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Noise & Cardiovascular Disease

Noise & Cardiovascular Disease. Can hearing conservation programs prevent heart attacks too? Hugh W Davies, PhD, CIH School of Environmental Health . Occupational risk factors for CVD. Noise and Heart Disease?. Sound Exposure. Modifying factors:. Intensity Frequency Dynamics.

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Noise & Cardiovascular Disease

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  1. Noise & Cardiovascular Disease Can hearing conservation programs prevent heart attacks too? Hugh W Davies, PhD, CIH School of Environmental Health

  2. NHCA Keynote, Feb 26th, Orlando, FL

  3. NHCA Keynote, Feb 26th, Orlando, FL Occupational risk factors for CVD

  4. NHCA Keynote, Feb 26th, Orlando, FL Noise and Heart Disease?

  5. NHCA Keynote, Feb 26th, Orlando, FL Sound Exposure Modifying factors: • Intensity • Frequency • Dynamics “Indirect” pathway “Direct” pathway Sound Perception • Situational factors: • Communications • Concentration Neural activation Appraisal • Individual factors: • Coping potential • Noise sensibility Noise Perception Disturbed activities, annoyance, STRESS

  6. NHCA Keynote, Feb 26th, Orlando, FL Stress Response Defense Reaction Defeat Reaction Sympathetic adrenal medullary system Hypothalamo-pituitary adrenal system Sympathetic Nervous system activation Elevated catecholamine levels Increased heart rate, blood pressure Increased ACTH Increased Cortisol Chronic or repeated stimulation Visceral Fat Accumulation Insulin resistance Increased BP Structural autoregulation - up-regulating BP Disease: Hypertension, Atherosclerosis, Myocardial Infarction, Stroke, Cardiac Arrhythmias

  7. NHCA Keynote, Feb 26th, Orlando, FL

  8. NHCA Keynote, Feb 26th, Orlando, FL Habituation? • Don’t you just “get used to it”? • Response rapidly extinguished with repetition in lab • However, response elicited by superimposing a new tone • Response more resilient if source unpredictable, variable • Griefan et al, 2008 • Noise-disturbed sleep: • Simulated traffic episodes 45-77 dBA over 32 dbA background • Awakenings subside, but heart rate increase does not extinguish

  9. NHCA Keynote, Feb 26th, Orlando, FL Noise & Hypertension - Epidemiology

  10. NHCA Keynote, Feb 26th, Orlando, FL BC Sawmill Exposure levels (N=1,901) Davies et al, Occup Environ Med. 2009; 66(6):388-94

  11. NHCA Keynote, Feb 26th, Orlando, FL BC Sawmill Cohort • 27,000 blue collar male workers • Employed at least one year, 1950-1995 at 14 BC Mills • Full sawmill employment histories • Retrospective Exposure Assessment • Modeled based on 1900+ full shift dosimetry measurements • Outcomes: • Hypertension • Acute myocardial infarction • Ischemic heart disease • Stroke

  12. NHCA Keynote, Feb 26th, Orlando, FL

  13. NHCA Keynote, Feb 26th, Orlando, FL Sawmill Cohort: Noise & Hypertension Sbihi, et al., Occup Environ Med 2008;65:643–646

  14. NHCA Keynote, Feb 26th, Orlando, FL Sawmill Cohort: Noise & Hypertension

  15. NHCA Keynote, Feb 26th, Orlando, FL Noise & Hypertension - Review Van Kempen, et al, 2002; Environ Health Perspectives 110(3): 307-17

  16. NHCA Keynote, Feb 26th, Orlando, FL Sawmill Cohort: Noise and Heart Disease Davies et al., 2005, Epidemiology, 16:25-32

  17. NHCA Keynote, Feb 26th, Orlando, FL Sawmill Cohort: Noise and AMI

  18. NHCA Keynote, Feb 26th, Orlando, FL Sawmill Cohort: Noise and AMI Reanalyzed excluding HPD users

  19. NHCA Keynote, Feb 26th, Orlando, FL Heart disease - Summary • Other occupational studies • McNamee et al 2006,Virkkunenet al 2005 • Ganet al, unpublished • Hypertension, Acute myocardial infarction, IHD, associated with noise exposure • Not stroke • Effect for AMI greatest while employed • Reversible effect? Or noise acts as a “trigger” • Effect levels 85 dBA; not able to test below this • “Burden of disease”: 20% of AMI deaths attributed to noise

  20. NHCA Keynote, Feb 26th, Orlando, FL Ganet al,. unpublished • NHANES 1999-2004, 6307 participants • Self-reported noise exposure (~85 dB or over) • Outcomes: • S/R of diagnosis of cardiovascular disease • Blood pressure monitoring • Results • 2-3 fold risk for angina, AMI, all types of CHD, isolated diastolic hypertension (<140/>90) • Higher risk in workers under 50 years

  21. NHCA Keynote, Feb 26th, Orlando, FL So can Hearing Conservation Programs prevent Heart Attacks?

  22. NHCA Keynote, Feb 26th, Orlando, FL Engineered/administrative Controls • Reduction of noise levels below “threshold” would negate risk • What is threshold? • Workplace • Our data suggest ~ 85 dBA • Community noise – 60 dBA • Chang - 85 dB threshold for sustained effects (24hr BP monitoring) • Noise control implementation weak • Weak enforcement • Lack of knowledge • Over-reliance on HPD

  23. NHCA Keynote, Feb 26th, Orlando, FL Hearing protection devices • Our results show HPD an “effect modifier” • Want to repeat our analyses adjusting for HPD • Exposure work done (Sbihiet al, 2010a,b, Ann OccupHyg, in press) • Studies overestimating exposure • Hypothesis: correction should “strengthen” dose-response curve • Melamed & Bruhis (1996): • Reduced stress markers correlated HPD use at 85 dBA + • But: • Melamed showed increased stress with HPD use in noise-annoyed • Other parameters? Impulsive nature? Predictability? Frequency? • And don’t know threshold…

  24. NHCA Keynote, Feb 26th, Orlando, FL Cumulative Exposure and AMI

  25. NHCA Keynote, Feb 26th, Orlando, FL Education • Potentially, but would require new materials/curriculum? • Problems with education (Nahidet al, unpublished) • Food & Beverage workers • Only training provided associated with annual audiometry • But • 80 % knew stress associated with noise • 48 %knew hypertension associated with noise

  26. NHCA Keynote, Feb 26th, Orlando, FL Other aspects of HCP • Noise Measurement • Identify hazardous areas • Same problem with threshold though • Audiometry • No – except as motivator to reduce noise exposure • Program Evaluation • Not currently reflecting the CVD hazard

  27. NHCA Keynote, Feb 26th, Orlando, FL To Summarize… • Noise and heart disease appear linked • Biological plausibility, dose response, experimental evidence • Acute MI, hypertension • But a lot we don’t know: • Effect levels – why are occupational and environmental effect levels so different? • Pathological mechanism • Interactions (shift work, other stressors) • HCP probably do reduce the impact of noise on heart health • Noise-reduction, HPD, education

  28. NHCA Keynote, Feb 26th, Orlando, FL Other non-auditory effects • Psychosocial • Annoyance • Learning • Other psychiatric disorders • Sleep Disturbance • Stress-related • Hypertension • Ischemic Heart Disease • Other • Accidents • Immune system • Effects on the fetus • Dementia?

  29. NHCA Keynote, Feb 26th, Orlando, FL The Future • Need to learn more about noise and CVD • Effect levels • Mechanism of effect • Interactions • UBC Vancouver traffic noise/air pollution study • CVD Health in 400,000 adults • Proposed: development effects in children

  30. NHCA Keynote, Feb 26th, Orlando, FL UBC Vancouver Noise Mapping

  31. NHCA Keynote, Feb 26th, Orlando, FL The Future – HCP’s and Heart Health • Emphasize noise reduction • Widest benefits • Programmatic implementation of HCP’s • Targeted education • Heart health, noise and stress • Noise reduction • Publicize exposure data • popdataBC exposure database

  32. NHCA Keynote, Feb 26th, Orlando, FL Acknowledgments • Paul Demers, Murray Hodgson, Kay Teschke, Jean Shoveller • Hind Sbihi, MusarratNahid, Amber Louie • WorksafeBC • Christine Harrison • Heather Gillis

  33. NHCA Keynote, Feb 26th, Orlando, FL

  34. NHCA Keynote, Feb 26th, Orlando, FL

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