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Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 11
Presentation of Phase 2 ResultsPresentation of Phase 2 Results
June 2-3, 2010June 2-3, 2010
The Pratt & Whitney The Pratt & Whitney Epidemiology Study Epidemiology Study
Phase 2 Phase 2 Incidence of Central Nervous Incidence of Central Nervous
System (CNS) Neoplasms System (CNS) Neoplasms
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 22
Research TeamsResearch Teams
Univ. of Pittsburgh (Epidemiology)Univ. of Pittsburgh (Epidemiology)Gary Marsh, PhDGary Marsh, PhD
Jeanine Buchanich, PhDJeanine Buchanich, PhDAda Youk , PhDAda Youk , PhD
Frank Lieberman, MDFrank Lieberman, MDMike Cunningham, MSMike Cunningham, MS
Terri WashingtonTerri Washington
Univ. of Illinois at Chicago (Exposure Assessment)Univ. of Illinois at Chicago (Exposure Assessment) Nurtan Esmen, PhDNurtan Esmen, PhDSteve Lacey, PhDSteve Lacey, PhD
Kathleen Kennedy, MSKathleen Kennedy, MSRoger Hancock, MCERoger Hancock, MCE
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 33
Two-Part PresentationTwo-Part Presentation
Part 1: Overview of Phase 2 Findings
(Gary Marsh)
Part 2: Overview of Exposure Assessment
(Nurtan Esmen)
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 44
Purpose of the Overall StudyPurpose of the Overall Study
To investigate the earlier perception of an To investigate the earlier perception of an unusual occurrence of glioblastoma at the unusual occurrence of glioblastoma at the P&W North Haven facilityP&W North Haven facility
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 55
P&W Study HighlightsP&W Study HighlightsRemains one of largest and most comprehensive occupational cohort studies ever done
Phase 1 mortality study and Phase 2 CNS neoplasm incidence study complete and published
Focus on malignant CNS neoplasms as registry data on benign neoplasms mostly not available before 2004
Final Phase 3 work needs to be done
Potential not only to learn more about health in the P&W workplace but also about possible causes of brain cancer
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 66
What was different about What was different about Phase 2 and Phase 1 ?Phase 2 and Phase 1 ?
Phase 2 evaluated the incidence or occurrence of new cases of CNS neoplasms - Phase 1 examined deaths from CNS neoplasms
The event date of interest in Phase 2 was cases’ date of diagnosis - Phase 1 used date of death
Phase 2 provided first opportunity to examine incidence risk for specific CNS histologies, including glioblastoma, the histology of the North Haven index cases that prompted the overall study
Phase 1 diagnostic specificity limited to “malignant brain cancer”
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 77
Very Large Very Large IncidenceIncidence Study Population Study Population
212,513 men and women who worked in 1 of 8 P&W 212,513 men and women who worked in 1 of 8 P&W sites during 1952–2001 sites during 1952–2001 and at risk of becoming a and at risk of becoming a case during 1976-2004case during 1976-2004
– North Haven (NH), East Hartford, Middletown, Rocky Hill, North Haven (NH), East Hartford, Middletown, Rocky Hill, Cheshire, Southington – Aircraft Rd, Southington – Newell Cheshire, Southington – Aircraft Rd, Southington – Newell St, Manchester FoundrySt, Manchester Foundry
Incidence evaluated 1976-2004 for 21 histological Incidence evaluated 1976-2004 for 21 histological categories based on CBTRUS codescategories based on CBTRUS codes
– 722 total CNS neoplasm cases 722 total CNS neoplasm cases – 489 malignant (275 glioblastoma)489 malignant (275 glioblastoma)– 233 benign233 benign
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 88
Data Analysis StrategyData Analysis StrategyAll workers at risk All workers at risk 1976 - 20011976 - 2001
Work-related factorsWork-related factors
Plant group, pay typePlant group, pay type
Year of hire, age at hireYear of hire, age at hire
Duration of workDuration of work
Time since first workTime since first work
Non work-related factorsNon work-related factors
Race, sexRace, sex
Age group, time periodAge group, time period
North Haven workers by North Haven workers by study factorsstudy factors
Combined DataCombined Data
Study factors Study factors
Subgroups by study Subgroups by study factorsfactors
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 99
Phase 2 Findings Phase 2 Findings Accepted for Accepted for Publication in Publication in Leading Peer-Leading Peer-Reviewed JournalReviewed Journal
Online version-Online version-June 7, 2010June 7, 2010
Print version-Print version-August 2010August 2010
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Center Department of Biostatistics Center for Occupational Biostatistics & Epidemiologyfor Occupational Biostatistics & Epidemiology PW_Phase 1 - PW_Phase 1 - 1010
Phase 2 – Results Phase 2 – Results
External ComparisonsExternal Comparisons
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1111
Total Cohort Level Findings – All Total Cohort Level Findings – All Malignant CNS Histology CategoriesMalignant CNS Histology Categories
We found that during the 1976-2004 study period, We found that during the 1976-2004 study period, the total study population was diagnosed with fewer the total study population was diagnosed with fewer than expected cases for nearly all malignant CNS than expected cases for nearly all malignant CNS neoplasm categories examined, including neoplasm categories examined, including glioblastoma, based on external comparisons with glioblastoma, based on external comparisons with US and CT.US and CT.
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1212
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Gliom
a
Anaplastic
ast
rocyt
oma
Astrocy
tom
a, NOS
Gliobla
stom
a
Oligoden
droglio
ma
Anaplastic
Olig
o.
Ependym
oma
Mix
ed G
liom
a
Gliom
o mal
ignant,
NOS
Men
ingio
ma
Lymphom
a
Neoplasm
, unspec
ified
SIR
US CT
No Statistically Significant Elevations in Total Cohort No Statistically Significant Elevations in Total Cohort Incidence Rates, 1976-2004, Compared with US and CT Incidence Rates, 1976-2004, Compared with US and CT
427427 2020 6363 275275 1515 77 88 66 2727 99 2626 2121
# = observed cases# = observed cases1.101.10
1.151.151.231.23
1.061.06
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1313
Subgroup Level Findings – Subgroup Level Findings – Glioblastoma – CT ComparisonsGlioblastoma – CT Comparisons
We found a not statistically significant overall 8% excess We found a not statistically significant overall 8% excess among “only NH” workers compared with deficits in the among “only NH” workers compared with deficits in the other plant groupsother plant groups
We found elevated SIRs in several subgroups of workers We found elevated SIRs in several subgroups of workers from the “only” and “partial” NH groups, but none was from the “only” and “partial” NH groups, but none was statistically significant and few consistent patterns statistically significant and few consistent patterns emerged emerged
Consistent patterns unique to N. Haven workers included Consistent patterns unique to N. Haven workers included elevated SIRs for salaried workers and workers at risk of elevated SIRs for salaried workers and workers at risk of becoming a case in the oldest age group and latest time becoming a case in the oldest age group and latest time periodperiod
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1414
Glioblastoma Incidence Slightly Elevated but Not Glioblastoma Incidence Slightly Elevated but Not Statistically Significant in “Only NH” GroupStatistically Significant in “Only NH” Group
1.08
0.860.76
0.57
0
0.5
1
1.5
2
SIR
-CT
Only N. Haven
Partial N. Haven
Never N. Haven
Unspecified # = observed cases
4343 1818 179179 3535
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1515
Glioblastoma Incidence Most Elevated but Not Statistically Glioblastoma Incidence Most Elevated but Not Statistically Significant in Salaried “Only” & “Partial” NH GroupsSignificant in Salaried “Only” & “Partial” NH Groups
0
0.5
1
1.5
2
2.5
Salary Hourly Mixed
SIR
-CT
Only N. Haven
Partial N. Haven
Never N. Haven
Unspecified
55 1212 3939 1616 3737 66 1717 00 1616 22
SIR= 1.50SIR= 1.50
# = observed cases# = observed cases
SIR= 1.03SIR= 1.03
124124 11
SIR = 2.17SIR = 2.17
SIR= 1.09SIR= 1.09
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Center Department of Biostatistics Center for Occupational Biostatistics & Epidemiologyfor Occupational Biostatistics & Epidemiology PW_Phase 1 - PW_Phase 1 - 1616
Phase 2 – Results Phase 2 – Results
Internal ComparisonsInternal Comparisons
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1717
Findings for Glioblastoma - Findings for Glioblastoma - Internal ComparisonsInternal Comparisons
For All Workers combined, none of the study factors For All Workers combined, none of the study factors considered was a statistically significant predictor of risk considered was a statistically significant predictor of risk and none of the factor subcategory-specific RRs was and none of the factor subcategory-specific RRs was statistically significant statistically significant
For “Ever NH” workers (Only+Partial), only payroll type For “Ever NH” workers (Only+Partial), only payroll type was a statistically significant predictor of risk due to was a statistically significant predictor of risk due to statistically significant RR=2.04 for salary vs. (hourly + statistically significant RR=2.04 for salary vs. (hourly + mixed) workersmixed) workers
For “Ever NH” workers, we found little or no evidence that For “Ever NH” workers, we found little or no evidence that risk was associated with other study factors including risk was associated with other study factors including duration of work and time since first workduration of work and time since first work
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1818
For All Workers, Glioblastoma Risk Higher in Only and For All Workers, Glioblastoma Risk Higher in Only and Partial N. Haven Compared with Never N. Haven Partial N. Haven Compared with Never N. Haven
0
0.5
1
1.5
2
Never N. Haven Only N. Haven Partial N. Haven Unspecified Plant
SIR
-CT
or
RR
External Comparison (SIR)
Internal Comparison (RR)
179 cases179 cases
RR= 1.00RR= 1.00
43 cases43 cases 18 cases18 cases 35 cases35 cases
RR= 1.29RR= 1.29
RR= 1.13RR= 1.13SIR= 1.08SIR= 1.08
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 1919
For “Ever NH” Workers (Only + Partial), Only Payroll Type Was For “Ever NH” Workers (Only + Partial), Only Payroll Type Was Statistically Significant Predictor of Glioblastoma Risk Statistically Significant Predictor of Glioblastoma Risk
0
0.5
1
1.5
2
2.5
Hourly + Mixed Salary
SIR
-CT
or
RR
External Comparison (SIR)
Internal Comparison (RR)
44 cases44 cases 17 cases17 cases
p < .05p < .05SIR= 1.65SIR= 1.65
RR= 1.00RR= 1.00
RR=2.04RR=2.04
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2020
For “Ever NH” Workers, Little Evidence That Glioblastoma For “Ever NH” Workers, Little Evidence That Glioblastoma Risk Associated with Duration of Work Risk Associated with Duration of Work
0
0.25
0.5
0.75
1
1.25
1.5
< 1 yr 1 - 4 yrs 5 - 19 yrs 20+ yrs
Duration of Time Worked
SIR
-CT
or
RR
External Comparison (SIR)
Internal Comparison (RR)
23 cases23 cases
SIR= 1.33SIR= 1.33
RR= 1.00RR= 1.00
12 cases12 cases 11 cases11 cases 15 cases15 cases
RRs adjusted for payroll typeRR= 1.32RR= 1.32
RR= 1.07RR= 1.07
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2121
For “Ever NH” Workers, No Evidence That Glioblastoma For “Ever NH” Workers, No Evidence That Glioblastoma Risk Associated with Time Since First Worked Risk Associated with Time Since First Worked
0
0.25
0.5
0.75
1
1.25
1.5
< 20 yr 20-29 yrs 30 - 39 yrs 40+ yrs
Time Since First Worked
SIR
-CT
or
RR
External Comparison (SIR)
Internal Comparison (RR)
5 cases5 cases
RR= 1.00RR= 1.00
16 cases16 cases 27 cases27 cases 13 cases13 cases
RRs adjusted for payroll type
SIR= 1.17SIR= 1.17
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Center Department of Biostatistics Center for Occupational Biostatistics & Epidemiologyfor Occupational Biostatistics & Epidemiology PW_Phase 1 - PW_Phase 1 - 2222
Phase 2 – Results Phase 2 – Results
Other FindingsOther Findings
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2323
Detailed Evaluation of Other Malignant CNS Neoplasm Histologies
Evaluated 3 categories with 25+ total cases Evaluated 3 categories with 25+ total cases (astrocytoma-NOS, glioma-malignant and (astrocytoma-NOS, glioma-malignant and lymphoma) using external and internal comparisonslymphoma) using external and internal comparisons
Limited to total incidence subcohort due to small Limited to total incidence subcohort due to small numbers of plant group-specific casesnumbers of plant group-specific cases
Revealed no consistent evidence of trends or Revealed no consistent evidence of trends or patterns in SIRs or RRs suggestive of an patterns in SIRs or RRs suggestive of an association related to P&W employmentassociation related to P&W employment
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2424
How did the main results of Phase 1 and Phase 2 compare?
Overall findings for cancer incidence consistent with overall Overall findings for cancer incidence consistent with overall findings for CNS neoplasm mortality during same 1976-findings for CNS neoplasm mortality during same 1976-2004 study period2004 study period
– Reduced SMRs for “all malignant CNS neoplasms”Reduced SMRs for “all malignant CNS neoplasms”
– Reduced SMRs for “malignant brain neoplasms”Reduced SMRs for “malignant brain neoplasms”
Patterns of study factor-specific glioblastoma risks similar to Patterns of study factor-specific glioblastoma risks similar to those observed for “malignant brain cancer” in Phase 1 those observed for “malignant brain cancer” in Phase 1 mortality studymortality study
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2525
Overall Findings Consistent for Similar CNS Overall Findings Consistent for Similar CNS Neoplasm Categories in Phase 1 and Phase 2 Neoplasm Categories in Phase 1 and Phase 2
0
0.5
1
1.5
2
MalignantCNS
Neoplasms
MalignantBrain
Neoplasms
Glioma Glioblastoma
SM
R o
r S
IR-C
T
1952 - 2004
1976 - 2004
# = observed deaths or cases
462462 381381 427427 275275398398
SIR= .76SIR= .76 SIR= .77SIR= .77SMR= .95SMR= .95SMR= .94SMR= .94
SMR= .87SMR= .87
Phase 2 IncidencePhase 1 Mortality
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2626
Example:Example: Phase 1 Findings for Malignant Brain Cancer Phase 1 Findings for Malignant Brain Cancer by by Payroll Type Consistent with Phase 2 Findings for Payroll Type Consistent with Phase 2 Findings for
Glioblastoma (1976-2004)Glioblastoma (1976-2004)
0
0.5
1
1.5
2
2.5
Salary Hourly Mixed
SMR-
CT
Only N. Haven
Partial N. Haven
Never N. Haven
Unspecified
Salary Hourly Mixed
SIR-C
T
Phase 1 – Malignant Brain Cancer Mortality Phase 2 – Glioblastoma Incidence
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2727
Conclusions from Phase 2 Conclusions from Phase 2 Total cohort incidence rates for malignant CNS Total cohort incidence rates for malignant CNS neoplasms, including glioblastoma, were not elevated neoplasms, including glioblastoma, were not elevated compared to US and CT general populationscompared to US and CT general populations
Glioblastoma excesses unique to certain subgroups of Glioblastoma excesses unique to certain subgroups of workers from NH may be due to work outside of P&W, workers from NH may be due to work outside of P&W, non-work factors or workplace factors unique to NH non-work factors or workplace factors unique to NH not measured in the current phase of the studynot measured in the current phase of the study
Glioblastoma excesses in NH will be further evaluated Glioblastoma excesses in NH will be further evaluated in Phase 3 of the studyin Phase 3 of the study
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Center Department of Biostatistics Center for Occupational Biostatistics & Epidemiologyfor Occupational Biostatistics & Epidemiology PW_Phase 1 - PW_Phase 1 - 2828
P&W Epidemiology StudyP&W Epidemiology Study
Upcoming WorkUpcoming Work
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 2929
What Comes Next ?What Comes Next ?Phase 3Phase 3
Completion of exposure assessment (Dr. Esmen Completion of exposure assessment (Dr. Esmen to discuss)to discuss)
Re-evaluate total and cause-specific Re-evaluate total and cause-specific mortalitymortality in in relation to detailed work history and workplace relation to detailed work history and workplace exposure informationexposure information
Re-evaluate Re-evaluate incidenceincidence of malignant CNS of malignant CNS neoplasms in relation to detailed work history and neoplasms in relation to detailed work history and workplace exposure informationworkplace exposure information
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 3030
Estimated Timeline for Estimated Timeline for Phase 3Phase 3
20102010 20112011Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4
Data AnalysisData Analysis
Article PublishedArticle Published
Public Public PresentationsPresentations
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 3131
AcknowledgmentsAcknowledgmentsWe gratefully acknowledge the support, We gratefully acknowledge the support, cooperation and assistance of the following cooperation and assistance of the following groups without whose help this study would not groups without whose help this study would not be possible: be possible: – The CT Dept. of Public HealthThe CT Dept. of Public Health– The Scientific Advisory CouncilThe Scientific Advisory Council– P&W HR and EHS personnelP&W HR and EHS personnel– The International Association of Machinists and The International Association of Machinists and
Aerospace Workers (IAMAW)Aerospace Workers (IAMAW)– The Communications Facilitation Workgroup The Communications Facilitation Workgroup
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 3232
Questions?Questions?
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology PW_Phase 1 - PW_Phase 1 - 3333
Part 2Part 2
Exposure AssessmentExposure Assessment
Graduate School of Public Health Graduate School of Public Health Department of Biostatistics Department of Biostatistics Center for Occupational Biostatistics & EpidemiologyCenter for Occupational Biostatistics & Epidemiology
PW_Phase 2 - PW_Phase 2 - 3434
END