Tobacco's negative impact on blood cholesterol was discovered in the 1970s, but it is still unclear which of the herb's almost 400 chemicals and compounds cause cholesterol problems, according to the Mayo Clinic. Studies proving tobacco's harmful effect on good (HDL) cholesterol are plentiful, but recent research also indicates that smokeless and secondhand tobacco raise total and bad cholesterol respectively.
Smoking tobacco causes 400,000 smokers and 50,000 nonsmokers to die annually, according to "Tobacco Use, Misuse, and Abuse," a chapter in "An Invitation to Health" textbook. High cholesterol levels increase your risk of heart disease, the leading cause of death in the United States. You are at a higher risk of heart disease if your total cholesterol is at least 240 mg per dL, your bad (LDL) cholesterol is at least 160 mg per dL or your good cholesterol is below 40 mg per dL, according to the National Cholesterol Education Program.
Tobacco and high cholesterol make a dangerous combination. "Elevated cholesterol levels increase the risk of heart disease much more in smokers than in nonsmokers," according to "Dr. Dean Ornish's Program for Reversing Heart Disease." A 35- to 39-year-old woman with healthy blood pressure has a 14 percent risk of having a heart attack within 10 years if she smokes, her total cholesterol is above 280 per dL and her good cholesterol is below 40 per dL, the National Cholesterol Education Program reports. Her risk is below 1 percent if she's a nonsmoker with no cholesterol problems.
The more cigarettes you smoke, the more your good cholesterol falls, according to the Lipid Research Clinics Program Prevalence Study, which was started in 1971. Men and women who smoked at least 20 cigarettes daily had a good cholesterol level 11 and 14 percent lower than nonsmoking men and women respectively, according to the study that was published in Circulation in 1980.
Quitting smoking can raise your good cholesterol by 15 to 20 percent, the Harvard Women's Health Watch's June 2008 issue reported. The landmark Framingham Study reported in the 1970s that it took between one and two years for ex-smokers to have good cholesterol levels similar to that of nonsmokers, according to the "Controlling Cholesterol" book.
Tobacco also harms nonsmokers' cholesterol levels. The Mayo Foundation for Medical Education and Research reported in 2009 that "people who use smokeless tobacco also have higher (total) cholesterol levels than those who don't use tobacco." Mayo Clinic Women's HealthSource reported in April, 2007 that secondhand smoke can increase nonsmokers' bad cholesterol levels by reducing the antioxidants in their blood.
Nicotine is the "primary active ingredient" in tobacco, according to "An Invitation to Health." Tobacco also includes ammonia, benzene, carbon monoxide, formaldehyde, nitrogen dioxide, phenol, tar and hundreds of other compounds and chemicals. Studies on whether nicotine harms blood cholesterol have been inconclusive, but "most studies of nicotine replacement medications" show no connection between nicotine and cholesterol, according to the Mayo Clinic.