Cigarettes with Reduced Tar Yield

for฀ Standardization,฀ founded฀ in฀ 1946฀ to฀ promote฀ worldwide฀ trade฀ and฀ collaboration.฀ Agencies฀in฀the฀USA฀including฀the฀Federal฀Trade฀Commission,฀the฀FDA฀and฀the฀National฀ Cancer฀Institute฀are฀now฀working฀towards฀a฀useful฀solution฀to฀the฀problem.฀The฀European฀ Commission฀is฀also฀preparing฀proposals฀for฀the฀correct฀measurement฀of฀tar฀and฀nicotine฀ yields฀in฀cigarettes. A฀few฀smokers฀may฀actually฀beneit฀minimally฀from฀low-tar฀cigarettes,฀but฀the฀health฀ consequences฀in฀a฀positive฀sense฀have฀not฀yet฀been฀demonstrated.฀However,฀it฀has฀been฀ shown฀that฀deeper฀inhalation฀is฀associated฀with฀an฀increase฀in฀adenocarcinomas,฀a฀type฀of฀ cancer฀rarely฀seen฀in฀the฀past฀and฀affecting฀the฀deep฀sections฀of฀lung฀tissue.฀One฀study฀ published฀in฀1997฀presented฀summary฀data฀on฀smokers฀who฀had฀smoked฀light฀and฀ultra- light฀cigarettes฀over฀the฀period฀from฀1959฀to฀1991฀and฀who฀were฀found฀to฀have฀an฀increased฀ incidence฀of฀adenocarcinomas;฀these฀tumours฀were฀found฀to฀occur฀17฀times฀more฀com- monly฀in฀women฀and฀10฀times฀more฀commonly฀in฀men฀ [90,฀91] . In฀2003,฀Kabat฀published฀a฀review฀on฀50฀years’฀experience฀of฀reduced-tar฀cigarettes฀and฀ posed฀the฀question฀about฀the฀known฀health฀effects฀ [92] .฀It฀was฀stated฀that฀since฀1950s,฀ciga- rettes฀sold฀in฀the฀United฀States฀have฀undergone฀a฀progressive฀modiication,฀including฀the฀ addition฀of฀ilters฀and฀a฀reduction฀in฀the฀average฀machine-measured฀tar฀and฀nicotine฀yield฀ per฀cigarette฀by฀over฀60.฀These฀and฀other฀temporal฀changes฀in฀manufactured฀cigarettes,฀ coupled฀with฀the฀complexity฀of฀smoking฀behaviour,฀make฀it฀dificult฀to฀assess฀the฀impact฀ of฀the฀newer฀cigarettes฀on฀health.฀Some฀researchers฀have฀suggested฀that฀the฀newer฀prod- ucts,฀marketed฀as฀being฀less฀harmful,฀may฀in฀fact฀provide฀no฀beneit฀compared฀to฀the฀older,฀ higher฀tar฀cigarettes.฀Kabat฀critically฀evaluated฀the฀available฀epidemiologic฀evidence฀on฀ the฀health฀effects฀of฀low-tar฀cigarettes.฀After฀identifying฀important฀methodological฀prob- lems฀ confronting฀ research฀ in฀ this฀ area,฀ studies฀ of฀ lung฀ cancer,฀ coronary฀ heart฀ disease,฀ chronic฀obstructive฀pulmonary฀disease฀and฀total฀mortality฀were฀examined฀in฀terms฀of฀their฀ strengths฀and฀weaknesses฀and฀their฀results.฀Thirty-ive฀studies฀of฀lung฀cancer฀were฀found฀ to฀be฀suggestive฀that฀smokers฀of฀low฀tar฀cigarettes฀have฀a฀lower฀risk฀by฀20–30฀com- pared฀to฀smokers฀of฀higher฀tar฀cigarettes.฀Only฀a฀minority฀of฀studies฀of฀heart฀disease฀pro- vided฀evidence฀of฀a฀reduction฀in฀risk,฀on฀the฀order฀of฀10.฀Studies฀concerning฀chronic฀ obstructive฀ pulmonary฀ disease฀ COPD฀ were฀ inconsistent,฀ but฀ the฀ majority฀ suggest฀ decreased฀risk฀in฀smokers฀of฀lower฀tar฀cigarettes.฀Finally,฀studies฀that฀included฀total฀mor- tality฀indicated฀with฀a฀high฀degree฀of฀consistency฀that฀the฀total฀death฀rate฀is฀reduced฀in฀ smokers฀of฀lower฀tar฀cigarettes,฀on฀the฀order฀of฀10–20฀ [92] . However,฀there฀are฀also฀studies฀that฀indicate฀that฀there฀are฀no฀major฀changes฀and฀addi- tional฀analyses฀of฀existing฀data฀sets฀could฀further฀clarify฀the฀impact฀of฀low-tar฀cigarettes.฀ In฀this฀respect,฀a฀further฀analysis฀by฀Thun฀and฀Burns฀also฀examined฀the฀epidemiological฀ evidence฀relevant฀to฀the฀health฀consequences฀of฀“reduced฀yield”฀cigarettes฀ [93] .฀They฀con- clude฀that฀some฀epidemiological฀studies฀have฀found฀attenuated฀risk฀of฀lung฀cancer,฀but฀not฀ other฀diseases,฀among฀people฀who฀smoke฀“reduced฀yield”฀cigarettes฀compared฀to฀smokers฀ of฀uniltered,฀high฀yield฀products.฀These฀studies฀probably฀overestimated฀the฀magnitude฀of฀ any฀association฀with฀lung฀cancer฀by฀overadjusting฀for฀the฀number฀of฀cigarettes฀smoked฀per฀ day฀one฀aspect฀of฀compensatory฀smoking฀and฀by฀not฀fully฀considering฀other฀differences฀ between฀smokers฀of฀“high฀yield”฀and฀“low฀yield”฀cigarettes.฀Selected฀cohort฀studies฀in฀the฀ USA฀and฀UK฀were฀found฀that฀showed฀that฀lung฀cancer฀risk฀continued฀to฀increase฀among฀ older฀smokers฀from฀the฀1950s฀to฀the฀1980s,฀despite฀the฀widespread฀adoption฀of฀lower฀yield฀ cigarettes.฀The฀change฀to฀ilter฀tip฀products฀was฀found฀not฀to฀prevent฀a฀progressive฀increase฀ in฀lung฀cancer฀risk฀among฀male฀smokers฀who฀began฀smoking฀during฀and฀after฀the฀second฀ world฀war฀compared฀to฀the฀irst฀world฀war฀era฀smokers฀ [93] . National฀trends฀in฀vital฀statistics฀data฀showed฀declining฀lung฀cancer฀death฀rates฀in฀young฀ adults,฀especially฀males,฀in฀many฀countries,฀but฀the฀extent฀to฀which฀this฀is฀attributable฀to฀ “reduced฀yield”฀cigarettes฀remained฀unclear.฀No฀studies฀have฀adequately฀assessed฀whether฀ health฀claims฀used฀to฀market฀“reduced฀yield”฀cigarettes฀delay฀cessation฀among฀smokers฀ who฀ might฀ otherwise฀ quit,฀ or฀ increase฀ initiation฀ among฀ non-smokers.฀ Thun฀ and฀ Burns฀ stated฀ that฀ there฀ is฀ no฀ convincing฀ evidence฀ that฀ past฀ changes฀ in฀ cigarette฀ design฀ have฀ resulted฀in฀an฀important฀health฀beneit฀to฀either฀smokers฀or฀the฀whole฀population฀ [93] .

3.6 Snuff Tobacco

Snuff฀tobacco฀has฀been฀used฀in฀England฀since฀the฀seventeenth฀century฀and฀had฀already฀ gained฀ worldwide฀ popularity฀ by฀ the฀ eighteenth฀ century.฀ In฀ eighteenth-century฀ France,฀ snuff฀taking฀was฀so฀intensive฀that฀olfactory฀disturbances฀through฀to฀total฀loss฀of฀the฀sense฀ of฀smell฀were฀widespread฀ [94] .฀For฀the฀most฀part,฀dark,฀strong฀tobacco฀varieties฀Kentucky฀ or฀Virginia฀are฀used฀for฀the฀preparation฀of฀snuff฀tobacco:฀in฀earlier฀times,฀after฀crushing,฀ drying฀and฀multiple฀fermentation,฀these฀were฀stored฀for฀4–7฀years฀as฀“carottes”฀pressed฀ and฀shaped฀tobacco.฀Only฀then฀was฀the฀tobacco฀ground฀down฀to฀a฀ine฀powder฀and฀per- fumed฀with฀a฀variety฀of฀aromatic฀substances฀oil฀of฀roses,฀lavender,฀garlic฀and฀jasmine,฀ menthol,฀etc..฀Larger฀quantities฀of฀nicotine฀are฀absorbed฀slowly฀from฀snuff฀tobacco฀across฀ the฀nasal฀mucosa฀Table฀4.5. As฀with฀cigarette฀smoking,฀the฀desired฀effect฀of฀snuff-taking฀is฀for฀nicotine฀to฀reach฀the฀ central฀nervous฀system฀ Chap.฀4.3 .฀Snuff฀users฀very฀often฀report฀a฀calming฀or฀stimulating฀ effect,฀as฀well฀as฀an฀increased฀ability฀to฀concentrate฀and฀a฀sense฀of฀wish-fulilment฀as฀part฀ of฀a฀reward฀system฀see฀ Chap.฀7.1.2 .The฀content฀of฀various฀nitrosamines฀Box฀ 3.1–3.3 ฀in฀ the฀snuff฀of฀different฀origin฀shows฀great฀differences฀Table฀ 3.8 . In฀Germany,฀snuff฀tobacco฀use฀is฀encountered฀only฀in฀a฀few฀individuals,฀most฀com- monly฀still฀in฀Bavaria.฀By฀contrast,฀snuff฀use฀is฀widespread฀in฀India฀and฀the฀Sudan,฀and฀ considerable฀adverse฀effects฀on฀health฀are฀encountered฀in฀the฀population฀also฀because฀of฀ the฀type฀of฀snuff฀tobacco฀used฀known฀as฀“toombak”฀in฀the฀Sudan฀ [95] .฀In฀India,฀2.8฀mil- lion฀kg฀of฀snuff฀tobacco฀are฀consumed฀annually,฀corresponding฀to฀an฀annual฀consumption฀ of฀1.1–1.2฀kg฀per฀adult฀ [96] . The฀tobacco฀used฀in฀India฀is฀produced฀from฀Nicotiana฀rustica฀mixed฀with฀a฀solution฀of฀ bicarbonate฀and฀has฀a฀pH฀of฀8–11.฀The฀moisture฀content฀is฀between฀6฀and฀60฀and฀the฀nico- tine฀content฀ranges฀from฀8฀to฀102฀mgg฀dried฀weight.฀Snuff฀tobacco฀brands฀differ฀in฀terms฀of฀ the฀tobacco฀variety฀used,฀fermentation฀method,฀ageing฀process,฀tobacco-speciic฀nitrosamines฀ present฀and฀expression฀of฀the฀p53฀suppressor฀gene฀important฀for฀cancer฀development. Due฀to฀its฀nicotine฀content,฀snuff฀tobacco฀initially฀causes฀increased฀secretion฀followed฀ by฀a฀long-lasting฀reduction฀in฀mucus฀production.฀In฀addition,฀the฀vessels฀in฀the฀venous฀ networks฀ in฀ the฀ middle฀ and฀ deeper฀ layers฀ of฀ the฀ nasal฀ mucosa฀ undergo฀ constriction,฀ Box 3.2 ฀฀฀Volatile฀nitrosamines฀in฀tobacco:฀NDMA฀dimethylamine;฀NEMA฀ethylmethylamine;฀NDEA฀ diethylamine;฀NDPA฀dipropylamine;฀NDBA฀dibutylamine;฀NPYR฀pyrrolidine;฀NPIP฀piperidine;฀ NMOR฀morpholine Me Me N NO Me Et N NO Et Et N NO Bu Bu N N N N O NO NO NO NO Pr Pr N NO NDPA NPYR NPIP NMOR NDBA NDEA NEMA NDMA Box 3.1 ฀฀฀Tobacco-speciic฀nitrosamines฀TSNA.฀NNN฀nitrosonornicotine;฀NAT฀N-nitrosoanatabine;฀ NAB฀ N-nitrosoanabatine;฀ iso-NNAL฀ 4-N-nitrosomethylamino-4-3-pyridyl-1-butanol;฀ NNK฀฀ 4-฀N-nitrosomethylamino-4-3-pyridyl-butanone;฀NNAL฀4-N-nitrosomethylamino-1-3-pyridyl- 1-butanol N CH 3 CH 3 CH 3 CH 3 N N NO NO NO NO NO NO NNN NAT NAB Anabasine Anatabine Nornicotine Nicotine iso-NNAL NNK NNAL N N N H N N OH OH O N N N N N N