Chapter 8 - Nicotine

Nicotine

• Per capita sales of cigs-peaked in early 60s-40% of adults smoked; today-21%

• 74% of Amer. Smokers-consider themselves addicted

• Avg. day in 2006-4,000 ages 12-17-smoked for first time

• 100 million-estimated # of people worldwide who died prematurely in 20th century

• Higher the education level-less likely to smoke• College grads-% less than half of non-grads• Men-24%; women 18%• Most likely-25-44 yrs.-25.6%• Below poverty level-30.5%; above-21.7%

How Nicotine Moves Through the Body

• Absorbed rapidly into blood through lungs; in brain within seconds

• Chew-takes longer; cig-1mg nicotine;chew-3-5 mg; both result in about same peak concentrations in blood

• More than 4,000 chemicals found in tobacco smoke

• Cigars-usually don’t inhale; absorbed through mucous membranes

• Peak concentration in lungs, blood, & brain-about 10 min

• Eliminated very quickly-almost all gone in 30 min

Is Nicotine Addictive?

• Affects brain quickly; activates reward pathways (dopamine)

• Effects dissipate quickly• Tolerance develops rapidly• Withdrawal: irritability, craving, depression,

anxiety, cognitive & attention deficits, sleep disturbances, increased appetite

• Peak in several days; usually subside in a few weeks

• Recent research: decreased levels of MAO-results in higher dopamine levels-may contribute to addiction

• Acetaldehyde-found in tobacco smoke-increases reinforcing qualities of nicotine, especially for adolescents

Carbon Monoxide & Tar

• Carbon monoxide: odorless, colorless, toxic gas

• Attaches to hemoglobin-prevents oxygen from getting to body from lungs

• Accumulates over time• Produces cardiovascular disease

• Tar: quantity varies in cigs; last 1/3 of cig-contains 50%

• Adheres to cells in lungs-cilia can’t function effectively

• Permits carcinogenic compounds that normally would have been eliminated to settle on tissue=lung cancer

Effects on Brain & Mental Function

• Stimulates a subtype of an ACh receptor-called the nicotinic acetylcholine receptor; many brain areas

• Excites cells & increases cell-cell signaling• Increases activity in areas associated with

memory and other cognitive functions; stimulation improves memory

• May help Alzheimer’s patients; adult ADHD; improve cognitive functioning in schizophrenia

• May lead to depression in some adolescents• Smoking adolescents: 2x as likely as

nonsmokers to experience an episode of major depression

Heart Disease

• Nicotine causes release of adrenaline-increases heart rate and blood pressure-heart works harder

• Toxic to inner linings of blood vessels; hardens them

• Smoking-30% of all deaths from coronary heart disease

• Raises risk of fatal heart attack 2-4x

• Increases platelet adhesiveness in blood=increased risk of blood clots=heart attack or stroke

• Increases cholesterol=atherosclerosis-fatty deposits impede blood flow

Other Problems Related to Smoking

• COPD: 80-90% of cases are the result of smoking• Adolescents: 5+ cigs a day-40% more likely to

develop asthma• 90% of approximately 213,000 new cases of lung

cancer in U. S. each year-caused by smoking• Increasing numbers of women; since 1988 lung

cancer has exceeded breast cancer deaths• In U. S.-about 30% of cancer deaths of all types-

linked to smoking

• Increased risk: 2-27x larynx; 13x mouth/lips; 2-3x bladder; 2x pancreatic; 5x kidneys and uterus

• Smokeless: leukoplakia (white spots) & erythroplakia (red spots)-inside mouth and nose; precancerous changes

Secondhand & Sidestream Smoke

• Sidestream-higher concentrations of carcinogens than secondhand or smoke taken in by smoker

• Nonsmoking adults: raises risk of heart disease by 25-30% (both men and women); lung cancer: +20-30%

• SIDS: 430 deaths per year in U. S.

• Children whose parents smoke-increased risk of bronchitis, middle-ear disease, wheezing, childhood asthma

• 46,000 premature deaths from heart disease; 3,000 from cancers

Prenatal & Postnatal Effects

• Babies: can go through symptoms of withdrawal

• Also cyanide and carbon monoxide to fetus• Smaller, lighter, smaller head circumference• Affects brain and mental functions after birth

(may be permanent)• Verbal and math abilities; hyperactivity;

greater likelihood of nicotine addiction

• Dad smokes-more likely to have children who develop childhood cancers.

• One study: fathers who smoked 20+ per day-42% increased risk of having a child with cancer; smoked 10-20: +31% risk

• Smoking may damage sperm, leading to cancer-causing alterations of DNA

Quitting

• Not just a matter of will power• About 1/3 try to quit each year; 3-5% succeed

on first try• About half quit after avg. of 8 attempts• Within 1 yr: risk of coronary heart disease is ½

of a smoker• Within 5-10 yrs: risk of stroke reduced to that

of nonsmoker

• Within 10 years: lung cancer death rate-about ½ of smoker

• Within 15 years: risk of coronary heart disease equal of nonsmoker