Watch more than your cholesterol

Ignorance is bliss – but not when it can lead to heart attack. Disregarding conditions that promote cardiovascular disease (CVD), which includes heart attack and stroke, means opportunities for improving health are lost, but the possibility of sudden illness or death continues to sneak closer.

Medical researchers now suggest 50-plus people who have three of five key risk factors are more prone to heart attack, stroke – and diabetes – than people who do not have these warning signs. This cluster of medical hazards, labelled “metabolic syndrome,” includes a too-large waist (more than 40 inches for men and 35 inches for women), high blood pressure, high levels of blood fats, low levels of the good cholesterol (HDL) and high fasting blood glucose levels.

These risk factors can be effectively addressed, usually through modest changes in lifestyle such as reducing weight, eating a healthy diet, increasing physical activity, quitting smoking and managing stress. In some cases, medication may be needed to lower blood pressure and cholesterol levels and to control elevated blood glucose. A study published in the medical journal Diabetes reported 44 pecent of 50-plus Americans fit this syndrome.

The Heart and Stroke Foundation of Canada (HSFC) estimates that one in four, approximately eight million Canadians, suffers from some type of cardiovascular condition. CVD is responsible for 22 per cent of deaths in men and 19 per cent of deaths in women in Canada and costs our country more than $18 billion a year. Worse, a Statistics Canada report notes that in 1998, it was our most dangerous disorder, killing nearly 80,000.

Some risk factors for CVD can’t be altered. They include a family history of CVD, advancing age and being post-menopausal. First Nation people and those of African or South Asian origins have higher risk levels for CVD.

An indicator of hazards to come
Dr. Paul Ridker of the Center for Cardiovascular Disease Prevention at Boston’s Brigham and Women’s Hospital says a simple blood test may help doctors do a better job of predicting heart attack and stroke. It measures a marker of inflammation called high-sensitivity C-reactive protein (hsCRP), which plays a role in the formation of waxy deposits in artery walls (atherosclerosis or hardening of the arteries) and in the susceptibility of these inflamed areas to rupture.

If these plaques burst, resulting blood clots can block arteries and deprive heart or brain tissue of oxygen. These tissues die unless blood supply is swiftly restored.

“Cholesterol tends to be a marker for your likelihood to develop those plaques,” Ridker says, “but CRP seems to be more of a marker of the likelihood of them rupturing, actually causing a heart attack or stroke.”

He says hsCRP values of less than one mg/l indicate low risk of such vascular events, values of 1 to 3 mg/l reflect a moderate risk, while those over 3 mg/l are highly predictive of a future heart attack or stroke (as well as the risk of developing Type 2 diabetes).

Almost half of heart attacks and strokes occur in people with low levels of low-density lipoprotein (LDL) – the “bad cholesterol” – who do not suspect they are at risk. Ridker notes the scientific community is considering including an hsCRP value greater than 3 mg/l in the definition of metabolic syndrome.

May provide key to HRT findings
Standard hormone therapy (HRT) has been shown to increase CRP levels, he reveals. “We think that may be part of the reason HRT ended up being not such a good thing for heart disease risk.”

Currently, Ridker is lead investigator for the JUPITER clinical trial now underway in Canada and the United States to determine whether a statin (in this instance, rosuvastatin), a class of drug prescribed to lower cholesterol levels, can reduce the incidence of those sudden cardiovascular events in people with low levels of LDL cholesterol but high hsCRP levels. “This is a very important public health issue,” he says.

Statins lower CRP levels, he says, “but the most important things are diet, weight loss and smoking cessation, because all of those things are not only proven to lower the risk of heart attack, stroke and diabetes, but they also happen to lower CRP levels, and I think that is the biggest issue.”