Document 85B9b3z8r9pMyXbvO2Mndxkje

ISTMUSMCO lt02 E, I. d u Po n t d eINCNMKeMmAToIOu r s & Co mp a n y Wil min g t o n , De l a w a r e i9S98 e n g in e e r in g d e p a r t me n t LOUVIERS BUILDING October 10, 1977 *0, Dr. Sergio Piomelli Director, Pediatric Hematology New York University Medical Center 550 First Avenue New York, NY 10016 Dear Dr. Piomel1i: Dr. Jacobs sent me copies of your charts which summarize analyses that you have made of the Azar data. He indicated that you Wished for me to review these charts and comment on the results. ? As you well appreciate, this is difficult to do since you did not provide any written discussion regarding the objectives of youiPinalyses or the assumptions of your model. With these reservation$x;l will attempt ttr-reviennyour findings.- You -point out that the B coefficients in my model show-a-correlation with air lead and derive the following model. Blood7 Lead 12.1 (Air Lead + .62 + ,98 Air Lead}$.2669 which can be written as Blood Lead * 14.5 (A1 r Lead + ,32)* 2669 , \TT In your model you have assigned al 1 the variation in blood'lead to air lead and have ignored the fact that the five groups ofVsubjects had different amount's of lead exposure from other non-air -sources. In the two analyses which I reported (1972, 1977), significant (p<0.01) group-to-group differences were found. I believe that any model which does not take this fact into account is not an appropri ate model for the data. In order to draw valid conclusions* the "model must be descriptive of the physical situation, "The five groups of subjects In the Azar study differed In many ways -- (e.g. occupation, diet, socioeconomic, ethnic) besides air lead exposure 1evel. A review of our record shows that the race distri* bution of the 30 Philadelphia cab drivers was 16 black and 14 white. Some .of the Los Angeles cab drivers were Mexican-Americans. As you know, recent studies have shown socioeconomic, environment, diet, occupation, and ethnic varlables to have significant effects on TEH 0470655 Dr, Sergio Plomelli October 10, 1977 blood lead levels. One has to conclude that It is not reasonable to attribute all of the observed blood lead variation to air lead differences,- Any attempt to do so is an oversimplification Of the true situation. Additional details and comments are attached. I appreciate;the opportunity to comment .on your analysis. Please contact me If you feel that further discussion would be useful. Very truly yours, ENGINEERING SERVICE DIVISION R. D. Snee, Consultant Supervisor Applied Statistics 1chni" .-IS- . Dr. V. Hassel bl ad TEH 0470656 DUP050083473 4 Dr. Piomelli's Analysis Dr. Plomelli observed that the B coefficients in Equation (3) showed a positive correlation with air lead level. He described this correlation with the linear equation B - 0.6249 + 0.9828 Air Pb (5) and rewrote Equation (4) as Blood Pb = 12.1 (Air Pb+0.6249+0.9828 Air Pb)'* 2669 - 14.5(Air Pb+0.32)* 2669 (6) Or. Plomel1i's Equation 6 is similar to Equation 3; however, it assigns all the variation in blood lead to air lead and ignores the fact that the different groups had significantly (p<*01) different amounts of lead exposure from other sources. The result of Or. Piomelli's assumption is shown in Figure 1 which is a plot of Equations 3,4, and 6. The analyses associated with both Equations 1 and 3 indicated that there were significant (pc.01) group differences after the effect of air lead was taken into account. It seems reason able to conclude that any model which does not take this fact into account is not an appropriate model for the data, It is unlikely that valid conclusions can be drawn from a model which isn't descriptive of the physical situation. * Tti 0470657 DUP050083474 N42488.01 REFERENCES 1. Azar, A., R. D, Snee, and K. Hablbl, "Relationship of Community Levels of Air Lead and Indices of Lead Absorption", Proceedings of the international Symposium Environmental Health Aspects of Lead, Amsterdam, 581-594 (1972), 2. Azar, A., R. D. Snee, and K, Habibi, "An Epidemiological Approach to Community Air Lead Exposure Using Personal Air Samples", Environmental Quality and Safety, Supplement Vol II. Lead, 152-196 (1975), 3. McCaughran, P, A., "Air Lead^Blood Lead Models", Presented at the International Conference of Heavy Metals in the Environment, Toronto, Ontario, Canada (1975). 4. Snee, R. D., "Development of An Air Quality Value for Lead from Community Studies", Report No. PLMR-3-77, Petroleum Laboratory, E. I. du Pont de Nemours & Co, Wilmington, Delaware (1/20/77), 5. Snee, R. D., "Evaluation of Studies of the Relationship between Blood Lead and Air Lead, Rep*ort No. PLMR-8-77, Petroleum Laboratory, E. I. du Pont de Nemours & Co, Wilmington, Delaware (4/7/77). '% TEH 0470659 DUP050083475 APPENDIX TABLES AND GRAPHS SUMMARIZING DR. PIOMELLI'S ANALYSIS OF BLOOD LEAD AND AIR LEAD DATA REPORTED BY AZAR ET AL. TEH 0470659 DUP050083476 BLOOD LEAD 3B.00r (MCG/DL) FUR LEAD <MCE/CUB(C METER) iO*3Jtr FHF<X>*lfl*U 2557+0.153*L6T<I>> 20 {Ok i-O.OOOOOuyl TO 10 STEP 0.2 30 36*B=FHFU> 1 37 f=1-1 50 OB-fl 55 FIXED 1 68 PRINT Ijfij Cj T0B35j C 70 NEXT I SO EEtt4jlli! - hfM RUN O. 0 (V.OTiOoflsn 0.2 O, 4 y, 6 e. s 1.0 i.2 1.4 1.0 1.8 2.0 ...... 4o- b>. 2.4 i.i 14. 1 15.7 16.7 17.4 1S.0 18.5 19.8 19.4 19.7 28.0 20.3 20.6 2. 6 2.8 2.0 3. 2 -*> 4 o. 6 3/8 4. O 4.2 4.4 4.6 4.8 5.8 5. 2 5.4 5.6 28.9 21, 1 21.3 21,5 21.7 21.9 22.1 22.3 22.4 22.6 22.8 22.9 28.0 23. 2 23,3 23.5 5.8 23, 6 , 8 23.7 . 2 23.8 6.4 23.9 6.6 w, W 24.8 24.2 7.0 24,3 7.2 24.4 7.4 24.5 7.6 24.6 7.8 24,7 8.8 24.8 8.2 24.9 8.4 25, 0 8.6 . Vo* 25.0 25.1 9.8 25.2 9.2 25. 3 9.4 8.6 2wT-V5iS t,4'cJ 9,8 25.5 jf* f <///"" % 16,9 4,4 2. 7 2.3 2.0 1.8 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 1.0 0.9 0,9 0,8 0,3 0.8 0.7 8.7 0,7 8.7 0,7 0.6 0, 6 0,6 0.6 0.6 0.6 0,5 ' 8.5 0,5 0.5 0.5 0.5 0.5 0.5 0.5 0.4 0.4 0.4 . 4 8.4 0,4 0.4 0.4 9.4 Qfi A/u f <-f i/cl tfb * \ \ \ i;* X {i \\\% * t t0 , ij \ \ \ * \l ii ,i i j* . " TEH 0470661 DUP050083478 to tiEF FMFOO-12. 1 *<X+<3.28> >tfi. 2figo 20 FOR 1-0 10 19 STEP 8.2 38 B=FI IF < I > 40 B=FHF-,1 + 1> 50 C-B -0 55 FIXED 1 0 PRINT I ' 0) TFiB35j C 79 NEXT I S0 END RUN 8.0 0.2 0.4 ' 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.8 2.2 2,4 2. 6 2.8 8t.8Oc 8.4 3. 6 3.8 4.8 4.2 4.4 4. 6 4.3 5. 8 5.2 5.4 5cv.*; .. 6oO 6.8 6.2 6.4 6,6 6. y 7.0 7.2 7.4 .7.6 1.0 8. 0 8, 2 8.4 8.6 8.8 9.8 9.2 9.4 9.6 ' bin 16.6 16.9 17.1 17.4 17.6 17.8 18.1 13.3 18.5 18.7 13.9 19,1 19.2 i'9.4 19. 6 19.8 19.9 20. 1 20.2 28.4 20.6 20. 7 20.8 21.0 21.1 21.3 21.4 21.5 21.7 21.8 21.9 22. 1 22.2 22. 3 22. 4 22.5 . .* r 22. 8 - 22.9 23.0 oo i Cocc.Vo<* *1 Otom 23.4 23.5 23.6 23.7 23.8 23.9 l*cn*s*. . ^ 1.2 1.2 1.1 1.1 1.1 1.0 1.0 1.0 6'. 9 0.9 0.9 8. 9 0.9 0. S 8.0 8.8 8.8 8.8 6.7 B.7 0. 7 0.7 0.7 8.7 8.7 " 0.7 8, 6 8. 6 8. 6 * 8, 8 0.6 8.6 86 0.6 8.6 0, 6 8.6 8 6 8.5 . 8.5 8.5 8.5 8.5 8.5 0. 5 0.5 0.5 8.5 R.S $V* M. / V " ?>'* re viz ***i TEH 0470662 DUP050083479 ' LIST 10. llLF FNF t. = 12. ] ?* o+ f 0,6249+ i O, 20 FOR 1-0 TO 10 STEP 0.2 30 H=FUF <I ) 1 40 3FNF<r+l> 50 C=B-fi 55 FINED 1 " 60 PRINT Isfi. TRB35}C ?0 NEXT I 80 END RUN 0,0 8.2 0.4 6,6 0.8 1.0 1.2 i. 4 16 1.8 2.0 2.2 2,4 2.6 *> C.m OC 3. & V* c- 3,4 3.6 3.8 4.0 4.2 4.4 4,6 4,8 5.0 5.2 5.4 5.6 5.8 6,0 6, 2 6.4 6.6 6.8 7,0 7.2 7.4 7. 6 7.8 8o .8o 8.4 8. 6 3. 8 3, O 9.2 9.4 9.6 9.0 10.0 STOP % t/P* I.? 12.2 13,3 14.2 15.0 15. 6 16.2 16.8 17.3 17.7 18.2 18.6 13.0 19.3 19.7 20.0 20.3 20.6 28, 9 21.2 21.5 21.7 22.0 22.2 22.5 22.7 22.9 23.1 23.3 23, 6 23.8 24.0 24,1 24.3 24.5 24.7 24.9 25.1 25.2 25.4 25, 6 25.7 25.9 26,0 26.2 26.4 26.5 26.6' 26.8 26.9 27.1 ')>>T0,265$ f*tt***f o, ( ** tmf /*> ' 5.04.1 3.5 3.1 2.8 5u> i SV 2.4 2.2 2.0 1.9 1,-8 1.7 | 1.7 1.6 1,5 145 1.4 1.4 1.3 1.3 1.2 . 1.2 1.2 1*1 1.1 1.1 1.0 i .0 1.0 1.0 1,0 0.9 * 0.9 9.9 6.9 6.9 0.8 0,8 0,8 6i 8 0.8 0,8 0^8 0.7 8.7 9.7, 0,7' 0. 7 0.7 0.7 6.7 C^tAa **" Svitt TEH 0470663 DUP050083480 I Estimates from Azar, Snee, Habibi Study Original equation (1) Average ,'B'V(2) "B" from regression(3) Air Pb 0.2 1.2 2.2 3.2 4.2 S.2 6.2 7.2 8.2 9.2 Blood Pb 14.1 18,5 20.3 21.5 22.4 23.2 23.8 24.4 24.9 25.3 Increase for Blood Pb lPg/m3 increase 4.4 26.9 1.8 18.1 1.2 19.1 . 0.9 19.9 0.7 20.7 0.6 21.4 0.6 22.1 0,5 22.7 0,4 23.2 0.4 23.7 Increase for Blood Pb lUg/m3 increase 1.2 12.2 1.0 16.2 0,9 18.6 0.8 20.3 0.7 21.7 0.6 22.9 0.6 24.0 0.6 24.9 0.5 25.7 0.5 26.5 increase for lUg/m3 increase 4.1 2.4 1.7 1.4 1.2 1.0 0.9 0.8 0.8 0,7 1) From original paper Blood Pb = antilog (1.2557 + 0.153 log Air Pb) Estimate of blood Pb at air Pb=0 is not possible C0EFFJClBhJTi BE J.22S7 at air Pb=lxl0 blood Pb 1.1 2) From Snee April 1977 Blood Pb = 12.1 (Air Pb + 3,28) 2669 At air Pb=Q> blood Pb = 16.6 3) From Snee April 1977, considering that "B" is a function of Air Pb. B - 0.6249 + 0.9828 Air Pb This formula is derived by linear regression from "B" values of Snee April 1977 and Air Pb of original study. * Blood Pb * 12,1 (Air Pb + (0.6249 + 0.9828 Air Pb)]G'2&69 At Air Pb = 0, blood Pb - 10.7 TEH 0470664 DUP050083481 ON DUTY fUR LEHD CMCE/CUBIC METER) DUP050083482 FT.NO. , is 1 1;0189 2 0.8100 3 3.0600 4 2.6280 5 6,1000 HO. POINTS * 5 X: riEfftl- 2.72 Y-' t1EHM= 3.298 CORK.COEFF.= @,782883 Y 8.4400 1.4680 2.3388 6.8088 6.2680 ST.DEV,= 2,128588868 ST.DEV.= 2.6?1963311 COEFFICIENTS B< 0>= B(. 1> = 6.6249 0.9828 R SC'UfiRE = 0,612906175 v'&" = , % I ps- + 0.&Z4-1 > i FT, HO. X Y 1 2.8460 6.4400 2.0000 1.4608 o 3,0560 2,3300 4 5.1000 6.0000 5 9.4200 6.2600 'O it tn HO. POINT X `1E0N= 4.432 Yi MEflH* 3.298 ST.DEV,= 2.986338 96 ST.DEV.= 2.6719 69 u COER.COEFF.* 0.843357576 COEFFICIENTS B< 0> = B<1 1> = -0,6864 0.7551 R SfiUfiRE 0.712264380 ,*7S5\*A\R ?& ~ TEH 0470666 DUP050083483 P=0.782893245 ftHB tl= 5 Tv 2.i?95*BF= '3 BY ui>E--T AILED T TEST: PROS T GREATER THAN BY TWO-TAILED T TEST: PROS T GREATER THAN 2.1735= 0.0587 2.1795= 0,1174 6 R= 6.84395757 AND H= 5 T= 2.7251> BF= BY OHE-TAILED T TEST: PRGB T GREATER THAN BY TAG-TAILED T TEST: PRGB T GREATER THRU ^ i i'J 1 "* 0.0361 2.7251= 0.0722 TEH 0470667 DUP050083484 Bl o o d p l g ------------------U_--------... L ... o z* ------- 1--___ ,______L_1______________ s /a \ ' TM* DUP050083485