In this study, we aimed to prospectively investigate the relationships between different types of dietary protein and changes in bone mass in Chinese middle-aged and elderly people. Dietary intakes were evaluated by means of a validated food frequency questionnaire. Bone mineral density (BMD) was measured using a dual-energy bone densitometer at multiple bone sites. Multivariable regression models were applied to investigate the associations of the participants’ dietary intakes of total protein, intakes of protein from various sources, and amino acid intakes with the annualized changes in BMD during a 3-year follow-up. A total of 1987 participants aged 60.3 ± 4.9 years were included in the analyses. Multivariable linear regression results showed that dietary intakes of total protein, animal protein, and protein from white meat were positively correlated with BMD changes, with standardized coefficients (β) of 0.104, 0.073, and 0.074 at the femur neck (p < 0.01) and 0.118, 0.067, and 0.067 at the trochanter (p < 0.01), respectively. With each increase of 0.1g·kg−1·d−1 in animal protein and white meat protein intakes, the BMD losses were reduced by 5.40 and 9.24 mg/cm2 at the femur neck (p < 0.05) and 1.11 and 1.84 mg/cm2 at the trochanter (p < 0.01), respectively. Our prospective data, obtained from Chinese adults, showed that dietary total and animal protein, especially protein from white meat, could significantly reduce bone loss at the femur neck and trochanter.

The study aims to establish trimester-specific reference ranges for serum iodine (SI) in Chinese pregnant women and explore its associations with maternal and infantile thyroid function. Apparently healthy pregnant women were enrolled during their first antenatal visit. Fasting venous and spot urine samples were collected for determining serum and urinary iodine (UI) levels by a validated inductively coupled plasma mass spectrometry. Serum free triiodothyronine (FT3), free thyroxine (FT4), thyrotropin (TSH) and neonatal TSH levels were tested by electro-chemiluminescent assay. The reference ranges of SI were established by percentile method and reported as 2.5–97.5%. ROC analysis was applied to compare the discriminative ability of SI, UI and UI to urinary creatine ratio (UI /UCr) in early pregnancy for various thyroid conditions. The trimester-specific reference ranges of SI for Chinese pregnant women were 60.91-114.53 µg/L for the first trimester (T1, n = 1029), 54.57-103.42 µg/L for the second trimester (T2, n = 379) and 52.03–110.40 µg/L for the third trimester (T3, n = 455). Maternal SI at T1 but not UI and UI/UCr, was significantly correlated with FT3 (r = 0.393, P < 0.001), FT4 (r = 0.637, P < 0.001) and TSH (r=-0.299, P < 0.001). Maternal SI change% from T1 to T2 (but not SI change% from T1 to T3) had marginal correlation with neonatal TSH (r=-0.106, P = 0.046). ROC analysis showed that maternal SI at T1 had better predictability for several thyroid conditions than UIC and UI/UCr.

This study aimed to explore the temporal associations between maternal serum iodine concentration (SIC) and common pregnancy outcomes in Chinese women. Eligible singleton pregnant women aged 20–34 years were selected, and their fasting blood samples were collected during early (T1, n = 1101) and mid-pregnancy (T2, n = 403) for SIC testing by inductively coupled plasma mass spectrometry. Multivariable linear regression indicated that log10SIC at T1 (β = −0.082), T2 (β = −0.198), and their % change (β = −0.131) were inversely associated with gestational weight gain (GWG, all p < 0.05). Maternal log10SIC at both T1 (β = 0.077) and T2 (β = 0.105) were positively associated with the Apgar score at 1 min (both p < 0.05). Women in the third quartile (Q3) of SIC at T1 had a lower risk of small for gestational age (SGA, OR = 0.405, 95% CI: 0.198–0.829) compared with those in Q4. Restricted cubic spline regression suggested a U-shaped association between SIC and SGA risk, and SIC above 94 μg/L at T1 was the starting point for an increased risk of SGA. The risk of premature rupture of membrane (PROM) increased by 96% (OR = 1.960, 95% CI: 1.010–3.804) in Q4 compared to that in Q1. Our longitudinal data from an iodine-replete region of China indicated that high maternal SIC could restrict GWG and improve Apgar scores at delivery, but might increase the risk of SGA and PROM.

Objectives The study aims to investigate the association of maternal iron status with subsequent risk of gestational diabetes mellitus (GDM) and adverse birth outcomes. Methods This was a longitudinal study embedded in Huizhou Birth Cohort. Eligible singleton pregnant women of 15 to 49 years were enrolled during their first antenatal visits from December 2018 to October 2019. Maternal serum ferritin (SF) and haemoglobin (Hb) and lipids were tested before 20 weeks of gestation. GDM was diagnosed by a standardized 75g oral glucose tolerance test (OGTT) at 24 to 28 gestational weeks. Birth outcomes were retrieved from the Hospital Information System. The adverse birth outcomes of small for gestation age (SGA) and large for gestation age (LGA) were diagnosed in accordance with an established criteria of Chinese population according to birth weight and gestational week at delivery. Multivariable linear and logistic regression models were applied to examine the associations of maternal iron status with the risk of GDM and adverse birth outcomes. The interactions of iron markers and lipids were explored to testify their combined impacts on GDM and birth outcomes. Results Total 2906 eligible mothers and their neonates were included for data analysis. The prevalence of GDM, SGA and LGA were 18.6%, 11.5% and 4.0%, respectively. Multivariable linear regression indicated that SF was positively associated with post-load glucose levels, while inversely linked with birth weight and height (all P &lt; 0.05). Compared with the lowest quartile group, the highest quartile of Hb were significantly associated with increased risk of GDM by 48.4% (OR = 1.484, 95% CI:1.094–2.013, Ptrend &lt; 0.05); the highest quartile of SF was significantly associated with increased risk of SGA by 47.0% (OR = 1.470, 95%CI:1.012∼2.137, Ptrend = 0.022) and decrease risk of LGA by 52% (OR = 0.480, 95% CI:0.245∼0.940, Ptrend = 0.017). A significant multiplicative interaction was observed between Hb and total cholesterol (TC). High levels of Hb and TC increased the risk of SGA by 73.2% (OR = 1.732, 95% CI:1.035–2.898, P = 0.037). Conclusions Maternal SF and Hb were positively associated with increased risk of GDM and post-load glucose level. Higher SF was associated with increased risk of SGA while decreased risk of LGA. Funding Sources One Hundred Person Project of Sun Yat-sen University (Funding no. 51,000–18,841,203).