Most people know that coronary heart disease is firmly linked to five basic risk factors: high cholesterol, high blood pressure, obesity, diabetes, and smoking.
But heart disease is a threat to practically everyone, not just hefty couch potatoes who smoke.
As scientists delve deeper into what causes and contributes to unhealthy hearts, they are finding an increasingly complex disease process. Inflammation, infection, and immune dysfunction are key players in the clogging, narrowing, and "hardening" of arteries that can lead to a complete cutoff of blood flow - a heart attack.
Researchers are also identifying a seemingly endless list of potentially dangerous habits. Last year, for example, a University of Miami study that followed 2,500 New Yorkers for nine years found that people who drank diet soda every day had a 61 percent higher risk of heart attacks and stroke than those who avoided the drinks - even after the researchers adjusted for age, smoking, exercise, and daily calories.
Critics quickly noted that the study could not say whether the diet-soda drinkers were downing Big Macs, fries, and other foods that might be the real villains.
While many suspected risk factors remain controversial, some unusual suspects have amassed a convincing body of evidence. Among them:
If your gums aren't healthy - and about a quarter of Americans have some periodontal (gum) disease - then your heart may be suffering along with your teeth.
Large population studies have consistently found that people with gum disease are more likely to develop heart disease than those with healthy gums.
This link is not simple, since people who don't brush and floss tend to have other bad habits such as smoking and eating junk food.
But the link "definitely" makes biological sense, concluded leading gum-disease specialists and cardiologists in a joint 2009 statement.
Gum disease is a bacterial infection, and infection triggers inflammation. Chronic inflammation plays a role in the buildup of fatty plaques that cause atherosclerosis, or hardening of the arteries. What's more, people with gum disease have elevated levels of C-reactive protein (CRP), a marker of bodily inflammation that is a risk factor for cardiovascular disease.
The experts recommend that if you have gum disease and at least one other cardiac risk factor, such as high cholesterol, get a medical evaluation. And if you already know you have heart disease, talk to your dentist about whether your "oral hygiene" needs brushing up.
Chronic inflammation is also a hallmark of autoimmune diseases, in which infection-fighting cells attack the body's own tissues.
In recent years, scientists have clearly shown that two autoimmune disorders - rheumatoid arthritis and lupus - increase the risk of heart disease.
Of course, you can't simply eliminate these risk factors if you have them. What's more, corticosteroids commonly used to treat autoimmune disorders can increase blood pressure.
But you can control traditional heart disease factors such as smoking and weight. You can also be on guard for symptoms of heart trouble. In their new book, Heart 411, cardiologists Marc Gillinov and Steven Nissen describe a middle-age woman who attributed unfamiliar pain in her back and shoulder to her rheumatoid arthritis. She was shocked when she belatedly discovered she'd had a heart attack and needed a procedure to unblock an artery.
Snoring can be even harder on the heart than on a marriage.
Snoring is now recognized as a classic symptom of sleep apnea - periods when breathing stops because relaxed throat muscles narrow or block the airway. These brief sleep interruptions are momentary cardiac mayhem, decreasing oxygen, increasing blood pressure, altering blood clotting and heartbeat. Over time, apnea increases the risk of hypertension, artery blockages, stroke, heart failure, irregular heartbeat, even sudden death.
Fortunately, awareness and treatment of apnea have grown. Unfortunately, most people don't know that almost any sleep disruption can be hard on the heart if it goes on indefinitely. Shift work, insomnia, frequent waking, or sleeping six hours a night or less can have harmful cardiovascular effects - not to mention make you tired and irritable.
The remedy, experts say, is as simple as it is difficult to achieve: Get about seven hours of sleep a night. (Go easy on the alcohol and caffeine near bedtime.)
Polycystic ovary syndrome, which affects an estimated 10 percent of women, is a complex metabolic disorder that varies in severity. The most common symptom is infrequent or prolonged menstrual periods, a result of hormonal imbalances.
In many cases, the syndrome goes undiagnosed, or is not treated until a woman has trouble getting pregnant.
Meanwhile, the disorder can wreak havoc with blood sugar, cholesterol, insulin, and other indicators of heart health.
If you're a woman with a history of menstrual irregularities, think about your cardiovascular system. Even if you think you're way too young for heart disease, make sure your doctor runs tests to evaluate blood glucose, triglyceride, and cholesterol levels.
Contact staff writer Marie McCullough
at 215-854-2720 or firstname.lastname@example.org.