The results suggest that interventions aimed at reducing musculoskeletal symptoms in the Chinese working population should take into account multiple risk areas including individual, physical job characteristics and work-related psychosocial factors.

Psychosocial Work Environment and Well-Being: A Cross-Sectional Study at a Thermal Power Plant in China: Shanfa YU, et al. Department of Occupational and Environment Medicine, Peking University Health Center, China-To investigate the effects of the job demand-control (DC) model and the effort-reward imbalance (ERI) model on worker's wellbeing, self-reports for psychosocial work conditions and well-being were made by a sample of 878 workers at a thermal power plant in China using the main dimensions of DC and ERI questionnaires. Logistic regression analyses were employed controlling for age, gender, and educational level, and negative and positive affection among others. Workers reporting high job demands and low job control or high efforts and low rewards had elevated risks of job dissatisfaction, psychosomatic complaints and depressive symptoms. Odds ratios were generally higher in workers reporting both high efforts and low rewards. Furthermore, low reward proved to be a stronger predictor of poor wellbeing when both job stress models were simultaneously adjusted. To some extent, interaction effects were found for social support, but no interaction effects were found for overcommitment. The findings indicate independent effects of both the DC model and the ERI model on well-being. Future work should explore the combined effects of these two models of psychosocial stress at work on health more thoroughly. (J Occup Health 2008; 50: 155-162)

BackgroundNoise-induced hearing loss (NIHL) is a complex, irreversible disease caused by the interaction of genetic and environmental factors. In recent years, a great many studies have been done to explore the NIHL susceptibility genes among humans. So far, high powerful detections have been founded that genes of potassium ion channel genes (KCNQ4 and KCNE1), catalase (CAT), protocadherin 15 (PCDH15), myosin 14 (MYH14) and heart shock protein (HSP70) which have been identified in more than one population may be associated with the susceptibility to NIHL. As for metabolic glutamate receptor7 gene (GRM7), a lot of researches mainly focus on age-related hearing loss (ARHL) and the results have shown that the polymorphisms of GRM7 are linked to the development of ARHL. However, little is known about the association of GRM7 and the susceptibility to NIHL. Therefore, the aim of this study was to explore the effect of GRM7 polymorphisms on the susceptibility to NIHL.MethodsA nested case-control study based on the cohort in a Chinese steel factory was implemented in 292 cases and 584 controls matched with the same sex, the age difference ≤ 5 years old, the same type of work, duration of occupational noise exposure ≤2 years. Five single nucleotide polymorphisms (SNPs) of GRM7 were gained through selecting and genotyping SNPs. Conditional logistic regression analysis was used to assess the main effect of GRM7 polymorphisms on the susceptibility to NIHL and the gene-by-environment interaction. Furthermore, the gene-by-gene interactions were analyzed by generalized multiple dimensionality reduction (GMDR).ResultsThis research discovered for the first time that the mutant allele C in rs1485175 of the GMR7 may decrease individuals’ susceptibility to NIHL. The interaction between rs1485175 and cumulative noise exposure (CNE) at high level was found after the stratification according to CNE (p/pbon = 0.014/0.007, OR = 0.550, 95% CI: 0.340–0.891). Permutation test of GMDR suggested that rs1920109, rs1485175 and rs9826579 in GRM7 might interact with each other in the process of developing NIHL (p = 0.037).ConclusionsThe results suggest that the mutant allele C of rs1485175 in GRM7 may reduce the susceptibility to NIHL in Chinese Han population.Electronic supplementary materialThe online version of this article (10.1186/s12881-017-0515-3) contains supplementary material, which is available to authorized users.

Noise-induced hearing loss (NIHL) is the second-most frequent form of sensorineural hearing loss. When exposed to the same noise, some workers develop NIHL while others do not, suggesting that NIHL may be associated with genetic factors. To explore the relationship between single nucleotide polymorphisms (SNPs) in heat shock protein 70 (HSP70) genes (HSPA1A, HSPA1B and HSPA1L) and susceptibility to NIHL in Han Chinese workers exposed to noise, a case-control association study was carried out with 286 hearing loss cases and 286 matched with gender, age, type of work, and exposure time, drawn from a population of 3790 noise-exposed workers. Four SNPs were selected and genotyped. Subsequently, the effects of the alleles and genotypes of the three HSP70 genes (HSPA1A, HSPA1B and HSPA1L) on NIHL were analyzed by using a conditional logistic regression. A generalized multiple dimensionality reduction (GMDR) was applied to further detect an interaction between the four SNPs. Compared with the combined genotypes CC/TC, carriers of the TT genotype of rs2763979 appeared to show greater susceptibility to NIHL (P = 0.042, adjusted OR = 1.731, 95% CI 1.021–2.935). A significant interaction between rs2763979 and CNE was found (P = 0.029), and a significant association was found between TT of s2763979 and NIHL (P = 0.024, adjusted OR = 5.694, 95%CI 1.256-25.817) in the 96 dB (A)≤CNE<101 dB (A) group. The results suggest that the rs2763979 locus of the HSP70 genes may be associated with susceptibility to NIHL in Chinese individuals, and other HSP70 genes may also be susceptibility genes for NIHL, but the results must be further replicated in additional independent sample sets.

Noise-induced hearing loss (NIHL) is an important occupational disease worldwide resulting from interactions between genetic and environmental factors. The purpose of this study was to examine whether genetic variations in POU4F3 and GRHL2 may influence susceptibility to NIHL in the Chinese population. A matched case-control study was carried out among 293 hearing loss individuals and 293 normal hearing workers drawn from a population of 3790 noise-exposed workers. Ten single-nucleotide polymorphisms (SNPs) in POU4F3 and GRHL2 were selected and genotyped. Logistic regression was performed to analyze the main effects of SNPs and the interactions between noise exposure and SNPs. Moreover, the interactions between predictor haplotypes and noise exposure were also analyzed. Analysis revealed that the CC genotype of rs1981361 in the GRHL2 gene was associated with a higher risk of NIHL (adjusted OR = 1.59; 95% CI: 1.08–2.32, p = 0.018). Additionally, the GG genotype of rs3735715 in the GRHL2 gene was also a risk genotype (adjusted OR = 1.48; 95% CI: 1.01–2.19, p = 0.046). Significant interactions were found between rs3735715, rs1981361 (GRHL2), rs1368402 as well as rs891969 (POU4F3) and noise exposure in the high-level exposure groups. Furthermore, the protective haplotype CA in the POU4F3 gene and the risk haplotype GCCG in the GRHL2 gene were identified combined with noise exposure. These results indicated that GRHL2 might be an NIHL susceptibility gene, but the effect of POU4F3 on NIHL could only be detected when taking noise exposure into account, and their effects were enhanced by higher levels of noise exposure. However, the differences were not significant after the Bonferroni correction was applied. These results should be seen as suggestive.