| Determinants of Bone and Blood Lead Levels among Minorities Living in the Boston Area Charles Lin,1 Rokho Kim,2,3,4 Shirng-Wern Tsaih,5 David Sparrow,3,6 and Howard Hu3,4 1School of Medicine, University of California at San Francisco, San Francisco, California, USA; 2Occupational Health Surveillance Program, Massachusetts Department of Public Health, Boston, Massachusetts, USA; 3Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; 4Occupational Health Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; 5Statistical Genetics Group, Jackson Laboratories, Bar Harbor, Maine, USA; 6Normative Aging Study, Department of Veterans Affairs Medical Center, Boston, Massachusetts, USA Abstract
We measured blood and bone lead levels among minority individuals who live in some of Boston's neighborhoods with high minority representation. Compared with samples of predominantly white subjects we had studied before, the 84 volunteers in this study (33:67 male:female ratio ; 31-72 years of age) had similar educational, occupational, and smoking profiles and mean blood, tibia, and patella lead levels (3 µg/dL, 11.9 µg/g, and 14.2 µg/g, respectively) that were also similar. The slopes of the univariate regressions of blood, tibia, and patella lead versus age were 0.10 µg/dL/year (p < 0.001) , 0.45 µg/g/year (p < 0.001) , and 0.73 µg/g/year (p < 0.001) , respectively. Analyses of smoothing curves and regression lines for tibia and patella lead suggested an inflection point at 55 years of age, with slopes for subjects  55 years of age that were not only steeper than those of younger subjects but also substantially steeper than those observed for individuals > 55 years of age in studies of predominantly white participants. This apparent racial disparity at older ages may be related to differences in historic occupational and/or environmental exposures, or possibly the lower rates of bone turnover that are known to occur in postmenopausal black women. The higher levels of lead accumulation seen in this age group are of concern because such levels have been shown in other studies to predict elevated risks of chronic disease such as hypertension and cognitive dysfunction. Additional research on bone lead levels in minorities and their socioeconomic and racial determinants is needed. Key words: blacks, blood lead, bone lead, minority groups, occupations, smoking, X-ray fluorescence. Environ Health Perspect 112:1147-1151 (2004) . doi:10.1289/ehp.6705 available via http://dx.doi.org/ [Online 3 May 2004]
Address correspondence to C. Lin, 1565 5th Ave. #202, San Francisco, CA 94122 USA. Telephone: (415) 665-2940. Fax: (415) 665-2940. E-mail: chlin@itsa.ucsf.edu. Address reprint requests to H. Hu, Landmark Center East, 3-110A, 401 Park Dr., Boston, MA 02215 USA. Telephone: (617) 384-8968. E-mail: hhu@hsph.harvard.edu We thank D. Burger, F. Milder, S. Harcourt, R. Heldman, G. Barbella, S. Oliveira, T. Luu, G. Fleischaker, M. Barr, L. Hennessey, and S. Datta for their assistance. Support was provided by National Institute of Environmental Health Sciences (NIEHS) grants ES 05257-06A1 and P42-ES05947 (with funding from the U.S. Environmental Protection Agency) , NIEHS Occupational and Environmental Health Center grant 2 P30 ES00002, and National Institutes of Health (NIH) 1P20 MD000501. Subjects were evaluated in the outpatient Clinical Research Center of the Brigham and Women's Hospital with support from NIH grant NCRR GCRC M01RR02635. The K X-ray fluorescence instrument used in this work was developed by ABIOMED, Inc. (Danvers, MA) with support from NIH grant SBIR 2R44 ES03918-02. The authors declare they have no competing financial interests. Received 27 August 2003 ; accepted 3 May 2004.
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