The long-term effects of exposure to noise on the levels of thyroid hormones: A four-year repeated measures study.

Masoud Khosravipour, Masoud Ghanbari Kakavandi, Farshad Nadri, Faramarz Gharagozlou

The Science of the total environment 2021 Oct 20

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Animal studies have suggested that noise exposure can be associated with changes in the levels of thyroid hormones. However, no evidence is available that quantified this effect on humans. This study aimed to quantify the long-term effects of exposure to noise and its different frequencies on thyroid hormone levels. A four-year repeated measures study was performed among male workers of a thermal power plant industry from 2016 to 2020. Overall, 1032 observations were examined. To determine exposure to noise for each participant, the 8-hour equivalent sound pressure levels (Leq) were measured at weighting channels of Z, A, and C for an octave-band including low (31.5, 63, 125 Hz), middle (250,500, and 1000 Hz), and high (2, 4, 8 kHz) frequency noises. The fasting blood samples were also taken to determine thyroid hormone levels (TSH, Thyroid-stimulating hormone; T4, Thyroxine; T3, Triiodothyronine). The mixed-effects linear regression was applied to specify the percent changes in the levels of thyroid hormones. The prevent changes (95% confidence interval) of T4, T3, and TSH levels per a 10-dB increase in Leq based on the full adjusted model were estimated -0.90 (-1.68, -0.11), -0.70 (-1.44, 0.05), and 3.94 (0.58, 7.40), respectively. The highest percent changes in the T4 and TSH hormones were identified at 500 Hz (percent change = -1.08 and 95% CI = -1.93, -0.23) and with little difference at 1 (percent change = 4.73 and 95% CI = 0.91, 8.70) and 2 kHz (percent change = 4.72 and 95% CI = 1.13, 8.52) frequencies, correspondingly. Our findings indicated that long-term noise exposure may be associated with changes in the levels of thyroid hormones. Although more studies are warranted, noise-induced thyroid dysfunction may play a significant role in the biological pathways of the effects of noise on the human body. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Masoud Khosravipour, Masoud Ghanbari Kakavandi, Farshad Nadri, Faramarz Gharagozlou. The long-term effects of exposure to noise on the levels of thyroid hormones: A four-year repeated measures study. The Science of the total environment. 2021 Oct 20;792:148315