OBJECTIVE: By recruiting reference population, we aimed to (1): estimate the 25(OH)D threshold that maximally inhibits the PTH, which can be defined as the cutoff value for vitamin D sufficiency; (2) establish the PTH reference interval (RI) in population with sufficient vitamin D.
METHODS: Study data were retrieved from LIS (Laboratory Information Management System) under literature suggested criteria, and outliers were excluded using Tukey fence method. Locally weighted regression (LOESS) and segmented regression (SR) were conducted to estimate the threshold of 25(OH)D. Multivariate linear regression was performed to evaluate the associations between PTH concentration and variables including 25(OH)D, gender, age, estimated glomerular filtration rate (EGFR), body mass index (BMI), albumin-adjusted serum calcium (aCa), serum phosphate(P), serum magnesium(Mg), and blood collection season. Z test was adopted to evaluate whether the reference interval should be stratified by determinants such as age and gender.
RESULTS: A total of 64,979 apparently healthy subjects were recruited in this study, with median (Q1, Q3) 25(OH)D of 45.33 (36.15, 57.50) nmol/L and median (Q1, Q3) PTH of 42.19 (34.24, 52.20) ng/L. The segmented regression determined the 25(OH)D threshold of 55 nmol/L above which PTH would somewhat plateau and of 22 nmol/L below which PTH would rise steeply. Multivariate linear regression suggested that gender, EGFR, and BMI were independently associated with PTH concentrations. The PTH RI was calculated as 22.17-72.72 ng/L for subjects with 25(OH)D ≥ 55 nmol/L with no necessity of stratification according to gender, age, menopausal status nor season.
CONCLUSIONS: This study reported 25(OH)D thresholds of vitamin D sufficiency at 55 nmol/L and vitamin D deficiency at 22 nmol/L, and consequently established PTH RIs in subjects with sufficient vitamin D for northern China population for the first time.

The abundant generation of construction and demolition waste (CDW) poses a threat to the sustainable development in China and recycling plays a vital role in complying with circular economy zero-waste goal. In this study, we first investigate the determinants of contractor\'s intention to recycle CDW by establishing an integrative model of the theory of planned behavior (TPB) and the norm activation model (NAM) with rational and moral considerations. Based on the questionnaire data of 210 valid responses, structural equation modeling is employed to test the proposed hypotheses and analyze the integrative structural model. The results show that the integrative model with adequate reliability and validity fits the empirical data well and the explanation power is superior to that of initial TPB model and NAM model, demonstrating the appropriateness of merging TPB and NAM in the area of CDW recycling research. Moreover, it is found that personal norms are the most critical determinant enhancing the CDW recycling intention, followed by perceived behavioral control. Although subjective norms fail to directly affect the CDW recycling intention, they can significantly strengthen personal norms and perceived behavioral control. These findings provide useful insights for government to develop effective management strategies to motivate CDW recycling intention of contractors.

UNASSIGNED: Nurses play a key role in the health care system. However, clinical nurses experience different kinds of stressors that might impact the nurses\' quality of life or quality of care. Family is one of the main social support resources, and quality family function might improve the quality of care provided by nurses. However, evidence on family function in Chinese clinical nurses is quite limited.
UNASSIGNED: The current study was to evaluate the family function of the Chinese clinical nurses, and to explore associated predicting factors.
UNASSIGNED: A multi-center cross-sectional anonymous online survey was carried out. Chinese Family Function Scale was used in the study. Spearman\'s rank correlation analysis, Mann-Whitney U test, or Kruskal-Wallis H test was performed in the univariate analysis. The pairwise comparison method was used to determine whether the difference was significant between pair groups. Categorical regression (optimal scaling regression) was the main method to analyze factors that had been confirmed to be statistically significant in the univariate analysis.
UNASSIGNED: Nineteen thousand four hundred and twenty-two nurses completed the online questionnaires. The median of the nurse\'s perceived family function score was three (Inter-quartile Range: IQR 2-5). The multivariate analysis showed that the highest education level (P <0.001), the hospital level (P <0 .001), rotation shift status (P <0.001), working department (P < 0.001), number of children (P < 0.001), monthly income per family member (P < 0.001) were significantly associated with family function. Moreover, the importance of the factors was the number of children (49.1%), monthly income per family member (20.7%), rotation shift status (12.4%), the highest education level (8.0%), the hospital level (7.6%), and working department (2.4%) in turn.
UNASSIGNED: The family function was associated with multiple factors, which hints that managers, leaders, and government could make strategies to improve nurses\' family function in order to lead nurses to make a balance between family and work. Policymakers, nursing managers, and employers should make strategies such as promoting children-care services, increasing nurses\' income, educating and training enough nurses, and building a well-established system of career development to help clinical nurses improve their family function so that to improve the quality of care.

Syphilis self-testing (SST) may help expand syphilis test uptake among female sex workers. However, there has been no studies on examining SST among female sex workers. We aim to examine SST experience and its determinants among female sex workers in China.
A venue-based, cross-sectional study of female sex workers was conducted in eight Chinese cities in 2019. Participants completed a survey including socio-demographic characteristics, sexual behaviors, and SST history. Multivariable logistic regression was conducted to evaluate the associated factors with SST.
Among 1,287 Chinese female sex workers, 72.1% (928/1,287) had ever tested for syphilis, and 5.9% (76/1,287) had ever used syphilis self-testing. Among syphilis self-testers, more than half (57.9%, 44/76) reported that the self-test was their first syphilis test, around one-fifth (18.4%, 14/76) reported that syphilis self-testing results influenced the price of commercial sex. After adjusting for covariates, female sex workers who received anal sex in the past month (adjusted odds ratio [aOR]: 2.6, 95%CI: 1.5-4.3, p < 0.001), used drugs before or during sex (aOR: 3.8, 95%CI: 2.3-6.4, p < 0.001), tested for other sexually transmitted infections (STIs) in the past 6 months (aOR: 3.4, 95%CI: 1.9-6.0), ever tested in the hospital (aOR: 5.1, 95%CI: 2.5-10.4, p < 0.001), and ever tested in the community (aOR: 1.7, 95%CI: 1.3-2.2, p < 0.001) were more likely to perform syphilis self-testing.
Syphilis self-testing has the potential to expand testing coverage, and increase testing frequency with limited potential harms among FSW. Further evaluation on the intervention effects based on syphilis self-testing among FSW are needed.