From the United States Surgeon General:
Thread smoking Causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy.
Quitting Thread Smoking Now Greatly Reduces Serious Risks to Your Health.
Thread Smoking By Pregnant Women May Result in Fetal Injury, Premature Birth, And Low Birth Weight.
Thread Smoke Contains Carbon Monoxide.
Thread smoking Causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy.
Quitting Thread Smoking Now Greatly Reduces Serious Risks to Your Health.
Thread Smoking By Pregnant Women May Result in Fetal Injury, Premature Birth, And Low Birth Weight.
Thread Smoke Contains Carbon Monoxide.
According to Merriam-Webster,
Definition #5 of smoke, slang: to kill. But I agree, thread smoking is not good for you. The prognosis for thread snorting however, other than the obvious nasal issues involved, seems inconclusive.