Introduction:Occupational exposure to hand-arm vibration generated by the use of powered hand tools is a major risk factor for workers' health, particularly when combined with high levels of occupational noise. Among these tools, angle grinders used by welders are recognized as important sources of both physical hazards. Objectives:To investigate the laterality of hand-arm vibration exposure among workers using 7-inch and 9-inch electric angle grinders by comparing vibration exposure between the control hand positioned on the rear handle and the supporting hand positioned on the front handle as well as to assess the intensity of occupational noise generated by these tools. Methods:A retrospective observational study was conducted involving six welders from three companies representing different industrial sectors under real-world working conditions. Vibration and noise measurements were performed in accordance with the procedures established by Brazilian Occupational Hygiene Standard 10 and Brazilian Occupational Hygiene Standard 01, using the normalized resultant acceleration and A-weighted sound pressure levels expressed in dB(A). Results:Hand-arm vibration exposure showed an asymmetric pattern, with higher vibration levels consistently recorded at the rear handle (control hand), regardless of tool size or grinding disc type. In all samples, vibration levels exceeded the action value and, in some cases, surpassed the occupational exposure limit established by Brazilian legislation. Noise levels also exceeded the action value, with no evidence of lateral predominance. Conclusions:These findings highlight the importance of measuring vibration exposure in both hands and reveal gaps in the current regulatory framework regarding objective criteria for the simultaneous assessment of hand-arm vibration exposure.
Introduction:Occupational stress and psychosocial factors at work are recognized as triggers of psychological distress, musculoskeletal disorders, and decreased functional capacity in the contemporary workplace. Objectives:This study investigated effort-reward imbalance and common mental disorders among 372 firefighters working in Brazil. Methods:This was a cross-sectional study conducted with a sample of 372 firefighters using a log-binomial regression model. Results:The prevalence of common mental disorders was 9.7% in the total sample and reached 10.7% in the high-risk group (effort-reward imbalance ratio > 1). Log-binomial regression showed that the effort-reward imbalance model increased the explanatory power of mental distress to 12.1%. High effort was associated with an increased risk of common mental disorders (prevalence ratio = 2.21), whereas overcommitment had the greatest impact on prevalence (prevalence ratio = 2.41). Effort was also the main predictor of symptom severity (β = 0.443; p < 0.001). Conclusions:These findings indicate that effort-reward imbalance constitutes an important marker of psychosocial risk among firefighters. The population attributable fraction for overcommitment was 51.1%, indicating that more than half of common mental disorder cases may be attributed to this dimension. Thus, occupational demands and perceived recognition emerged as key determinants of mental health in this professional category. The study reinforces the need for mental health surveillance and promotion strategies that consider the specific characteristics of firefighters' military operational environment.
