846303, 91843302). The CKB baseline survey and the first re-survey were supported by a grant from the Kadoorie Charitable Foundation in Hong Kong. The long-term follow-up is supported by grants (2016YFC0900500, 2016YFC0900501, 2016YFC0900504, 2016YFC1303904) from the National Key R&D Program of China, National Natural Science Foundation of China (81390540, 81390541, 81390544), and Chinese Ministry of Science and Technology (2011BAI09B01). The funders had no role in the study design, data collection, data analysis and interpretation, writing of the report, or the decision to submit the article for publication.

Association of egg protein levels in dust with allergy status and related factors

BACKGROUND

Levels of peanut protein in dust have been reported to be associated with sensitization and allergy to it, so controlling food protein in dust may help prevent food allergy. However, studies of factors associated with egg protein levels in dust are scarce. This study aimed to determine the factors contributing to egg protein levels in dust.

METHODS

This cross-sectional study included 159 participants in the Sub-Cohort Study of the Japan Environment and Children's Study in Yamanashi Prefecture at a 6 year follow up. House dust at 6 years was collected and egg protein concentrations were measured for whole egg protein. Household factors, including the maternal frequency of egg consumption, were assessed by questionnaires. A linear regression model was used to analyze the effect of household environmental factors on egg protein in dust.

RESULTS

In multivariate analysis, frequent maternal egg consumption (≥5 times a week) was associated with higher egg protein concentrations in house dust (β = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, β = 0.85, P = 0.02) in addition to frequent maternal egg consumption. Among the participants, 140 (88.1%) had no egg allergy, 15 (9.4%) were egg tolerant, and 4 (2.5%) had an egg allergy at 6 years old. There was no significant association between the current egg allergy status and egg protein concentrations in dust.

CONCLUSIONS

The frequency of maternal egg consumption and the number of inhabitants are contributing factors to egg protein levels in dust.

Egg consumption improves vascular and gut microbiota function without increasing inflammatory, metabolic, and oxidative stress markers

Egg consumption is one of the many inconsistencies in evidence linking dietary cholesterol to cardiovascular disease (CVD). In addition, the gut microbiota and its metabolite, trimethylamine-N-oxide (TMAO), have been shown to play a crucial role in the development of CVD. The fact that egg is rich in choline suggests that excessive egg consumption may increase TMAO production by altering the gut microbiota. However, the effects of egg consumption on vascular function and gut microbiota remain unclear. Here, the diet of nine young male subjects was supplemented with two boiled eggs daily for 2 weeks. Changes in vascular function, inflammation, metabolism, oxidative stress, and gut microbiota were examined. We found that egg consumption increased flow-mediated dilation and decreased brachial-ankle pulse wave velocity. Furthermore, egg consumption positively modulated the gut microbiota function but had no effects on the levels of C-reactive protein, glucose, lipid profile, malondialdehyde, superoxide dismutase, or TMAO. The current study provides evidence that egg consumption improves vascular function, which may be related to the alterations seen in the gut microbiota. Therefore, moderate egg consumption may help to improve vascular and intestinal function in individuals at low risk of developing CVD and other metabolic disorders.

Eggs, dietary cholesterol, choline, betaine, and diabetes risk in the Women's Health Initiative: a prospective analysis

BACKGROUND

Epidemiological studies have been inconsistent regarding the relations between diabetes risk and the consumption of eggs and nutrients in eggs, such as choline, betaine, and cholesterol. There have been few studies among elderly women.

OBJECTIVES

The objective of this study was to examine associations between consumption of eggs, cholesterol, choline, and betaine and the risk of diabetes among elderly US women.

METHODS

Multivariable Cox regression was used with data from the prospective Women's Health Initiative. Population attributable risks were calculated. Consumption of eggs alone (not mixed in foods) and nutrients were assessed with an FFQ. Diabetes incidence was defined as the first incidence of self-reported diabetes treated with oral diabetes medication or insulin injections.

RESULTS

There were 46,263 women at follow-up baseline. During 13.3 y and 592,984 person-years of follow-up, there were 5480 incident diabetes cases. Higher egg, cholesterol, and choline consumption were each significantly associated with increases in diabetes risk. The associations for eggs and choline were not significant after adjustment for cholesterol consumption. The association for eggs was attenuated after adjustment for non-egg cholesterol consumption, with 1 significant HR in the top consumption quintile (≥3 eggs/wk) of 1.15 (95% CI: 1.05, 1.27; P for linear trend = 0.0001). The population attributable risks for obesity, overweight, consumption of ≥3 eggs/wk, inadequate exercise, and poor diet were 25.0 (95% CI: 22.3, 27.6), 12.8 (95% CI: 11.1, 14.5), 4.2 (95% CI: 2.3, 6.1), 3.5 (95% CI: 1.2, 5.8), and 3.1 (95% CI: 0.5, 5.7), respectively.

CONCLUSIONS

As egg consumption increased to ≥3 eggs/wk, there was a steady increase in diabetes risk that may have been due to the cholesterol in the eggs. The population attributable risk for ≥3 eggs/wk was far lower than that for being obese or overweight.

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.

Whole Egg Consumption Decreases Cumulative Weight Gain in Diet-Induced Obese Rats

BACKGROUND

Whole egg (WE) consumption has been demonstrated to attenuate body weight (BW) gain and adiposity in genetic animal models of type 2 diabetes (T2D). This finding was accompanied by increased food consumption.

OBJECTIVES

This study aimed to examine the effects of long-term WE intake on BW gain, fat distribution, and food intake in a rat model of diet-induced obesity (DIO).

METHODS

Male Sprague Dawley rats (n = 24) were obtained at 5 wk of age and were randomly weight-matched across 1 of 4 dietary intervention groups (6 rats per group): a casein-based diet (CAS), a high-fat high-sucrose CAS diet (HFHS CAS), a whole egg-based diet (EGG), or a high-fat high-sucrose EGG diet (HFHS EGG). All diets provided 20% (w/w) protein and were provided for 33 wk. HFHS diets provided ∼61% of kilocalories from fat and 10% from sucrose. Daily weight gain and food intake were recorded, biochemical parameters were measured via ELISA, and epididymal fat pad weights were recorded at the end of the study.

RESULTS

At 33 wk, cumulative BW gain in DIO rats fed HFHS EGG resulted in 23% lower weight gain compared with DIO rats fed HFHS CAS (P < 0.0001), but no significant differences in BW gain were observed between the HFHS EGG group and the control EGG and CAS groups (P = 0.71 and P = 0.61, respectively). Relative food intake (grams per kilogram BW) was 23% lower (P < 0.0001) in rats fed HFHS CAS compared with CAS, whereas there was no difference in food intake within the EGG dietary groups. DIO rats fed HFHS EGG exhibited a 22% decrease in epididymal fat weight compared with their counterparts fed the HFHS CAS.

CONCLUSIONS

Our data demonstrate that consumption of a WE-based diet reduced BW gain and visceral fat in the DIO rat, similar to our previous findings in a genetic rat model with T2D.

The responses of different dosages of egg consumption on blood lipid profile: An updated systematic review and meta-analysis of randomized clinical trials

Diverse notions exist regarding egg intake, which is one of the main sources of dietary cholesterol, and its effect on blood lipids. We conducted this study to update the previous meta-analysis for their flaw in calculated effect size. PubMed, Scopus, ISI, and Cochrane were searched up to April 2019, for relevant randomized controlled clinical trials. Mean changes in total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglyceride (TG), very low-density lipoprotein cholesterol (VLDL-C), LDL-C/HDL-C, TC/HDL-C, apolipoprotein (apo)A1, and apoB100 were assessed. Meta-analysis of 66 RCTs with 3,185 participants revealed that egg consumption can significantly increase TC, LDL-C, HDL-C, TC/HDL-C, apoA1/and B100, but there was no significant effect on other serum lipids. Dose-response analysis showed a linear effect for TC, HDL-C, ApoA1, ApoB100, and nonlinear for LDL-C, and TC/HDL-C. In conclusion, intake of more than one egg daily in less than 12 weeks may increase some blood lipids without any changes in the ratio of LDL-C/HDL-C. PRACTICAL APPLICATIONS: There are controversies reports for egg intake, which is one of the main sources of dietary cholesterol. This study provides comprehensive information about the effect of the number of eggs consumed per day (dietary cholesterol) on blood lipids for nutritionists, physicians, researchers, and the general population. In this regard, our results indicated that there is a linear correlation between consumption of greater than one egg per day in a short time (no long time) and increasing lipid profiles which may increase the risk of cardiovascular diseases. However, consumption of one egg daily can be safe and this can be a useful recommendation for prevention of cardiovascular disease and promotion of healthy life which indeed are the potential or actual uses of this research.

Egg consumption and risk of type 2 diabetes mellitus in middle and elderly Chinese population: An observational study

Data on the association between egg consumption and the risk of type 2 diabetes mellitus (T2DM) in the Chinese population are scarce. In the present study, we aimed to examine the association between egg consumption and the risk of T2DM in a middle and elderly Chinese population. A total of 3298 subjects (1645 men and 1653 women) from the Nutrition and Health Survey (2015-2017) in Hangzhou city were selected for the final analysis. Egg consumption was assessed using a validated food frequency questionnaire. All biochemical data and anthropometric measurements were collected following standardized procedures. Multivariable logistic regression analyses were used to assess the association between egg consumption and the risk of T2DM and the results were presented as odds ratios and 95% confidence interval (CI). Restricted cubic spline combined with logistic regression was used to explore the dose-response relationship between egg consumption and T2DM. Among 3298 subjects, 693 (21.0%) people had T2DM. Compared with participants who did not consume egg per week, the multivariable-adjusted odds ratios were 0.97 (95%CI : 0.78-1.21), 1.08 (95%CI : 0.91-1.06), 1.20 (95%CI : 0.94-1.55), 1.27 (95%CI : 0.99-1.68) in men (P > .05); 1.06 (95%CI : 0.81-1.37), 0.97 (95%CI : 0.78-1.21), 1.26 (95%CI : 0.99-1.59), 1.19 (0.92-1.54) in women (P > .05); 0.89 (95%CI : 0.79-1.04), 0.98 (95%CI : 0.91-1.06), 1.06 (95%CI : 0.87-1.30), 1.09 (95%CI : 0.88-1.34) in both men and women for egg consumption 0∼7, 7, 7∼14, and ≥14 eggs/week, respectively (P > .05). The dose-response curve showed that, with the increase of egg consumption, the risk of T2DM first increased and then decreased (P = .027).We found that the association between egg consumption and T2DM was nonlinear, and higher egg consumption was not associated with an elevated risk for T2DM in middle-aged and elderly Chinese. However, future prospective studies are needed to confirm these findings.

Associations of egg consumption with incident cardiovascular disease and all-cause mortality

Eggs are nutrient-dense while also loaded with abundant cholesterol, thus making the public hesitant about their consumption. We conducted the study to investigate if egg consumption is associated with incident cardiovascular disease (CVD) and all-cause mortality. Using the project of Prediction for Atherosclerotic Cardiovascular Disease Risk in China, we included 102,136 adults free of CVD and assessed their egg consumption with food-frequency questionnaires. CVD endpoints and all-cause mortality were confirmed during follow-ups by interviewing participants or their proxies and checking hospital records/death certificates. The HRs (95% CIs) were calculated using the cohort-stratified Cox regression models. During 777,163 person-years of follow-up, we identified 4,848 incident CVD and 5,511 deaths. U-shaped associations of egg consumption with incident CVD and all-cause mortality were observed. Compared with consumption of 3-<6/week, the multivariable-adjusted HRs (95% CIs) of <1/week and ≥10/week for incident CVD were 1.22 (1.11 to 1.35) and 1.39 (1.28 to 1.52), respectively. The corresponding HRs (95% CIs) for all-cause mortality were 1.29 (1.18 to 1.41) and 1.13 (1.04 to 1.24). Our findings identified that both low and high consumption were associated with increased risk of incident CVD and all-cause mortality, highlighting that moderate egg consumption of 3-<6/week should be recommended for CVD prevention in China.

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.

Egg Consumption, Multi-Domain Cognitive Performance, and Short-Term Cognitive Change in a Representative Sample of Older U.S. Adults

Objective: Existing research supports a positive relationship between egg intake and cognitive function in older populations, although the impact of whole egg consumption on multi-domain cognitive function and cognitive decline in representative samples of older adults has not been described. We examined the association between egg consumption, cognitive performance, and cognitive change in a representative sample of U.S. adults aged 65 and older. Methods: We drew observations from the 2012 and 2014 Health and Retirement Study and the recently released 2013 Health Care and Nutrition Study. The analytic sample contained 3835 respondents, representing a weighted population of 37,806,082 community-dwelling adults aged 65 and older in 2013. Multivariate path analytic models were used to estimate the association between egg consumption groups (none, ≤ 1 serving per week, 2-6 servings per week, ≥ 7 servings per week) and cognitive performance across domains of working memory, executive function, and global mental status. First-order autoregressive models were used to estimate cognitive change over the 2-year observational period. Follow-up analyses examined associations between egg consumption group, dietary patterns, and nutrient intake. Results: On average, older adults consumed 0.34 eggs per day (SD = 0.36). Although bivariate analyses suggested that moderate egg consumers had the best cognitive performance at baseline assessment, egg consumption was not associated with cognitive performance or cognitive change when adjusting models for covariates known to have a robust association with cognitive health. Conclusions: Our results suggest that egg consumption does not benefit, nor is detrimental to, the cognitive health of older adults. Further studies of whole egg consumption and cognitive performance would benefit from controlled experimental settings, longer follow-up periods to measure cognitive change, and assessment of both community-dwelling and institutionalized older adults.

Frequency and Quantity of Egg Intake Is Not Associated with Dyslipidemia: The Hellenic National Nutrition and Health Survey (HNNHS)

BACKGROUND

Gaps remain on the safety of egg intake on cardiovascular health, setting the study's aim to investigate the association between quantity and frequency of egg consumption, with established dyslipidemia.

METHODS

Study participants (N = 3558, 40.3% males) included individuals from the Hellenic National and Nutrition Health Survey (HNNHS), of national representation. Quantity and frequency of egg consumption was determined. Minimally adjusted, multivariable logistic and linear analysis were used to assess egg consumption and dyslipidemia.

RESULTS

The more frequent egg consumption compared to no or rare egg consumption significantly decreased the odds of dyslipidemia in the minimally adjusted (Odds Ratio (OR) for frequency: 0.83; 95% Confidence Interval (CI): 0.752, 0.904; OR for quantified frequency: 0.87; 95% CI: 0.796, 0.963) and the fully adjusted models (OR for frequency: 0.80; 95% CI: 0.718, 0.887; OR for quantified frequency: 0.85; 95%CI: 0.759, 0.945). Level of serum cholesterol and LDL-c were significantly lower with higher frequency and quantified frequency of egg consumption in all models.

CONCLUSION

Eggs do not increase the risk of dyslipidemia and can be consumed as part of a healthy diet that is high in fiber and low in saturated fat, without excessive energy intake, by all individuals.

Whole Egg Consumption Impairs Insulin Sensitivity in a Rat Model of Obesity and Type 2 Diabetes

BACKGROUND

The literature regarding the relation between egg consumption and type 2 diabetes (T2D) is inconsistent and there is limited evidence pertaining to the impact of egg consumption on measures of insulin sensitivity.

OBJECTIVES

The aim of this study was to investigate the effect of dietary whole egg on metabolic biomarkers of insulin resistance in T2D rats.

METHODS

Male Zucker diabetic fatty (ZDF) rats (n = 12; 6 wk of age) and age-matched lean controls (n = 12) were randomly assigned to be fed a casein- or whole egg-based diet. At week 5 of dietary treatment, an insulin tolerance test (ITT) was performed on all rats and blood glucose was measured by glucometer. After 7 wk of dietary treatment, rats were anesthetized and whole blood was collected via a tail vein bleed. Following sedation, the extensor digitorum longus muscle was removed before and after an intraperitoneal insulin injection, and insulin signaling in skeletal muscle was analyzed by Western blot. Serum glucose and insulin were analyzed by ELISA for calculation of the homeostatic model assessment of insulin resistance (HOMA-IR).

RESULTS

Mean ITT blood glucose over the course of 60 min was 32% higher in ZDF rats fed the whole egg-based diet than in ZDF rats fed the casein-based diet. Furthermore, whole egg consumption increased fasting blood glucose by 35% in ZDF rats. Insulin-stimulated phosphorylation of key proteins in the insulin signaling pathway did not differ in skeletal muscle of ZDF rats fed casein- and whole egg-based diets. In lean rats, no differences were observed in insulin tolerance, HOMA-IR and skeletal muscle insulin signaling, regardless of experimental dietary treatment.

CONCLUSIONS

These data suggest that whole body insulin sensitivity may be impaired by whole egg consumption in T2D rats, although no changes were observed in skeletal muscle insulin signaling that could explain this finding.

Mechanism and Potential of Egg Consumption and Egg Bioactive Components on Type-2 Diabetes

Type-2 diabetes (T2D) is one of the major global health challenges and a substantial economic burden. Egg and egg-derived components have been indicated to possess antioxidant, anti-inflammatory, anti-hypertensive, immunomodulatory, and anti-cancer activities. However, the scientific evidence about the benefits of egg on T2D is debatable. The relationship between egg consumption and the risk of T2D from observational epidemiological studies is not consistent. Interventional clinical studies, however, provide promising evidence that egg consumption ameliorates the risk of T2D. Current research progress also indicates that some egg components and egg-derived peptides might be beneficial in the context of T2D, in terms of insulin secretion and sensitivity, oxidative stress, and inflammation, suggesting possible application on T2D management. The current review summarizes recent clinical investigations related to the influence of egg consumption on T2D risk and in vivo and in vitro studies on the effect and mechanism of egg components and egg-derived peptides on T2D.

Egg Intake in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) are often instructed to adhere to a renal-specific diet depending on the severity and stage of their kidney disease. The prescribed diet may limit certain nutrients, such as phosphorus and potassium, or encourage the consumption of others, such as high biological value (HBV) proteins. Eggs are an inexpensive, easily available and high-quality source of protein, as well as a rich source of leucine, an essential amino acid that plays a role in muscle protein synthesis. However, egg yolk is a concentrated source of both phosphorus and the trimethylamine N-oxide precursor, choline, both of which may have potentially harmful effects in CKD. The yolk is also an abundant source of cholesterol which has been extensively studied for its effects on lipoprotein cholesterol and the risk of cardiovascular disease. Efforts to reduce dietary cholesterol to manage dyslipidemia in dialysis patients (already following a renal diet) have not been shown to offer additional benefit. There is a paucity of data regarding the impact of egg consumption on lipid profiles of CKD patients. Additionally, egg consumption has not been associated with the risk of developing CKD based on epidemiological studies. The egg yolk also contains bioactive compounds, including lutein, zeaxanthin, and vitamin D, which may confer health benefits in CKD patients. Here we review research on egg intake and CKD, discuss both potential contraindications and favorable effects of egg consumption, and describe the need for further research examining egg intake and outcomes in the CKD and end-stage renal disease population.

Associations of egg consumption with cardiovascular disease in a cohort study of 0.5 million Chinese adults

OBJECTIVE

To examine the associations between egg consumption and cardiovascular disease (CVD), ischaemic heart disease (IHD), major coronary events (MCE), haemorrhagic stroke as well as ischaemic stroke.

METHODS

During 2004-2008, over 0.5 million adults aged 30-79 years were recruited from 10 diverse survey sites in China. Participants were asked about the frequency of egg consumption and were followed up via linkages to multiple registries and active investigation. Among 461 213 participants free of prior cancer, CVD and diabetes, a total of 83 977 CVD incident cases and 9985 CVD deaths were documented, as well as 5103 MCE. Stratified Cox regression was performed to yield adjusted hazard ratios for CVD endpoints associated with egg consumption.

RESULTS

At baseline, 13.1% of participants reported daily consumption (usual amount 0.76 egg/day) and 9.1% reported never or very rare consumption (usual amount 0.29 egg/day). Compared with non-consumers, daily egg consumption was associated with lower risk of CVD (HR 0.89, 95% CI 0.87 to 0.92). Corresponding multivariate-adjusted HRs (95% CI) for IHD, MCE, haemorrhagic stroke and ischaemic stroke were 0.88 (0.84 to 0.93), 0.86 (0.76 to 0.97), 0.74 (0.67 to 0.82) and 0.90 (0.85 to 0.95), respectively. There were significant dose-response relationships of egg consumption with morbidity of all CVD endpoints (P for linear trend <0.05). Daily consumers also had an 18% lower risk of CVD death and a 28% lower risk of haemorrhagic stroke death compared to non-consumers.

CONCLUSION

Among Chinese adults, a moderate level of egg consumption (up to <1 egg/day) was significantly associated with lower risk of CVD, largely independent of other risk factors.

Towards a Food-Based Intervention to Increase Protein Intakes in Older Adults: Challenges to and Facilitators of Egg Consumption

Abstract: Background: Dietary protein intake is important for health. Eggs, as a protein-rich food with characteristics that appeal to older adults, may provide opportunities for increasing protein intake. Interventions that focus on the challenges or facilitators that affect a large proportion of the population will be of increased impact on a population-wide scale. This work aimed to investigate the relative importance of a number of challenges to and facilitators of egg consumption in a UK population-wide sample of older adults.

METHODS

A cross-sectional postal questionnaire, measuring habitual egg intake, reasons for eating/not eating eggs and a range of demographic and lifestyle characteristics, was administered by post to 1082 older adults.

RESULTS

230 questionnaires suitable for analysis were returned (110 females, ages 55⁻80+ years). Habitual egg intake ranged from 1⁻89 eggs/month, mean (standard deviation) = 18 (13) eggs/month. Reasons for eating/not eating eggs were reduced using Principal Components Analysis to 23 challenges and facilitators of egg consumption. Regression analyses revealed habitual egg intake to be associated with 10 challenges and facilitators (smallest β = 0.14, p = 0.04), and with protein consumption, age and Body Mass Index (smallest β = 0.14, p = 0.03).

DISCUSSION

Many possibilities for future intervention based on existing challenges or facilitators were found. Our results suggest that strategies to increase egg consumption in older adults should focus on: improving liking, tastiness and adding variety; promoting eggs as an everyday type of food; reducing stereotypes about who does and who does not consume eggs; and promoting eggs for people who have noticed the effects of ageing on their food intake. Strategies that highlight value-for-money may be counterproductive. Future work evaluating the value of these strategies for improving protein intake in this age group would be of value.

Association between Egg Consumption and Metabolic Disease

The effect of high egg intake on metabolic syndrome (MetS), a major risk factor for cardiovascular disease (CVD), has not been clearly elucidated. This study was conducted to review the literature related to egg consumption and the risk of metabolic disease as well as to examine the association between high egg intake and MetS in Korean adults. A literature review was conducted using published papers in PubMed and EMBASE through December 2017. We have reviewed 26 articles, which were associated with egg consumption and metabolic diseases, and found that the results were controversial. Therefore, we analyzed data from 23,993 Korean adults aged 19 yrs and older. MetS was defined based on criteria from the Adult Treatment Panel III. Egg consumption of 4-6 times/wk and 1 time/day were significantly associated with reduced prevalence of MetS (Odds ratio (OR)=0.82; 95% Confidence interval (CI)=0.71-0.95 for 4-6 times/wk, OR=0.83; 95% CI=0.69-0.99 for 1 time/day) compared to those who consumed eggs less than once monthly. However, consuming two or more eggs per day was not associated with MetS. As for the components of MetS, an egg intake of once daily decreased the prevalence of abdominal obesity and an intake of 2-7 eggs weekly was shown to prevent a reduction in the high-density lipoprotein cholesterol levels. This study suggests that while consuming eggs 4-7 times weekly is associated with a lower prevalence of MetS, consuming two or more eggs daily is not associated with a reduced risk for MetS.

Re-evaluation of a 2014 multi-country European outbreak of Salmonella Enteritidis phage type 14b using recent epidemiological and molecular data

A European multi-country outbreak of Salmonella Enteritidis phage type (PT) 14b occurred from March to November 2014 associated with the consumption of eggs. The outbreak involved more than 400 human cases from France, Luxembourg, Austria and the United Kingdom. In 2016-2017, it has been re-evaluated combining recent epidemiological results with latest molecular data. The outbreak was traced back to one large Bavarian egg producer with four distinct premises, three located in Bavaria, one in the Czech Republic. The outbreak isolates of S. Enteritidis PT 14b were grouped into three closely related clades by whole genome sequencing. Two of these clades could be referred to two Bavarian premises of the egg producer on the basis of epidemiological and molecular data, while epidemiological data presumably linked the third clade to another premises of the egg producer. Interestingly and in contrast to the situation in other European countries where several outbreaks were documented, all notified 91 laboratory-confirmed cases of S. Enteritidis PT 14b from Bavaria were sporadic, singular cases not belonging to any epidemiological outbreaks. In conclusion, as demonstrated here, the resolution of food-related outbreaks with such a high discriminatory power is rare in outbreak investigation.

Egg Consumption and Risk of Metabolic Syndrome in Korean Adults: Results from the Health Examinees Study

Metabolic syndrome (MetS) is defined as a cluster of metabolic alterations such as abdominal obesity, dyslipidemias, elevated fasting glucose, and hypertension. Studies on the association between egg consumption and MetS are limited and inconsistent. A cross-sectional analysis was conducted to examine the association of egg consumption with MetS among Korean adults aged 40–69 years. A total of 130,420 subjects (43,682 men and 86,738 women) from the Health Examinees Study were selected for the final analysis. Egg consumption was estimated using a validated 106-item food frequency questionnaire. MetS was defined using the National Cholesterol Education Program, Adult Treatment Panel III. Logistic regression analyses were performed to identify the association of egg consumption with MetS via odds ratios (ORs) and 95% confidence intervals (CIs) after adjusting for potential variables. Among 130,420 subjects, 34,039 (26.1%) people had MetS. Consumption of more than 7 eggs/week was associated with a lower odds of MetS risk compared to those who consumed less than one egg/week in women (OR: 0.77, 95%CI: 0.70–0.84, p trend < 0.0001). Higher egg consumption was inversely associated with the MetS components: elevated waist circumference (OR: 0.80, 0.75–0.86), elevated triglyceride (OR: 0.78, 0.72–0.85), reduced high-density lipoprotein cholesterol (HDL-C) (OR: 0.82, 0.77–0.88), elevated blood pressure (OR: 0.86, 0.80–0.92), and elevated fasting glucose (OR: 0.94, 0.83–0.99) in women; reduced HDL-C (OR: 0.89, 0.80–1.00) in men. Our results suggest that higher egg consumption may be associated with a reduction in the odds for MetS and all five metabolic components in women, and the risk of reduced HDL-C in men.

Differing statistical approaches affect the relation between egg consumption, adiposity, and cardiovascular risk factors in adults

BACKGROUND

Associations between food patterns and adiposity are poorly understood.

OBJECTIVE

Two statistical approaches were used to examine the potential association between egg consumption and adiposity.

METHODS

Participants (n = 18,987) aged ≥19 y were from the 2001-2008 NHANES who provided 24-h diet recall data, body mass index (BMI) and waist circumference (WC)-determined adiposity measures, and blood pressure, circulating insulin, glucose, and lipid concentrations were considered cardiovascular risk factors (CVRFs). Covariate-adjusted least-squares means ± SEs were generated.

RESULTS

The first statistical approach categorized participants into egg consumers or nonconsumers. Consumers had higher mean BMI (in kg/m(2); 28.7 ± 0.19; P = 0.006) and WC (98.2 ± 0.43 cm; P = 0.002) than did nonconsumers (28.2 ± 0.10 and 96.9 ± 0.23 cm, respectively). Second, cluster analysis identified 8 distinct egg consumption patterns (explaining 39.5% of the variance in percentage of energy within the food categories). Only 2 egg patterns [egg/meat, poultry, fish (MPF)/grains/vegetables and egg/MPF/grains], consumed by ≤2% of the population, drove the association (compared with the no-egg pattern) between egg consumption and BMI and WC. Another analysis controlled for the standard covariates and the other food groups consumed with eggs in those 2 egg patterns. Only the egg/MPF/other-grains pattern remained associated with BMI and WC (both P ≤ 0.0063). The pattern analyses identified associations between an egg pattern (egg/MPF/other grains/potatoes/other beverages) and diastolic blood pressure (DBP) and serum LDL cholesterol (both P ≤ 0.0063). A final analysis was conducted by adding percentage of energy from fast foods and medication use for diabetes to the covariates. The association between the egg/MPF/grains pattern and BMI and the egg/MPF/potatoes/other beverages and DBP and LDL cholesterol disappeared.

CONCLUSIONS

Care needs to be taken with data interpretation of diet and health risk factors and the choice of statistical analyses and covariates used in the analyses because these studies are typically used to generate hypotheses. Additional studies are needed to better understand these relations.

Egg consumption and insulin metabolism in the Insulin Resistance Atherosclerosis Study (IRAS)

OBJECTIVE

To examine the association between egg consumption and measures of insulin sensitivity (SI), acute insulin response (AIR) and metabolic clearance rate of insulin (MCRI).

DESIGN

Cross-sectional analysis.

SETTINGS

Egg consumption, categorized as <1/week, 1 to <3/week, 3 to <5/week and ≥5/week, was measured using a validated FFQ. SI, AIR and MCRI were determined from frequently sampled intravenous glucose tolerance tests.

SUBJECTS

Non-diabetic participants (n 949) in the Insulin Resistance Atherosclerosis Study (IRAS).

RESULTS

Egg consumption was inversely associated with SI and MCRI, and positively associated with fasting insulin in regression models adjusted for demographic, socio-economic, lifestyle and dietary factors (β = -0·22, 95 % CI -0·38, -0·045, P = 0·05 for SI; β = -0·20, 95 % CI -0·34, -0·055, P = 0·005 for MCRI; β = 0·35, 95 % CI 0·15, 0·54, P = 0·002 for fasting insulin; all P values for linear trend). These associations remained significant after additionally adjusting for energy intake or dietary saturated fat, although dietary cholesterol and BMI attenuated these associations to non-significance. Egg consumption was not associated with AIR.

CONCLUSIONS

Dietary cholesterol and BMI appear to mediate the inverse association of egg consumption with insulin sensitivity and clearance. Alternatively, egg consumption may be clustered with other dietary behaviours which increase BMI, hence negatively impacting on insulin sensitivity and clearance.

Serum dioxin-like activity is associated with reproductive parameters in young men from the general Flemish population

BACKGROUND

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and some related environmental contaminants are aryl hydrocarbon receptor (AhR) ligands that exert reproductive and developmental toxicity in laboratory animals. In humans, fertility-related effects are less documented.

OBJECTIVE

The aim of this study was to investigate the relationship between dioxin-like biological activity in serum and parameters of reproductive status in men from the general population 5 months after a polychlorinated biphenyl and dioxin food-contamination episode in Belgium.

DESIGN

In the framework of the cross-sectional Flemish Environment and Health Study (FLEHS), we recruited 101 men 20-40 years of age and evaluated sperm parameters, measured sex hormones, and gathered information on a number of lifestyle factors. In addition, we determined the AhR-mediated enzymatic response elicited by individual serum samples and expressed it as TCDD equivalent concentrations (CALUX-TEQs) using an established transactivation assay.

RESULTS

Age (p = 0.04) and the frequency of fish (p = 0.02) and egg (p = 0.001) consumption were independent positive determinants of serum dioxin-like activity. After correcting for possible confounders, we found that a 2-fold increase in CALUX-TEQ > 16 pg/L was associated with a 7.1% and 6.8% (both p = 0.04) decrease in total and free testosterone, respectively. We also observed a more pronounced drop in semen volume of 16.0% (p = 0.03), whereas sperm concentration rose by 25.2% (p = 0.07). No relationship was found with total sperm count or sperm morphology.

CONCLUSIONS

These data suggest an interaction of dioxin-like compounds with the secretory function of the seminal vesicles or prostate, possibly indirectly through an effect on testosterone secretion, at levels not affecting spermatogenesis as such.