Noise-induced hearing loss (NIHL) remains a significant occupational hazard, especially in manufacturing environments where loud machinery is commonplace. A recent systematic review and meta-analysis aimed to quantify the impact of prolonged noise exposure on hearing health among industrial workers. The findings focus on one of the most preventable occupational conditions linked to modern industrial development.

The study analyzed 10 cross-sectional studies from regions including Asia, Africa, and the Middle East, encompassing a total of 5,910 manufacturing workers. It compared workers exposed to noise levels at or above 85 decibels (dB) to those in quieter settings. According to the meta-analysis, workers subjected to noise ≥85 dB were 1.9 times more likely to suffer from NIHL than their counterparts exposed to lower noise levels (aOR=1.90; 95% CI: 1.61–2.26; p<0.001) (Aqsyari et al., 2023).

This threshold aligns with global occupational safety standards, which flag 85 dB as a critical limit beyond which hearing protection is recommended. The analysis also noted moderate heterogeneity (I²=63%) among the studies, suggesting consistent but varied findings across different industrial contexts.

Findings from the reviewed studies revealed additional concerns such as poor adherence to hearing protection device (HPD) use, despite regulations and available equipment. In some settings, only 42.6% of workers reported using ear protection, even where high-noise levels were well-documented.

Additional factors such as prolonged work shifts, exposure to organic solvents, and poor enforcement of safety policies were linked to higher risks of hearing deterioration. These environmental and behavioral contributors underscore the complexity of mitigating NIHL, especially in resource-limited or under-regulated regions (Makame et al., 2020; Ahmed, 2012).

This meta-analysis reinforces the critical importance of hearing conservation programs in noisy industrial environments. While the biological mechanisms behind NIHL are well understood - particularly damage to cochlear hair cells due to chronic sound exposure - the challenge lies in effective prevention. The findings provide strong evidence for prioritizing engineering controls, regular hearing screenings, and mandatory use of protective equipment in settings where noise levels regularly exceed safe limits.