Navy Asbestos Medical Surveillance Program : Demographic Features and Trends in Abnormal Radiographic Findings

Transcription

1 MILITARY MEDICINE, 171, 8:717, 2006 Nvy Asbestos Medicl Surveillnce Progrm : Demogrphic Fetures nd Trends in Abnorml Rdiogrphic Findings Gurntor: Dnielle M. Dell, MPH Contributors: Dnielle M. Dell, MPH; CAPT Bruce K. Bohnker, MC USN(FS) (Ret.); John G. Muller, MD MPH; CDR Aln F. Philippi, MC USNR; LCDR Frncesc K. Litow, MC USNR; CAPT W. Grry Rudolph, MC USN; Jose E. Hernndez, CIH; CAPT Dvid A. Hilnd, MC USN A 10-yer cross-sectionl nlysis ws conducted for 233,353 rdiogrphic exmintions performed s prt of the Nvy Asbestos Medicl Surveillnce Progrm. Demogrphic nd temporl trends in bnorml rdiogrphs were ssessed during this nlysis. Abnorml rdiogrph prevlence incresed significntly with ge, nd bnorml rdiogrphs were nerly 30 times more likely to occur mong prticipnts 60 to 69 yers of ge, compred with prticipnts 20 yers of ge (odds rtio, 27.57; 95% confidence intervl, ). Men were 5 times more likely thn women to hve n bnorml rdiogrph (odds rtio, 5.84; 95% confidence intervl, ); fter controlling for differences in ge, this gender ssocition remined significnt only for prticipnts 30 yers of ge. The proportion of bnorml rdiogrphs decresed significntly over the study period [ 2 (df 1) test for trend, , p ], lthough the cohort men ge incresed. Despite ging of the Asbestos Medicl Surveillnce Progrm popultion, the overll prevlence of rdiogrphic bnormlities is declining; future studies should exmine the resons for this observtion. Introduction sbestos hs been widely used in ships nd shipyrds A throughout the United Sttes. Growing concerns in the 1970s bout the helth effects of sbestos led to the development of Occuptionl Sfety nd Helth Administrtion (OSHA) stndrds tht regulte workplce exposure, provide guidelines for protective mesures, nd outline medicl surveillnce procedures for exposed workers. 1 3 In 1979, the U.S. Nvy implemented these OSHA stndrds, including medicl surveillnce of exposed workers. The U.S. Nvy Asbestos Medicl Surveillnce Progrm (AMSP) includes both civilin nd ctive duty militry personnel who hve been occuptionlly exposed to sbestos for 30 dys per yer, t or bove the permissible exposure limit of 0.1 fibers per cm 3 of ir over n 8-hour workdy. 4 In ddition, employees engged in clss I, II, or III work re enrolled in the AMSP. 4 The prescribed OSHA procedures for medicl surveillnce re documented in greter detil elsewhere. 1 3 Briefly, medicl nd work histories re obtined nd physicl exmintion tht includes chest rdiogrph nd pulmonry function tests (forced expirtory volume in 1 second nd forced vitl cpcity) Nvy Environmentl Helth Center, Portsmouth, VA The views expressed re the privte ones of the uthors nd should not be considered pproved by or representtive of the Bureu of Medicine nd Surgery, the Deprtment of the Nvy, or the Deprtment of Defense. This mnuscript ws received for review in June 2004 nd ws ccepted for publiction in August is performed. The chest rdiogrph is coded for chnges ccording to the uniform stndrds developed nd mintined by the Interntionl Lbor Office. The Nvy Environmentl Helth Center (NEHC) in Portsmouth, Virgini, hs mintined n electronic dtbse of the AMSP exmintions since the inception of the AMSP. Severl peer-reviewed journl rticles hve been published on the entire AMSP cohort, 5 7 s well s geogrphic subsets of tht popultion. 8,9 Recent rticles exmined demogrphic fetures nd smoking for 1995 to 1999 nd chnges in pulmonry functions from 1991 to 1999 nd from 1984 to These nlyses demonstrted tht history of sbestos exposure hd dverse effects on forced expirtory volume in 1 second nd forced vitl cpcity from 1984 to 1990; however, no such ssocition ws observed from 1991 to These results suggest tht exposure-btement progrms might hve resulted in decrese in sbestos exposure nd subsequent decrese in dverse spirometry findings in the AMSP cohort. Asbestos exposure is ssocited with chnges in lung function, s well s rdiologicl chnges in the lung The purposes of this rticle re to provide n initil description of the trends in rdiogrphic findings ccording to demogrphic fetures, to present temporl trends in the prevlence of rdiogrphic bnormlities for the 10-yer period from 1990 to 1999, nd to ssist in the development of priorities for future nlyses with the AMSP dtbses. This rticle ws written s prt of the ongoing efforts of NEHC to nlyze nd to ssess the effectiveness of the AMSP. Methods The AMSP dtbse (Ashton-Tte Corportion, Torrnce, Cliforni) ws mintined in dbse III formt until 1999, when it ws converted into Microsoft Access 2000 (Microsoft, Redmond, Wshington). The dtbse includes severl different individul files, with one file contining records for 1979 to 1989 nd nother file contining records for 1990 to This ws becuse of formt chnges in 1989, which mde the two dtsets generlly comprble but not completely identicl. To dte, no dt nlysis hs been performed on ny of the rdiogrphic dt. Therefore, n initil, popultion-bsed, cross-sectionl nlysis ws conducted for the most recent computerized AMSP rdiogrph file ( ), to ssess overll demogrphic fetures nd temporl trends in rdiogrphic findings. Rdiogrphs were coded nd scored by B-reders, who re trined nd certified through the Ntionl Institute for Occuptionl Sfety nd Helth. 18 The B-reder findings re recorded on the 717

2 718 Nvy AMSP Trends NAVMED 6260/7 form, which is equivlent to the CDC/NIOSH (M) 2.8 REV. 4/80 form. The following informtion is recorded on the NAVMED 6260/7 form: evidence of pneumonoconiosis; presence of prenchyml bnormlities, s well s shpe, zones, nd profusion of the bnormlities; nd presence of pleurl thickening, s well s loclity, width, extent, nd clcifiction of the thickening. In ddition to the B-reder findings, the AMSP rdiogrph dtbse includes demogrphic informtion, such s dte of birth, gender, nd rce, nd informtion regrding ctive duty sttus nd the purpose of the exmintion (i.e., initil, periodic, or termintion). Informtion regrding sbestos exposure is not mintined in the AMSP rdiogrph dtbse. The rdiogrphic dt re mintined in dtbse seprte from the clinicl exmintion dt; the current nlysis used only the AMSP rdiogrphic dt. The rdiogrphic dt file includes personl identifiers (Socil Security numbers), nd privcy ws mintined by using pssword-protected computers nd dtbses; becuse NEHC nlysis of the dt is mndted element of the AMSP, no informed consent ws obtined. Descriptive demogrphic findings were generted for the entire cohort, including ge, gender, nd rce/ethnicity. For the demogrphic vribles, odds rtios (ORs) nd 95% confidence intervls (CIs) were clculted. In ddition, nnul trends in the presence of ny bnormlities consistent with pneumoconiosis, s well s prenchyml nd pleurl bnormlities, were ssessed by using the 2 test for trend. Dt nlysis ws conducted with EpiInfo version 6.0 softwre (Centers for Disese Control nd Prevention, Atlnt, Georgi) nd SPSS version 10.0 softwre (SPSS, Chicgo, Illinois). Dt were clened, nd obviously incorrect dt vlues (e.g., gender coded s U or ge of 0 yers) were censored from nlysis. Tests for sttisticl significnce were conducted t the 0.05 level. Results A totl of 233,353 records were included in the AMSP rdiogrph dtbse ( ). Annul rdiogrphic submissions generlly exceeded the nnul physicl exmintion submissions reported previously. 11 The reson for this disprity is not known. Initil nlysis found tht the number of records for 1999 ws reltively smll, compred with erlier yers. Dt entry for the 1999 records ws hlted becuse of Y2K concerns, which likely explins the pucity of records. For the study period, 86% of the rdiogrphs were tken s prt of periodic exmintions (Tble I). As shown in Tble I, the mjority of records were for mle prticipnts (97.3%), which is consistent with previous reports. 10,11 Cucsin subjects (73.3%) represented the lrgest rcil/ethnic group in the dtbse. The following rcil/ethnic groups were lso represented: Africn Americn (11.5%), Asin (7.6%), Hispnic (2.5%), nd other (4.9%). These results re lso consistent with previous nlysis. 11 Tble I illustrtes the men ges of prticipnts ccording to gender nd rce. The overll men ge t the time of the rdiogrph ws 46.2 yers. Mle subjects were 4 yers older thn femle subjects (46.3 yers vs yers); this difference ws sttisticlly significnt (t 32.4, p ). It is lso importnt to note tht the men ge of prticipnts t the time of the rdiogrph incresed significntly over time (one-wy nlysis TABLE I DEMOGRAPHIC CHARACTERISTICS OF THE AMSP X-RAY DATABASE (N 233,353) Mle Femle Totl Age 20 yers 648 (0.3) 56 (0.9) 704 (0.3) yers 11,746 (5.2) 784 (12.6) 12,530 (5.4) yers 37,742 (16.9) 1,649 (26.6) 39,391 (17.1) yers 95,265 (42.5) 2,321 (37.4) 97,586 (42.4) yers 66,256 (29.6) 1,190 (19.2) 67,446 (29.3) yers 12,270 (5.5) 208 (3.4) 12,478 (5.4) Totl 223,927 (100.0) 6,208 (100.0) 230,135 (100.0) Men SD Rce/ethnicity Cucsin 166,258 (73.4) 4,413 (66.1) 170,401 (73.2) Africn Americn 25,193 (11.1) 1,470 (23.5) 26,663 (11.5) Asin 17,474 (7.7) 269 (4.3) 17,743 (7.6) Hispnic 5,774 (2.6) 134 (2.1) 5,908 (2.5) Indin 616 (0.3) 25 (0.3) 641 (0.3) Other rce 11,081 (4.9) 223 (3.6) 11,304 (4.9) Totl b 226,396 (100.0) 6,264 (100.0) 232,660 (100.0) Visit type Initil 18,488 (8.2) 1,093 (17.4) 19,581 (8.4) Periodic 195,317 (86.3) 4,711 (75.2) 200,028 (86.0) Termintion 12,496 (5.5) 463 (7.4) 12,959 (5.6) Totl c 226,301 (100.0) 6,267 (100.0) 232,568 (100.0) Dt re missing for 3,218 (1.4%) records. b Dt re missing for 693 (0.3%) records. c Dt re missing for 785 (0.3%) records.

3 Nvy AMSP Trends of vrince, F , p ), from 45.2 yers during the 1990 exmintions to 48.3 yers for the exmintions conducted in 1999 (dt not shown). Tble II displys the proportion of rdiogrphs coded for the presence of ny bnorml findings consistent with pneumoconiosis, ccording to gender nd rce. Rdiogrphs conducted mong mle subjects were 5 times more likely to demonstrte n bnormlity, compred with rdiogrphs performed for femle subjects (OR, 5.84; 95% CI, ). Age ws lso significnt risk fctor for hving n bnormlity pper on rdiogrph (Tble II). Compred with prticipnts 20 yers of ge, the risk of hving n bnorml rdiogrph ws nerly 30-fold greter mong prticipnts 60 to 69 yers of ge (OR, 27.57; 95% CI, ). Rdiogrphs were 3 times more likely to demonstrte n bnormlity if they were tken during periodic visit (OR, 2.95; 95% CI, ) or termintion visit (OR, 2.89; 95% CI, ). Strtifiction ccording to ge group controls for potentil confounding tht ge might confer on the ssocition between gender nd bnorml rdiogrphs. Age-strtified reltive risks demonstrted tht the significnt ssocition between gender nd bnorml rdiogrphs ws restricted to prticipnts who were 30 yers of ge t the time of exmintion (Tble III). Tble IV lists the proportions of rdiogrphs coded for the presence of bnorml findings consistent with pneumoconiosis, ccording to yer of exmintion. For the entire study period, % of the rdiogrphs were coded s positive for pneumoconiosis. The proportion of rdiogrphs coded s positive for pneumoconiosis decresed significntly over time ( 2 [df 1] test for trend, , p ). Among the 1990 rdiogrphs, 15.5% were coded s positive for pneumoconiosis, compred with 9.7% of the rdiogrphs tken in When the dt were strtified ccording to gender, significnt declines in bnorml rdiogrphs were observed for both mle subjects ( 2 [df 1] test for trend, , p ) nd femle subjects ( 2 [df 1] test for trend, 2 6.0, p 0.014) (dt not shown). Abnormlities were further ctegorized s prenchyml or pleurl. Tble V presents the proportions of rdiogrphs coded s showing prenchyml bnormlities, ccording to yer of exmintion. Although the overll prevlence of prenchyml bnormlities ws low (3.6%), there ws significnt trend of decresing prevlence over time ( 2 [df 1] test for trend, , p 0.001). Approximtely 5% of the rdiogrphs were coded s positive for prenchyml bnormlities, compred with 2.3% of the rdiogrphs in Similr results were observed for pleurl bnormlities (Tble VI). The proportion of rdiogrphs coded for pleurl bnormlities decresed from 2.4% in 1990 to 1.4% in 1999 ( 2 [df 1] test for trend, , p ). Interntionl Lbor Office profusion codes were ggregted ccording to the degree of bnormlity (Tble VII). The proportion of rdiogrphs coded s 1/0 on the NAVMED 6260/7 form TABLE II PROPORTION OF X-RAYS POSITIVE FOR PNEUMOCONIOSIS, ACCORDING TO GENDER, AGE, AND RACE, 1990 TO 1999 (N 233,353) X-ry Positive X-ry Negtive Totl OR (95% CI) Gender Mle 32,071 (14.2) 193,373 (85.8) 225,444 (100.0) 5.84 ( ) Femle 172 (2.8) 6,069 (97.2) 6,241 (100.0) Totl 32,243 (13.9) 199,442 (86.1) 231,685 (100.0) Age 20 yers 10 (1.4) 689 (98.6) 699 (100.0) yers 267 (2.1) 12,186 (97.9) 12,453 (100.0) 1.51 ( ) yers 1,995 (5.1) 37,197 (94.9) 39,192 (100.0) 3.70 ( ) yers 11,503 (11.9) 85,534 (88.1) 97,037 (100.0) 9.27 ( ) yers 14,344 (21.4) 52,667 (78.6) 67,011 (100.0) ( ) yers 3,532 (28.6) 8,827 (71.4) 12,359 (100.0) ( ) Totl b 31,651 (13.9) 197,100 (86.1) 228,751 (100.0) Rce/ethnicity Cucsin 24,425 (14.4) 144,939 (85.6) 169,364 (100.0) Africn Americn 3,214 (12.1) 23,265 (87.9) 26,479 (100.0) 0.82 ( ) Asin 2,157 (12.2) 15,522 (87.8) 17,679 (100.0) 0.83 ( ) Hispnic 741 (12.6) 5,138 (87.4) 5,879 (100.0) 0.86 ( ) Indin 102 (15.9) 538 (84.2) 640 (100.0) 1.13 ( ) Other 1,565 (14.0) 9,648 (86.0) 11,213 (100.0) 0.96 ( ) Totl c 32,204 (13.9) 199,050 (86.1) 231,254 (100.0) Visit type Initil 1,074 (5.5) 18,382 (94.5) 19,456 (100.0) Periodic 29,239 (14.7) 169,613 (85.3) 198,852 (100.0) 2.95 ( ) Termintion 1,860 (14.5) 11,000 (85.5) 12,860 (100.0) 2.89 ( ) Totl d 32,173 (13.9) 198,995 (86.1) 231,168 (100.0) Dt re missing for 1,668 (0.7%) records. b Dt re missing for 4,602 (2.0%) records. c Dt re missing for 2,099 (0.9%) records. d Dt re missing for 2,185 (0.9%) records.

4 720 Nvy AMSP Trends TABLE III AGE-STRATIFIED GENDER-SPECIFIC, RELATIVE RISK FOR X-RAYS POSITIVE FOR PNEUMOCONIOSIS (N 233,353) Adjusted OR Age X-ry Positive X-ry Negtive Totl (95% CI) 20 yers Mle 9 (1.4) 635 (98.6) 644 (100.0) 0.75 ( ) Femle 1 (1.9) 53 (98.1) 54 (100.0) Totl 10 (1.4) 688 (98.6) 698 (100.0) yers Mle 254 (2.2) 11,409 (97.8) 11,663 (100.0) 1.31 ( ) Femle 13 (1.7) 766 (98.3) 779 (100.0) Totl 267 (2.1) 12,175 (97.9) 12,442 (100.0) yers Mle 1,974 (5.3) 35,557 (94.7) 37,531 (100.0) 4.73 ( ) Femle 19 (1.2) 1,620 (98.8) 1,639 (100.0) Totl 1,993 (5.1) 37,177 (94.9) 39,170 (100.0) yers Mle 11,441 (12.1) 83,257 (87.9) 94,698 (100.0) 5.15 ( ) Femle 60 (2.6) 2,250 (97.4) 2,310 (100.0) Totl 11,501 (11.9) 85,507 (88.1) 97,008 (100.0) yers Mle 14,271 (21.7) 51,508 (78.3) 65,779 (100.0) 4.84 ( ) Femle 64 (5.4) 1,117 (94.6) 1,181 (100.0) Totl 14,335 (21.4) 52,625 (78.6) 66,960 (100.0) yers Mle 3,515 (28.9) 8,632 (71.1) 12,147 (100.0) 6.01 ( ) Femle 13 (6.3) 192 (93.7) 205 (100.0) Totl 3,528 (28.6) 8,824 (71.4) 12,352 (100.0) TABLE IV PROPORTION OF X-RAYS POSITIVE FOR PNEUMOCONIOSIS, ACCORDING TO YEAR OF EXAMINATION Yer X-ry Positive for Pneumoconiosis Dt re missing for 515 (0.2%) records. The 2 test for trend: 2 (df 1) (p ). incresed over the study period, from 64.6% in 1990 to 79.4% in (The numbers for 1999 re smll nd therefore should be interpreted with cution.) Conversely, the proportion of rdiogrphs coded s 1/1 or 1/2 decresed by 13.8% from 1990 to A similr declining trend ws observed for the progressively bnorml profusions, lthough ctul rtes of bnormlities were very low. Discussion X-ry Negtive for Pneumoconiosis Totl ,687 (15.5) 14,668 (84.5) 17, ,714 (15.1) 26,593 (84.9) 31, ,666 (16.6) 28,527 (83.4) 34, ,387 (13.4) 28,288 (86.6) 32, ,649 (12.4) 25,736 (87.6) 29, ,413 (12.7) 23,500 (87.3) 26, ,495 (11.7) 18,813 (88.3) 21, ,659 (13.4) 17,180 (86.6) 19, ,315 (14.5) 13,668 (85.5) 15, (9.7) 2,580 (90.3) 2,857 Totl 32,262 (13.9) 200,389 (86.1) 232,838 Our nlysis of 233,000 rdiogrphic records from the Nvy AMSP found sttisticlly significnt decreses in the rtes of TABLE V PROPORTION OF X-RAYS POSITIVE FOR PARENCHYMAL ABNORMALITIES, ACCORDING TO YEAR OF EXAMINATION Yer X-ry Positive for Prenchyml Abnormlities X-ry Negtive for Prenchyml Abnormlities Totl (4.7) 16,540 (95.3) 17,354 (100.0) ,245 (4.0) 30,054 (96.0) 31,299 (100.0) ,719 (5.0) 32,461 (95.0) 34,180 (100.0) ,129 (3.5) 31,541 (96.5) 32,670 (100.0) (2.9) 28,511 (97.1) 29,370 (100.0) (3.4) 25,972 (96.6) 26,894 (100.0) (2.9) 20,671 (97.1) 21,294 (100.0) (2.8) 19,280 (97.2) 19,834 (100.0) (2.5) 15,582 (97.5) 15,981 (100.0) (2.3) 2,792 (97.7) 2,857 (100.0) Totl 8,329 (3.6) 223,404 (96.4) 231,733 (100.0) Dt re missing for 1,620 (0.7%) records. The 2 test for trend: 2 (df 1) (p ). bnorml findings over 10-yer study period ( ). This decline ws pprent despite n increse in the men ge of the popultion over the study period. The overll prevlence of bnorml rdiogrphic findings cross the entire study period ws 13.9%, which is comprble to surveillnce reports from other sbestos-exposed cohorts, such s the Long Bech shipyrd workers. 17 Temporl declines in the prevlence of bnorml rdiogrphs were observed for mle nd femle subjects, lthough the re-

5 Nvy AMSP Trends TABLE VI PROPORTION OF X-RAYS POSITIVE FOR PLEURAL ABNORMALITIES, ACCORDING TO YEAR OF EXAMINATION Yer X-ry Positive for Pleurl Abnormlities X-ry Negtive for Pleurl Abnormlities Totl (2.4) 16,938 (97.6) 17,353 (100.0) (1.9) 30,688 (98.1) 31,275 (100.0) (2.7) 33,244 (97.3) 34,175 (100.0) (2.1) 31,982 (97.9) 32,671 (100.0) (1.7) 28,875 (98.3) 29,377 (100.0) (2.2) 26,293 (97.8) 26,898 (100.0) (1.8) 20,908 (98.2) 21,298 (100.0) (1.5) 19,546 (98.5) 19,836 (100.0) (1.0) 15,820 (99.0) 15,980 (100.0) (1.4) 2,812 (98.6) 2,853 (100.0) Totl 4,610 (2.0) 227,106 (98.0) 231,716 (100.0) Dt re missing for 1,637 (0.7%) records. The 2 test for trend: 2 (df 1) (p ). sons for these declines cnnot be determined from the present nlysis. Age ws identified s strong risk fctor for hving n bnorml rdiogrph; future studies of other risk fctors, including sbestos exposure, should ccount for potentil ge effects on rdiogrphic outcomes. In ddition to ll rdiogrphic bnormlities, proportions of pleurl nd prenchyml bnormlities demonstrted temporl declines. The overll proportion of prenchyml bnormlities coded s 1/0 nd bove in this study ws greter thn vlues reported from previous study of the first 45,647 records in the AMSP. 5 The resons for this difference re not known but could be ttributed to chnges in cohort composition over time, differences in B-reder interprettion over time, chnges in AMSP forms, or chnges in risk fctors. Although this rticle provides n initil descriptive look t the trends in AMSP rdiogrphic results, the nlysis does hve limittions. Becuse of the cross-sectionl nture of this nlysis, it is not possible to determine whether the decrese over time is ttributble to rdiogrphic chnges for individuls with bnorml findings or cohort turnover. It is importnt to note tht 85% of ll records were periodic rther thn initil or 721 termintion; therefore, the decline in rdiogrphic bnormlities cnnot be ttributed solely to chnges in cohort composition. Moreover, the proportion of rdiogrph visits coded s initil declined stedily from 12.9% in 1990 to 3.3% in 1999; therefore, proportionlly fewer new cohort members re entering the AMSP. The AMSP rdiogrph dtbse contins personl identifiers, including Socil Security numbers, nd future reserch could include n ttempt to link follow-up visits for individuls, to determine whether there re temporl chnges in rdiogrphic results ccording to prticipnt. Chnges in rdiogrphic findings over time my lso be ttributed to differences in B-reders; study conducted with the AMSP dt reveled significnt differences in the identifiction of rdiogrphic bnormlities depending on the B-reder. 4 Within the context of this cross-sectionl nlysis, it ws not possible to ssess individul risk fctors or vritions in B- reder interprettion. It is importnt to note, however, tht films re rndomly ssigned to B-reders; consequently, this bis should be minimized. Temporl differences in risk fctors, such s cigrette smoking nd sbestos exposure, my lso contribute to the observed chnges in rdiogrphic findings. These risk fctors were not exmined in this cross-sectionl nlysis. Self-reported sbestos exposure informtion nd cigrette smoking history re obtined during the clinicl exmintion; these dt could be linked to the rdiogrph dtbse to llow future nlysis of rdiogrphic findings ccording to sbestos exposure nd/or cigrette smoking. Despite these limittions, this rticle presents the first descriptive epidemiologicl nlysis of the AMSP rdiogrphic dt nd presents number of options for future reserch. The size of the dtbse llows for multiple studies, lthough the first logicl study would exmine the dtbse for records for 1980 to Future nlyses could lso include n nlysis of sequentil rdiogrphs for consistency nd progression of disese, which would be informtive, given the AMSP smple size nd durtion of film collection. It would lso be useful to integrte smoking nd sbestos exposure from the medicl history/ physicl exmintion dtbse into the rdiogrph dtbse, to determine wht effect these exposures hve on lung bnormlities. Differences in the proportions of bnorml rdiogrphs c- TABLE VII INTERNATIONAL LABOR OFFICE PROFUSION CODES ACCORDING TO YEAR OF EXAMINATION, Yer 1/0 1/1 1/2 2/1 2/3 Totl (64.6) 264 (32.6) 23 (2.8) 811 (100.0) (71.3) 323 (26.0) 33 (2.7) 1,241 (100.0) ,206 (70.3) 468 (27.3) 41 (2.4) 1,715 (100.0) (72.4) 275 (24.4) 36 (3.2) 1,125 (100.0) (70.5) 237 (27.7) 16 (1.9) 857 (100.0) (71.1) 239 (26.0) 26 (2.8) 918 (100.0) (68.1) 190 (30.0) 12 (1.9) 633 (100.0) (77.1) 117 (21.2) 9 (1.6) 551 (100.0) (79.4) 75 (18.8) 7 (1.8) 398 (100.0) (66.2) 19 (29.2) 3 (4.6) 65 (100.0) Totl 5,901 (71.0) 2,207 (26.5) 206 (2.5) 8,314 (100.0)

6 722 Nvy AMSP Trends cording to ge, gender, nd rce were observed; whether these differences re ttributble to differences in sbestos exposure, cigrette exposure, or some other unmesured risk fctor is not known. The proportion of bnorml rdiogrphs decresed significntly over time; similr trends were noted specificlly for prenchyml nd pleurl bnormlities. Within the context of this cross-sectionl nlysis, it is not possible to determine whether this decline is ttributble to decreses in occuptionl sbestos exposure, chnges in cigrette smoking, or differences in B-reders. Future reserch should be conducted to explore potentil resons for the observed differences in bnorml rdiologicl findings cross demogrphic groups nd the observed temporl decline in bnorml rdiologicl findings. Given the low prevlence of rdiogrphic bnormlities nd the demonstrted temporl decline in bnormlities, it my be worthwhile to trget future surveillnce efforts towrd workers most hevily exposed to sbestos. Conclusions This initil nlysis of 233,000 rdiogrphic records from the Nvy AMSP from 1990 to 1999 found tht the nnul prevlence of bnorml redings decresed significntly over the study period, which suggests effectiveness of sbestos-btement efforts, lthough other explntions cnnot be ruled out. This temporl decrese ws significnt for men, women, nd Africn Americn nd Asin subgroups. The men ge for the studied popultion incresed over the study period, nd ge ws strong risk fctor for bnorml rdiogrphic findings. The study did not include sbestos exposure levels or smoking history. Demogrphic fetures within the group were generlly similr to previous findings, lthough more rdiogrphic records thn physicl exmintion records were vilble for the period studied. This initil cross-sectionl study lso identified priorities for ongoing nlysis of the Nvy AMSP dtbse. References 1. Title 29, Code of Federl Regultions Section , OSHA Asbestos Stndrd, ltest revision, December 1, Title 29, Code of Federl Regultions Section , OSHA Asbestos Construction Stndrd, ltest revision, December 1, Title 29, Code of Federl Regultions Section , OSHA Asbestos Exposure in All Shipyrd Work, ltest revision, December 1, Chief of Nvl Opertions: OPNAVINST F. Wshington, DC, Government Printing Office, Avilble t _23G.pdf; ccessed December 1, Ductmn AM, Withers BF, Yng WN: Smoking nd roentgenogrphic opcities in U.S. Nvy sbestos workers. Chest 1990; 97: Withers BF, Ductmn AM, Yng WN: Roentgenogrphic evidence for predominnt left-sided loction of unilterl pleurl plques. Chest 1989; 95: Ductmn AM, Yng WN, Formn SA: B-reders nd sbestos medicl surveillnce. J Occup Med 1988; 30: Li VC, Young JK, Terry PB, et l: Behviorl, ttitudinl nd physiologicl chrcteristics of smoking nd nonsmoking sbestos-exposed shipyrd workers. J Occup Med 1983; 25: Kolonel LN, Yoshizw CN, Hiroht T: Cncer occurrence in shipyrd workers exposed to sbestos in Hwii. Cncer Res 1985; 45: Bohnker BK, Betts LS, Sck DM, Crft N: Nvy Asbestos Medicl Surveillnce Progrm, : demogrphic chrcteristics nd smoking sttus. Milit Med 2001; 166: Bohnker BK, Betts LS, Sck DM, Crft N: Nvy Asbestos Medicl Surveillnce Progrm ( ): liner regression nlysis for the effect of sbestos exposure on pulmonry functions. Milit Med 2004; 169: Bohnker BK, Betts LS, Sck DM, Crft N: Nvy Asbestos Medicl Surveillnce Progrm ( ): liner regression nlysis for the effect of sbestos exposure on pulmonry functions. Milit Med 2004; 169: Muller JG, Bohnker BK, Philippi AF, Litow FK, Rudolph G, Hernndez JE: Trends in pleurl rdiogrphic findings in the Nvy Asbestos Medicl Surveillnce Progrm ( ). Milit Med 2005; 170: Rosenstock L, Hudson LD: The pleurl mnifesttions of sbestos exposure. Occup Med 1987; 2: Zitting AJ, Krjlinen A, Impivr O, et l: Rdiogrphic smll lung opcities nd pleurl bnormlities s consequence of sbestos exposure in n dult popultion. Scnd J Work Environ Helth 1995; 21: Kilburn KH, Lilis R, Anderson HA, Miller A, Wrshw RH: Interction of sbestos, ge nd cigrette smoking in producing evidence of diffuse pulmonry fibrosis. Am J Med 1986; 80: Felton JS: Rdiogrphic serch for sbestos-relted disese in nvl shipyrd. Ann NY Acd Sci 1979; 330: Morgn RH: Proficiency exmintion of physicins for clssifying pneumoconiosis chest films. AJR Am J Roentgenol 1979; 132: