We all know smoking isn't good for us. It increases our risk of heart attack—whether we smoke ourselves or breathe in others' toxins—and costs us millions of dollars in health care every year (as discussed in last week's post).

Evidence in the case against smoking continues to mount, as more and more studies reveal the real and sometimes hidden effects this habit has on our bodies and lives. But now, the latest controversy centers on aspirin, a common anti-heart-attack treatment.

Doctors usually prescribe a small daily dose of aspirin for patients at increased risk of heart attack, either because they've already experienced one, they've had a stroke or high blood pressure is a problem. But a new study by Dr. Michael Domanski of the National Heart, Lung and Blood Institute in Bethesda, Maryland, now reveals that caring for smokers with this normally highly effective course of treatment may not reduce their risk of further heart-related complications, as experienced by those who don't light up.

In fact, according to the study by Dr. Domanski and his colleagues (as published in the American Journal of Cardiology last month), smokers are nearly 12 times more likely to be resistant to aspirin and its anti-clotting effects than non-smokers.

Translation: If you smoke, taking aspirin won't help keep your arteries clear…and that can mean life-threatening blood clots—another killer.

A story in Reuters on the subject concludes, "The finding adds still more weight to the importance of abstinence from smoking."