Population-Based Case-Control Study of Chinese Herbal Products Containing Aristolochic Acid and Urinary Tract Cancer Risk.
J Natl Cancer Inst. 2009 Dec 21;
Authors: Lai MN, Wang SM, Chen PC, Chen YY, Wang JD
Background Consumption of Chinese herbs that contain aristolochic acid (eg, Mu Tong) has been associated with an increased risk of urinary tract cancer. Methods We conducted a population-based case-control study in Taiwan to examine the association between prescribed Chinese herbal products that contain aristolochic acid and urinary tract cancer. All patients newly diagnosed with urinary tract cancer (case subjects) from January 1, 2001, to December 31, 2002, and a random sample of the entire insured population from January 1, 1997, to December 31, 2002 (control subjects), were selected from the National Health Insurance reimbursement database. Subjects who were ever prescribed more than 500 pills of nonsteroidal anti-inflammatory drugs and/or acetaminophen were excluded, leaving 4594 case patients and 174 701 control subjects in the final analysis. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by using multivariable logistic regression models for the association between prescribed Chinese herbs containing aristolochic acid and the occurrence of urinary tract cancer. Models were adjusted for age, sex, residence in a township where black foot disease was endemic (an indicator of chronic arsenic exposure from drinking water [a risk factor for urinary tract cancer]), and history of chronic urinary tract infection. Statistical tests were two-sided. Results Having been prescribed more than 60 g of Mu Tong and an estimated consumption of more than 150 mg of aristolochic acid were independently associated with an increased risk for urinary tract cancer in multivariable analyses (Mu Tong: at 61-100 g, OR = 1.6, 95% CI = 1.3 to 2.1, and at >200 g, OR = 2.1, 95% CI = 1.3 to 3.4; aristolochic acid: at 151-250 mg, OR = 1.4, 95% CI = 1.1 to 1.8, and at >500 mg, OR = 2.0, 95% CI = 1.4 to 2.9). A statistically significant linear dose-response relationship was observed between the prescribed dose of Mu Tong or the estimated cumulative dose of aristolochic acid and the risk of urinary tract cancer (P < .001 for both). Conclusions Consumption of aristolochic acid-containing Chinese herbal products is associated with an increased risk of cancer of the urinary tract in a dose-dependent manner that is independent of arsenic exposure.
Dr.Steve’s BOTTOM LINE: The FDA first issued warnings about herbs containing aristolochic acid almost 10 years ago for cancer risk as well as severe damage to kidneys. This study adds evidence that the risks are real and the more aristolochic acid you consume, the higher the risk. Unfortunately, this is the negative side of herbals. It is for this reason we should determine both the risk and the benefit of EACH component of herbals. Once you know this risk and benefit, it is up to you. Otherwise, it is no better than finding out that the headache drug you were taking for years also causes brain cancer. You probably would have liked to know that and might have taken something else instead. Finally, one other warning. Many herbals come over in contaminated form, which may contain harmful components including aristolochic acid. Learn about the benefits and risk of ANYTHING you take in to your body and buy from reputable sources.
