The research provides some evidence that long term exposure to loud noise at work is associated with increased risk of some forms of heart disease.
Evidence from:
W Q Gan et al. Occup Environ Med (2011) Vol.68 p 183-190
Exposure to occupational noise and cardiovascular disease in the United States: the National Health and Nutrition Examination Survey 1999-2004
No account was taken of shift work, physical workload, noise exposure from road traffic, fine particulate air pollution in the workplace and residence.
This was a cross-sectional experiment; causation is unclear.