Association between dietary inflammatory index and inflammatory biomarkers with outcomes of in vitro fertilization treatment

Dietary Inflammatory Index and female infertility: findings from NHANES survey

Background and objectives

Infertility is a pressing public health concern on a national scale and has been linked to inflammatory conditions. However, limited research has been conducted on the impact of the Dietary Inflammatory Index (DII) on female infertility. This study sought to investigate the association between DII and infertility utilizing data from the National Health and Nutrition Examination Survey (NHANES).

Methods

This cross-sectional study included a cohort of 3,071 women aged 20-44 years from three NHANES cycles (2013-2018). Dietary information was collected to calculate the Dietary Inflammatory Index (DII), while infertility status was determined through positive responses to specific questions in a questionnaire. The association between DII scores and infertility was assessed using adjusted multivariate logistic regression analyses. Subgroup analysis and restricted cubic spline (RCS) was conducted for further investigation.

Results

Among the participants, 354 women (11.53%) were identified as experiencing infertility. Upon adjusting for all covariates, a positive correlation was observed (OR = 1.61, 95% CI: 1.12-2.31). Individuals with DII scores in the highest quartile exhibited significantly greater odds of infertility compared to those in the lowest quartile (OR = 1.71, 95% CI = 1.17-2.51). The relationship between DII and infertility in the RCS models demonstrated an S-shaped curve. When using the median DII as a reference point, a higher DII was associated with an increased prevalence of infertility. Additionally, obesity was found to be a significant factor.

Conclusions

Our research indicated that the DII was positively correlated with an increased likelihood of infertility in American women among the ages of 20 and 44. These results contribute to the existing literature and underscore the need for further validation through larger prospective cohort studies.

Predicting the Outcomes of In Vitro Fertilization Using Baseline Maternal Serum Inflammatory Markers: A Retrospective Cohort Study

PROBLEM

Achieving pregnancy through in vitro fertilization (IVF) remains a challenge, with less than one-third of women succeeding. There is a pressing need for reliable predictive tools to assess the likelihood of post-IVF pregnancy. While some serum inflammatory biomarkers have been investigated for their predictive potential, substantial knowledge gaps persist. This study examined the utility of different inflammatory markers in predicting IVF outcomes.

METHOD OF STUDY

Inflammatory markers including the white blood cell count, neutrophil-to-lymphocyte ratio (NLR), platelet count, mean platelet volume, platelet distribution width, platelet-to-lymphocyte ratio (PLR), C-reactive protein (CRP), erythrocyte sedimentation rate, and vitamin D3 were assessed. Study outcomes were chemical pregnancy (positive serum beta-human chorionic gonadotropin 2 weeks post-embryo transfer), clinical pregnancy (detection of pregnancy sac via transvaginal ultrasonography), and viable pregnancy (detection of fetal heart rate). Univariate and multivariate logistic regression analyses were conducted, with multivariate analysis incorporating age, body mass index, infertility duration, type, and etiology, as well as all studied serum inflammatory markers, embryo count, stage, quality, and endometrial thickness.

RESULTS

Lower NLR (p < 0.001, odds ratio [OR] = 0.372 [0.247-0.559]) and CRP (p = 0.035, odds ratio = 0.956 [0.916-0.997]) predicted chemical pregnancy in univariate analysis, with NLR maintaining significance in multivariate analysis (p = 0.022, OR = 0.319 [0.120-0.848]). Lower NLR (p < 0.001, OR = 0.309 [0.198-0.482]) and PLR (p = 0.013, OR = 0.994 [0.990-0.999]) predicted clinical pregnancy, with NLR surviving multivariate analysis (p = 0.005, OR = 0.217 [0.075-0.626]). Lower NLR (p < 0.001, OR = 0.320 [0.198-0.516]) also predicted viable pregnancy, maintaining statistical significance in multivariate analysis (p = 0.002, OR = 0.177 [0.058-0.541]). Other studied inflammatory markers did not predict IVF outcomes.

CONCLUSIONS

NLR emerged as a robust independent predictor of pregnancy attainment after IVF.

Meta-analysis of the association between dietary inflammation index and C-reactive protein level

BACKGROUND

There have been various clinical studies on the effect of dietary inflammatory index (DII) on circulating inflammatory biomarkers, but the findings from these are contradictory. The aim of the present study was to clarify any association.

METHODS

The PubMed, Embase, Web of Science and Cochrane Library database were searched for relevant studies from inception February 2021. There were no language restrictions. Two investigators independently selected eligible studies. Measures of association were pooled by using an inverse-variance weighted random-effects model. The heterogeneity among studies was examined using the I2 index. Publication bias, sensitivity and subgroup analyses were also performed.

RESULTS

A total of 13 cross-sectional studies were identified, involving 54,813 participants. The adjusted pooled OR of C-reactive protein (CRP) levels for the highest (the most pro-inflammatory diet) versus lowest (the most anti-inflammatory diet) DII categories was 1.25 (95% CI: 1.18-1.32; I2  = 59.4%, P = .002). Subgroup analyses suggested the main source of study heterogeneity was the geographic area (Asia, Europe, or USA) and CRP levels (>3 mg/L or others). This finding was remarkably robust in the sensitivity analysis.

CONCLUSION

The meta-analysis suggests that more pro-inflammatory DII scores were positively associated with CRP, the DII scores can be useful to assess the diet inflammatory properties and its association with low-grade inflammation.

High Dietary Inflammatory Index increases the risk of female infertility: An analysis of NHANES 2013-2018

Diet-related inflammation, which can be evaluated using the dietary inflammatory index (DII), is increasingly related to female infertility. However, studies on the association between DII and infertility are limited. In this study, we aim to explore the association between DII and infertility and its dose-effect relationship among women aged 20 to 45 years through a cross-sectional analysis of the National Health and Nutrition Examination Survey 2013-2018. A total of 2613 women aged 20 to 45 years were included and analyzed. The DII was calculated using the first 24-hour dietary recall interview data and divided into quartiles. Weighted multivariable logistic regression and restricted cubic spline analysis were used to explore the relationship between DII and infertility. The odds ratio (OR) (95% confidence interval [CI]) for the association between DII and infertility was 1.06 (0.96-1.19) after multivariable adjustment. Compared with the first quartile (anti-inflammatory diet), the fourth quartile of DII (pro-inflammatory diet) was more strongly associated with an increased risk of infertility, with an OR of 1.61 (95% CI, 1.05-2.47). Restricted cubic splines showed a J-shaped nonlinear association between DII and infertility (P for nonlinear = .003), with a cutoff point of 2.45. When DII was higher than 2.45, the OR for infertility was 1.95 (95% CI, 1.49-2.54). Similar results were observed among the subgroup analyses. In conclusion, this study found high DII (pro-inflammatory diet) increases the risk of female infertility. DII had a J-shaped nonlinear relationship with female infertility, whose cut point is 2.45. Controlling the intake of pro-inflammatory food may be beneficial for female infertility.

How phytochemicals influence reproductive outcomes in women receiving assisted reproductive techniques: a systematic review

CONTEXT

Over the past few years, there has been an increasing amount of scholarly literature suggesting a connection between the nutritional status of pregnant mothers and early fetal development, as well as the long-term health consequences of their offspring. Multiple studies have documented that alterations in dietary patterns prior to conception have the potential to affect the initial stages of embryonic development.

OBJECTIVES

The aim of this study was to perform a comprehensive review of the research pertaining to the correlation between phytochemicals ( specifically, polyphenols, carotenoids and phytoestrogens) and assisted reproductive technology (ART).

DATA SOURCES

PubMed, Scopus, Web of Science, and Clinical Trials databases were searched from January 1978 to March 2023.

STUDY SELECTION

This study comprised observational, randomized controlled, and cohort studies that examined the effects of phytochemicals on ART results. The study's outcomes encompass live birth rate, clinical pregnancy, and ongoing pregnancy.

DATA EXTRACTION

The assessment of study quality was conducted by 2 researchers, independently, using the Quality Criteria Checklist for Primary Research.

RESULTS

A total of 13 studies were included, of which there were 5 randomized controlled studies, 1 nonrandomized controlled study, 6 prospective cohort studies, and 1 retrospective cohort study.

CONCLUSION

This research focused on investigating the impact of phytochemicals on ART and has highlighted a dearth of articles addressing that topic. Collaboration among patients, physicians, and nutritionists is crucial for doing novel research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023426332.

Association between dietary inflammatory index and self-reported female infertility from the National Health and Nutrition Examination Survey 2013-2020

BACKGROUND

To explore the association between the diet inflammatory index (DII) and infertility.

METHODS

Multivariable logistic regression was performed to investigate the relationship between infertility and DII, and restricted cubic spline (RCS) was utilised to test for nonlinear relationships in this cross-sectional study. Data of this study were collected from the 2013 to 2020 National Health and Nutrition Examination Survey (NHANES) database. Considering women's child-bearing age, we enrolled a total of 2066 women aged 20-45 years in this study.

RESULTS

After all covariates were adjusted, a positive association was found between DII score and odds of infertility by multivariable logistic regression (odds ratio [OR] = 1.19, 95% confidence interval [CI] 1.03, 1.38; p = 0.027). Compared with participants with DII scores in the lowest quartile, those with DII scores in the highest quartile had significantly higher odds of infertility (OR = 2.42, 95% CI 1.09, 5.34; p = 0.034). The RCSs model suggested a linear relationship between DII and infertility (p for nonlinear = 0.1827).

CONCLUSIONS

A positive association between a pro-inflammatory diet and self-reported infertility was detected. Our study extends the application of the DII scoring system to infertility prevention.

Assessing the influence of preconception diet on female fertility: a systematic scoping review of observational studies

BACKGROUND

Preconception diet is a proposed modifiable risk factor for infertility. However, there is no official guidance for women in the preconception period as to which dietary approaches may improve fertility.

OBJECTIVE AND RATIONALE

A comprehensive synthesis of the relevant evidence is key to determine the potentially effective dietary patterns and components as well as evidence gaps, and to provide information for nutritional recommendations for couples planning a pregnancy.

SEARCH METHODS

In this systematic scoping review, four electronic databases (Medline and EMBASE via Ovid processing, CAB Direct, and CINAHL via EBSCO) were searched for observational studies (prospective and retrospective cohort, cross-sectional, and case-control studies) from inception to 27 September 2021. Eligible studies included women of reproductive age during the preconception period, and evaluated exposures related to preconception diet and outcomes related to fertility. Results were synthesized using a descriptive approach.

OUTCOMES

A total of 36 studies were eligible for inclusion (31 prospective, 3 cross-sectional, and 2 case-control studies) and were published between 2007 and 2022. Of the assessed dietary exposures, increased adherence to the Mediterranean diet displayed the strongest and most consistent association with improved clinical pregnancy rates. Reducing trans fatty acids (TFAs), saturated fatty acids, and discretionary food intake (fast food and sugar-sweetened beverages) were associated with improvements in live birth, clinical pregnancy rates, and related ART outcomes. The dietary components of seafood, dairy, and soy demonstrated inconsistent findings across the few included studies.

WIDER IMPLICATIONS

Due to heterogeneity and the limited available literature on most exposures, there is insufficient evidence to support any specific dietary approach for improving fertility. However, following some of the dietary approaches outlined in this review (anti-inflammatory diets, reducing TFA, and discretionary food intake) are consistent with broad healthy eating guidelines, have little to no associated risk, and offer a plausible set of possible benefits. This warrants further exploration in randomized controlled trials.

Glycemic index, glycemic load, dietary inflammatory index, and risk of infertility in women

The dietary glycemic load (GL) indicates the quantity and quality of carbohydrates, which can affect ovulation and fertility by controlling insulin sensitivity. Also, past studies confirm the role of the dietary inflammatory index (DII) in many diseases, including metabolic syndrome and cardiovascular disorders, so it may be related to reproductive health. This case-control study aims to study the association between glycemic index (GI), GL, and DII with infertility in women. This study was conducted on 300 infertile women in the case group and 300 fertile women in the control group in Kermanshah, Iran. Food intake was evaluated using FFQ, and using NUTRITIONIST IV software programs, GI and GL values were determined. DII was computed as well using FFQ data. Physical activity was assessed using IPAQ-SF. The association between GI, GL, and DII with infertility was evaluated using a logistic regression test, using STATA version 14 software. The results showed that the DII, GI, and GL were higher in the case group compared to the control group ([p = .009], [p = .0001], and [p = .0007], respectively). The increase in GI, GL, and DII caused an increase in infertility factors, and consequently enhanced chance of infertility ((adjusted odd ratio [OR] 2; 95% confidence interval [CI], 1.16, 3.45), (OR 3.68; 95% CI, 1.99, 6.82), and (OR 1.7; 95% CI, 0.97, 2.95), respectively). The present study indicated that the chance of infertility is higher in women who follow a diet with high GI, GL, and DII. Therefore, a positive association may be present between GI, GL, and DII with infertility.

The relationship of dietary inflammatory index and dietary patterns with premenstrual syndrome among women in Kermanshah: An analytical cross-sectional study

Premenstrual syndrome (PMS) is a common psychological condition that occurs continuously during the luteal phase of the menstrual cycle. Potential factors in this syndrome comprise the central nervous system, hormones, genetic background, and nutritional indicators. Little is known about foods or eating patterns that may be associated with this syndrome, yet nutritional factors can be considered in strategies for the management of PMS. The current study purposed to investigate the relationship between PMS and dietary inflammation index as well as PMS and food patterns. The present cross-sectional study was conducted on 125 women and girls aged 20-46 years who experienced symptoms of PMS. The inclusion criteria included cooperation and consent to enter the study, a body mass index of 18.5-25 kg/m², no underlying disease, no use of contraceptives or antidepressants, and no use of multivitamin or mineral supplements. In the first stage of this study, participants' height, weight, waist circumference, and hip circumference were measured. In the second stage, eating habits were examined using a semiquantitative Food Frequency Questionnaire. This study found a significant correlation between glycemic load quintiles as well as between energy and macronutrient intake and the dietary inflammatory index; however, it revealed a direct correlation between PMS and both Western-mixed dietary and high-salt-high-sugar dietary patterns. Moreover, the Western food pattern was found to have a direct correlation with dietary inflammatory index, and the healthy food pattern had an inverse correlation with this index. This study showed that PMS symptoms are more severe with the consumption of high-salt-high-sugar or a Western-mixed food dietary pattern. It seems that an imbalance in hormones and neurotransmitters can affect the metabolism of proteins, carbohydrates, and fats. Also, some foods, such as vegetables, and low-fat and high-fiber diets reduce plasma estrogen levels and the duration of PMS symptoms.

Can Dietary Patterns Impact Fertility Outcomes? A Systematic Review and Meta-Analysis

There are conflicting results on the effect of diet on fertility. This study aimed to assess the effect of different dietary patterns on fertility outcomes in populations who conceive spontaneously and those requiring assisted reproductive technology (ART). A systematic search and meta-analysis were performed for studies investigating dietary patterns or whole diets in reproductive aged women requiring ART or conceived naturally. Outcomes were live births, pregnancy rates and infertility rates. In amount of 15,396 studies were screened with 11 eligible studies. Ten different diet patterns were grouped broadly into categories: Mediterranean, Healthy or Unhealthy. For the Mediterranean diet, on excluding high risk-of-bias studies (n = 3), higher adherence was associated with improved live birth/pregnancy rates in ART [OR 1.91 (95% CI 1.14-3.19, I² 43%)] (n = 2). Adherence to various Healthy diets was associated with improved ART outcomes (ProFertility diet and Dutch Dietary Guidelines) and natural conception outcomes (Fertility diet). However, due to the variability in Healthy diets' components, results were not pooled. Studies demonstrated preliminary evidence for the role of dietary patterns or whole diets in improving pregnancy and live birth rates. However, due to heterogeneity across the literature it is currently unclear which diet patterns are associated with improvements in fertility and ART outcomes.

Anti-Inflammatory Diets in Fertility: An Evidence Review

Infertility is a global health concern affecting 48 million couples and 186 million individuals worldwide. Infertility creates a significant economic and social burden for couples who wish to conceive and has been associated with suboptimal lifestyle factors, including poor diet and physical inactivity. Modifying preconception nutrition to better adhere with Food-Based Dietary Guidelines (FBDGs) is a non-invasive and potentially effective means for improving fertility outcomes. While several dietary patterns have been associated with fertility outcomes, the mechanistic links between diet and infertility remain unclear. A key mechanism outlined in the literature relates to the adverse effects of inflammation on fertility, potentially contributing to irregular menstrual cyclicity, implantation failure, and other negative reproductive sequelae. Therefore, dietary interventions which act to reduce inflammation may improve fertility outcomes. This review consistently shows that adherence to anti-inflammatory diets such as the Mediterranean diet (specifically, increased intake of monounsaturated and n-3 polyunsaturated fatty acids, flavonoids, and reduced intake of red and processed meat) improves fertility, assisted reproductive technology (ART) success, and sperm quality in men. Therefore, integration of anti-inflammatory dietary patterns as low-risk adjunctive fertility treatments may improve fertility partially or fully and reduce the need for prolonged or intensive pharmacological or surgical interventions.