EHS 655 Lecture 2 Introduction and overview continued

EHS 655 Lecture 2: Introduction and overview, continued

Setting the stage o So, what exposure will we be focusing on this semester? o Exposure selected based on… n n n Ubiquity of exposure (e. g. , many sources) Variability of exposure Range of health effects Availability of dataset Over-emphasis on chemicals at SPH 2

Setting the stage o Will use dataset of noise exposures and two health outcomes related to noise n n o Hearing loss Hypertension Concepts from this analysis can be readily applied to n n Any hazard Workplace and community exposures 3

Noise and associated health effects o Noise among most common occupational exposures o Noise-induced hearing loss (NIHL) among most common, well-understood occupational diseases n n o 100% preventable, but permanent, irreversible Profound social and occupational effects Linked to injuries and non-auditory effects Time course of NIHL from variable noise unclear Non-auditory effects of noise less well-understood n Hypertension, ischemic heart disease, etc NIOSH, 1998; Berger, Royster, Driscoll, Layne, 2000 4

Noise and hearing loss Henderson D et al, Ear Hear 2006 5

Noise and hearing loss Henderson D et al, Ear Hear 2006 6

Noise and hearing loss 7

Noise and hearing loss 8

Noise and CVD Van Kempen et al, Environ Health Persp, 2002 9

Environmental noise and CVD Meta-analysis, 7 -17% increase in CVD per 10 d. B increase Basner et al, Lancet, 2014 10

Environmental noise and CVD World Health Organization: >1 million healthy life years (i. e. , Disability-Adjusted Life Years, DALYs) lost annually due to environmental noise (Note: does not consider occupational noise) Basner et al, Lancet, 2014 11

Environmental noise and CVD Estimated US CVD savings from 5 d. B reduction in population noise in 2014: $3. 9 billion Swinburn et al, Am J Prev Med, 2015 12

Occup. noise and CVD Retrospective cohort, 27, 464 workers, mean 92 d. BA, 24 years avg f/u Davies et al, Epidemiol, 2005 13

One way to assess CVD: blood pressure o o Measured using 2 numbers (e. g. , 120 over 80 or 120/80) First number = systolic blood pressure n o Measures the pressure in blood vessels when heart beats Second number = diastolic blood pressure n Measures pressure in blood vessels when heart rests between beats https: //www. cdc. gov/bloodpressure/measure. htm 14

Okay, so noise is bad. Why do we need another study? o Anyone know Hill’s Criteria for Causality? http: //nfs. unipv. it/nfs/minf/dispense/patgen/lectures/files/disease_causality. html 15

NIHL claims in one industry with highly variable noise 7. 5% workforce 1984 -96, 21% accepted NIHL claims 1998 cost: $57 mil All Industries Daniell, Fulton-Kehoe, Cohen, Swan, Franklin, 2002 16

Overview of study (some of) our data come from o Prospective study of early NIHL among construction workers, 2000 -2010 n Why are studies like this rare? o Workers recruited at start of apprenticeship programs o Annual subject visit to University of Washington, Seattle with: n n o Extensive battery of hearing tests Survey of work experience, tasks, perceptions of exposure Direct exposure measurements on cohort infeasible 17

Blood pressure data from study o Did not actually collect blood pressure data o I have simulated data and added it to dataset provided n Everything else in the dataset is real 18

Data needed to understand risk of health effects of noise Frequency Protective behaviors Duration Dose Personal risk factors Intensity Variability Frequency x Duration x Intensity = Exposure 19

Exposure assessment in construction 20

Exposure assessment o Full-shift dosimetry measurements n n o Dosimeters datalog exposure parameters at 1 -min intervals n n o Convenience sample of construction workers at sites around Puget Sound Shifts not all exactly 8 hours Average level (LEQ) Maximum level (LMAX) Workers simultaneously record tasks, hearing protector use, etc. 21

Task-based exposure assessment 22

Subjective rating (SR) of noise exposure o Workers assess own noise exposure via SR o Simultaneously measure noise exposure o Combine for quantitative exposure estimate Neitzel, Daniell, Sheppard, Davies, Seixas, 2009 23

Data needed to understand risk of health effects of noise Frequency Protective behaviors Duration Dose Personal risk factors Intensity Variability 24

Variability – alternative metrics o Different exposure parameters may help explain health effects n n o Average Maximum or peak Can also compute ratios of these parameters n Maximum/average (peakiness of levels) Seixas, Sheppard, Neitzel, 2005; Rappaport, 1991 25

Data needed to understand risk of health effects of noise Frequency Protective behaviors Duration Dose Personal risk factors Intensity Variability 26

Non-occupational sources of noise in life Others? 27

Data needed to understand risk of health effects of noise Frequency Protective behaviors Duration Dose Personal risk factors Intensity Variability 28

Factors to consider regarding use of hearing protectors o Is it used and is it effective? 29

Other protective “behaviors” o Acoustic reflex o Biomarker of exposure and susceptibility n Temporary Threshold Shift at 2 mins postexposure, TTS 2 30

Data needed to understand risk of health effects of noise Frequency Protective behaviors Duration Dose Personal risk factors Intensity Variability 31

From the reading Kauppinen 1991, Appl Occup Environ Hyg 32

Introduction to the data files o Types of files n n Dataset files Variable description files o You’ll be using and referring to both regularly o How they’ll be introduced n New version of dataset most weeks, with additional variables and (at least once) more measurements 33

Introduction to Stata o The program o The do-file o Why use a do-file? n n Ease of manipulation of data Documentation of manipulations and analyses Preserve original data file I’m forcing you to 34

Resources o Statistics Consulting Group, University of California-Los Angeles Institute for Digital Research and Education n o Which statistical analysis should I use? http: //www. ats. ucla. edu/stat/mult_pkg/whatstat/ Stata online help files n Frequently asked questions on using Stata http: //www. stata. com/support/faqs/ 35