Night Heart Rate Variability and Particulate Exposures among Boilermaker Construction Workers

Details

• Alternative Title:
  Environ Health Perspect
• Personal Author:
  Cavallari, Jennifer M. ; Eisen, Ellen A. ; Chen, Jiu-Chiuan ; Fang, Shona C. ; Dobson, Christine B. ; Schwartz, Joel ; Christiani, David C.
• Description:
  Background
  
  Although studies have documented the association between heart rate variability (HRV) and ambient particulate exposures, the association between HRV, especially at night, and metal-rich, occupational particulate exposures remains unclear.
  
  Objective
  
  Our goal in this study was to investigate the association between long-duration HRV, including nighttime HRV, and occupational PM2.5 exposures.
  
  Methods
  
  We used 24-hr ambulatory electrocardiograms (ECGs) to monitor 36 male boilermaker welders (mean age of 41 years) over a workday and nonworkday. ECGs were analyzed for HRV in the time domain; rMSSD (square root of the mean squared differences of successive intervals), SDNN (SD of normal-to-normal intervals over entire recording), and SDNNi (SDNN for all 5-min segments) were summarized over 24-hr, day (0730–2130 hours), and night (0000–0700 hours) periods. PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 μm) exposures were monitored over the workday, and 8-hr time-weighted average concentrations were calculated. We used linear regression to assess the associations between HRV and workday particulate exposures. Matched measurements from a nonworkday were used to control for individual cardiac risk factors.
  
  Results
  
  Mean (± SD) PM2.5 exposure was 0.73 ± 0.50 mg/m3 and ranged from 0.04 to 2.70 mg/m3. We observed a consistent inverse exposure–response relationship, with a decrease in all HRV measures with increased PM2.5 exposure. However, the decrease was most pronounced at night, where a 1-mg/m3 increase in PM2.5 was associated with a change of −8.32 [95% confidence interval (CI), −16.29 to −0.35] msec nighttime rMSSD, −14.77 (95% CI, −31.52 to 1.97) msec nighttime SDNN, and −8.37 (95% CI, −17.93 to 1.20) msec nighttime SDNNi, after adjusting for nonworking nighttime HRV, age, and smoking.
  
  Conclusion
  
  Metal-rich particulate exposures were associated with decreased long-duration HRV, especially at night. Further research is needed to elucidate which particulate metal constituent is responsible for decreased HRV.
  
  
• Subjects:
  Adult Circadian Rhythm Electrocardiography Environmental Cardiology Heart Rate Heart Rate Variability Humans Male Occupational Occupational Exposure Particulate Exposures Research Welders

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• Source:
  Environ Health Perspect. 2007; 115(7):1046-1051.
• Document Type:
  Journal Article
• Funding:
  ES00002/ES/NIEHS NIH HHS/United States ; ES009860/ES/NIEHS NIH HHS/United States ; T42 OH008416/OH/NIOSH CDC HHS/United States
• Volume:
  115
• Issue:
  7
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:4f77e290baf3790327cd80f779a0d6558442feae7a37ae063161fe05f7b8fdcf
• Download URL:
  https://stacks.cdc.gov/view/cdc/31267/cdc_31267_DS1.pdf
• File Type:
  [PDF - 128.95 KB ]