title: The Association between Noise, Cortisol and Heart Rate in a Small-Scale Gold Mining Community-A Pilot Study.
abstract: We performed a cross-sectional pilot study on salivary cortisol, heart rate, and personal noise exposures in a small-scale gold mining village in northeastern Ghana in 2013. Cortisol level changes between morning and evening among participants showed a relatively low decline in cortisol through the day (-1.44 ± 4.27 nmol/L, n = 18), a pattern consistent with chronic stress. A multiple linear regression, adjusting for age, sex, smoking status, and time between samples indicated a significant increase of 0.25 nmol/L cortisol from afternoon to evening per 1 dBA increase in equivalent continuous noise exposure (Leq) over that period (95% CI: 0.08-0.42, Adj R(2) = 0.502, n = 17). A mixed effect linear regression model adjusting for age and sex indicated a significant increase of 0.29 heart beats per minute (BPM) for every 1 dB increase in Leq. Using standard deviations (SDs) as measures of variation, and adjusting for age and sex over the sampling period, we found that a 1 dBA increase in noise variation over time (Leq SD) was associated with a 0.5 BPM increase in heart rate SD (95% CI: 0.04--0.9, Adj. R(2) = 0.229, n = 16). Noise levels were consistently high, with 24-hour average Leq exposures ranging from 56.9 to 92.0 dBA, with a mean daily Leq of 82.2 ± 7.3 dBA (mean monitoring duration 22.1 ± 1.9 hours, n = 22). Ninety-five percent of participants had 24-hour average Leq noise levels over the 70 dBA World health Organization (WHO) guideline level for prevention of hearing loss. These findings suggest that small-scale mining communities may face multiple, potentially additive health risks that are not yet well documented, including hearing loss and cardiovascular effects of stress and noise.
authors: Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA. aggreen@umich.edu.
authors: Allyson
authors: A
authors: Green
authors: Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA. jonesand@umich.edu.
authors: Andrew D
authors: AD
authors: Jones
authors: Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA. kansun@umich.edu.
authors: Kan
authors: K
authors: Sun
authors: Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA. rneitzel@umich.edu.|Risk Science Center, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA. rneitzel@umich.edu.
authors: Richard L
authors: RL
authors: Neitzel
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005869:Ghana; D006046:Gold; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D000067572:Miners; D008906:Mining; D009622:Noise / Q000009:adverse effects*; D010865:Pilot Projects; D012463:Saliva / Q000737:chemistry; D013312:Stress, Physiological; D055815:Young Adult
chemical_list: D006046:Gold; D006854:Hydrocortisone
keywords: ASGM; Ghana; dietary diversity; health determinants; heart rate; noise exposure; salivary cortisol; small-scale gold mining; stress