A significant association
As expected, the prevalence of hearing loss increased in tandem with the number of years that the participants had spent working with occupational noise exposure.
Overall, the researchers found that workers with “mild and high BHFHL had [an increased] hypertension risk of 34% and 281%, respectively.” The authors conclude:
“The present study suggested that occupational noise exposure was positively associated with blood pressure levels and hypertension risk.”
They also report that a “dose-response relationship between BHFHL and hypertension was found in both males and females.”
In this study, the authors found that the link between noise exposure and hypertension was most pronounced in men. They believe that this might be because “[m]ale workers [are] usually exposed to higher noise intensity in their workplace, compared with female workers.”
Strengths and limitations
This study’s large sample size lends weight to the findings. Similarly, the scientists used both BHFHL and duration of work to assess noise exposure. The authors believe that this tandem approach might “strengthen the effectiveness and credibility of the results by mutual confirmation.”
However, there are certain shortfalls. Firstly, as the authors recognize, because the study is cross-sectional — meaning that the team did not track the participants over the years — it is not possible to prove cause and effect.
Also, the authors note that their analysis could not account for some variables that affect hypertension risk. These include body mass index (BMI), smoking status, alcohol intake, and psychological factors.
In addition, the researchers did not visit workplaces to assess actual noise levels, and they did not have any information on whether the participants used ear defenders.
Although this study concludes that noise exposure affects blood pressure, other studies have not found the same relationship. Despite this study’s size, scientists will need to carry out more work before noise exposure becomes an official risk factor for hypertension.
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With an increasing prevalence of high blood pressure cases especially amongst the working class in Nigeria, it will be imperative to study this as well.
As a precaution though, limit exposure to occupational noise as much as possible.