Dietary patterns and semen quality: a systematic review and meta-analysis of observational studies

Do Popular Diets Impact Fertility?

Infertility affects 15% of the population in developed countries, and its prevalence is increasing. Fertility can be influenced by different factors. Although key factors like maternal age cannot be changed, there is growing evidence that other modifiable factors, such as diet, can have an impact on fertility. Diet has become increasingly important in recent years for a number of reasons: the new trend toward a healthy lifestyle, the higher prevalence of certain digestive disorders, a lack of time that leads people to consume more prepared and processed food, and personal choice to not eat meat, among others. To meet these needs, several diets have recently become popular, such as the Mediterranean diet, known as the gold standard of health; the DASH diet, known for preventing hypertension; the Western diet, characterized by processed food; the ketogenic diet, characterized by low carbohydrate intake; and the vegetarian diet, which is the choice for people who do not eat meat or animal by-products. Diets present a unique composition characterized by the presence or absence of specific nutrients, which have also been associated with male and female fertility individually. This review assesses the impact of these diets and of macro- and micronutrients on both female and male fertility.

Effects of Korean Versus Western Diets on Reproductive Function in Young Korean Men: A 12-Week Randomized Parallel Clinical Trial

Background

Studies report that diet may have contributed to a 50-60% decrease in human sperm quality over the past few decades. Unhealthy lifestyles affect the structure of spermatozoa, affecting the male reproductive potential. This study aimed to compare the effects of Korean and Western diets on reproductive function in young male Koreans.

Methods

Study participants were provided either the Korean Diet (KD group) or the Western Diet (WD group) for 12 weeks. Semen quality parameters such as volume, motility, cell count, and sex hormone levels were evaluated. Sexual function was assessed using the International Index of Erectile Function and the Male Sexual Health Questionnaire. Efficacy and safety evaluations were conducted at baseline, 8 weeks, and 12 weeks.

Results

The KD group demonstrated a significantly increased sperm motility after 8 weeks relative to baseline but decreased after 12 weeks. In contrast, sperm motility in the WD group significantly decreased after 8 weeks compared with baseline and remained constant after 12 weeks. Statistically, a near-significant difference was observed between groups (p = 0.057). Similarly, free testosterone levels in the KD group increased after 12 weeks compared with baseline, whereas that in the WD group decreased. The free testosterone levels in the KD group were significantly higher than those in the WD group (p = 0.020). There were no statistically significant differences in other sex hormone and sexual function questionnaires between the groups. None of the participants reported any severe side effects, and no significant alterations in clinical diagnostic test values were detected.

Conclusion

The results of the study strongly reveal that KD positively affects sperm motility and male hormone levels in young men, indicating potential benefits for reproductive function.

Role of Mediterranean diet in endocrine diseases: a joint overview by the endocrinologist and the nutritionist

PURPOSE

The purpose of this review is to examine the current evidence on the potential role of Mediterranean diet (MD) in the prevention and management of endocrine disorders and to highlight the importance of interdisciplinary collaboration between endocrinologists and nutritionists.

METHODS

A literature search was conducted using PubMed and Google Scholar databases to identify relevant studies published in English. Studies were selected based on their relevance to the role of MD in the prevention and management of endocrine disorders. The search terms included "Mediterranean diet," "endocrine disorders," "thyroid disorders," "gonadal disorders," and "neuroendocrine tumors".

RESULTS

The studies reviewed suggest that MD may have a beneficial effect in the prevention and management of various endocrine disorders, including thyroid disorders, gonadal disorders, and neuroendocrine tumors. MD has been associated with decreased risk of nodular thyroid disease and thyroid cancer, improved male and female reproductive health, and a potential role in the management of neuroendocrine tumors. MD's anti-inflammatory and antioxidant properties, as well as its high levels of phytochemicals, may play a role in its beneficial effects.

CONCLUSION

Interdisciplinary collaboration between endocrinologists and nutritionists is essential for the optimal management of endocrine disorders, including the potential role of MD in their prevention and management. While further research is needed, the current evidence suggests that MD may have a protective effect against endocrine disorders, and its incorporation into dietary recommendations may be beneficial.

Diet and recreational drug use in relation to male reproductive health

Diet and lifestyle interventions present promising avenues for the improvement of male fertility. Our objective was to review and synthesize the existing observational and experimental studies among humans on the associations of diet and recreational drug use with semen quality and fertility outcomes. The available data on this topic are limited and, at times, conflicting. Nevertheless, on the basis of this review, dietary patterns that are composed of higher intakes of fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lower intakes of red and processed meats, sweets, and sugar-sweetened beverages were identified as having the strongest evidence for associations with better sperm quality. However, whether these dietary patterns translate into positive associations with clinical fertility endpoints such as assisted reproductive technology success rates or time-to-pregnancy among couples trying to conceive without medical assistance remains unclear. Male caffeine and alcohol intake, within low-to-moderate ranges of intake, do not appear to be detrimental to semen quality. Yet high-quality research on this topic, focused on clinical fertility endpoints, should continue given the conflicting evidence, particularly in populations undergoing infertility treatment with assisted reproductive technology. Recreational drug use, including marijuana, electronic cigarettes, and other illicit drugs, does not appear to be beneficial for male reproductive health and should be avoided or ceased. In conclusion, men should be encouraged to consume a healthy diet rich in fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lacking in red and processed meats, sweets, and sugar-sweetened beverages, and to avoid recreational drug use for improved male reproductive health.

Observational Cross-Sectional Study on Mediterranean Diet and Sperm Parameters

Infertility, affecting 15 to 25% of couples in the most developed countries, is recognized by the World Health Organization as a public health issue at a global level. Different causes are acknowledged to reduce fertility in both sexes. In particular, about 40-50% of cases recognize a male factor. Dietary habits and lifestyle are acknowledged to influence sperm quality and are therefore important modifiable factors in male reproductive health. Conditions such as overweight/obesity, impaired glucose metabolism and determinants of metabolic syndrome, together with unhealthy lifestyle behavior, i.e., smoking cigarettes and physical inactivity, are suggested to have a negative impact on male fertility. While individual elements and characteristics of the Western diet and habits are considered risk factors for male infertility, the Mediterranean diet (MD) seems to promote reproductive potential for improving sperm quality. It is also interesting to note that previous observational studies reported a positive correlation between the consumption of the single food classes of the MD pattern (i.e., vegetables and fruits, poultry, fish and seafood, whole grains, low-fat dairy products) and the quality of several sperm parameters. To evaluate the relationship between sperm parameters and MD adherence, we performed a cross-sectional study on the seminal data of 300 males (mean age 34.6 ± 9.1 years) who spontaneously referred to our center of reproductive medicine. The evaluation of adherence to MD was performed with a validated 14-point Mediterranean Diet Adherence Screener (MEDAS) questionnaire. Our findings showed that sperm parameters such as sperm count, motility, viability and normal morphology are significantly and positively correlated with MEDAS, independently of BMI and age. In addition, the application of an ROC curve on MEDAS value vs. seminal alterations identified 6.25 as the score threshold value below which altered sperm parameters were more likely to occur [AUC = 0.096 (CI: 0.059-0.133; p < 0.00)]. Therefore, adhering to the MD with at least a MEDAS score of 6.26 increases the probability of normozoospermia. Moreover, subjects who had a MEDAS value lower than 6.25 had an Odds Ratio of 6.28 (CI = 3.967-9.945) for having at least one altered sperm parameter compared to those who were more adherent to the MD. In conclusion, our findings show that a higher adherence to the MD is associated with better semen parameters, in particular in relation to sperm count, sperm concentration, typical sperm morphology, and sperm progressive motility.

Association between dietary total antioxidant capacity and semen quality among men attending an infertility clinic: a cross-sectional study

STUDY QUESTION

Is dietary non-enzymatic antioxidant capacity related to semen quality?

SUMMARY ANSWER

The only statistically significant association of semen quality parameters with dietary total antioxidant capacity (DTAC) detected was an inverse association between DTAC and ejaculate volume.

WHAT IS KNOWN ALREADY

Growing interest exists regarding the role of diet in influencing semen quality. While DTAC is linked to favorable health outcomes, its association with semen quality, especially among men attending infertility clinics, remains understudied.

STUDY DESIGN SIZE DURATION

This cross-sectional study was carried out between June and December of 2020. In total, 1715 participants were included in the final analysis.

PARTICIPANTS/MATERIALS SETTING METHODS

Men who attended an infertility clinic in China were enrolled. Experienced clinical technicians performed the semen analysis. The DTAC indices included the ferric-reducing ability of plasma, oxygen radical absorbance capacity, total reactive antioxidant potential, and Trolox equivalent antioxidant capacity. The quantile regression model was used for multivariate analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

After adjustment for a variety of confounding variables, a significant inverse association was identified between DTAC and ejaculate volume (βcontinuous FRAP = -0.015, 95% CI = -0.023, -0.006, βT3 vs T1 = -0.193, 95% CI = -0.379, -0.006, Ptrend = 0.007; βcontinuous TRAP = -0.019, 95% CI = -0.041, 0.002, βT3 vs T1 = -0.291, 95% CI = -0.469, -0.112, Ptrend = 0.002). The majority of DTAC indices have no statistically significant association with semen quality parameters.

LIMITATIONS REASONS FOR CAUTION

We cannot infer causality because of the nature of the cross-sectional study design. The robustness of the conclusion may be compromised by the exactness of non-enzymatic antioxidant capacity estimation.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrated no association between DTAC indices and semen quality parameters among men attending an infertility clinic, except for ejaculate volume. Even though our findings are mostly non-significant, they contribute novel knowledge to the field of study while also laying the groundwork for future well-designed studies.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the JieBangGuaShuai Project of Liaoning Province [grant number 2021JH1/10400050], the Clinical Research Cultivation Project of Shengjing Hospital [grant number M1590], and the Outstanding Scientific Fund of Shengjing Hospital [grant number M1150]. The sponsors had no role in study design, or in the collection, analysis, and interpretation of data, or in the writing of the report, or in the decision to submit the article for publication. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Association of dietary total antioxidant capacity, alternative healthy eating index, and dietary inflammatory index with semen quality in men seeking infertility treatment

Background

Since the association between dietary quality scores and semen quality remains unclear, we carried out a hospital-based cross-sectional study to investigate the association of Dietary Total Antioxidant Capacity (dTAC), Dietary Inflammatory Index (DII), and Alternative Healthy Eating Index (AHEI) scores with semen quality in men seeking infertility treatment.

Methods

This study enrolled 210 men with unexplained or idiopathic infertility. Semen samples were collected and analyzed according to the WHO 2010 criteria. Dietary data was collected using a 168-item semi-quantitative food frequency questionnaire (FFQ) developed for Tehran Lipid and Glucose Study. Multivariable logistic regression models were used to estimate the relationship between dTAC, AHEI, and DII scores with abnormal semen in crude and adjusted models.

Results

There were no significant differences across quartile categories of the dTAC, AHEI, and DII scores regarding semen parameters. There was a trend toward a significant direct association between DII and abnormal semen risk (p = 0.01). Infertile men in the highest quartile of DII had a 2.84 times higher risk of abnormal semen in the crude model (OR: 3.84; 95% CI: 1.64-8.95); such that remained after adjusting for several potential confounders. There was no significant association between dTAC or AHEI and the risk of abnormal semen in infertile men, either before or after adjusting for potential confounders. Total energy (p = 0.05), fat (p = 0.02), saturated fat (p = 0.02), mono-saturated fat (p = 0.009), Thiamine (Vitamin B1) (p = 0.02), Niacin (Vitamin B3) (p = 0.03), Calcium (p = 0.01), and Selenium (p = 0.01) were inversely associated with semen normality.

Discussion

The study suggests that certain dietary factors may affect semen quality, and the mechanisms underlying the observed associations are likely multifactorial, involving complex interactions between diet, oxidative stress, inflammation, and hormone levels. Further research is required to confirm the results, fully elucidate the mechanisms underlying the associations, and identify specific dietary interventions that may improve male fertility outcomes.

Functional MRI-specific alterations in frontoparietal network in mild cognitive impairment: an ALE meta-analysis

Background

Mild cognitive impairment (MCI) depicts a transitory phase between healthy elderly and the onset of Alzheimer's disease (AD) with worsening cognitive impairment. Some functional MRI (fMRI) research indicated that the frontoparietal network (FPN) could be an essential part of the pathophysiological mechanism of MCI. However, damaged FPN regions were not consistently reported, especially their interactions with other brain networks. We assessed the fMRI-specific anomalies of the FPN in MCI by analyzing brain regions with functional alterations.

Methods

PubMed, Embase, and Web of Science were searched to screen neuroimaging studies exploring brain function alterations in the FPN in MCI using fMRI-related indexes, including the amplitude of low-frequency fluctuation, regional homogeneity, and functional connectivity. We integrated distinctive coordinates by activating likelihood estimation, visualizing abnormal functional regions, and concluding functional alterations of the FPN.

Results

We selected 29 studies and found specific changes in some brain regions of the FPN. These included the bilateral dorsolateral prefrontal cortex, insula, precuneus cortex, anterior cingulate cortex, inferior parietal lobule, middle temporal gyrus, superior frontal gyrus, and parahippocampal gyrus. Any abnormal alterations in these regions depicted interactions between the FPN and other networks.

Conclusion

The study demonstrates specific fMRI neuroimaging alterations in brain regions of the FPN in MCI patients. This could provide a new perspective on identifying early-stage patients with targeted treatment programs.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023432042, identifier: CRD42023432042.

The Influence of Metabolic Factors and Diet on Fertility

Infertility is a disease globally affecting 20-30% of the reproductive age female population. However, in up to 50% on recorded cases, problems with infertility are ascribed to men; therefore, it is important to popularize healthy eating also in this group. During the last decade, it has been observed that society's lifestyle changed drastically: reduced energy expenditure in physical activity per day, increased consumption of hypercaloric and high-glycemic-index foods with high content of trans fats, and reduced consumption of dietary fiber, which negatively affects fertility. Increasing evidence points to a link between diet and fertility. It is becoming clear that well-planned nutrition can also contribute to the effectiveness of ART. The low-GI plant-based diet appears to have a positive effect, especially when it is based on Mediterranean dietary patterns: rich in antioxidants, vegetable protein, fiber, MUFA fatty acids, omega-3, vitamins, and minerals. Importantly, this diet has been shown to protect against chronic diseases associated with oxidative stress, which also translates into pregnancy success. As lifestyle and nutrition seem to be important factors affecting fertility, it is worth expanding knowledge in this regard among couples trying to conceive a child.

Effect of Paternal Diet on Spermatogenesis and Offspring Health: Focus on Epigenetics and Interventions with Food Bioactive Compounds

Infertility is a growing public health problem. Consumption of antioxidant bioactive food compounds (BFCs) that include micronutrients and non-nutrients has been highlighted as a potential strategy to protect against oxidative and inflammatory damage in the male reproductive system induced by obesity, alcohol, and toxicants and, thus, improve spermatogenesis and the fertility parameters. Paternal consumption of such dietary compounds could not only benefit the fathers but their offspring as well. Studies in the new field of paternal origins of health and disease show that paternal malnutrition can alter sperm epigenome, and this can alter fetal development and program an increased risk of metabolic diseases and breast cancer in adulthood. BFCs, such as ascorbic acid, α-tocopherol, polyunsaturated fatty acids, trace elements, carnitines, N-acetylcysteine, and coenzyme Q10, have been shown to improve male gametogenesis, modulate epigenetics of germ cells, and the epigenetic signature of the offspring, restoring offspring metabolic health induced by stressors during early life. This indicates that, from a father’s perspective, preconception is a valuable window of opportunity to start potential nutritional interventions with these BFCs to maximize sperm epigenetic integrity and promote adequate fetal growth and development, thus preventing chronic disease in adulthood.

Diet Quality Scores and Asthenoteratozoospermia Risk: Finding From a Hospital-Based Case–Control Study in China

Objective

We aimed to examine associations of diet quality scores, including the dietary approaches to stop hypertension (DASH), alternate Healthy Eating Index (AHEI), and Chinese Healthy Eating Index (CHEI) with asthenoteratozoospermia risk in China.

Methods

Among 254 cases and 633 controls in a hospital-based case–control study in Shenyang, Liaoning Province, China, DASH, AHEI, and CHEI were calculated using a validated food frequency questionnaire. Asthenotetrazoospermia was evaluated according to World Health Organization guidelines. Unconditional multiple logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between quality diet scores and asthenoteratozoospermia risk.

Results

We found that the CHEI score was inversely associated with asthenoteratozoospermia risk, with ORs of 0.59 (95% CI 0.39, 0.88) and 0.59 (95% CI 0.39, 0.88) for the 2nd and 3rd tertiles vs. the 1st tertile, respectively (P trend < 0.05). In addition, our data indicated that each standard deviation increase in CHEI, AHEI-2010, and DASH score was associated with 19, 13, and 17% decreased risk of asthenoteratozoospermia, respectively.

Conclusion

Our findings suggest that higher adherence to the CHEI, AHEI-2010, and DASH diet quality scores may reduce the risk of asthenoteratozoospermia, especially for younger participants.

The Effect of Dietary Patterns on Clinical Pregnancy and Live Birth Outcomes in Men and Women Receiving Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis

The nutritional status of reproductive-aged couples can have a significant impact on fertility status, but the effect of dietary patterns on pregnancy outcomes in people using assisted reproductive technologies (ARTs) is currently unknown. This review aimed to synthesize the published research investigating the relation between preconception dietary patterns and clinical pregnancy or live birth in men and women of reproductive age undergoing ART. Six electronic databases were systematically searched for original research published between January 1978 and June 2021. Original research reporting on the effect of predefined dietary patterns on either clinical pregnancy and/or live birth rates following in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in men and women aged 18-49 y was eligible for inclusion. Studies were assessed for risk of bias according to the Cochrane guidelines. Included studies underwent qualitative and quantitative synthesis using random-effects model meta-analyses. Thirteen studies (12 cohort studies, 1 randomized controlled trial) reporting on 3638 participants (93% female) were included in the review. All studies had a moderate-high risk of bias. In individual studies, maternal adherence to 4 dietary patterns [Mediterranean diet (RR: 1.22; 95% CI: 1.05, 1.43), novel profertility diet (OR: 1.43; 95% CI: 1.19, 1.72), Iranian traditional medicine diet (OR: 3.9; 95% CI: 1.2, 12.8), Dutch national dietary recommendations diet (OR: 1.65; 95% CI: 1.08, 2.52)] was associated with increased likelihood of achieving a clinical pregnancy, while 2 dietary patterns [novel profertility diet (OR: 1.53; 95% CI: 1.26, 1.85), Mediterranean diet (RR: 1.25; 95% CI: 1.07, 1.45)] were associated with increased probability of live birth. Meta-analyses showed an association between adherence to the Mediterranean dietary pattern and live birth across 2 studies (OR: 1.98; 95% CI: 1.17, 3.35; I2 = 29%, n = 355), but no association with clinical pregnancy. As the relation between dietary patterns and ART outcomes is currently inconsistent, higher-quality nutrition research is required to further explore this emerging field of interest (PROSPERO registration: CRD42020188194).

Diet and Male Fertility: The Impact of Nutrients and Antioxidants on Sperm Energetic Metabolism

Diet might affect male reproductive potential, but the biochemical mechanisms involved in the modulation of sperm quality remain poorly understood. While a Western diet is considered a risk factor for male infertility, the Mediterranean diet seems to protect against male infertility; moreover, the role of a vegetarian habitus in the preservation of sperm quality is controversial. The aim of this review is to analyze the molecular effects of single nutrients on sperm quality, focusing on their involvement in biochemical mechanisms related to sperm bioenergetics. It appears that diets rich in saturated fatty acids (SFA) and low in polyunsaturated fatty acids (PUFA) negatively affect sperm quality, whereas unsaturated fatty acids supplementation ameliorates sperm quality. In fact, the administration of PUFA, especially omega-3 PUFA, determined an increase in mitochondrial energetic metabolism and a reduction in oxidative damage. Carbohydrates and proteins are also nutritional modulators of oxidative stress and testosterone levels, which are strictly linked to sperm mitochondrial function, a key element for sperm quality. Moreover, many dietary natural polyphenols differentially affect (positively or negatively) the mitochondrial function, depending on their concentration. We believe that an understanding of the biochemical mechanisms responsible for sperm quality will lead to more targeted and effective therapeutics for male infertility.

Paternal adherence to healthy dietary patterns in relation to sperm parameters and outcomes of assisted reproductive technologies

OBJECTIVE

To investigate whether men's adherence to dietary patterns promoted for the prevention of cardiovascular disease is associated with semen parameters and couples' assisted reproductive technology (ART) outcomes.

DESIGN

Prospective cohort study.

SETTING

Fertility center at an academic medical center.

PATIENT(S)

A total of 245 men and their female partners who underwent 438 ART cycles between 2007 and 2020.

INTERVENTION(S)

Male pretreatment dietary intake was assessed with a 131-item food frequency questionnaire from which we calculated eight a priori defined scores: Trichopoulou Mediterranean, Alternate Mediterranean, Panagiotakos Mediterranean, Healthy Eating Index, Alternative Healthy Eating Index, American Heart Association, Dietary Approaches to Stop Hypertension, and Plant-based.

MAIN OUTCOME MEASURE(S)

The primary outcome was live births per treatment cycle. The secondary outcomes were fertilization, implantation, and clinical pregnancy and seminogram parameters.

RESULT(S)

There was an inverse association between greater adherence by men to the Panagiotakos Mediterranean diet and the American Heart Association dietary pattern and lower fertilization rate. However, there were no significant associations between men's adherence to any of the analyzed dietary patterns and the probabilities of implantation, clinical pregnancy, or live birth in multivariable-adjusted models. No significant differences in any of the semen parameters were found between participants of the lowest quartile and those of the highest quartile of the eight dietary patterns.

CONCLUSION(S)

These findings suggest that men's adherence to several a priori defined dietary scores with documented cardiovascular benefits is not related to major outcomes of infertility treatment with ART or semen quality.

Is there a relationship between serum vitamin D and semen parameters? A cross-sectional sample of the Iranian infertile men

BACKGROUND

Recent studies suggest that serum vitamin D may be associated with semen parameters. In the present cross-sectional study, we attempted to investigate the association between serum vitamin D levels and semen parameters among Iranian sub-fertile men.

RESULTS

A total of 350 infertile men recruited for this cross-sectional study using a simple random sampling method with a mean age of 34.77 years old, body mass index of 26.67 kg/m², serum vitamin D of 20.17 ng/ml, semen volume of 3.82 mL, sperm count of 44.48 (10⁶/mL), sperm total motility of 38.10 %, and morphologically normal sperm of 7.0 %. After controlling for potential confounders, serum vitamin D was positively associated with semen volume (β = 0.63, 95 % CI: 0.06, 1.20), sperm count (β = 14.40, 95 % CI: 4.56, 24.25), sperm total motility (β = 18.12, 95 % CI: 12.37, 23.86), and sperm normal morphology (β = 1.95, 95 % CI: 1.07, 2.83).

CONCLUSIONS

The present findings suggest that higher serum vitamin D levels are positively associated with higher semen volume, sperm count, sperm total motility, and normal morphology rate. These findings, however, do not specify a cause-and-effect relationship, and there is a need for further research in this area to understand whether vitamin D supplementation can improve semen parameters.

Is Ejaculation Frequency in Men Related to General and Mental Health? Looking Back and Looking Forward

Despite its relevance for human sexuality, literature on potential effects of ejaculation frequency and masturbation on general and mental health outcomes is sparse. Reasons for this knowledge gap include a general lack of interest, but also methodological challenges and still existing superstition. This paper reconciles literature from various fields to extract relevant information on how ejaculation frequency effects general and mental health outcomes. Culture-bound syndromes have been reported in countries still strictly tabooing or condemning masturbation. Masturbatory guilt describes a phenomenon in individuals experiencing a discrepancy between moral standards and own behavior with respect to masturbation. Abstinence is one aspect under study in the area of fertility treatment. Specific time frames and their respective implications on quality of sperm remain inconclusive. Limited temporal resolution capacities hamper the precise study of brain structures directly activated during ejaculation. The relation between ejaculation frequency and hormonal influences remains poorly understood. Future research that specifically addresses ejaculation frequency and potential mental and general health outcomes is needed. In contrast to extracting knowledge as a byproduct from other studies with a different focus, this enables sound study designs and could provide evidence-based results which could then be further discussed and interpreted.

Dietary Antioxidants in the Treatment of Male Infertility: Counteracting Oxidative Stress

Infertility affects about 15% of the population and male factors only are responsible for ~25-30% of cases of infertility. Currently, the etiology of suboptimal semen quality is poorly understood, and many environmental and genetic factors, including oxidative stress, have been implicated. Oxidative stress is an imbalance between the production of free radicals, or reactive oxygen species (ROS), and the capacity of the body to counteract their harmful effects through neutralization by antioxidants. The purpose of this review, by employing the joint expertise of international researchers specialized in nutrition and male fertility areas, is to update the knowledge about the reproductive consequences of excessive ROS concentrations and oxidative stress on the semen quality and Assisted Reproduction Techniques (ART) clinical outcomes, to discuss the role of antioxidants in fertility outcomes, and finally to discuss why foods and dietary patterns are more innocuous long term solution for ameliorating oxidative stress and therefore semen quality results and ART fertility outcomes. Since this is a narrative review and not a systematic/meta-analysis, the summarized information in the present study should be considered cautiously.

Pneumonia Is Associated with Increased Mortality in Hospitalized COPD Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) are at a heightened risk of pneumonia. Whether coexisting community-acquired pneumonia (CAP) can predict increased mortality in hospitalized COPD patients is still controversial.

OBJECTIVE

This systematic review and meta-analysis aims to assess the association between CAP and mortality and morbidity in COPD patients hospitalized for acute worsening of respiratory symptoms.

METHODS

In this review, cohort studies and case-control studies investigating the impact of CAP in hospitalized COPD patients were retrieved from 4 electronic databases from inception until December 2019. Methodological quality of included studies was assessed using Newcastle-Ottawa Quality Assessment Scale. The primary outcome was mortality. The secondary outcomes included length of hospital stay, need for mechanical ventilation, intensive care unit (ICU) admission, length of ICU stay, and readmission rate. The Mantel-Haenszel method and inverse variance method were used to calculate pooled relative risk (RR) and mean difference (MD), respectively.

RESULTS

A total of 18 studies were included. The presence of CAP was associated with higher mortality (RR = 1.85; 95% CI: 1.50-2.30; p < 0.00001), longer length of hospital stay (MD = 1.89; 95% CI: 1.19-2.59; p < 0.00001), more need for mechanical ventilation (RR = 1.48; 95% CI: 1.32-1.67; p < 0.00001), and more ICU admissions (RR = 1.58; 95% CI: 1.24-2.03; p = 0.0002) in hospitalized COPD patients. CAP was not associated with longer ICU stay (MD = 5.2; 95% CI: -2.35 to 12.74; p = 0.18) or higher readmission rate (RR = 1.02; 95% CI: 0.96-1.09; p = 0.47).

CONCLUSION

Coexisting CAP may be associated with increased mortality and morbidity in hospitalized COPD patients, so radiological confirmation of CAP should be required and more attention should be paid to these patients.

Beneficial Role of Calcium in Premenstrual Syndrome: A Systematic Review of Current Literature

Since premenstrual syndrome (PMS) is one of the most common and debilitating disorders in women, risk factor modification is an urgent health priority. Therefore, this systematic review aimed to summarize and discuss the outcomes of observational and interventional studies in humans regarding the relationship between Calcium and PMS. PubMed, Scopus, ISI web of sciences and Google scholar were searched up to January 2019 to identify relevant studies. The Newcastle-Ottawa and Jadad scales were used for quality assessment. A total of 14 studies (8 interventional and 6 observational) met our inclusion criteria. Majority of the studies showed that not only serum calcium levels are lower in PMS subjects, but also calcium supplementation could significantly improve the incidence of PMS and its related symptoms. This systematic review suggests a beneficial role for calcium in PMS subjects. However, in order to draw a firm link between calcium and PMS, further dose-response clinical trials with larger sample size and better methodological design are warranted.

Associations of Major Dietary Patterns and Dietary Diversity Score with Semen Parameters: A Cross-Sectional Study in Iranian Infertile Men

Background

This cross-sectional study pointed to assess the relationship between major dietary patterns and dietary diversity score with semen parameters, in infertile Iranian males.

Materials and Methods

In this cross-sectional study, 260 infertile men (18-55 years old) who met the inclusion criteria, entered the study. Four Semen parameters, namely sperm concentration (SC), total sperm movement (TSM), normal sperm morphology (NSM) and sperm volume were considered according to spermogram. A 168-item food frequency questionnaire (FFQ) was used to collect dietary intakes and calculate dietary diversity score. Factor analy- sis was used to extract dietary patterns.

Results

The following four factors were extracted: “traditional pattern”, “prudent pattern”, “vegetable-based pattern” and “mixed pattern”. After adjusting potential confounders, those in the highest quartile of the traditional pattern had 83% less odds for abnormal concentration, compared with the first quartile (OR=0.17, 95% CI: 0.04-00.73); however, subjects in the highest quartile of this pattern had 2.69 fold higher odds for abnormal sperm volume as compared with those of the first quartile (95%Cl: 1.06-6.82). Men in the second quartile of prudent pattern had 4.36 higher odds of an abnormal sperm volume in comparison to the reference category (95%CI: 1.75-10.86), after considering potential confounders. With regard to mixed pattern, men in the second, third and fourth quartile of this pattern had respectively 85 (5%Cl: 0.03-0.76,), 86 (95%Cl: 0.02-0.75) and 83 % (95%Cl: 0.034-0.9) less odds of abnormal concentration, compared with the first quartile. Additionally, no significant association was found between dietary diversity score and sperm quality parameters.

Conclusion

Higher intake of the traditional diet was linked to lower abnormal semen concentration and poorer sperm volume. Also, the mixed diet was associated with reduced prevalence of abnormal semen concentration.

The association between serum omentin level and bodyweight: A systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

A number of studies have examined the association between omentin and body weight, but the findings have been inconclusive. Here in, we systematically reviewed available observational studies to elucidate the overall relationship between omentin and body weight, by comparison of serum omentin level in overweight/obese and normal weight subjects.

METHODS

PubMed, Science direct, Scopus and ISI web of science databases were searched for all available literature until January 2020 for studies assessing the association between omentin and body weight. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of each study.

RESULTS

A total of 27 articles met the inclusion criteria and were included in our systematic review and meta-analysis. There was a significant association between omentin serum level and body weight (Standard Mean Difference (SMD) -0.43; 95% CI, -0.70 to -0.15; P = 0.002; I² = 93.2%). In order to find the probable source of heterogeneity subgroup analysis based on the participants' age (adolescent, adult), gender (male, female, both gender), health status (healthy, unhealthy), geographical location (Asian, non-Asian countries), study quality (low, medium, high), study design (case-control, cross-sectional), participants' health status (healthy, unhealthy) and BMI (obese, overweight) was carried out.

CONCLUSION

According to what was discussed, we found that serum omentin level is significantly lower in overweight subjects but not obese ones. This finding should be interpreted cautiously because of significant heterogeneity among included studies.

Online Japanese-Language Information on Lifestyle Factors Associated With Reduced Fertility: Content Analysis

Background

Approximately one-third of Japanese couples currently worry or previously worried about infertility. To develop strategies for the primary prevention of infertility as a population approach, it is important for the general population to be knowledgeable about fertility and infertility. The internet may contribute to the dissemination of information regarding infertility and fertility. However, few studies have examined online information about fertility.

Objective

This study aimed to quantitatively examine online Japanese-language information about lifestyle factors associated with reduced fertility.

Methods

We conducted online searches, using the 10 search terms with the highest numbers of searches that people hoping to conceive are likely to input in two major search engines in Japan (Google Japan and Yahoo! Japan). From the 2200 retrieved websites, 1181 duplicates and 500 websites unrelated to our objective were excluded, resulting in a final dataset of 519 websites. Coding guidelines were developed for the following lifestyle factors associated with reduced fertility: sexually transmitted diseases, psychological stress, cigarette smoking, alcohol use, nutrition and diet, physical activity and exercise, underweight, overweight and obesity, and environmental pollutants.

Results

In terms of the website author’s professional expertise, 69.6 % of the coding instances for the selected lifestyle factors were mentioned by hospitals, clinics, or the media, whereas only 1.7% were mentioned by laypersons. Psychological stress (20.1%) and sexually transmitted diseases (18.8%) were the most frequently mentioned lifestyle factors associated with reduced fertility. In contrast, cigarette smoking, alcohol use, nutrition and diet, physical activity and exercise, underweight, overweight and obesity, and environmental pollutants were mentioned relatively infrequently. The association between reduced fertility and sexually transmitted diseases was mentioned significantly more frequently by hospitals and clinics than by the media (P<.001). The association between reduced fertility and nutrition and diet was mentioned significantly more frequently by the media than by hospitals and clinics (P=.008). With regard to the sex of the target audience for the information, female-specific references to psychological stress, sexually transmitted diseases, nutrition and diet, underweight, physical activity and exercise, and overweight and obesity were significantly more frequent than were male-specific references to these lifestyle factors (psychological stress: P=.002, sexually transmitted diseases: P<.001, nutrition and diet: P<.001, underweight: P<.001, physical activity and exercise: P<.001, overweight and obesity: P<.001).

Conclusions

Of the lifestyle factors known to be related to reduced fertility, cigarette smoking, alcohol use, and male-specific lifestyle factors are mentioned relatively infrequently in online information sources in Japan, and these factors should be discussed more in information published on websites.

Empiric therapy for idiopathic oligoasthenoteratozoospermia

Male infertility accounts for 50% of the causes of infertile couples, being more than 30% of unknown etiology. In these cases, empiric treatment can be an option prior to the application of assisted reproduction techniques. Empiric treatment can be categorized as hormonal, such as gonadotropins, antiestrogens and aromatase inhibitors, and antioxidant, with vitamins, trace elements and carnitine, among others. Although scientifically acceptable evidence is limited due to the absence of large randomized and controlled clinical trials, recent systematic reviews and meta-analyses show that treatment with gonadotropins, antiestrogens and antioxidants increases pregnancy and live birth rates and improves seminal parameters. Empiric medical treatment for idiopathic infertility can be considered in specific cases in order to improve semen quality and spontaneous fertility.

Food insecurity and mental health: a systematic review and meta-analysis

OBJECTIVE

Food security has been suggested to be a risk factor for depression, stress and anxiety. We therefore undertook a systematic review and meta-analysis of available publications to examine these associations further.

DESIGN

Relevant studies were identified by searching Web of Science, Embase, Scopus and PubMed databases up to January 2019.

SETTING

OR was pooled using a random-effects model. Standard methods were used for assessment of heterogeneity and publication bias.

PARTICIPANTS

Data were available from nineteen studies with 372 143 individual participants from ten different countries that were pooled for the meta-analysis.

RESULTS

The results showed there was a positive relationship between food insecurity (FI) and risk of depression (OR = 1·40; 95 % CI: 1·30, 1·58) and stress (OR = 1·34; 95 % CI: 1·24, 1·44) but not anxiety. Subgroup analysis by age showed that subjects older than ≥65 years exhibited a higher risk of depression (OR = 1·75; 95 % CI: 1·20, 2·56) than younger participants (OR = 1·34; 95 % CI: 1·20, 1·50), as well as a greater risk of depression in men (OR = 1·42; 95 % CI: 1·17, 1·72) than women (OR = 1·30; 95 % CI: 1·16, 1·46). Finally, subgroup analysis according to geographical location illustrated that food insecure households living in North America had the highest risk of stress and anxiety.

CONCLUSIONS

The evidence from this meta-analysis suggests that FI has a significant effect on the likelihood of being stressed or depressed. This indicates that health care services, which alleviate FI, would also promote holistic well-being in adults.

Association of Dietary Patterns With Testicular Function in Young Danish Men

IMPORTANCE

Diet may play a role in testicular function, but data on how adherence to different diet patterns influences human testicular function are scarce.

OBJECTIVE

To determine whether adherence to specific dietary patterns is associated with testicular function in young men.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 2935 young Danish men unselected regarding fertility status who were enrolled from April 1, 2008, through May 31, 2017. Data were analyzed from July 1, 2017, to January 30, 2019.

EXPOSURES

Dietary patterns identified with principal component analysis based on responses to a validated food frequency questionnaire.

MAIN OUTCOMES AND MEASURES

Standard semen quality assessment; serum concentrations of testosterone, free testosterone, estradiol, inhibin B, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin; and testicular volume measured with ultrasonography.

RESULTS

Among the 2935 participants included in the analysis, median age was 19 (interquartile range, 19-20) years and 2290 (78.0%) had normal body mass index. The 4 dietary patterns identified included Western, prudent, open-sandwich (a traditional Danish eating pattern), and vegetarianlike. The greatest adherence to the prudent pattern was associated with the highest total sperm count (median, 167 [95% CI, 146-183] million), followed by adherence to vegetarianlike (median, 151 [95% CI, 134-168] million) and open-sandwich (median, 146 [95% CI, 131-163] million) patterns. Adherence to the Western pattern was associated with the lowest total sperm count (median, 122 [95% CI, 109-138] million), which was significantly lower than sperm count in the other 3 diet patterns. After adjusting for confounders, the median total sperm count for men in the highest quintile of adherence to the Western pattern was 26 million lower (95% CI, -42 to -9 million) than for men in the lowest quintile of adherence to this pattern. Conversely, the median total sperm count of men in the highest quintile of adherence to the prudent pattern was 43 million (95% CI, 23-63 million) higher than that of men in the lowest quintile. Men with the highest adherence to the Western pattern had a lower median ratio of inhibin B to follicle-stimulating hormone (-12 [95% CI, -20 to -3]) and higher median ratio of free testosterone to luteinizing hormone (10 [95% CI, 2-19]) compared with men with lowest adherence to this pattern.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, adherence to generally healthy diet patterns was associated with better semen quality, with potentially more favorable fertility potential among adult men.

Diabetes Mellitus Is Associated with a Lower Risk of Gout: A Meta-Analysis of Observational Studies

AIMS

Although several epidemiological studies have investigated the relationship between diabetes mellitus (DM) and the risk of gout, the results are inconsistent. Therefore, we systematically retrospected available observational studies to clarify the impact of DM on the risk of gout.

METHODS

Embase, PubMed, Cochrane Library, Scopus, Web of Science, and China National Knowledge Infrastructure were searched for relevant articles from inception to 2 March 2020. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. The multivariate adjusted relative risks (aRR) and corresponding 95% confidence intervals (CI) were pooled based on a random-effect model. Cochran's Q test and I ² were used to evaluate heterogeneity.

RESULTS

Five studies involving 863,755 participants were included in our meta-analysis. DM was associated with a lower risk of gout (aRR: 0.66; 95% CI: 0.59 to 0.73) but had a high heterogeneity (I ² = 89.2%). Metaregression analysis revealed that the types of DM were the source of heterogeneity. Subgroup analysis by types of DM showed that the risk of gout was significantly lower in type 1 DM (T1DM) (aRR: 0.42; 95% CI: 0.28 to 0.63) than in type 2 DM (T2DM) (aRR: 0.72; 95% CI: 0.70 to 0.74). Furthermore, when stratified according to gender in DM, sex-specific association was found. The inverse association was observed in males only (aRR: 0.57; 95% CI: 0.43 to 0.77) and not in females (aRR: 0.96; 95% CI: 0.87 to 1.05). Further stratified based on glycated hemoglobin (HbA1c) levels in DM, raised A1C levels were associated with a reduced risk of gout in patients with DM.

CONCLUSIONS

This meta-analysis indicated that DM was related to a lower risk of gout, and the protective effect of DM on the risk of gout was stronger in males, T1DM, or DM with high HbA1c levels. However, more prospective cohort studies are required to confirm these results.

Association of the Dietary Approaches to Stop Hypertension, Physical Activity, and Their Combination with Semen Quality: A Cross-Sectional Study

The influence of individual lifestyle factors is widely described in studies on semen quality. However, their synergistic effect is often neglected. The aim of the study was to examine the association between semen quality and dietary approaches to stop hypertension (DASH) diet, physical activity (PA), and the two separately and in combination. A cross-sectional study was carried out among 207 men aged 20–55. Dietary data were collected by a food frequency questionnaire (FFQ) and analysed according to the DASH scoring index. Physical activity was evaluated by the International Physical Activity Questionnaire. Semen parameters were assessed via the computer-aided semen analysis (CASA). Adherence to the DASH diet was associated with higher sperm count (Δ_T3-T1 = 82.1 mln/ej) and concentration (Δ_T3-T1 = 24.6 mln/mL). Higher PA was related to higher sperm count (Δ_T3-T1 = 69.4 mln/ej), total (Δ_T3-T1 = 11.9%), and progressive motility (Δ_T3-T1 = 8.5%) and morphology (Δ_T3-T1 = 2.8%) in the crude model and remained significant after adjustment. The combination of the DASH diet and PA, was significantly positively associated with sperm count (Δ_T3-T1 = 98.1 mln/ej), sperm concentration (Δ_T3-T1 = 17.5 mln/mL), total (Δ_T3-T1 = 11.8%), and progressive motility (Δ_T3-T1 = 10.0%) and morphology (Δ_T3-T1 = 3.3%) in both models. Adherence to the DASH diet was related to higher sperm count and concentration, whereas after its combination with physical activity it was also positively correlated with sperm motility and morphology.

The Association Between Serum Magnesium and Premenstrual Syndrome: a Systematic Review and Meta-Analysis of Observational Studies

A number of studies have assessed the association between serum magnesium (Mg) and premenstrual syndrome (PMS) in different population, but the findings have been inconclusive. Herein, we systematically reviewed available observational studies to elucidate the overall relationship between Mg and PMS. PubMed, Cochrane's library, ScienceDirect, Scopus, Google Scholar, and ISI web of science databases were searched for all available literature until January 2019 for studies evaluating the association between Mg and PMS. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of observational studies. A total of 13 studies out of 196 met our inclusion criteria and were included in our systematic review and meta-analysis. There were no associations between serum magnesium and PMS (WMD - 0.04; 95% CI, - 0.14 to 0.06; P = 0.46) during follicular or serum/erythrocyte magnesium (WMD - 0.37; 95% CI, - 1.01 to 0.27; P = 0.25)/(WMD - 0.04; 95% CI, - 0.10 to 0.03; P = 0.26) and during luteal phase except for the sub-group of studies done outside of the US in which recent association became significant and means that serum Mg is lower in PMS subjects. According to what have been discussed, although our study did not show any significant association between serum/erythrocyte Mg and PMS except for serum Mg in luteal phase in the sub-group of studies done outside of the USA, heterogeneity between studies should be taken into accounts when interpreting these results. Additional well-designed clinical trials should be considered in future research to develop firm conclusions on the efficacy of magnesium on PMS.Registration number: CRD42018114473 .

The effect of a Mediterranean diet on metabolic parameters in patients with non-alcoholic fatty liver disease: A systematic review of randomized controlled trials

BACKGROUND

Dietary habit can play a key role in the prevention and treatment of fatty liver disease (NAFLD). Although many studies have investigated the effect of Mediterranean diet on NAFLD, findings are inconsistent and there is no systematic review on this topic. Therefore, the aim of this systematic review is to summarize the effect of Mediterranean diet on serum metabolic indices and anthropometric measures among NAFLD patients.

METHODS

We searched titles, abstracts, and keywords of articles indexed in Science Direct, MEDLINE, and Google Scholar databases up to October 2018 to identify eligible RCT studies. Randomized clinical trials assessing the effects of MD on NAFLD were included.

RESULTS

The present study included 10 randomized controlled trials, which involved a total of 856 adults with NAFLD. According to the result, MD may improve anthropometric measures, lipid profile, glycemic indices, liver enzyme, and NAFLD severity indices among patients with NAFLD.

CONCLUSION

We found that MD could alleviate NAFLD severity parameters but differences between studies should be taken into account. Finally, in order to draw a firm link between MD and NAFLD, more clinical trials with adequate sample size and better methodology should be done.

The association between serum vitamin D, fertility and semen quality: A systematic review and meta-analysis

PURPOSE

A number of studies have examined the association between vitamin D, fertility and semen quality, however, findings have been inconclusive. Herein, we systematically reviewed available observational studies to elucidate the overall relationship between vitamin D, fertility and semen quality in adult population.

METHODS

PubMed, Cochrane's Library, Science Direct, Scopus, Google Scholar and ISI Web of Science databases were searched until December 2018 for all available studies evaluating the association between vitamin D, fertility and semen quality. The Newcastle-Ottawa Quality Assessment Scale was used to examine the quality of each study.

RESULTS

A total of 18 studies out of 1843 met our inclusion criteria and were included in our systematic review and meta-analysis. Serum 25(OH)D3 was significantly higher in fertile subjects compared to infertile ones (WMD -0.63; 95% CI, -1.06 to -0.21; P = 0.003). Furthermore, there was a significant association between serum 25(OH)D, sperm motility (WMD -5.84; 95% CI, -10.29 to -1.39; P = 0.01) and sperm progressive motility (WMD -5.24; 95% CI, -8.71 to -1.76; P = 0.003).

CONCLUSION

Our findings add to the existing literature supporting the concept that nutrition, especially vitamin D, plays an important role in men's sexual health. It should be noted that because of significant heterogeneity among the included studies, caution is warranted when interpreting the results. Further well-designed prospective cohort studies and clinical trials are needed for better understanding of the relationship between vitamin D and fertility and its components.

The association between omentin and diabetes: a systematic review and meta-analysis of observational studies

AIMS

A number of studies have examined the association between the serum levels of omentin and diabetes, but the findings have been inconclusive. Herein, we systematically reviewed available observational studies to elucidate the overall relationship between omentin and diabetes, including type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and impaired glucose tolerance (IGT) among adolescent and adult population.

METHODS

PubMed, Cochrane's Library, Science Direct, Scopus, Google Scholar, and ISI Web of Science databases were searched for all available literature until January 2019 for studies assessing the association between omentin and diabetes. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of each study.

RESULTS

A total of 28 articles met the inclusion criteria and were included in our systematic review and meta-analysis. There was a significant association between serum omentin and diabetes (WMD-1.68; 95% CI, -2.17 to -1.19; P<0.001). The result of our sub-group analysis based on participants' health status revealed that omentin was significantly lower in T2DM and IGT subjects but not in T1DM ones compared to healthy controls.

CONCLUSION

We found that serum omentin level is significantly lower in T2DM and IGT patients but not in T1DM ones. These data could be used by clinicians for early diagnosis and management of diabetes. Furthermore, we need more clinical trials to investigate new agents which could influence omentin levels.

Dietary quality, as measured by the Alternative Healthy Eating Index for Pregnancy (AHEI-P), in couples planning their first pregnancy

OBJECTIVE

Dietary quality (DQ), as assessed by the Alternative Healthy Eating Index for Pregnancy (AHEI-P), and conception and pregnancy outcomes were evaluated.

DESIGN

In this prospective cohort study on couples planning their first pregnancy. Cox proportional hazards regression assessed the relationship between AHEI-P score and clinical pregnancy, live birth and pregnancy loss.

SETTING

Participants were recruited from the Northeast region of the USA.Participants: Healthy, nulliparous couples (females, n 132; males, n 131; one male did not enrol).

RESULTS

There were eighty clinical pregnancies, of which sixty-nine resulted in live births and eleven were pregnancy losses. Mean (sd) female AHEI-P was 71·0 (13·7). Of those who achieved pregnancy, those in the highest tertile of AHEI-P had the greatest proportion of clinical pregnancies; however, this association was not statistically significant (P = 0·41). When the time it took to conceive was considered, females with the highest AHEI-P scores were 20 % and 14 % more likely to achieve clinical pregnancy (model 1: hazard ratio (HR) = 1·20; 95 % CI 0·66, 2·17) and live birth (model 1: HR = 1·14; 95 % CI 0·59, 2·20), respectively. Likelihood of achieving clinical pregnancy and live birth increased when the fully adjusted model, including male AHEI-P score, was examined (clinical pregnancy model 4: HR = 1·55; 95 % CI 0·71, 3·39; live birth model 4: HR = 1·36; 95 % CI 0·59, 3·13).

CONCLUSIONS

The present study is the first to examine AHEI-P score and achievement of clinical pregnancy. DQ was not significantly related to pregnancy outcomes, even after adjustments for covariates.

The Association Between Vitamin D and Premenstrual Syndrome: A Systematic Review and Meta-Analysis of Current Literature

A number of studies have assessed the association between vitamin D and premenstrual syndrome (PMS) in different populations, but the findings have been inconclusive. Herein, we systematically reviewed available observational and interventional evidence to elucidate the overall relationship between vitamin D and PMS. PubMed, Cochrane Library, ScienceDirect, Scopus, Google Scholar, and ISI Web of Science databases were searched for all available articles until September 2018. The Newcastle-Ottawa quality assessment scale and Jadad scale were used to assess the quality of the observational and interventional studies, respectively. A total of 16 studies out of 196 met our inclusion criteria and were included in the final analysis. Although no significant association between serum 25(OH)D and PMS (weighted mean difference (WMD) = 3.35; 95% confidence interval, -7.80 to 1.11; p = 0.14) was indicated in observational studies, vitamin D supplementation was effective in ameliorating PMS symptoms based upon findings from interventional studies. These results add to the existing literature supporting the fact that nutrition, especially vitamin D, plays an important role in women's health. Additional well-designed clinical trials should be considered in future research to develop firm conclusions on the efficacy of vitamin D on PMS. KEY TEACHING POINTS 5-8% of women experience severe PMS. Nutrition especially vitamin D plays an important role in the women's health. Vitamin D could exert significant clinical effects on PMS symptoms. This is a systematic review and meta-analysis in this regard.

The relationship between diet, energy balance and fertility in men

Research conducted in recent years provides more and more evidence that diet can have a significant impact on male fertility. The aim of the study was to analyze the relationship between diet, energy balance and fertility in men. A comprehensive literature search of published studies in various languages, was carried out in electronic databases. The direct analysis included 96 works published between 2008 and 2018, including 12 randomized controlled trials and 23 systematic reviews and meta-analyses. A strong adherence to a healthy dietary pattern is positively correlated with total sperm count, progressive motility and total motile sperm count (all p < 0.05). However, attention is drawn to the fact that foods that are considered "healthy" can sometimes contain a significant amount of pollution, which negatively affect the semen parameters. An adequate intake of antioxidants or their supplementation have been quite effective in the prevention and treatment of male infertility. The improvement of pregnancy rate after antioxidant therapy ranged in various studies from 11% to 41%. An important problem, however, may be choosing the right dose of the supplement or finding an appropriate combination of antioxidants that may be more effective than any single antioxidant. The normalization of men's body weight is beneficial for the quality of sperm and the concentration of male reproductive hormones. Further, long-term studies require the assessment of the impact of drastic weight loss after bariatric surgery on male fertility.

Male partners of subfertile couples in which the spouse is obese display adverse weight and lifestyle associated with reduced sperm quality

OBJECTIVES

To assess: 1-the spousal concordance of lifestyle and anthropometric characteristics between partners of infertile couples in which the woman is obese; and 2-in men, the influence of these characteristics on their conventional seminal parameters.

DESIGN

Cross-sectional study.

SETTING

Fertility clinic of the Centre hospitalier universitaire de Sherbrooke, Canada, between January 2012 and February 2015.

PATIENTS

97 infertile heterosexual couples in which women were obese and seeking fertility treatments.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Weight and percentage of fat mass were evaluated using a scale with foot-to-foot bio-impedance. Abdominal obesity was estimated with waist circumference and lifestyle habits, by a self-reported questionnaire. Seminal parameters were analysed and collected according to the WHO guidelines (Kruger's strict criteria for seminal morphology).

RESULTS

There was a significant spousal concordance for the percentage of fat mass, leisure activities and overall nutritional quality. Accordingly, male participants displayed anthropometric and lifestyle characteristics at higher risk than Canadian men of similar age. Moreover, BMI, daily consumption of fruits & vegetables and sleeping hours in men were independently associated to the total motile sperm count.

CONCLUSION

This is the first study to report concordance for anthropometric and lifestyle characteristics between partners of infertile couples in which the woman is obese. These characteristics in men were more adverse than in the general population and were associated with reduced sperm quality. Altogether, our results suggest that male partners of infertile couples could benefit from participating in the lifestyle intervention that is already recommended for their spouse affected by obesity.

CAPSULE

Because partners of subfertile couples in which the woman is obese share adverse anthropometric and lifestyle characteristics, male partners should be implicated in lifestyle interventions already indicated for their spouse.

Adherence to the Mediterranean diet is positively associated with sperm motility: A cross-sectional analysis

The aim of this cross-sectional analysis is to investigate the associations between the adherence to the Mediterranean Diet (MD) and semen quality parameters. To assess the adherence to the MD, the Trichopoulou score was used. Semen parameters were assessed as described in the 2010 WHO’s report and the results are showed across tertiles of MD adherence. A total of 106 participants were included. Compared to those in the lowest MD adherence tertile, participants in the top tertile had statistically significant higher BMI and waist circumference and consumed more energy, and also had statistically significant higher semen pH, and total sperm motility and progressive sperm motility percentages, and lower sperm immotility percentages. Moreover, percentage of total and progressive motility were significantly higher among those subjects in the higher adherence to MD in comparison with those in low-medium adherence category. The multivariable linear regression models evaluating the relationship between the sperm quality parameters and tertiles of MD adherence adjusted by age, energy and BMI showed that compared with the lowest tertile, men in the highest tertile had a higher percentage of total sperm motility [β non-standardized coefficient = 12.785]. These findings suggest that adherence to the MD was positively associated with sperm motility.