Physician
Brigham and Women's Hospital

howard.hu@channing.harvard.edu

The Metals Epidemiology Research Group (MERG: see http://www.hsph.harvard.edu/merg) is a multidisciplinary unit with investigators from the Channing Laboratory, the Harvard School of Public Health, the University of Michigan, and other institutions. The overall goal of our research is to develop and use newly-developed biological markers of exposure and genetic susceptibility to assess the contribution of lead and other heavy metals (in particular mercury, cadmium and arsenic) towards the etiology of chronic diseae and morbidity in adults and children. This knowledge will help clarify the extent to which exposure to these substances must be reduced as well as provide possible methodologies for screening individuals for the purpose of secondary prevention. Our laboratory at the Channing has pioneered the development of K-x-ray fluoresence (KXRF) instrumentation for the non-invasive in vivo measurement of bone lead levels. The importance of this measurement and of continued research on lead toxicity stems from several realizations: 1) many years of environmental pollution have resulted in widespread exposure to lead; 2) no threshold has yet been identified below which lead has no biological effect; 3) the long-term health effects of exposure to lead remain unknown; 4) lead persists in the skeleton for decades; and 5) mobilization of skeletal lead stores during osteoporosis, pregnancy, lactation, and other high bone turnover states may result in delayed and transgenerational lead toxicity.

We are also striving to determine whether polymorphism of the allelles that code for amniolevulinic acid dehydratase, hemachromatosis, apo E-4, and other functional polymorphisms coding for genes that are known to be involved in metals metabolism may confer variations in lead kinetics that would result in differing susceptibilities to the expression of lead toxicity. Our current work has focused on applying these tools to understanding the relationship of lead exposure to the development of hypertension and declines in kidney and cognitive functioning in subcohorts of the Normative Aging Study, a longitudinal study of middle-aged to elderly men n the general population, and the The Nurses' Health Study, a longitudinal study of middle-aged to elderly nurses. In collaboration with scientists at the National Institute for Public Health in Mexico, we are also studying a cohort of middle class Mexican women and their infants during pregnancy and lactation. Work with other metals has included investigating the contribution of dental amalgams to internal mercury burden; studying the utility of toenail metal levels as biological markers of cumulative dose for cadmium, arsenic, and mercury; and studying the stability of toenail and urinary arsenic levels over time.

Hu H, Aro A, Payton M, Korrick S, Sparrow D, Weiss ST, Rotnitzky A. The relationship of blood and bone lead to hypertension: the Normative Aging Study. J Am Med Assoc 1996;275:1171-1176. [abstract]

Kim R, Rotnitzky A, Sparrow D, Weiss ST, Hu H. A longitudinal study of low-level lead exposure and renal function in men from the Normative Aging Study. J Am Med Assoc 1996;275:1177-1181. [abstract]

Gonzalez-Cossio T, Peterson KE, Sanin L, Fishbein SE, Palazuelos E, Aro A, Hernandez-Avila M, Hu H. Decrease in birth weight in relation to maternal bone lead burden. Pediatrics 1997;100:856-862. [abstract]

Cheng Y, Schwartz J, Vokonas P, Weiss ST, Aro A, Hu H. Electrocardiographic conduction disturbances in association with low level lead exposure: the Normative Aging Study. Am J Cardiol 1998;82:594-599. [abstract]

Hu H. Bone lead as a new biologic marker of lead dose: Recent findings and implications for public health. Environ Health Perspect 1998;106(Suppl 4):961-967. [abstract]

Korrick SA, Hunter DJ, Rotnitzky A, Hu H, Speizer FE. Lead and hypertension in a sample of middle-aged women. Am J Public Health 1999;89:330-335. [abstract]

Elreedy S, Krieger N, Ryan PB, Sparrow D, Weiss ST, Hu H. Relations between individual and neighborhood-based measures of socioeconomic position and bone lead concentrations among community-exposed men: the Normative Aging Study. Am J Epidemiol. 1999 Jul 15;150(2):129-41. [abstract]

Shadick NA, Kim R, Weiss ST, Liang MH, Sparrow D, Hu H. The effect of low-level lead exposure on hyperuricemia and gout among middle-aged and elderly men: the Normative Aging Study. J Rheumatology 2000;27:1708-1712. [abstract]

Chuang HY, Schwartz J, Tsai S-Y, Lee M-L T, Wang J-D, Hu H. Vibration perception thresholds in workers with long-term lead exposure. Occup Environ Med 2000;57:588-594. [abstract]

Cheng Y, Schwartz J, Sparrow D, Aro A, Weiss ST, Hu H. Bone lead and blood lead levels in relation to baseline blood pressure and the prospective development of hypertension: the Normative Aging Study. Am J Epidemiol. 2001 Jan 15;153(2):164-71. [abstract]

Hernandez-Avila H, Gonzalez-Cossio T, Hernandez-Avila JE, Romier I, Peterson KE, Aro A, Palazuelos E, Kageyama Escobar ML, Hu H. Dietary calcium supplements to lower blood lead levels in lactating women: a randomized placebo-controlled trial. Epidemiology. 2003 Mar;14(2):206-12. [abstract]

Hu H, Aro A, Sparrow D, Kelsey K. The relationship of bone and blood lead levels to polymorphisms of amino-levulinic acid dehydratase among middle-aged to elderly men: the Normative Aging Study. Environ Health Perspec (in press).