Cigarette Smoking and Cancer Risk Epidemiology 242 Cancer

Cigarette Smoking and Cancer Risk Epidemiology 242: Cancer Epidemiology 2009

Prevalence of Cigarette Smoking § 1880 to after World War 1, cigarette represented a small proportion of overall tobacco consumption. § 1920 -1945, cigarettes rose dramatically and commercially produced cigarettes became the dominant form of tobacco § 1945 -1965, cigarette consumption leveled off § 1965 -1995, cigarette consumption declined dramatically

Trends in Per Capita Consumption of Various Tobacco Products – United States, 1880 -2001 Source: Tobacco Situation and Outlook Report, U. S. Department of Agriculture, U. S. Census Note: Among persons >18 years old. Beginning in 1982, fine-cut chewing tobacco was reclassified as snuff.

Adult Per Capita Cigarette Consumption and Major Smoking and Health Events – United States, 1900 -2001 1 st World Conference on Smoking and Health 1 st Surgeon General’s Report Broadcast Ad Ban 1 st Great American Smoke-out End of WW II OTC Nicotine Medications Master Settlement Agreement Fairness Doctrine Messages on TV and Radio 1 st Smoking-Cancer Concern Non-Smokers Rights Movement Begins Surgeon General’s Report on ETS Federal Cigarette Tax Doubles Great Depression Source: United States Department of Agriculture

Decreased Cigarette Consumption in the US since 1965 § Since 1950, scientific reports linking cigarette smoking with cancers and other chronic diseases § Bans on TV and radio advertising § The growth of the nonsmokers rights movement § A dramatic increase in federal and state cigarette tax

Trends in cigarette smoking* among adults aged >18 years, by sex - United States, 1955 -2002 Men Women 24. 5% 18. 8% *Before 1992, current smokers were defined as persons who reported having smoked >100 cigarettes and who currently smoked. Since 1992, current smokers were defined as persons who reported having smoked >100 cigarettes during their lifetime and who reported now smoking every day or some days. Source: 1955 Current Population Survey; 1965 -2002 National Health Interview Survey; 2002 estimates for first quarter only

Current Use Among U. S. Adults of Various Tobacco Products, by Sex – National Health Interview Survey, 2000 31. 3 25. 7 21. 3 21. 0 4. 5 0. 2 1. 0 2. 5 0. 1 2. 5 0. 2 0. 1 Note: Current users report using either every day or on some days Source: National Center for Health Statistics

Restrictiveness Of State Laws Regulating Smoking In Public Places – U. S. , 1960 -2001 Sources: 1989 Surgeon General’s Report, ALA’s SLATI, CDC’s STATE system, Roswell Park Cancer Institute. Note: Includes the District of Columbia; Alabama = only state with no restrictions on public smoking.

Number of U. S. States including D. C. *, with Legislation Restricting the Purchase of Cigarettes to Persons aged >18 years, 1988 -2001 *District of Columbia Source: “State Legislated Actions On Tobacco Issues”, 1988 -2001, CDC’s STATE system, Roswell Park Cancer Institute.

Smoking in Young People § 3 million young people under age 18 smoke half a billion cigarettes each year and that more than one-half of them consider themselves dependent upon cigarettes. § The decision to use tobacco is nearly always made in the teen years, and about one-half of young people usually continue to use tobacco products as adults.

Age at Initiation of Smoking § The initiation of daily smoking most often occurs in grades six through nine among children between the ages of 11 and 14. About half (51. 3%) of high-school seniors who smoke daily began smoking by age 15. § About 80% of regular smokers started smoking before the age of 18.

Stages of Initiation (Flay) Preparatory stage Never smokes Trying stage No longer smokes Experimental stage No longer smokes Regular use Quits smoking Addiction/Dependent smoker

Cumulative Age of Initiation of Cigarette Smoking* Among Persons Aged 30 – 39 Years—United States, 1996 -1998 Age First Tried a Cigarette Age Began Smoking Daily * Among persons 30 -39 years old who have ever smoked daily Source: National Household Survey on Drug Abuse, 1996 -1998 public use data tapes

Incidence of Initiation of Cigarette Smoking*, by Age -- United States, 1994/1995 Source: National Household Survey on Drug Abuse, 1994 -B and 1995 public use data tapes. *Among persons 12 -39 years old.

Cigarette Smoking among youth and adults in 24 states and the District of Columbia, 1997 KY SD NV UT DC r 2 = 0. 552 ß = 0. 940 P < 0. 001 N = 25 Sources: 1997 Youth Risk Behavior Survey (14 -18 year old public school students) 1997 Behavioral Risk Factor Survey (adults 18+ years old) Note: Frequent Smoking among youth = smoking on > 20 days during the previous 30 days Adult current smoking = smoking every day or on some days

Trends in cigarette smoking* among adults aged >18 years, by sex - United States, 1955 -2002 Men Women 24. 5% 18. 8% *Before 1992, current smokers were defined as persons who reported having smoked >100 cigarettes and who currently smoked. Since 1992, current smokers were defined as persons who reported having smoked >100 cigarettes during their lifetime and who reported now smoking every day or some days. Source: 1955 Current Population Survey; 1965 -2002 National Health Interview Survey; 2002 estimates for first quarter only

Heavy Cigarette Smoking* Among Adults Aged 18+ by Gender – United States, 1974 -2000 Men Women Source: NHS, 1974 -2000 *Smoking 25+ cigarettes per day

Percentage of Ever Smokers* Who Have Quit, Adults Aged > 18 Years, by Sex-United States, 1965 - 2002 Men Women Source: National Health Interview Surveys, 1965 -2002; 2002 estimate is for first quarter ony Centers for Disease Control and Prevention: National Center for Health Statistics and Office on Smoking and Health. *Ever-smoked >100 cigarettes, Also known as the quit ratio. Note: estimates since 1992 incorporate same-day smoking

Percent of Current Smokers Who Want to Quit by Age and Number of Previous Quit Attempts – United States, 2000 Source: National Center for Health Statistics, NHIS 2000 (with NCI Cancer Supplement)

Estimated Assisted Quit Attempts (in thousands) Annual use of pharmacologic aids to smoking cessation— United States, 1984 -1998 Patches 1/92 Gum OTC 4/96 2 patches OTC 8/96 Nasal spray 8/96 Gum (2 mg) 2/84 Source: CDC. MMWR 2000; 665 -668. Gum (4 mg) 3/93 Zyban 5/97 Vapor inhaler 3/98

Tobacco Control Model of Nicotine Addiction Tobacco Products Agent Environment Familial, Social, Cultural, Political, Economic, Media, Historical Vector Tobacco Industry; Other Users Adapted from: Orleans & Slade, 1993 Host Smoker/Chewer/User Incidental Host Involuntary Smoker

Paradigm for Tobacco Control t Minor’s access t Advertising Individual s Cessation activities s Prevention activities s Clean indoor air s Regulation/Liability s Price/Economic

Tobacco and Addiction § Cigarettes and other forms of tobacco are addictive. Nicotine is the drug in tobacco that causes addiction. § The pharmacologic and behavioral processes that determine tobacco addiction are similar to those that determine addiction to drugs such as heroin and cocaine.

Tobacco Addiction § Nicotine is found in substantial amounts in tobacco § It is absorbed readily from tobacco smoke in the lungs and from smokeless tobacco in the mouth or nose and is rapidly distributed throughout the body.

SGR: Preventing Youth Tobacco Use Criteria for Drug Dependence Primary Criteria Highly controlled or compulsive use Psychoactive effects Drug-reinforced behavior Additional criteria Stereotypic patterns of use Use despite harmful effects Relapse following abstinence Recurrent drug cravings Dependence-producing drugs often manifest the following: Tolerance Physical dependence Pleasant (euphoric) effect Source: Adapted from USDHHS (1988)

Nicotine is A Poison § An injection of one drop of nicotine in its purest form (70 mg) will kill an averagesized man. § Cigarettes contain a very small amount of nicotine (between. 1 and 2. 2 mg). This amount will not kill you, but will make your heart beat faster and can make your hands shake.

Smoking and Health § An estimated 47 million adults in the U. S. smoke cigarettes, which will result in death or disability for half of all regular users § Over 46 million Americans have quit smoking but 3, 000 adolescents try their first cigarette every day.

Chronic Disease and Related Factors *NHCS National Vital Statistics, Vol. 49 Sept. 2001 †Mc. Ginnis JM, Foege WH. Actual causes of death in the United States. JAMA 1992; 270: 2207 -12

Diseases Caused by Tobacco Use Cigarette smoking increases the risk of: Coronary heart disease Atherosclerotic peripheral vascular disease Cerebrovascular disease Cancers of the lung, larynx, mouth, esophagus, bladder, pancreas, kidney, and cervix Chronic obstructive pulmonary disease Intrauterine growth retardation, premature rupture of membranes Low-birthweight babies, perinatal mortality Cataract, macular degeneration; hip fracture Peptic ulcer disease Possibly liver, stomach, and colorectal cancers and acute myelocytic leukemia

Disease Caused by Tobacco Use Involuntary smoking (environmental tobacco smoke) is a cause of: Lung cancer and coronary heart disease in nonsmokers Respiratory infections and symptoms in the children of parents who smoke Smokeless tobacco causes: Oral Cancer Oral leukoplakia Dental caries (possibly) Cigars cause: Cancers of the mouth, larynx, and lung Coronary heart disease COPD

Domestic Market Share of Cigarettes by Tar Yield, Filter Status, Length, and Menthol Status: United States, 1963 - 2000 Filter <15 mg. tar yield > 94 mm. Menthol Source: United States Department of Agriculture, 1962; Federal Trade Commission, 2001

Smoking and Health § It is estimated that every cigarette a person smokes takes about 12 minutes off his or her life. § Smoking increases your risk of getting many serious diseases including cancer, heart disease, emphysema and bronchitis.

Year of Potential Life Lost (YPLL) § 65 – age at death form smoking related disease: 1, 152, 635 YPLL § Current gender-specific life expectancy – age at death from smoking related diseases: 5, 048, 740 YPLL

Smoking and Health § Direct medical care cost from smoking related diseases were estimated to be $50 billion in 1993 § Another $50 billion in indirect costs, such as time lost from work, housekeeping expenses, and lost income, etc.

Tobacco Smoking § Tobacco smoke contains over 4, 000 chemical compounds § includes at least 60 different carcinogenic substances.

§ § § § § Group 1: Carcinogenic to Humans Tobacco Smoking Tobacco Products, Smokeless 4 -Aminobiphenyl (4 -ABP) Benzene Carmium Chromium 2 -Naphthylamine (2 -NA) Nickel Polonium-210 (Radon) Vinyl Chloride

Group 2 A: Probably Carcinogenic to Humans § § § § Acrylonitrile Benzo[a]pyrene Benzo[a]anthracene 1, 3 -Butadiene Dibenz(a, h)anthracene Formaldehyde N-Nitrosodiethylamine N-Nitrosodimethylamine

Tobacco Smoking and Lung Cancer

Smoking and Lung Cancer § Smoking accounts for more than 85% of all lung cancer deaths. § The risk of developing lung cancer is affected by the number and type of cigarettes smoked and the numbers of years a person has been smoking.

Lung Cancer: Distributions § The commonest cancer in the world (1. 2 million new cases in 2000, 12. 3% of all new cases) § 52% in the developed countries and 48% in the developing countries § More common in men (75%) than in women § Areas with highest incidence include Europe (Eastern Europe), North America, Australia /New Zealand, and Southern America. § The rates in China, Japan, and Southeast Asia are moderately high.

Lung Cancer: Distributions § For US blacks, New Zealand Maoris men, about 13% chance of developing a lung cancer before the age of 75 years. § In developing countries, the highest rate are seen where the tobacco smoking habit has been longest established – the Middle East, China, the Caribbean, South Africa, Zimbabwe, and the Pacific.

Lung Cancer: Distributions § In women, the highest rates are observed in North America and North West Europe (UK, Iceland, Denmark) with moderate incidence rates in Australia and New Zealand China.

Lung Cancer: Cigarette Smoking § Overall, 86% of cases in men and 49% in women are due to smoking. § For regions with longest history of smoking, 90% cases in men. The proportions are more variable in women from 0% to 80% (UK)

Lung Cancer: Cigarette Smoking § The most important cause of lung cancer § A clear dose-response relationship between lung cancer risk and the number of cigarettes smoked per day, degree of inhalation and age at initiation § A life-time smoker has a risk 20 -30 times that of a non-smoker. § The risk is diminished in smokers of filter and low tar cigarettes and increasing use of these has contributed to declines in risk in recent generations of smokers (as well as the declining prevalence of smoking)

Lung Cancer: Other Tobacco § The early observation that pipe-smokers and smokers of cigars had a lower risk of lung cancer than cigarette smokers is due to the lesser amount of tobacco smoked and to the lower degree of inhalation. § Smokers of other types of tobacco (e. g. bidis in India) are at similar risk to smokers of cigarette.

Lung Cancer: Histological Types and Smoking § Smoking is related to all histological types of lung cancer § The relative risk is greater for squamous-cell and small-cell carcinomas than for adenocarcinomas. § Adenocarcinoma is more common in women than men in both smokers and non-smokers. § Risk of lung cancer between men and women at equivalent levels of exposure is similar.

Lung Cancer: Other Risk Factors § Passive smoking may increase 30 -50% of risk § Family history of lung cancer may also related to lung cancer risk, which is probably because of polymorphisms of genetic metabolic genes. § Chinese female non-smokers have a high risk of adenocarcinoma, which may be related to exposure to cooking fumes, indoor smoky coal emission, or air pollution.

Lung Cancer: Other Risk Factors § Occupational exposures to asbestos, some metals (nickel, arsenic and cadmium), radon (among miners) and ionizing radiation. § Diet high in vegetables and fruits can protect against lung cancer. Although intakes of carotenoids is associated with decreased risk, beta-carotene does not prevent lung cancer, in 3 intervention trials.

Lung Cancer: Time Trends § Trends in lung cancer incidence and mortality reflect the maturity of the smoking epidemic in different countries. § Study of time trends in lung cancer incidence or mortality by age group shows that the level of risk is closely related to the birth cohort, or the cohort specific incidence is related to the smoking habit of the same generation.

Lung Cancer: Time Trends § Decreased smoking prevalence leads to a decreased risk of lung cancer in several countries such as U. K. , Finland, Australia, the Netherlands, New Zealand, the USA, Singapore, and more recently Denmark, Germany, Italy, and Sweden. § In most other countries, there is a continuing rise in rates, and this is most dramatic in the countries of Eastern Europe. § In women, with increase smoking prevalence, the risk of lung cancer increase.

Ecological Observation of Smoking Prevalence and Lung Cancer Incidence § Male lung cancer incidence started to decrease in 1980’s and early 1990’s, which is the direct result of the dramatic decrease in smoking prevalence during 1960 s and 1970 s § The rise in lung cancer incidence rates among women during 1970 s and early 1980 s and ended in the early 1990 s is also the direct result of increase prevalence of smoking several decades ago.

The Consistency of the Association § In 1984 surgeon general’s report, 29 retrospective and 7 prospective studies have all demonstrated an association between cigarette smoking and lung cancer § Similar findings had thus reported from a large number of studies by different investigators, using different methodological approaches, and in different populations

First Two Case-Control Studies § A case-control study included 1045 lung cancer cases and 605 controls at Roswell Park Memorial Institute at Buffalo by Levin et al. (1950) § A case-control study included 684 lung cancer cases and 780 controls by Wynder et al. (1950)

The Strength of the Association § In men, the relative risk ranged from 3. 8 to 14. 2 § In women, the relative risk ranged from 2 to 5 § Men and women who smoked one of more packs per day experienced a 25 to 30 -fold increased risk of dying from lung cancer when compared with non-smokers

RR of lung cancer for current smoking of cigarette only. IARC, 1986 14. 9 14 12. 1 9. 9 9. 2 9. 5 7. 0 Canada Sweden US Vets

Dose-Response Relationship § The existence of a dose-response relationship between smoking and lung cancer constitutes further evidence of a causal relationship. § Many studies have demonstrated a doseresponse relationship between cigarette smoked per day, years of smoking and pack -years of smoking and lung cancer.

Specificity of the Association § The degree of specificity between lung cancer and smoking is measured by the attributable risk. § It is estimated that 85% to 90% of lung cancer deaths in men is due to cigarette smoking § The observation that all smokers do not develop lung cancer indicate the genetic susceptibility, competing causes of death.

Temporal Relationship § Temporal relationship is approved by several prospective cohort studies when exposure to cigarette smoking was obtained before the occurrence of lung cancer § The latent period between first exposure and the onset of the disease is about 20 -30 years

Coherence of the Association § Distribution of the disease and of the cigarette smoking are similar with regards to person, place, and time. § Rapid rise in cigarette consumption resulted in the rapid rise of lung cancer after a period of latency. § The distribution of cigarette smoking among sexes, among rural and urban residents, and among different socioeconomic classes was similar to the distribution of lung cancer among these groups. § These who quit smoking had a decreased risk.

Biological Credibility § § § Over 60 carcinogens in cigarette smoking Carcinogens may cause DNA damage Mutation of Tumor suppresser genes are linked to cigarette smoking § Animal studies also support the relationship between cigarette smoking and lung cancer.

Prospects for Prevention § Smoking cessation among smokers § Reinforcing social pressure to make smoking unattractive and difficult for adolescents to start smoking § Early detection of early lesions, by x-ray or other means

Smoking and Other Cancers § Head and neck cancers (oral, laryngeal and pharyngeal cancers) § Esophageal cancer § Stomach cancer § Pancreatic Cancer § Bladder cancer § Cervical cancer § Liver cancer

Environmental Tobacco Smoke § 3, 000 nonsmoking Americans die of lung cancer § 300, 000 children suffer from lower respiratory tract infections.

Major Sources of Data on Tobacco Use in the United States Surveys of Young People • Teenage Tobacco Surveys • Monitoring the Future Surveys (MTFS) • National Household Survey on Drug Abuse (NHSDA) • National Health and Nutrition Examination Survey (NHANES) • Youth Risk Behavior Surveillance System (YRBSS) • National Youth Tobacco Survey (NYTS) • Youth Tobacco Survey (YTS) • Global Youth Tobacco Survey (GYTS) • Legacy Media Tacking Surveys

Major Sources of Data on Tobacco Use in the United States Surveys of Adults • Current Population Surveys (CPS) • Adult Use of Tobacco Surveys (AUTS); Adult Tobacco Surveys (ATS) • National Health Interview Survey (NHIS) • National Household Survey on Drug Abuse (NHSDA) • National Health and Nutrition Examination Survey (NHANES) • Behavioral Risk Factor Surveillance System (BRFSS) • American Smoking and Health Survey (ASHES)

A bidi is a small, flavored, filterless cigarette made in India. A bidi is a dried tendu leaf rolled around tobacco, usually tied with a red string. They come in a variety of flavors, including vanilla, cherry, menthol, and chocolate etc.