The effect of vitamin D (VD) on the risk of preeclampsia (PE) is uncertain. Few of previous studies focused on the relationship between dietary VD intake and PE risk. Therefore, we conducted this 1:1 matched case-control study to explore the association of dietary VD intake and serum VD concentrations with PE risk in Chinese pregnant women. A total of 440 pairs of participants were recruited during March 2016 to June 2019. Dietary information was obtained using a 78-item semi-quantitative food frequency questionnaire. Serum concentrations of 25(OH)D2 and 25(OH)D3 were measured by liquid chromatography–tandem mass spectrometry. Multivariate conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic splines (RCS) were plotted to evaluate the dose-response relationship of dietary VD intake and serum VD concentrations with PE risk. Compared with the lowest quartile, the ORs of the highest quartile were 0.45 (95%CI: 0.29-0.71, Ptrend = 0.001) for VD dietary intake and 0.26 (95%CI: 0.11-0.60, Ptrend = 0.003) for serum levels after adjusting for confounders. In addition, the RCS analysis suggested a reverse J-shaped relationship between dietary VD intake and PE risk (P-nonlinearity = 0.02). A similar association was also found between serum concentrations of total 25(OH)D and PE risk (P-nonlinearity = 0.02). In conclusion, this study provides evidence that higher dietary intake and serum levels of VD are associated with the lower risk of PE in Chinese pregnant women.

Salt iodization is one of the most cost-effective strategies to eliminate iodine deficiency disorders (IDD). However, China’s dismantling of salt monopoly has reduced the availability of iodized salt in the susceptible population in pregnancy, which might cause IDD and have adverse health effects on both themselves and their offspring. The aim of our study was therefore to explore the association between IDD and women’s reproductive health. This is a population-based cross-sectional study conducted in 2018 in Zhejiang Province, China. A total of 1653 pregnant women participated in this study. Median urinary iodine concentration (UIC) in the population was used to assess iodine intake. Cox regression analyses were used to estimate the association between iodine intake and time to pregnancy, which was indicated with fecundability ratio (FR) and 95% confidence interval (CI). The percentage of participants with iodine deficiency who had been waiting longer than 13 months to get pregnant (20%; median UIC 119.6 μg/L) was significantly higher than those with iodine sufficiency (14%; median UIC 147.1 μg/L). A significant decrease in fecundity was observed in participants with iodine deficiency (FR, 0.820; 95% CI, 0.725−0.929) than those with iodine sufficiency. These findings indicate the importance of ongoing monitoring of iodine nutrition in women of reproductive age. Keeping a safe and optimal level of iodine nutrition during pregnancy should be emphasized.

Background The association between serum uric acid (SUA) and all-cause and cardiovascular disease (CVD) mortality in peritoneal dialysis (PD) patients is controversial. Therefore, we aimed to determine the relationship between SUA and all-cause and CVD mortality in PD patients. Method Web of Science, EMBASE, PubMed and the Cochrane Library databases were searched from their inception to 7 April 2021. Effect estimates were presented as hazard ratios (HRs) with 95% confidence intervals (95% CIs) and pooled using random effects model. Result Thirteen cohort studies with 22418 patients were included in this systematic review, of which 9 were included in the meta-analysis. Before switching the reference group, pooled result for the highest SUA category was significantly greater than the median for all-cause mortality (HR = 2.41, 95% CI: 1.37–4.26). After switching the reference group, the highest SUA category did not demonstrate an increased all-cause (HR = 1.40, 95% CI: 0.95–2.05) or CVD (HR = 1.30, 95% CI: 0.72–2.34) mortality compared with the lowest SUA category. Dose-response analysis suggested a nonlinear association between SUA and all-cause mortality risk (Pnonlinearity = 0.002). Conclusion This meta-analysis didn’t find the relationship between SUA levels and all-cause and CVD mortality risk in PD patients. More rigorously designed studies are warranted in the future.

Background The effect of carotenoids on the risk of preeclampsia (PE) is uncertain. We aimed to examine the associations between the intake of dietary carotenoids and related compounds by pregnant women in China, and the risk of their developing PE. Methods Four hundred and forty PE cases and 440 age- (± 3 years), gestational age- (± 1 weeks) and gestational diabetes mellitus status- (yes/no) matched healthy controls were recruited from March 2016 to June 2019. Dietary intake of carotenoids was assessed using a 79-item validated food-frequency questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. Results After adjusting for potential confounders, we found that the intake of total carotenoids, β-carotene, β-cryptoxanthin, lycopene, and lutein and zeaxanthin (lut-zea) were negatively associated with the odds of developing PE. Compared with the lowest quartile intake, the multivariate-adjusted OR (95% CI) of the highest quartile intake was 0.29 (0.16–0.54, Ptrend <  0.001) for total carotenoids, 0.31 (0.16–0.58, Ptrend <  0.001) for β-carotene, 0.50 (0.27–0.90, Ptrend = 0.007) for β-cryptoxanthin, 0.55 (0.30–0.99, Ptrend = 0.04) for lycopene and 0.32 (0.17–0.61, Ptrend = 0.001) for lut-zea. However, no significant associations were observed between the risk of developing PE and α-carotene intake (OR = 0.75, 95% CI: 0.41–1.36, Ptrend = 0.28). Moreover, similar negative associations were found for every one-standard-deviation increase in the intake of total carotenoids, β-carotene, β-cryptoxanthin, lycopene and lut-zea. Conclusion These results indicate that a high intake of total carotenoids, β-carotene, β-cryptoxanthin, lycopene and lut-zea may be associated with a low risk of developing PE.

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