Abstract Background: studies have shown that dietary factors are linked to female infertility, but the relation between dietary fiber consumption and infertility has not been proven. The purpose of this research was to investigate whether there is an independent association between dietary fiber intake and infertility in American women. Material and methods: a secondary analysis of the National Health and NUTRITION Examination Survey (NHANES) dataset has been conducted, covering three cycles from 2013 to 2018. A total of 3,497 participants were included in the data analysis. The independent and dependent variables of interest were dietary fiber intake and infertility. Covariates included sociodemographic, questionnaire, diet, and physical examination data. Multiple logistic regression and sensitivity analyses were performed to investigate the relationship of dietary fiber intake with infertility. Results: each additional increase in log10 dietary fiber consumption was associated with a 32 % lower risk of infertility (OR, 0.68; 95 % CI, 0.48-0.96). The outcome is still robust in the minimally as well as the fully adjusted model. The possibility of a nonlinear association between dietary fiber intake and infertility was ruled out by the GAM model and smooth curve fitting. The RESULTS showed that there is an inverse linear correlation between dietary fiber intake and infertility. Conclusions: the association between intake of dietary fiber and infertility is linear, and increasing dietary fiber intake may be beneficial for lower infertility.

Resumen Antecedentes: el consumo de fibra dietética es un factor importante en la infertilidad femenina. El objetivo del estudio fue investigar si existe una relación independiente entre el consumo de fibra dietética y la infertilidad en las mujeres estadounidenses. Material y métodos: se realizó un análisis secundario del conjunto de datos de la encuesta nacional de salud y nutrición (NHANES), que abarcó tres ciclos entre 2013 y 2018. Se incluyeron 3497 participantes para el análisis de datos. Las variables independientes y dependientes asociadas fueron la ingesta de fibra dietética y la infertilidad. Las covariables incluyeron datos sociodemográficos, de los cuestionarios, dietéticos y médicos. Se realizó un análisis de regresión logística multivariada y un análisis de sensibilidad para determinar la relación entre el consumo de fibra dietética y la infertilidad. Resultados: cada aumento log10 en el consumo de fibra dietética se asoció con una reducción del 32 % en el riesgo de infertilidad (OR: 0,68; intervalo de confianza del 95 %: 0,48-0,96). En el modelo mínimo y totalmente ajustado, los resultados siguen siendo robustos. El modelo GAM y el ajuste de curvas suavizadas descartaron la posibilidad de una relación no lineal entre la ingesta de fibra dietética y la infertilidad. Los resultados muestran una correlación lineal negativa entre la ingesta de fibra dietética y la infertilidad. Conclusiones: se observó una relación lineal entre la ingesta de fibra dietética y la infertilidad. El aumento de la ingesta de fibra dietética redujo la incidencia de la infertilidad.

Abstract Most chronic kidney disease inevitably progress to renal fibrosis. Tubular epithelial- to-mesenchymal transition (EMT) is recognized to play major roles in renal fibrosis. Oxymatrine (OM) is a major alkaloid component found in a Chinese herb Sophora roots and has many effects. The aim is to investigate the effect of OM on renal tubular EMT and elucidate its mechanism. Mice underwent unilateral ureteral obstruction (UUO) followed by intraperitoneal injection of OM (120 mg/kg) or control vehicle. Human kidney proximal tubular cell line (HK-2) was used and EMT was induced with 5 ng/mL of transforming growth factor-β1 (TGF-β1). In vivo, renal tubulointerstitial fibrosis was induced and E-cadherin was down-regulated, while the expressions of fibronectin (FN), α-smooth muscle actin (α-SMA), TGF-β1 and its type I receptor (TGF-βRI) were up-regulated in UUO mice. In contrast, OM significantly ameliorated renal fibrotic lesions and attenuated the expressions of FN, α-SMA, TGF-β1 and TGF-βRI, but increased E-cadherin in the obstructed kidneys. In vitro, OM abolished TGF-β1-mediated E-cadherin suppression and FN, α-SMA and TGF-βRI induction in HK-2 cells in a dose-dependent manner. These observations strongly suggest that the renal protective effects of OM could be mediated by prevention of EMT and manifested as suppression of TGF-β1 and TGF-βRI expressions.