A study, conducted by the United States’ National Institute of Occupational Safety and Health (NIOSH), has reported that high blood pressure and high cholesterol are more common among workers exposed to loud noise at work[i].
NIOSH researchers analysed data from the 2014 National Health Interview Survey to estimate the prevalence of occupational noise exposure, hearing difficulty and heart conditions within US industries and occupations. The association between workplace noise exposure and heart disease was also investigated. Analysis showed that:
- 25% of current workers had a history of work-related noise exposure; 14% were exposed in the last year.
- 12% of current workers had hearing difficulties, 24% had high blood pressure and 28% had high cholesterol. Of these cases, 58%, 14% and 9%, respectively, can be attributed to occupational noise exposure.
- Industries with the highest prevalence of occupational noise exposure were mining (61%), construction (51%) and manufacturing (47%).
- Occupations with the highest prevalence of occupational noise exposure were production (55%), construction and extraction (54%), and installation, maintenance and repair (54%).
A history of occupational noise exposure was associated with elevated risks of hypertension (with a prevalence ratio of 1.16), and elevated cholesterol (with prevalence ratio of 1.10). Both findings were statistically significant. There was no association between coronary heart disease or stroke and occupational noise exposure.[ii]
‘Loud noise’, for the purpose of the study, was defined as being exposed to loud or very loud sounds or noise for 4 or more hours a day, several days a week. ‘Loud’ was defined as so loud that they had to speak in a raised voice to be heard and ‘very loud’ was defined as having to shout in order to be understood by someone an arm’s length away[iii].
The authors of the study emphasised that they were unable to determine whether noise was the direct cause of these conditions. The mechanism by which noise causes heart disease is unknown, but effects on the nervous system and endocrine system have been suggested. Other factors, such as stress, can also cause heart disease.
Study co-author Elizabeth Masterton said:
‘This study provides further evidence of an association of occupational noise exposure with high blood pressure and high cholesterol, and the potential to prevent these conditions if noise is reduced’.
In a news release from NIOSH, Director John Howard said:[iv]
‘Reducing workplace noise levels is critical not just for hearing loss prevention – it may also impact blood pressure and cholesterol’, and, ‘Worksite health and wellness programs that include screenings for high blood pressure and cholesterol should also target noise-exposed workers’.
This study is not the first to report an association between noise and cardiovascular disease. A review, published earlier in February, found that environmental noise is associated with an increased incidence of raised blood pressure, heart attack, heart failure and stroke[v].
[i] Kerns, E., Masterson, E. A., Themann, C. L. & Calvert, G. M. Cardiovascular conditions, hearing difficulty, and occupational noise exposure within US industries and occupations. Am J Ind Med (2018). doi:10.1002/ajim.22833 https://onlinelibrary.wiley.com/doi/full/10.1002/ajim.22833 (Accessed 18 April 2018)
[iv] High Blood Pressure and High Cholesterol Associated with Noisy Jobs. NIOSH press release. 21 March 2018. https://www.cdc.gov/media/releases/2018/p0321-noisy-jobs.html (Accessed 18 April 2018)
[v] Münzel, T. et al. Environmental Noise and the Cardiovascular System. Journal of the American College of Cardiology 71, 688–697 (2018). http://www.onlinejacc.org/content/71/6/688 (Accessed 18 April 2018)