Variant of 'bad cholesterol' can raise heart disease risk

• Older adults with higher levels of a variant of “bad cholesterol” known as lipoprotein(a) may have a higher risk of recurrent coronary artery disease.
• Experts say cholesterol-lowering medications don’t appear to effectively reduce this risk.
• They add that diet may also not have an impact on lipoprotein(a) levels, but a healthy eating plan still can improve heart health.

Increased levels of lipoprotein(a) – (Lp(a)) – a variant of low-density lipoprotein (LDL), could be a risk factor for recurrent coronary artery disease in people 60 and over, according to a study published today in the journal Current Medical Research & Opinion.

The research suggests that cholesterol-lowering medications might not effectively reduce the risk of recurrent heart disease because of high Lp(a).

In their study, scientists in Australia followed 607 people 60 and older with coronary heart disease (CHD) for 16 years. During that time, there were 399 cardiovascular events.

Their findings included:

• The median Lp(a) level in people who had a recurrent coronary heart disease event was 130 mg/L compared to 105 mg/L in those who did not have disease.
• 26% of people who had a recurrent coronary heart disease event – and 19% of those who did not – had Lp(a) levels of more than 300 mg/L.
• 18% of people who had a recurrent coronary heart disease event – and 8% of those who did not – had Lp(a) levels of more than 500 mg/L.

Study participants with the highest 20% Lp(a) levels (>355 mg/L) had a 53% excess risk of having a recurrent coronary heart disease event over the 16-year follow-up period compared to the lowest 20% Lp(a) levels. (<50 mg/L).

Lipoproteins and heart disease risk

The researchers concluded that elevated Lp(a) is an essential predictor of recurrent heart events in people over 60.

Current medications prescribed to lower LDL, though, do not influence Lp(a).

Previous research has examined the connection between Lp(a) and heart disease. However, most of these studies looked at the first event.

The new study looked at whether it was a risk factor for a second or recurrent event.

“I find the study’s findings intriguing but expected,” said Dr Rigved Tadwalkar, a cardiologist at Providence Saint John’s Health Center in California who was not involved in the study.

“While LDL cholesterol has long been recognized as a major contributor to [coronary heart disease], this research sheds light on the importance of Lp(a) as a risk factor for recurrent CHD. It suggests that Lp(a) may play an even more significant role than previously acknowledged,” Tadwalkar told Medical News Today.

“However, it is important not to dismiss the significant impact of LDL cholesterol in cardiovascular disease development,” he added. “Rather, the study emphasizes the potential additional value of considering Lp(a) levels in conjunction with LDL cholesterol measurements in certain contexts, in this case, recurrent CHD in older individuals.”

What you need to know about Lp(a)

Cholesterol goes through the blood attached to lipoproteins, according to the Centers for Disease Control and Prevention.

There are three types of lipoproteins:

• Low-density lipoprotein (LDL)
• High-density lipoprotein (HDL)
• Lipoprotein A (Lp(a))

Like LDL, high Lp(a) levels can increase your risk of heart disease. It can build up on the walls of blood vessels, increase the risk of clotting, promote inflammation, and lead to the narrowing of the aortic valve.

High Lp(a) runs in families. However, routinely blood tests don’t include high Lp(a) levels. A medical professional must specifically order the test that checks Lp(a).

“Because Lp(a) does not change much throughout life, I usually order it once for my patients,” said Dr. Yu-Ming Ni, a cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in California who was not involved in the study.

“This is especially true if someone has a family history of elevated risks or a history of heart disease,” Ni told Medical News Today. “Lifestyle changes like diet and exercise do not influence Lp(a). However, a healthy lifestyle typically lowers LDL levels, which does reduce your risk of heart disease.”

“PCSK9 inhibitors are sometimes used to lower LDL if other methods do not work, but they are problematic,” he added. “Unlike statins, which are oral medications taken once a day, PCSK9 inhibitors must be injected once or twice a month which is difficult for some patients.”

Checking your risk of heart disease

Dr. Eugenia Gianos, the director of women’s heart health at Lenox Hill Hospital in New York as well as the director of cardiovascular prevention for Northwell Health, says that Lp(a) is often unrecognized as a cause of heart disease.

“In the field of preventive cardiology, we are very attuned to assessing patients for Lp(a), but a greater awareness among clinicians and patients is needed to get more patients screened,” she told Medical News Today.

“The European Atherosclerosis Society recommends checking lipoprotein(a) at least once in one’s lifetime to help recognize high-risk patients for targeted prevention,” Gianos told Medical News Today.

“It would be great to see other major societies come on board with similar recommendations. A greater awareness among clinicians and patients is needed to get more patients screened,” she added.

How diet can help

Anne Danahy, an Arizona-based registered dietitian, and integrative nutritionist, told Medical News Today that diet isn’t usually effective in lowering Lp(a).

“Still, I would recommend someone with elevated Lp(a) follow a low fat (especially saturated fat) heart-healthy diet – maybe even try a vegan diet,” she said. “It absolutely won’t hurt, and it may help somewhat. Some people may respond to diet more than others because other genes influence how they metabolize nutrients and produce cholesterol.”

“I always tell people your genes determine one part of your risk, but they don’t always guarantee you’ll develop a condition like heart disease (or cancer),” she added. “Diet, environment, stress, and lifestyle play a role in whether those genes are expressed. You can’t control your genes, but you can do all you can to control many other risk factors.”

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