Associations of weight-adjusted-waist index and depression with secondary infertility.

Background: Obesity and psychological factors were identified as risk factors for female infertility. The study investigated the correlation between WWI, depression, and secondary infertility, focusing on the potential mediating role of depression. Methods: According to the data from NHANES, this cross-sectional study used multiple regression analysis, subgroup analysis, and smooth curve fitting to explore the relationship between WWI, depression, and secondary infertility. The diagnostic ability of WWI was evaluated and compared to other obesity indicators using the ROC curve. The mediating effect test adopted the distribution of the product. Results: This study involved 2778 participants, including 381 (13.7%) women with secondary infertility. Results showed that higher WWI (OR = 1.31; 95% CI, 1.11-1.56) and depression scores (OR = 1.03; 95% CI, 1.01-1.06) were associated with secondary infertility. There was a positive correlation between WWI and secondary infertility (nonlinear p = 0.8272) and this association was still consistent in subgroups (all P for interaction> 0.05). Compared with other obesity indicators, WWI (AUC = 0.588) also shows good predictive performance for secondary infertility. Mediation analysis showed that depression mediated the relationship between 3.94% of WWI and secondary infertility, with a confidence interval of Za * Zb excluding 0. Conclusion: WWI exhibited a relatively good correlation in predicting secondary infertility than other obesity indicators, and depression may be a mediator between WWI and secondary infertility. Focusing on the potential mediating role of depression, the risk of secondary infertility due to obesity may be beneficially reduced in women.

Short-chain fatty acid (SCFA) and medium-chain fatty acid (MCFA) concentrations in human milk consumed by infants born at different gestational ages and the variations in concentration during lactation stages.

This study aimed to quantify the short-chain fatty acids (SCFAs) and medium-chain fatty acids (MCFAs) in human milk triacylglycerols (TAGs) and investigate their concentrations in human milk consumed during lactation by infants born at different gestational ages. One hundred and eighty milk samples from the mothers of 30 full-term, 10 early-preterm (≤32 weeks), 10 mild-preterm (32-34 weeks), and 10 near-term (34-37 weeks) infants were collected from the colostrum, transitional, and mature milk. The human milk TAGs were transferred into fatty-acid methyl esters via potassium methoxide in methanol and determined using gas chromatography (GC). The total SCFA (4:0) and MCFA concentrations (6:0 and 8:0) were highest in the mature milk (1.47 ± 0.66 mg g-1 fat from full-term infant milk), approximately 42.18% higher than those in transitional milk. Significantly higher SCFA and MCFA concentrations were found in full-term milk than in preterm milk (p = 0.001). The milk TAGs were analyzed using ultra-high-performance supercritical fluid chromatography with quadrupole-time-of-flight mass spectrometry (UHPSFC-Q-TOF-MS), which showed that the SCFAs and MCFAs were mainly esterified with long-chain fatty-acid groups (16:0, 18:1 n-9, and 18:2 n-6) at the glycerol backbone. The infants' daily SCFA intake from human milk was estimated; this was highest from mature milk for full-term infants (∼14 mg d-1) which was significantly different from that of preterm infants from colostrum and transitional milk (p < 0.001). The correlation between dietary SCFAs and MCFAs in human milk and nutrition in newborns, especially in the gut microbiotas of preterm infants, requires further study.