Document kDwkgJ8X7oLYv2Y4zZ8B3pkMn

FROM: TO: ft.RS. CHUCK PFEIFER Engineering Department Louviers 31E55 Ext. 360*3540 (fLMtl-ft-TZ ) *4 S'*1'?- '* /iM*A*4rG~ of Uyy HJhJs by. * Auv* 'vp* t/AA& - `****4' TEH 0532506 SUMMARY OF DU POUTS ANALYSIS OF THE NHANES II BLOOD LEAD RESULTS tPierrard, J. M., Pfeifer, C. G., and Snee, R. D. E. I. du Pont de Nemours & Co., Inc.) PLMR-55-83 Alden j. Pahnke Technical Manager Petroleum Laboratory E. 1. du Pont de Nemours & Co., Inc. Wilmington, Delaware TEH 0532507 DUP050033776 SUMMARY A split plot covariance analysis of the NHANES 11 blood lead results indicates changes in site specific gasoline lead use accounts for only 0.5 ug/dl of the observed 5.6 ug/dl change in blood lead reported for the four year test period. Changing demographics of subject groups at the 64 sites sampled accounted for over half of the observed decrease. The 0.5 ug/dl decrease is in agreement with the change expected due to the decrease in air lead. The 0.5 ug/dl is also in agreement with the change expected based on the change in blood levels observed in Frankfurt, Germany when gasoline lead levels were changed from 0.4 g/i to 0.15 g/l. A special statistical analytical technique was required because the NHANES 11 protocol was not designed nor intended to provide 'Within study" chronological trends. Variations in subject and site characteristics throughout the four year test period limited or negated the utility of common data handling methods. The use of national rather than site specific gasoline lead statistics also caused difficulties in data interpretation. The split plot covariance analysis method provided a meaningful way of analyzing the NHANES II results. Results of the Du Pont analysis are being presented at International Conference on Heavy Metals in the Environment, Heidelberg, Germany, 6-9 September, 1983. A copy of the paper, "Assessment of Blood Lead Levels in the USA from NHANES II Data," by J. M. Pierrard, C. G. Pfeifer, and R, D. Snee is included in this report. Additional analyses carried out since preparation of this paper have confirmed and strengthened the conclusions made in the paper. TEH 0532508 DUP050033777 NHANES I) PROTOCOL National health and nutritional examination survey. Public Health Service. Carefully designed, stratified, multistage, probability cluster sample survey. t February 1976 to February 1980. 64 Primary sampling locations, 6 months to 74 years of age. Special groups (young and aged). 27,801 persons sampled -- 20,322 examined, Lead phase -- blood leads requested on all 6 months-6 years and one-half of others. Blind quality control on blood lead analyses. Not designed to provide "within-study" chronological trends. Quality control program probably did not cover the complete sampling process. TEH 0532509 DUP050033778 ORIGINAL FIGURE RELEASED BY V. HOUK, U.S. CENTERS FOR DISEASE CONTROL LEAD USED IN GASOLINE PRODUCTION AND AVERAGE NHANES II BLOOD LEAD LEVELS (FEB, 1976 - FEB, 1980) TEH 0532510 DUP050033779 CENTERS FOR DISEASE CONTROL ANALYSIS NHANES 11 Protocol Not Designed to provide 'Vvithin-study" chronological trends Variable demographics No repeats CDC Analysis Method Not Appropriate Sample population not homogeneous National gasoline lead use not representative of individual site lead use Other lead exposure variations were not considered TEH 0532511 DUP050033780 VARIATION IN URBAN DWELLER PERCENTAGE IS AN EXAMPLE OF THE NON-UNIFORM SAMPLING WHICH OCCURRED DURING NHANES II PROGRAM TEH 0532512 DUP050033781 INDIVIDUAL CHARACTERISTICS POTENTIALLY INFLUENCING BLOOD LEAD TREND Sex Age Race Income TEH 0532513 DUP050033782 SITE CHARACTERISTICS POTENTIALLY INFLUENCING BLOOD HAD TREND Geographic area Season Degree of urbanization Gasoline lead use TEH 0532514 DUP050033783 INFORMATION USED TO DETERMINE GASOLINE LEAD USE AT A SITE State gasoline lead use Lead content State population Site population Site area TEH 0532515 DUP050033784 Site Lead Density, Tonnes/Ml /Quarter VARIATION IN GASOLINE LEAD USE SITE-TO-SITE TEH 0532516 DUP050033785 STEPS IN BLOOD LEAD TREND ANALYSIS Withln-Slte Analysis 1 ______ 2L-_____ Between-Site Analysis Adjust for differing characteristics of individual subjects Further adjust for differing site characteristics -- with and without gasoline lead Residual Tune Analysis --h i -- _______ ________ Gasoline Lead Contribution Analysis Quantify unexplained time trend Compare unexplained time trend with and without gasoline lead exposure TEH 0532517 DUP050033786 TYPICAL RESULTS OF PIERRARD, PFEIFER, SNEE ANALYSIS (216 DIFFERENT MODELS CONSIDERED IN TOTAL STUDY) Effects Removed Remaining Four Year Decrease, ug/dl Attributable to Gasoline Lead, ug/dl NONE 5.8 DEM 1,6 DEM, G Pb DEM, G Pb, G Pb,DEM, G Pb, G Pbjy G Pb^ 1.3 0.3 1.2 0.4 1.2 0.4 DEM, log G Pb DEM, log G Pb, log G Pb,. DEM, log G Pb, log G Pbg log G Pb^ 1.5 1.1 1.1 0.1 0.5 0.5 G Pb log G Pb 5.2 0.6* 4.9 0.9* 2 * Not significant as shown by low R. <CM cc 0.5 0.6 0.6 0.6 0.6 0.6 0.6 0.2 0.2 TEH 0532518 DUP050033787 NHANES II STUDY CONTRIBUTIONS TO BLOOD LEAD DECREASE - 1976-80 PIERRARD, PFEIFER, SNEE ANALYSIS o> L. i --i s TEH 0532519 DUP050033788 CONCLUSIONS National gasoline lead use is not a valid index of exposure at NHANES I I sites. Over 50% of the apparent blood lead decrease is attributable to demographics. 5 to 10% of the apparent blood lead decrease is attributable to gasoline lead exposure. 3 The blood lead decrease of 0.3 to 0.6 ug/m attributable to gasoline lead is consistent with the observed air lead decrease. A significant blood lead time trend remains after accounting for demographics and gasoline lead exposure. TEH 0532520 DUP050033789 COMMENTARY Du Pont analysis of NHANES I I results will be presented at the International Conference on Heavy Metals in the Environment, Heidelberg, Germany, 6-9 September, 1983, An EPA appointed review group has concluded: "...despite the strong association between the decline in gasoline-lead usage and the decline in blood-lead levels, the survey results and statistical analyses do not confirm the causal hypothesis." Results of the Du Pont analysis using a split plot covariance analysis method were not addressed by the EPA appointed review group. This split plot covariance analysis method is particularly useful for analyzing NHANES II type data. TEH 0532521 DUP050033790