ORLANDO — Higher serum levels of high-density lipoprotein cholesterol were linked with lower risk for incident cancer in a meta-analysis of 21 randomized, controlled trials involving nearly 140,000 people.
An unadjusted analysis of cancer incidence rates in the 21 studies relative to baseline levels of high-density lipoprotein (HDL) cholesterol showed that every 10-mg/dL increment in HDL was linked with a 24% relative reduction in new-onset cancers.
The association was statistically stronger in a multivariate analysis that adjusted for baseline levels of low-density lipoprotein (LDL) cholesterol, age, body mass index, and smoking status. In this model, every 10-mg/dL increment in baseline HDL cholesterol correlated with a 21% drop in incident cancers, Dr. Haseeb Jafri and his associates reported in a poster at the annual scientific sessions of the American Heart Association.
This is the first report of a strong and significant inverse relationship between serum level of HDL cholesterol at baseline and subsequent development of cancer, according to Dr. Jafri, an internal medicine physician at Tufts Medical Center in Boston, and his coauthors.
The antioxidant and anti-inflammatory effects of HDL cholesterol particles is one hypothesized mechanism for the link between HDL cholesterol levels and cancer susceptibility, said Dr. Richard H. Karas, director of preventive cardiology and vice chairman of the department of medicine at Tufts and senior investigator on the report.
For example, HDL cholesterol particles carry the antioxidant enzyme paraoxonase, Dr. Karas said in an interview.
The 21 lipid-intervention trials included in the meta-analysis appeared in journal articles published during 1987-2009, and included more than 73,000 people allocated to lipid interventions and more than 66,000 in the control arms.
For inclusion in the analysis, published reports had to contain data on both baseline HDL cholesterol levels and incident cancer rates. The median duration of follow-up was 5 years, and the cumulative exposure studied totaled 586,000 person-years.
The median serum level of HDL cholesterol at baseline was about 45 mg/dL. During follow-up, the study participants developed 7,928 new-onset cancers.
In the multivariate model, baseline levels of LDL cholesterol and age also were significantly related to the rate of incident cancers.
Future studies should look at the relationship between HDL cholesterol and cancer incidence in other databases, Dr. Karas said.
Disclosures: Dr. Karas disclosed receiving research support from AstraZeneca, and honoraria from Abbott and Merck. Dr. Jafri reported no financial relationships.