1.Scientific applications of interaction, moderation, and mediation analyses in occupational health psychology research
Journal of Environmental and Occupational Medicine 2026;43(4):395-401
In recent years, interaction, moderation, and mediation analyses have been widely used in occupational health psychology research to explore the relationships among independent variables, dependent variables, and other related variables; however, issues of misuse and abuse still exist. This article introduced the concepts, theoretical foundations, research designs, and data analysis methods of these three analytical approaches, examined their application scenarios, strengths and limitations, as well as common forms of misuse and abuse in occupational health psychology research, proposed recommendations for their scientific application, and discussed prospects for future application.
2.Effect of maternal pyrethroid pesticides exposure during pregnancy on lymphocytes in 1-year-old children: A birth cohort study
Zhiye QI ; Xia XIAO ; Shuqi CHEN ; Dandan ZHAO ; Xiaoxiao SONG ; Yan LI
Journal of Environmental and Occupational Medicine 2026;43(4):402-409
Background Pyrethroid pesticides (PYRs) can cross the placental barrier to cause intrauterine fetal exposure, which may lead to developmental immunotoxicity (DIT). However, the specific effect of maternal PYR exposure during pregnancy on the cellular immune function of 1-year-old children remains unclear. Objective To explore the effect of PYRs exposure throughout the entire pregnancy on peripheral blood lymphocytes in 1-year-old children and potential sensitive window period of PYRs exposure. Methods A birth cohort was established by enrolling pregnant women in their first trimester and following them and their infants until one year of age. Ultra-high performance liquid chromatography-tandem mass spectrometry was used to detect the levels of PYRs metabolites, including 3-phenoxybenzoic acid (3PBA), 4-fluoro-3-phenoxybenzoic acid (4F3PBA), and cis-3-(2,2-dichlorovinyl)-2,2- dimethylcyclopropane carboxylic acid (cis-DBCA), in the urine of pregnant women during the first trimester (gestational weeks 6-12), the second trimester (gestational weeks 21-24), and the third trimester (gestational weeks 33-36). Peripheral blood leukocyte and lymphocyte counts were measured in children at 12 months of age using the Coulter principle combined with flow cytometry. Exposure levels of PYRs metabolites in each trimester were divided into low, moderate, and high exposure groups based on the 25th (P25) and 75th (P75) percentiles. Meanwhile, participants were classified as having repeated high or low exposure if their metabolite levels were > P75 or <P25 in at least two trimesters, respectively, while all others were categorized as having repeated moderate exposure. Generalized linear models were used to analyze the associations between trimester-specific and repeated PYRs metabolite exposure levels and the peripheral blood white blood cell (WBC) and lymphocyte counts in children aged 1 year. Results A total of 336 mother-child pairs were included in this study. For the pregnant women, the total detection rates of maternal urinary 3PBA, 4F3PBA, and cis-DBCA across the three trimesters of pregnancy were 80.5%, 100.0%, and 81.3%, respectively; and median creatinine-corrected concentrations were 0.24, 0.36, and 0.42 μg·g−1, respectively. In children aged 1 year, the mean WBC and lymphocyte counts in peripheral blood were (8.9±2.0)×109·L−1 and (5.7±1.6)×109·L−1, respectively. The results of the generalized linear model analysis indicated that compared to the low exposure group, the high cis-DBCA exposure group during the third trimester of pregnancy had significantly lower peripheral blood WBC count (β=−0.87, 95%CI: −1.51, −0.23) and lymphocyte count (β=−0.64, 95%CI: −1.15, −0.13); and the repeated high-exposure group of cis-DBCA had significantly lower peripheral blood WBC count (β=−1.34, 95%CI: −2.34, −0.34) and lymphocyte count (β=−0.80, 95%CI: −1.60, −0.01) than the repeated low exposure group. Similarly, the repeated moderate-exposure group of cis-DBCA had a significantly lower peripheral blood WBC count (β=−0.83, 95%CI: −1.59, −0.07) than the repeated low exposure group. Conclusion High maternal exposure to PYRs with cis-DBCA as the major metabolite exposure is associated with decreased peripheral leukocyte and lymphocyte counts in children aged 1 year, and repeated high-level exposure throughout gestation appears to exacerbate DIT in offspring. The third trimester of pregnancy maybe a sensitive window for children's DIT induced by exposure to PYRs during pregnancy.
3.Aluminum suppresses humoral immunity through counteracting oxidative stress and repair effects of iron supplementation
Yihuai LIANG ; Chuanxuan WANG ; Yubin ZHANG
Journal of Environmental and Occupational Medicine 2026;43(4):410-418
Background Aluminum (Al) is a lightweight metal that is widely present in the environment and the human body. It has been documented to cause various adverse health effects including the suppression of humoral immunity. Objective To investigate the role of oxidative stress in Al-induced humoral immunity suppression and to evaluate the possible protective effects of iron supplementation on this process. Methods Adult C57BL/6J mice were exposed to Al at concentrations of 0, 200, or 800 μg·mL−1 via drinking water for three consecutive months. The expression of major histocompatibility complex class Ⅱ (I-A), proliferating cell markr-67 (Ki-67), and 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) in splenic B cells was evaluated through flow cytometry. Splenic B cells from the mice treated with 800 μg·mL−1 Al or the control were sorted and treated in vitro with glutathione (GSH), N-Acetyl-L-cysteine (NAC), or a control vehicle. After 24 h, the expression of I-A was evaluated; and the hydroxyl radical (·OH)-generating potential, ·OH production, malondialdehyde (MDA) production, and iron content were assessed using commercial kits. Sixteen mice treated with 800 μg·mL−1 Al received an intravenous injection of either a ferric chloride solution containing 0.3 g·L−1 iron or a 0.9% sodium chloride solution, while eight control mice received 0.9% sodium chloride solution; the injection volume was 0.1 mL per mouse. Two and a half days after injection, I-A and Ki-67 expressions, ·OH-generating potential, ·OH production, and MDA production in splenic B cells were measured; and the concentrations of serum immunoglobulin (Ig) M and IgG were measured through (enzyme-linked immunosorbent assay) ELISA. The splenic B cells sorted from untreated mice were exposed to 0, 12.5, 25, or 50 μg·L−1 Al in vitro. The splenic B cells treated with 50 μg·L−1 Al and the splenic B cells sorted from 800 μg·mL−1 Al-treated mice were additionally treated with GSH and NAC in vitro. The iron supplementation groups, which included the 50 μg·L−1 Al-treated group and splenic B cells sorted from 800 μg·mL−1 Al-treated mice, were treated with a culture medium containing 30 μmol·L−1 iron in vitro. I-A and Ki-67 expressions, ·OH-generating potential, ·OH production, and MDA production in B cells were detected after a 24-h treatment period. Results In the in vivo mouse model, exposure to 800 μg·mL−1 Al significantly inhibited the I-A and Ki-67 expressions (P<0.05), increased DCFH-DA expression and ·OH-generating potential (P<0.05, P<0.01), decreased iron content (P<0.01) and ·OH and MDA production (P<0.01, P<0.001) of splenic B cells, as well as serum IgM and IgG concentrations (P<0.05, P<0.01) in the mice. Exposure to 200 μg·mL−1 Al showed a tendency to decrease the I-A and Ki-67 expressions, and to increase the DCFH-DA expression in splenic B cells, but these differences were not significant. In the in vitro splenic B-cell model, Al (12.5, 25, and 50 μg·L−1) inhibited I-A and Ki-67 expressions (P<0.05, P<0.01) across all concentrations; 50 μg·L−1 Al increased the ·OH-generating potential (P<0.05), and decreased ·OH and MDA production (P<0.01, P<0.05) in B cells. Treatment with GSH and NAC further suppressed I-A expression (P<0.05) in B cells. Iron supplementation increased the ·OH and MDA production (P<0.05), restored I-A and Ki-67 expressions (P<0.05, P<0.01) in B cells, and elevated the serum IgM and IgG concentrations (P<0.05) in Al-treated mice. Conclusion Al suppresses humoral immunity and ·OH production in B cells. The underlying mechanism may involve the decreased iron content and the subsequent retardation of the Fenton reaction in B cells. Supplementing with iron can restore the Fenton reaction in B cells and potentially reverse Al-induced impairment of humoral immunity.
4.Effects and mechanisms of combined exposure to noise and microwave on hippocampal structure and function in mice
Chunxue LU ; Lei SHI ; Yue WANG ; Yanhui HAO ; Xuelong ZHAO ; Yang LI ; Hongyan ZUO ; Liqian ZHU
Journal of Environmental and Occupational Medicine 2026;43(4):419-426
Background Co-exposure to noise and microwave radiation occurs frequently. The central nervous system has been identified as a sensitive target organ for both noise and microwave exposure individually, and the underlying mechanisms remain poorly understood. The specific biological effects resulting from co-exposure to these two factors have yet to be fully elucidated. Objective To clarify the effects of co-exposure to noise and microwave on neurobehavior and hippocampal tissue structure, and to explore the underlying mechanism through the assessment of serum cytokines. Methods C57BL/6N mice were selected and randomly assigned to a blank control group, a noise group, a microwave group, and a combined noise & microwave exposure group. To establish the exposure models, the noise group was subjected to broadband noise at 100 dB for 2 h, while the microwave group received radiation at a central frequency of 9.375 GHz with an average power density of 12 mW·cm−2 and a specific absorption rate of 2.58 W·kg−1 for 15 min. Open field and tail suspension tests assessed anxiety-like emotional behaviour; novel object recognition and Y-maze tests evaluated cognitive function. Histological changes in hippocampal tissue were examined using haematoxylin and eosin (HE) staining, and Nissl staining under light microscopy. Serum cytokine levels were measured using radioimmunoassay and enzyme-linked immunosorbent assay (ELISA). Results After 3 d of exposure, the noise, microwave, and combined exposure groups showed significant reductions in exploration frequency, duration, and distance within the central zone of the open field test compared to the control group (P < 0.01); the combined exposure group exhibited increased ratios of peripheral-to-central exploration time and distance (P < 0.05). After 7 d of exposure, compared with the control group, the noise group maintained a decrease in central zone exploration time (P < 0.01), while the combined exposure group showed persistent decline across all central zone metrics (P < 0.05) and elevated peripheral-to-central ratios (P < 0.05); compared to the microwave group, the combined exposure group showed significant less time in the central zone (P < 0.05) and higher peripheral-to-central ratios (P < 0.05). Regarding behaviour and cognition, compared with the control group, the combined exposure group showed increased immobility time in the tail suspension test after 3 d of exposure (P < 0.01). At this interval, all exposure groups demonstrated reduced frequency and duration of novel object recognition (P < 0.05), with the combined exposure group showing a marked decrease in novel arm exploration time (P < 0.01). After 7 d of exposure, compared with the control group, the noise group showed reduced novel object recognition frequency (P < 0.05), and both the noise and microwave groups exhibited decreased novel arm exploration time (P < 0.05). Pathological alterations including an increased number of hyperchromatic nuclei and depleted Nissl bodies were observed in the CA3 and DG regions across all exposure groups with the most severe lesions observed in the combined exposure group. Serum levels of central nervous system-specific protein β (S-100β), glial fibrillary acidic protein (GFAP), and corticosterone (CORT) were significantly elevated in all exposure groups compared with the control group (P < 0.05). Aquaporin-4 (AQP4) levels increased in the combined exposure group (P < 0.05), while CXC chemokine ligand 10 (CXCL10) levels rose in both the noise and combined groups compared with the control group (P < 0.05). Specifically, S-100β and CXCL10 levels in the combined exposure group were higher than those in the microwave group (P < 0.05); moreover, levels of S-100β, GFAP, CORT, AQP4, and CXCL10 in the combined exposure group were significantly higher than those in the noise group (P < 0.05). Conclusion Combined exposure to noise and microwave radiation induces pathological changes in the hippocampus of mice, increases levels of serum stress hormones and neuro-specific biomarkers. These impairments are more severe than those observed following single-factor exposure. The underlaying mechanism may be related to systemic stress response, neuronal damage, astrocyte activation, and changes in blood-brain barrier permeability, leading to emotional behavioral abnormalities and cognitive decline.
5.Prevalence of frailty and its relationship with working hours among full-time middle-aged and older workers in China
Xiaonan SHI ; Yihao ZHAO ; Shuai GUO ; Talifu ZULIYAER ; Xiaoying ZHENG
Journal of Environmental and Occupational Medicine 2026;43(4):427-434
Background Frailty serves as a significant precursor to falls, disability, and mortality. Epidemiological evidence examining the impact of working hours on frailty remains scarce. Objective To explore the prevalence of frailty and the relationship between frailty and working hours among full-time middle-aged and older workers in China. Methods Data were derived from the 2020 China Health and Retirement Longitudinal Study (CHARLS). The study included full-time workers aged 45 years and above with a weekly working duration exceeding 35 h. Frailty was assessed using the Frailty Index (FI). First, the dose-response relationship between working hours and FI was explored using a generalized additive model (GAM). Second, univariate analyses were performed using t-tests, χ2 tests, and the Jonckheere–Terpstra trend test. Restricted cubic splines (RCS) were introduced for modeling. Based on ordinal logistic regression models, covariates were adjusted sequentially to examine whether differences in frailty prevalence existed across different weekly working hour categories. Finally, subgroup analyses were performed. Results Among the
6.Construction of a risk prediction model for blood pressure abnormality in occupational populations based on longitudinal occupational health surveillance data
Tengxiao SHAN ; Jiming ZHANG ; Tianyang SHEN ; Zhijun ZHOU
Journal of Environmental and Occupational Medicine 2026;43(4):435-442
Background The prevalence of chronic diseases among the Chinese occupational population is rising steadily, with hypertension and diabetes becoming important health concerns. Occupational health examinations (OHE) provide stable population coverage, standardized protocols, and fixed follow-up intervals, offering a robust data foundation for risk assessment. However, most existing hypertension prediction studies rely on cross-sectional data and mainly focus on clinic onset, failing to capture the dynamic progression and cumulation of individual risk. Objective To construct a machine learning-based risk prediction model for blood pressure abnormality in occupational populations, providing a reference for health risk stratification and targeted health interventions. Methods Longitudinal data from 2020 to 2023 were extracted from the occupational health examination database of an institution in Shanghai. After excluding individuals with hypertension in any of the first three years,
7.Neck-related work-related musculoskeletal disorders: Prevalence and associated factors among occupational workers from 8 industries in Shanghai
Yan LIU ; Feng YANG ; Weiwei GUO ; Niu DI ; Yan YIN
Journal of Environmental and Occupational Medicine 2026;43(4):443-450
Background Neck-related work-related musculoskeletal disorders (WMSDs) are a major type of musculoskeletal disorders with a relatively high proportion. Shanghai has a large number of occupational populations; however, the occurrence of WMSDs at neck among the occupational populations across industries in this city has not been reported, and needs to be addressed. Objective To understand the occurrence of neck-related WMSDs and their influencing factors among occupational populations in 8 industries in Shanghai, and to provide a scientific basis for the prevention and control of WMSDs in this population. Methods From February 2024 to February 2025, a cross-sectional survey employed stratified cluster sampling to select
8.Time series study on influence of sulfur dioxide exposure on hospitalization of chronic obstructive pulmonary disease in Lanzhou from 2016 to 2020
Sheng LIN ; Boxi FENG ; Yongyue LI ; Yiwei HUANG ; Kai ZHENG ; Mingxuan LIU ; Yingying YANG ; Xingmin WEI ; Jianjun WU
Journal of Environmental and Occupational Medicine 2026;43(4):451-457
Background In 2021, chronic obstructive pulmonary disease (COPD) emerged as the forth leading cause of death in the world. However, the impact of air pollutants on COPD is still inconsistent across current studies. Objective To analyze the relationship between ambient sulfur dioxide (SO2) exposure and hospital admissions for COPD in Lanzhou, and to examine the modified effects of SO2 across different genders, age groups, and seasons. Methods A total of
9.Time-series analysis of daily temperature, atmospheric pressure, and pre-hospital cardiovascular and cerebrovascular disease emergencies in Yantai, Shandong Province, 2016–2022
Mingshun WU ; Qing ZHANG ; Liang CHANG ; Lan LI ; Suqiu YANG ; Jiarong LI ; Xinhui YU ; Linlin LI ; Jiawei FENG ; Tieying NI
Journal of Environmental and Occupational Medicine 2026;43(4):458-466
Background Meteorological factors are among the key extrinsic triggers for the onset and exacerbation of cardiovascular and cerebrovascular diseases (CVD). Against the backdrop of sustained global warming, elucidating the impact of ambient temperature and atmospheric pressure on CVD, especially on pre-hospital CVD emergent events, has become imperative for evidence-based prevention and emergency preparedness. Objective To quantify the temporal trends of daily mean temperature and atmospheric pressure and their associations with pre-hospital CVD emergent events in Yantai, and to explore effect modification by demographic subgroups and geographic areas, thereby providing an empirical basis for the rational allocation of emergency medical resources. Methods Pre-hospital CVD emergency data from January 1, 2016 to December 31, 2022 were selected from the Yantai 120 Emergency Medical Command System. Synchronous meteorological factors and environmental pollutant data were obtained from the websites of the National Oceanic and Atmospheric Administration and the National Centers for Environmental Information of the United States. Time-series analysis combined with distributed lag non-linear model was used to analyze the association between daily temperature, atmospheric pressure, and pre-hospital CVD emergencies. Average annual percentage changes (AAPC) were calculated using Joinpoint (version 5.2.0.0) to reflect temporal trends. Spearman correlation analysis was employed to screen variables with low collinearity for inclusion in the multi-pollutant adjusted models. Results From 2016 to 2022, a total of
10.Current status of climate change-related health literacy and evaluation of comprehensive intervention effects among residents in Shenzhen
Guomin CHEN ; Jiamin JIANG ; Xun WANG ; Qiuling WANG ; Jiajia JI ; Xiaoheng LI
Journal of Environmental and Occupational Medicine 2026;43(4):467-474
Background Climate change poses a significant threat to public health. In China, relevant health intervention research is still in its early stages, and evidence for evaluating the effectiveness of regional climate change health adaptation strategies and measures is scarce. Objective To investigate the level of climate change-related health literacy among residents in Shenzhen, implement targeted health interventions, and assess the intervention effects as well as their influencing factors. Methods From July 2023 to January 2024, 4 communities were randomly selected in Shenzhen, and a total of 896 community residents were enrolled and divided into an intervention group (444 participants) and a control group (452 participants). Baseline and follow-up surveys on climate change-related health literacy were conducted among residents for both groups. During the period between the two surveys, the intervention group received targeted health interventions. Health literacy—comprising 3 dimensions: basic health knowledge and concepts, basic health skills, and healthy lifestyles—was defined as achieving ≥80% of the total score. A differences-in-differences model was adopted to analyze the impact of the intervention, and multiple linear regression was used to explore the factors influencing the intervention effect. Results The baseline survey showed that 240 out of the 896 surveyed residents (26.79%) possessed climate change health literacy. For the 3 dimensions, the number of residents and the proportions with corresponding literacy in descending order were: basic health skills (521, 58.15%), healthy lifestyles (345, 38.50%), and basic health knowledge and concepts (44, 4.91%). After the intervention, the intervention group showed a 3.19% increase in the total health literacy score, a 3.55% increase in basic health knowledge and concepts, and a 4.24% increase in basic health skills (t=2.79, 2.77, and 2.47 respectively) (P<0.05). No significant change was observed in healthy lifestyle scores (t=0.70, P>0.05). Further analysis showed that awareness of the “dual carbon goals” and occupation were significantly associated with the intervention effect on overall health literacy (P<0.05). For basic health knowledge and concepts, occupation, history of chronic diseases, and awareness of the “dual carbon goals” had statistically significant effects on the intervention outcomes (P<0.05). Regarding basic health skills, awareness of the “dual carbon goals” significantly influenced the intervention effect (P<0.001). In terms of healthy lifestyles, gender, educational level, occupation, and awareness of climate change were significantly associated with the intervention effect (P<0.05). Conclusion The climate change-related health literacy among community residents in Shenzhen is in urgent need of improvement. Health interventions can effectively enhance residents' basic health knowledge and concepts, basic health skills, and overall literacy level. In the future, it is necessary to strengthen the popularization of climate change health knowledge based on different population characteristics and further optimize intervention strategies, to comprehensively improve residents' health adaptation capacity to climate change.

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