‘Good cholesterol’ might not be good for you

[Naveed Yaseen]

Is ‘good cholesterol’ really good for you; not so, suggests a new study. University of Chicago (U-C) researchers challenged popular notion that simply having high levels of good cholesterol (HDL) and low levels of bad cholesterol (LDL) is necessary for good heath.

Instead, they show that the good cholesterol has varying degrees of quality and that poor quality HDL is actually bad for you. Cholesterol is a waxy, fat-like substance used by the body to maintain the proper function of cell membranes and is encapsulated within two types of proteins as it travels in the body - low density lipoproteins (LDL) and high-density lipoproteins (HDL).

High levels of LDL or total cholesterol are an indicator of increased risk for heart disease. High blood cholesterol elicits no physical symptoms, making medical screenings necessary for detection.

“For many years, HDL has been viewed as good cholesterol and has generated a false perception that the more HDL in the blood, the better,” said Angelo Scanu, pioneer in blood lipid chemistry from U-C and co-author of the study.

“It is now apparent that subjects with high HDL are not necessarily protected from heart problems and should ask their doctor to find out whether their HDL is good or bad,” he added.

The researchers came to this conclusion after reviewing published research on this subject. They found that the HDL from people with chronic diseases like rheumatoid arthritis, kidney disease, and diabetes is different from the HDL in healthy individuals, even when blood levels of HDL are comparable.

They observed that normal, ‘good’ HDL reduces inflammation, while the dysfunctional, ‘bad’ HDL does not, according to an U-C release.

“This is yet one more line of research that explains why some people can have perfect cholesterol levels, but still develop cardiovascular disease,” said Gerald Weissmann, editor-in-chief of The FASEB Journal, which published the study in its December edition.

“Just as the discovery of good and bad cholesterol rewrote the book on cholesterol management, the realisation that some of the ‘good cholesterol’ is actually bad will do the same,” he added.

US Centres for Disease Control and Prevention said approximately 17 percent of all American adults have high total cholesterol, putting them at risk for heart disease.

Post-heart attack stress can be damaging: A patient who receives an implantable cardiac defibrillator (ICDs) after a heart attack is more than twice as likely to die within five years from sheer anxiety over their heart condition, according to a team of German scientists.

An ICD is a small battery-powered impulse generator implanted in the patient to boost heart’s activity.

Even patients who display no severe heart problems after the ICD is implanted have a higher risk of death owing to post-traumatic stress disorder (PTSD) brought on by the trauma of having suffered a heart attack, they said.

Cardiologists often overlook such fears. They tell their patients they have nothing to fear but fear itself. But the patients remain terrified that another heart attack could strike at any time - and that fear increases the chances of another heart event.

Researchers from the Technische University of Munich in Germany found that PTSD symptoms in this patient population were associated with a 2.4-fold increased mortality risk. “We were struck by the finding that patients suffering from PTSD symptoms had a substantially higher risk of mortality, and it was particularly striking that this association was strengthened after adjustment for known risk factors. The study shows there is direct evidence that PTSD independently influences mortality risk,” said principal investigator Karl-Heinz Ladwig.

The study was published in the November 2008 issue of Archives of General Psychiatry.

According to Ladwig, PTSD is often overlooked in cardiac patients.

Although it is generally recognized that ICD patients should undergo psychological screening and possible treatment as part of their follow-up care, this does not always translate into clinical practice.

“In part, this may have to do with the patients themselves, many of whom are resistant to this type of care and are intent on coping by themselves, but there is no doubt that they need help,” said Ladwig.

The German researchers followed 211 patients with ICDs who routinely attended a cardiac outpatient clinic after a cardiac event in 1998. The study’s primary outcome was mortality risk per 1,000 person-years.

Participants were surveyed an average of 27 months after implantation, and at that time 38 reported severe PTSD symptoms and 109 reported low or moderate PTSD symptoms. During an average of 5.1 years, 45 (30.6 percent) of the patients died: 32 of 109 patients with low or moderate symptoms and 13 of 38 with high levels of symptoms.

In their adjusted analyses, which controlled for age, sex diabetes mellitus, measures of cardiac disease, comorbid anxiety and depression, the researchers found that PTSD symptoms substantially increased mortality risk.

Despite assurances from cardiologists that they were doing fine, some patients continued to have nagging doubts about their heart. And those patients displayed higher risk of having another heart attack.

“Therefore, the perceived severity rather than the objective severity of a cardiac condition, as determined by cardiac criteria, may be associated with PTSD,” the authors write.

According to Ladwig, more research is needed to assess the behavioural and biologic pathways by which PTSD contributes to excess mortality risk in patients with ICDs.

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