TUESDAY, Feb. 15 (HealthDay News) -- People whose blood levels of bilirubin are on the high side may have a lowered risk for lung cancer, chronic obstructive pulmonary disease (COPD) and death from any cause, British researchers report.
Bilirubin is a protein made as the hemoglobin in red blood cells breaks down. It is in excreted urine, and high levels may indicate certain diseases. It is responsible for the yellow color of bruises and the yellow discoloration in jaundice. Bilirubin may also have antioxidant and anti-inflammatory effects, which help protect cells, the researchers said.
"Bilirubin levels, which are routinely tested in patients mainly to assess liver function, may also be useful for assessing the risk of respiratory disease and death," said lead researcher Laura J. Horsfall, from the Division of Biosciences at University College London.
Animal studies have shown that raised bilirubin levels in the blood appears to protect the lungs against environmental damage, which may be due to the potent antioxidant and anti-inflammatory properties of bilirubin, she added.
"There are already a number of studies showing that moderately higher bilirubin levels in people without evidence of liver disease are associated with lower rates of heart disease," Horsfall said.
"We have now shown similar associations for COPD, another important cause of global morbidity and mortality. Thus, within the range typically considered normal, bilirubin may be useful for objectively quantifying a patient's risk of a range of common diseases," she said.
More work is needed to see if higher blood bilirubin levels reduce the risk of lung disease and death itself, or if they're a marker for lower exposure to other factors, such as air pollution and passive smoking, Horsfall noted.
For the study, which is published in the Feb. 16 issue of the Journal of the American
All rights reserved