Cholesterol Watch

Diesel Fumes Can PromptClogged Arteries

Scientists have found a biochemical process that makesexhaust from diesel engines a danger to human arteries. Aninteraction between the fine particles found in diesel smokeand the fatty acids in low-density lipoproteins (LDLs) triggersgenes that cause inflammation in the blood vessels. Theprocess speeds up atherosclerosis.

The mechanism is one way that ?chemicals in dieselexhaust impact the cardiovascular (CV) system,? accordingto researchers at the University of California, Los Angeles.Their research was reported in the July 26, 2007, online editionof Genome Biology.

The investigators conducted a series of studies in whichthey combined particulate diesel pollutants with fatty acidsfound in LDLs and studied how the substances interactedwith free radicals. They exposed cells to the mixture andextracted genetic material from the cells.

The researchers found that the genes that promote theinflammation of cells were highly activated by the exposure.They concluded that ?for people who have CV risk factors . . .exposure to diesel air pollution can enhance damage.?High Triglycerides Linked toHeart Risk

A finding by researchers in both Denmark and the UnitedStates shows that high levels of triglycerides are associatedwith an increased risk of cardiovascular (CV) problems, butonly if they are measured in the hours right after a meal.

The Denmark study found no relationship when the levelswere tested in the usual manner: after a 12- to 14-hour fast.The nonfasting results, however, were considerably different:women with the highest triglyceride levels when tested aftera meal had up to 5 times the risk of dying from a heart attackor other CV event as those with the lowest levels; men hadtwice the risk.

The American study looked at more than 25,000 participantsin the Women?s Health Study who were followed for anaverage of 11 years. This study found that women with hightriglyceride levels soon after a meal had a 44% increased riskof a CV event. This risk decreased steadily with time, disappearingafter ~4 hours.

The results of both studies were published in the July 18,2007, issue of the Journal of the American MedicalAssociation.Cancer Risk from Low Cholesterol Extremely Small

Researchers at Tufts University School of Medicine conducteda meta-analysis of 23 different trials involvingstatins. The researchers examined the records of 41,173patients to determine adverse effects and found that therewas a slight increase in cancer incidence in 13 trials.

This finding involved patients who achieved the lowestlow-density lipoprotein levels, and it did not entail any specifictype or location of cancer.

The actual incidence of cancer among statin users wasabout 1 in every 1000 patients. The study appeared in theJuly 31, 2007, issue of the Journal of the American Collegeof Cardiology.

The researchers emphasized that this information wasnot significant enough to recommend the cessation of statinuse. ?Most studies don?t get cholesterol levels low enough,?said John C. LaRosa, MD, professor of medicine and presidentat the State University Downstate Medical Center inBrooklyn, NY, who wrote an editorial on the study. The benefitsof statins far outweigh the risk, and ?this data is hardlyconclusive of anything real enough to cause a change.?Higher Doses of Statins Cut Elderly Heart Risk

The aggressive lowering of low-densitylipoprotein (LDL) levels with highdoses of atorvastatin reduces the riskof cardiovascular (CV) events in elderlypatients with coronary disease morethan lower doses.

The researchers analyzed the dataon about 3800 patients, aged 65 yearsor older, who were part of a group of10,000 patients with coronary diseaseparticipating in a clinical trial of atorvastatin.

All the patients had LDL levels below130 mg/dL. They were randomly assignedto receive either 10 mg or 80 mgof the statin per day. The usual targetLDL level is <100 mg/dL, but patientswith actual coronary heart disease areencouraged to keep their levels evenlower.

The researchers found that those onthe higher statin dose reduced their LDLlevels to ~70 mg/dL, while those whotook the lower dose reduced their levelsto ~100 mg/dL. The risk of sufferinga stroke, heart attack, or cardiac arrestwas lowered by 19% in those taking the80-mg dose. The findings were publishedin the July 3, 2007, issue of theAnnals of Internal Medicine.