High blood lead levels may shorten life

A new study suggests that high blood lead levels are associated with an increased risk of death from all causes, especially circulatory disease and cancer. As a result, the researchers are calling for a reduction in allowable blood lead levels for the people who are exposed to lead. The researchers from the University of Maryland, Baltimore, USA used the mortality follow-up data of the Second National Health and Nutrition Examination Survey of the general population conducted from 1976 to 1980. They evaluated the relationship between death and blood lead levels for a group of 4,292 adults between the ages of 30 and 74, after adjusting for a variety of factors that affect life span such as smoking, body mass index, age, sex, income and education. The study group including blood lead levels was followed up till December 1992. They found that individuals with blood lead levels between 20 micrograms per decilitre (mcg/dL) and 29 mcg/dL experienced a 46% increased risk of death from all causes, a 39% higher risk of death from diseases of the circulatory system, and a 68% increased risk of death from cancer compared to people with blood lead levels at or below 10 mcg/dL. The main sources of the toxic metal lead are gasoline additives, food can soldering, lead-based paints, ceramic glazes, drinking water systems, cosmetics and folk remedies. It can be absorbed into the body through the skin, lungs or digestive tract and can damage the brain, nerves, kidneys and other organs. Most of the metal ends up in the bones, but it can also bind to red blood cells. According to National Referral Centre for Lead Poisoning in India, the main source of lead pollution in India is automobile exhaust. The World Health Organisation estimates that 15-18 million children in developing countries are suffering from permanent brain damage due to lead poisoning. Hundreds of millions of children and pregnant women in these countries are exposed to elevated levels of lead. Efforts to reduce lead exposure for occupationally exposed workers and the people are strongly encouraged.