Lead Accumulation May Lead to Cataracts

Howard Hu, MD, MPH, ScD
Harvard University School of Public Health
R01ES05257, P42ES05947, and P30ES00002

Background: Even though lead toxicity in humans had been recognized for centuries, industrial uses and practices in the 20th century led to far wider distribution of its effects. Worldwide, lead was a common component of many consumer products including gasoline, paint, craft materials, and plumbing materials. Some of these routes of exposure still exist in other countries making them and other uses of lead a remaining concern in all parts of the world.

NIEHS-supported research has been pivotal in identifying the adverse health effects of lead including learning disorders in children, sources of exposure, non-invasive and accurate methods of detection of cumulative lead exposure, methods to prevent exposure and clinical treatments. This NIEHS grantee has uncovered what could be another adverse health effect with global implications.

Advance: Results from this study show that lifetime lead exposure may cause an increase in the risk of developing cataracts, the leading cause of blindness. The study contained over 600 men and found that participants with high levels of lead in the tibia were more than a 2.5 times as likely to develop cataracts as men with low levels of lead. Since lead is stored in bones, blood lead levels, which are more indicative of short-term lead exposure, were not significantly associated with increased risk of cataract development.

Implications: This study suggests that accumulated lead exposure, common in the United States and other parts of the industrialized world, may be an important, but as yet, unrecognized risk factor for cataract development. Furthermore, reduction of lead exposure could help decrease the global burden and suffering caused by cataracts. There are about 13 million people over the age of 40 in the United States alone that have cataracts. Reducing lead exposure may not only preserve the vision of many Americans as they age, it may also reduce the financial burden for cataract surgery which stands at about $4 billion/year.

Citation: Schaumberg DA, Mendes F, Balaram M, Dana MR, Sparrow D, Hu H. Accumulated lead exposure and risk of age-related cataract in men. JAMA. 2004 Dec 8;292(22):2750-4.