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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence 6 Overview of Key Studies of the Effects of Smoking Bans on Acute Coronary Events In this chapter, the committee discusses key studies, and 11 publications from those studies, of the effects of smoking bans on acute coronary events. The articles reviewed in this chapter address two of the associations that the committee is evaluating: The association between secondhand-smoke exposure and acute coronary events (Questions 2, 3, and 5, see Box 1-1). The association between smoking bans and acute coronary events (Questions 4, 5, 6, 7, and 8, see Box 1-1). Eleven publications deal with studies that looked at the effects of smoking bans in eight natural experiments: three studies in overlapping regions of Italy (Barone-Adesi et al., 2006; Cesaroni et al., 2008; Vasselli et al., 2008); one study in Pueblo, Colorado, after 18 months of followup (Bartecchi et al., 2006) and after 3 years of followup (CDC, 2009); and one study each in Helena, Montana (Sargent et al., 2004), Monroe County, Indiana (Seo and Torabi, 2007), Bowling Green, Ohio (Khuder et al., 2007), New York state (Juster et al., 2007), Saskatoon, Canada (Lemstra et al., 2008), and Scotland (Pell et al., 2008). The legislation in Bowling Green, Ohio, allowed smoking in some restaurants and bars; it called for a smoking restriction rather than a smoking ban. The studies examined changes in heart-attack rates, or acute myocardial infarctions (acute MIs) after the implementation of the bans (and one restriction) and were not designed to answer questions about the association between exposure to secondhand smoke and cardiovascular disease. Most of the studies did not measure individual exposures
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence to secondhand smoke or the smoking status of individuals; thus, they were designed to evaluate the association between smoking bans and acute MIs, not the effects of secondhand-smoke exposure. The publications on the smoking bans in Monroe County, Indiana, and Scotland, however, contain data on smoking status and results of analyses only in nonsmokers; these two studies were designed to assess the association between secondhand-smoke exposure and acute MIs. The committee discusses the studies below, including information on the smoking bans and restriction in the different locations, available information on secondhand-smoke exposure, study designs, and study results. Publications that examine the effect of the same smoking ban are discussed together; the most comprehensive or recent publication is discussed first. The different smoking bans are discussed in order by earliest publication date. Details of the smoking bans and restriction in the different regions are presented in Table 6-1; available information on the effect of the bans on potential secondhand smoke exposure—including data on enforcement and compliance, air monitoring, and biomonitoring—is presented in Table 6-2; and details of the study designs and published results are presented in Table 6-3. HELENA, MONTANA Smoking Ban and Exposure Information Helena, Montana, enacted and enforced legislation requiring smoke-free workplaces and public places for the period June 5–December 3, 2002. The legislation banned smoking in restaurants, bars, and other workplaces and protected an estimated population of 28,726 (ANRF, 2009). One publication examined the relationship between the Helena smoking ban and acute coronary events (Sargent et al., 2004). The committee did not identify any studies reporting air monitoring or biomonitoring for potential secondhand-smoke exposure in Helena before and after the ban compared with during the ban. Regarding compliance, Sargent et al. (2004) state that “the city–county health department reported that all but two businesses complied” with the ordinance, citing a letter to the editor of the Helena Independent Review. The study provided information directly related to the association between smoking bans and acute coronary events. Published Results on Acute Coronary Events Sargent et al. (2004) studied the effect of the smoking-ban legislation on hospital admissions for acute MI in Helena, Montana. The study
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence TABLE 6-1 Characteristics of Smoking Bans Assessed in Key Surveillance Studies Location Referencesa Effective Date Restaurants Bars Workplaces Other Helena, Montanab Sargent et al., 2004 6/05/2002 Gaming establishments Italy Barone-Adesi, 2006; Cesaroni et al., 2008; Vasselli et al., 2008 1/10/2005 Retail shops, cafés, discotheques Pueblo, Colorado Bartecchi et al., 2006; CDC, 2009 7/01/2003 Monroe County, Indiana Seo and Torabi, 2007 8/01/2003 (effective 1/1/2005) Bowling Green, Ohio Khuder et al., 2007 03/2002 (except isolated bar, isolated smoking area) Bars at owner discretion Bowling alleys at owner discretion New York statec Juster et al., 2007 7/24/2003 Saskatoon, Canada Lemstra et al., 2008 7/01/2004 Scotlandd Pell et al., 2008 03/2006 a Data from cited references unless otherwise stated. b Information on smoking-ban locations also from helenair.com (http://www.helenair.com/articles/2002/09/25/stories/helena/1a2.txt), accessed July 2009. c A number of local smoking bans and restrictions were in place in New York state before the implementation of the statewide ban. d Exceptions included “residential accommodation and designated room in hotels, care homes, hospices, and psychiatric units” (Haw and Gruer, 2007).
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence TABLE 6-2 Potential Secondhand-Smoke Exposure Reductions in Key Publicationsa Location of Ban (Implementation Date) Smoking Ban Details Helena, Montana (June 5, 2002; rescinded December 3, 2002) No prior ban mentioned Legislation to require smoke-free workplaces and public places; suspended as a result of litigation after about 6 months Smoking banned in restaurants, bars, other workplaces Italy (January 10, 2005) Ban on smoking in all indoor public places, including offices, retail shops, cafes, bars, restaurants, discotheques in Italy; provision for smoking rooms Pueblo, Colorado (July 1, 2003) Ban prohibiting smoking in workplaces, all public buildings (including restaurants, bars, bowling alleys, other business establishments) within city limits Monroe County, Indiana (August 1, 2003; extended to bars January 1, 2005) Ban in all restaurants, retail stores, workplaces; extended to previously exempt bars and clubs January 1, 2005 Bowling Green, Ohio (March 2002) Ban in public places except bars, restaurants with bars if bars are isolated with separate smoking areas; bars, bowling alleys could allow smoking at owners’ discretion
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence Information on Decreased Exposure or Compliance No air monitoring, but key publication (Sargent et al., 2004) refers to newspaper letter to editor that reports that City–County Health Department reported that all but two businesses complied No information in key publications looking at acute MI (Barone-Adesi et al., 2006; Cesaroni et al., 2008) Survey indicated that almost 90% of surveyed population (selected locations in Italy) perceived that ban was observed in bars, restaurants; 70% in workplaces (Gallus et al., 2006) Letter to editor presented data on nicotine vapor phase in pubs, discos in Florence before, after implementation of ban; pre-implementation median, 138.9 μg/m3 (range, 33.0–276.5 μg/m3), postimplementation median, 4.5 μg/m3 (range, 1.7–8.7 μg/m3)—decreased to average of 3.2% of the pre-ban concentrations (Gorini et al., 2005) Fine, ultrafine particles before and after implementation in 40 establishments in Rome, urinary cotinine in nonsmoking employees (Valente et al., 2007): Average PM2.5: decreased from 119.3 μg/m3 to 38.2 μg/m3 (p < 0.005), 43.3 μg/m3 (p < 0.01) 2–3 months, 11–12 months after implementation, respectively Average ultrafine particles: decreased but not to as great an extent—from 76,956 particles/cm3 to 38,079 particles/cm3 (p < 0.0001), 51,692 particles/cm3 (p < 0.01) 2–3 months, 11–12 months after implementation, respectively Average urinary cotinine: decreased from 17.8 ng/mL (95% CI, 14–21.6 ng/mL) to 5.5 ng/mL (95% CI, 3.8–7.2), 3.7 ng/mL (95% CI, 1.8–5.6 ng/mL) 2–3 months, 11–12 months after implementation, respectively No information on decreased concentrations of SHS components, but enforcement officials strongly supported ban with strict fines and ban was implemented after vote indicating public support for it (Bartecchi et al., 2006; CDC, 2009) No information on decreased concentrations of SHS components or compliance (Seo and Torabi, 2007) No information on concentrations of SHS components or compliance provided in key health publication (Khuder et al., 2007) Concentrations of SHS-related compounds (including nicotine, 3-ethenylpyridine, total RSP, RSP based on Solanesol, UVPM, FPM) in four restaurants, one smoke-free and one smoking (that is, with bar) each in Toledo, Bowling Green, Ohio; data from previous study were compared with data from average concentrations in two cities combined; analyses indicated that concentrations of SHS-related contaminants did not change after smoking restrictions, but concentrations were lower in nonsmoking restaurants than restaurants that allow smoking in separate areas (Akbar-Khanzadeh et al., 2004)
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence Location of Ban (Implementation Date) Smoking Ban Details New York state (July 24, 2003) New York’s Clean Indoor Air Act is 100% statewide ban on smoking in all workplaces, including restaurants, bars, gaming establishments, with limited exceptions Statewide smoking restrictions (limiting or prohibiting smoking in some public places, such as schools, hospitals, public buildings, retail stores) had been implemented in 1989 Previously, smoking bans of various levels implemented at city or county level in some parts of state, including ban in workplaces—such as restaurants, bars—in New York City, several other large jurisdictions State law does not pre-empt passage of local laws Saskatoon, Canada (July 1, 2004) Smoking ban in city of Saskatoon prohibiting smoking in any enclosed public space open to public or to which public is customarily admitted or invited; smoking also prohibited in outdoor seating areas for restaurants, licensed premises Previously, smoking prohibited in government buildings As of January 1, 2005, 100% smoke-free law in all public places, workplaces, including restaurants, bars, bingo halls, bowling alleys, casinos in Saskatchewan; local municipalities have right to enact smoke-free air regulations Scotland (March 2006) Smoking prohibited in all enclosed public places, workplaces throughout Scotland, including bars, pubs, restaurants, cafes; exceptions included residential accommodations, designated rooms in hotels, care homes, hospices, psychiatric units Abbreviations: CI, confidence interval; FPM, fluorescent particulate matter; MI, myocardial infarction; NYATS, New York Adult Tobacco Survey; PM, particulate matter; RSP, respirable suspended particulate matter; SHS, secondhand smoke; UVPM, respirable suspended ultraviolet particulate matter. a This table contains information on the concentration of airborne tracers or biomarkers of secondhand smoke in locations of key surveillance studies. The locations are presented in the order they are presented in the text.
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence Information on Decreased Exposure or Compliance No information in key study (Juster et al., 2007), but authors cite NYATS study showing decrease in salivary cotinine from 0.078 ng/mL (range, 0.054–0.111 ng/mL) to 0.041 ng/mL (range, 0.036–0.047 ng/mL) in sample of New York state adults after implementation of ban (CDC, 2007) NYATS (CDC, 2007) also asked about exposures to SHS; number of respondents reporting exposure to SHS in restaurants, bars decreased, but not significantly in workplaces, after implementation of ban: In Restaurants: from 19.8% (95% CI, 15.6–24.1%) reporting exposure to 3.1% (95% CI, 2.0–4.2%) 9–10 months after ban In Bars: from 52.4% (95% CI, 41.5–63.4%) reporting exposure to 13.4% (95% CI, 9.5–17.3%) 10 months after ban In Workplaces: from 13.6% (95% CI, 8.1–19.1%) reporting exposure to 7.6% (95% CI, 5.1–10.2%) 9–10 months after ban Hospitality venues in western New York before, after 2003 ban: average PM2.5 concentration decreased from 324 μg/m3 before implementation of ban to 25 μg/m3 after (p < 0.001) (CDC, 2004) Juster et al. (2007) cite report by Research Triangle Institute, International (RTI International, 2004) that showed that 93% of restaurants, bars, bowling facilities were in compliance in year after implementation Business compliance with ban measured by reviewing warnings, tickets issued by public-health inspectors to eligible businesses; of 924 eligible establishments, 914 were inspected within first 6 months of ban; of 914, only 13 had to be issued noncompliance warning (for not posting signs or not removing ashtrays); one ticket was issued on reinspection (Lemstra et al., 2008) Self-reported survey provided information about exposure to SHS; number of people who had never smoked reporting no exposure to smoke increased (from 57 to 78%; p < 0.001); individual serum cotinine measurements taken; geometric mean in never smokers decreased from 0.68 to 0.56 ng/mL (p < 0.001) after legislation enacted; similar data seen in former smokers (Pell et al., 2008) Before ban, PM2.5 concentrations ranged from 8 to 902 μg/m3 (average, 246 μg/m3); after implementation of ban, concentrations ranged from 6 to 104 μg/m3 (average, 20 μg/m3) (Semple et al., 2007a) In nonsmokers, geometric mean cotinine concentration decreased by more than 39%, from 0.43 to 0.26 ng/mL after implementation of ban (p < 0.001) (Haw and Gruer, 2007) In nonsmokers, geometric mean salivary cotinine concentration decreased from 2.9 ng/mL before ban to 0.7 ng/mL 2 months after and to 0.4 ng/mL 1 year after in 301 bar workers (Semple et al., 2007b) Serum cotinine concentrations in bar workers in Dundee and Perth, Scotland, decreased from 5.15 ng/mL before ban to 3.22 ng/mL 1 month after (reduction of 1.93 ng/mL; 95% CI, 1.03–2.83 ng/mL; p < 0.001) and to 2.93 ng/mL 2 months after (reduction of 2.22 ng/mL; 95% CI, 1.34–3.10 ng/mL; p < 0.001) (Menzies et al., 2006)
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence population included consecutive patients admitted to St. Peter’s Community Hospital with a primary or secondary diagnosis of acute MI (International Classification of Diseases, Revision 9 [ICD-9] 410.xx) during the period December 1997–November 2003. Selection of patients to include in the study was based on a review of paper and electronic medical records and billing records for June–November (the months during which the ban was in effect in 2002) of 1998–2003. Data were included if a patient had primary or secondary acute MI, on the basis of the attending physician’s diagnosis of acute MI, the onset of symptoms occurred in the study area, and there was no recent procedure that could have precipitated the acute MI. If a patient had a secondary diagnosis of acute MI, patient information was included only if there was increased troponin I concentration or creatine phosphokinase activity at admission or within 24 h of admission and there was no recent precipitating procedure. The authors compared the number of hospital admissions during the months when the smoking ban was in effect in 2002 with the average number of admissions during the same months in the 4 years before and 1 year after the ban. A total of 304 admissions met the inclusion criteria. The authors found a statistically significant reduction in the number of hospital admissions during the period when the smoking ban was in effect, from an average of 40 in June–November in the years before and after the ban was in place (1998–2001 and 2003) to a total of 24 admissions in the same months of 2002, when the smoking ban was in effect (16 fewer admissions; 95% confidence interval [CI], 0.3 to 31.7). The authors noted a nonsignificant increase of 5.6 additional events in hospital admissions in the unincorporated area surrounding Helena used as a control during the same study period. An advantage of the study design is that the suspension of enforcement of the smoking ban allowed a “cross-over comparison” of incidence before, during, and after the ban and the presence of a control community. Study limitations included the small population, the reliance on historical controls, and the lack of direct exposure information or information on individual smoking status. The study did not account for the potential effect of the ban on primary smokers (for example, if smokers quit), so direct conclusions can be drawn only on the effect of the smoking ban and associated activities, not on the effect of secondhand-smoke exposure. The study also lacked controls for other cardiovascular risk factors. With regard to the outcome information, collection of data only from records of those who reached the hospital could miss some fatal cases of acute MI, and the criteria for diagnosing acute MI changed during the study period as the hospital began requiring a troponin I concentration for diagnosis. The authors did, however, conduct a regression analysis to test whether troponin I
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence concentration was an important factor in the analysis and found that it did not affect the study results. ITALY Smoking Ban and Exposure Information On January 10, 2005, Italy implemented a nationwide smoking ban in all indoor public places, including offices, retail shops, cafés, bars, restaurants, and discotheques. Smoking was not banned in private houses or specifically equipped public areas (for example, the law had requirements for exempted areas, including ventilation systems that create negative pressure and a requirement for doors) (Vasselli et al., 2008). Although no exposure data are available on the specific populations, some general compliance and monitoring data are available from before and after implementation of the ban. Gallus et al. (2006) found that of 3,114 people ages 15 years or older who were surveyed in Italy, almost 90% perceived that the ban was observed in bars, and 70% had that perception for workplaces. As reported by Gorini et al. (2005) in a letter to a journal editor, the median concentration of nicotine in the vapor phase of samples from four pubs and three discotheques in Florence decreased to an average of 3.2% of the pre-ban median: from 138.9 μg/m3 (range, 33.0–276.5 μg/m3) to 4.5 μg/m3 (range, 1.7–8.7 μg/m3). Valente et al. (2007) measured fine and ultrafine particles in 40 establishments in Rome and urinary cotinine in nonsmoking employees of the establishments before and after implementation of the ban. The average concentration of PM2.5 particles (particles smaller than 2.5 μm in aerodynamic diameter) decreased from 119.3 μg/m3 before the ban to 38.2 μg/m3 (p < 0.005) 2–3 months after implementation and to 43.3 μg/m3 (p < 0.01) 11–12 months after implementation. The average concentration of ultrafine particles also decreased but to a smaller extent, from 76,956 particles/cm3 before the ban to 38,079 particles/cm3 (p < 0.0001) and 51,692 particles/cm3 (p < 0.01) 2–3 months and 11–12 months after implementation, respectively. Urinary cotinine in the employees decreased from an average of 17.8 ng/mL (95% CI, 14–21.6 ng/mL) before the ban to 5.5 ng/mL (95% CI, 3.8–7.2 ng/mL) and 3.7 ng/mL (95% CI, 1.8–5.6 ng/mL) 2–3 months and 11–12 months after implementation, respectively. Those data indicate that the smoking ban resulted in a decrease in exposure to secondhand smoke. Published Results on Acute Coronary Events Three publications report on acute coronary events after implementation of the Italian smoking ban (Barone-Adesi et al., 2006; Cesaroni et
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence TABLE 6-3 Summary of Results of Key Publications (Studies Listed by Smoking-Ban Region in Order of Publication) Publication (Region) Study Design and Duration Selection of Patients Helena, Montana Sargent et al., 2004 (Helena, Montana) Retrospective based on hospital records; 6 months of ban, 11 months after ban compared with same months of 5 years before ban Patients 18 years old and older admitted to St. Peter’s Community Hospital for primary or secondary diagnosis of acute MI (ICD-9 410. xx) Selection criteria: onset of symptoms in study area, no recent procedure that could have precipitated acute MI, primary diagnosis of acute MI or secondary diagnosis with chemical evidence of acute MI at time of admission (cTn or creatine phosphokinase) Control population: county residents who lived outside city boundaries Italy Vasselli et al., 2008 (four regions in Italy: Piedmont, Friuli–Venezia–Giulia, Latium, Campania) Retrospective based on hospital discharge registry; study period January 10–March 10, 2001–2005; compared 2 months after ban with same 2 months of 4 years before ban Patients in public, private hospitals with primary discharge diagnosis of acute MI, 40–64 years old; hospital data from National Hospital Discharge Registry (2001, 2002, 2003), which is based on regional data, or from regional hospital discharge registries for years not previously incorporated into national registry (2004, 2005)
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence Results Statistical Analysis Comments Total of 304 cases met selection criteria; 24 cases in Helena during ban; 18 cases outside Helena during ban Average monthly admissions declined from 40 to 24 (16 fewer admissions; 95% CI, 0.3–31.7) during same months in years before and after implementation of ban Nonsignificant increase of 5.6 in number of acute MI admissions from outside Helena during same period Mean comparisons before, after ban implementation, and between areas with Poisson distribution for counts No information on individual smoking status; no measures of individual SHS exposure Small population Advantage of having data before ban, during ban, after rescinding of ban Criteria for diagnosing acute MI changed during study period Cases: 2001, 1,309; 2002, 1,408; 2003, 1,511; 2004, 1,589; 2005, 1,488 Total of all four regions: rates increased linearly from 2001 to 2004, decreased by 6.4% from 2004 to 2005 Regional level: rates less linear than total of all four regions; rates increased or unchanged from 2001 to 2004; rates decreased from 2004 to 2005 (significantly in Piedmont, Latium, Campania) Total of all four regions, observed 2005 versus expected based on linear regression: risk reduction 13.1% (age-standardized risk ratio, 0.86; 95% CI, 0.83–0.92) Significant decrease from expected numbers in 2005 in men but not women 45–49 years old but not other age ranges, all regions except Friuli–Venezia–Giulia Comparison of age-standardized rates, subgroup comparisons for sex, age, region separately No information on individual smoking status; no measures of individual SHS exposure Limited study duration; looked only at effects 2 months after implementation of; population was less than 30% of Italy Rates standardized by overall total, age, region, sex
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence One publication examines acute coronary events after implementation of the ordinance (Khuder et al., 2007). It provides information directly related to the question of the association between smoking bans and acute coronary events. The publication contains no information on compliance with the restrictions or on air monitoring or biomonitoring before or after the ban. Akbar-Khanzadeh et al. (2004), however, measured the concentrations of secondhand-smoke–related compounds in restaurants in Toledo and Bowling Green, Ohio, using standard methods (including nicotine, 3-ethenylpyridine, total respirable suspended particulate matter [RSP], RSP based on solanesol particles, respirable suspended ultraviolet-absorbing particulate matter, and fluorescent particulate matter). One smoke-free restaurant and one smoking restaurant (that is, with a bar) in each city were chosen. Data from a previous study were compared with data on average concentrations of the various compounds in the two cities combined. Analyses indicated that the concentrations of secondhand-smoke–related contaminants did not change after the adoption of the smoking restrictions, but the data also indicated that the concentrations of secondhand-smoke–related compounds were lower in the nonsmoking restaurants than in the restaurants that allowed smoking in separate areas. Published Results on Acute Coronary Events Khuder at al. (2007) compared hospital admissions related to coronary heart disease (CHD; ICD-9-CM 410–414, 428) in Bowling Green, Ohio, with a matched control city, Kent, Ohio, over a 6.5-year period to assess the effect of the ordinance. The study took advantage of a natural experiment. The authors obtained hospital discharge data on residents of the two cities from all hospitals in Ohio and analyzed the primary diagnoses for admission of people at least 18 years old, using 2000 census population information as the denominator throughout the study period. The authors present annual standardized admission rates in their Table 1, in which the data for the first half of 2005 are doubled to provide numbers for the full year. Despite showing those annual rates, they used monthly time-series data for the analysis in the study, and only the available data for 2005 were used. They calculated age-standardized rates and found that CHD admission rates decreased significantly in Bowling Green after the implementation and enforcement of the smoking restrictions by 39% from 2002 (36/10,000 residents) to 2003 (22/10,000 residents) and by 47% from 2002 to the first half of 2005 (19/10,000 residents). Kent did not show any significant change in CHD admission rates, nor did admission rates for causes unrelated to smoking change significantly in either city. In addition, in November 2002, 7 months after implementation of the restrictions, the monthly admission rates for CHD in Bowling Green showed a significant
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence decline (the value of the parameter representing a change in the series level, ω, was −11.69; p = 0.04) The results of the study have to be understood in relation to its limitations: the residents of Kent were assumed not to be affected by the restrictions, other risk factors for CHD may have affected admission rates, and smoking status and exposure to secondhand smoke were not accounted for. The study showed a peak in acute MIs in 2002, the year with which postimplementation years are being compared. The smoking ban was implemented in March 2002, but, on the basis of previous studies, the authors “postulated that at least 6 months would be needed to allow for the potential health effects from reduction in exposure to second hand smoke, reduction in smoking prevalence and smokers reducing the quantity of cigarettes smoked.” The authors therefore “waited until October 2002 before assessing the impact of the ordinance.” The sensitivity of the analysis to that choice would have been helpful to see. Annual standardized admission rates varied greatly across years, but the Autoregressive Integrated Moving Average (ARIMA) model used to analyze the data, which estimates the effect of the intervention and accounts for residual correlation, would take that variability into account. The published report provides little information on the fit of the time-series model used to measure the effect of the restrictions. As with Seo and Torabi (2007), a differences-in-differences analysis, as is often used to evaluate the effect of a program (Buckley and Shang, 2003), could have been explored, but it is not clear how it would be done with the information provided in the publication. NEW YORK STATE Smoking Ban and Exposure Information On July 24, 2003, New York implemented a statewide ban on smoking in all workplaces, including restaurants, bars, and gaming establishments. Statewide smoking restrictions implemented in 1989 had limited or prohibited smoking in particular public places, such as schools, hospitals, public buildings, and retail stores. By 1995, countywide restrictions had begun to be put into place; by 2002, 75% of residents of New York state were subject to local restrictions more stringent than the statewide restrictions implemented in 1989 (Juster et al., 2007). Juster et al. (2007) published the only report on the effect of the New York state smoking ban on acute coronary events. The authors did not measure compliance, enforcement, or markers of secondhand-smoke exposure for the report, but they cited a report by RTI International (2004) that showed that 93% of restaurants, bars, and bowling facilities were in compliance in the year after implementation. They took into consideration
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence preexisting smoking bans, and they collected information on those bans and categorized them as comprehensive (including the statewide ban and the preexisting bans in Nassau County and New York City) or moderate2 (all other county bans). Their report provides information directly related to questions about the association between smoking bans and acute coronary events. Other data on compliance and potential secondhand-smoke exposure in New York state are available. The New York Adults Tobacco Survey showed decreases in saliva cotinine from 0.078 ng/mL (range, 0.054–0.111 ng/mL) to 0.041 ng/mL (0.036–0.047 ng/mL) in a sample of New York state adults before and after implementation of the ban, respectively (CDC, 2007). That study also surveyed participants about exposures to secondhand smoke. The number of respondents reporting exposure to secondhand smoke in restaurants and bars decreased significantly after implementation of the ban—in restaurants, from 19.8% reporting exposure (95% CI, 15.6–24.1%) before the ban to 3.1% (95% CI, 2.0–4.2%) 9–10 months after implementation; in bars, from 52.4% reporting exposure (95% CI, 41.5–63.4%) before the ban to 13.4% (95% CI, 9.5–17.3%) 9–10 months after implementation. However, those reporting exposure in the workplace did not decrease significantly3—from 13.6% reporting exposure before the ban (95% CI, 8.1–19.1%) to 7.6% (95% CI, 5.1–10.2%) 9–10 months after implementation. CDC (2004) measured indoor-air quality in hospitality venues in western New York before and after implementation of the 2003 ban. Average PM2.5 concentration decreased from 324 μg/m3 before the ban to 25 μg/m3 after implementation (p < 0.001). Published Results on Acute Coronary Events Juster et al. (2007) assessed the effect of the statewide smoking ban in New York on hospital admissions for acute MI and stroke. The authors analyzed monthly hospital admissions associated with primary diagnoses of acute MI (ICD-9-CM 410.0–410.99) and stroke (ICD-9-CM 430.00–438.99) from January 1995 to December 2004 in 62 counties in New York state. They used data from a comprehensive database maintained by the New York State Department of Health and included data from all public and private hospitals in the state. The number of hospital admissions was combined with county population data to obtain a monthly rate of hospital admissions for acute MI and stroke; the data were age-adjusted to the 2000 2 The authors of the report defined a moderate ban as one that restricts smoking but provides little or no protection in hospitality venues. 3 Statistical analysis used a t test for trend.
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence New York population. Multiple linear-regression analysis was applied to monthly age-adjusted county rates for acute MI and stroke, and estimated regression coefficients were used to predict the potential reduction in hospital admissions related to comprehensive and moderate smoking bans. During the study period, there were more than 46,000 hospital admissions per year for acute MI and more than 58,000 for stroke. Regression analysis indicated that no sudden decrease in hospital admissions for acute MI was associated with the implementation of the smoking ban in 2003. However, the interaction between the law and time—assessed by comparing the changes in the slope of the line for observed versus expected events after the ban—indicated that the decline in monthly acute MIs associated with the countywide and statewide bans was greater than the decline expected in the absence of those bans. Moderate smoking bans reduced the monthly trend rate by an estimated average of 0.15/100,000 persons per month; the statewide comprehensive ban reduced the monthly trend rate by an estimated average of 0.32/100,000 per month. The analysis indicated that there were 8% (3,813) fewer hospital admissions for acute MI in 2004 in the presence of the comprehensive statewide ban than would have been expected that year with only the previous local smoking restrictions and bans in place. Although it was not reported in Juster et al. (2007), the authors stated in response to questions from this committee that a similar analysis of mortality in 1998–2005 in New York state had similar results, although an interaction between law and time did not reach significance, with a p-value of 0.059 (personal communication, H. Juster, New York State Department of Health, Albany, January 14, 2009). At the time of the study, some partial or full bans were in place in various locations in the state before the statewide ban (that is, there was not a “zero to all” implementation throughout the state) and would be expected to affect the magnitude of any change seen. Juster et al. (2007) estimated that if no local bans had been in place when the state ban was implemented, the effect of the state ban would have been a 19% decrease in acute MIs. The study included some measures of exposure but did not assess individual patient-level data (including smoking status or other risk factors) or the effect of changes in smoking prevalence on hospital admissions. There was no control for repeat admissions of the same person. The considerable data aggregation in the study could mask heterogeneity and overstate statistical significance. From the data in Figure 1 of Juster et al. (2007), it appears that the effect of the ban on acute MIs and stroke was not immediate: an apparently anomalous initial drop in both observed admissions and admissions expected in the absence of the statewide ban (as predicted by the model) was followed by a separation between the observed occurrences with the statewide ban and the expected number in the absence of the ban. The committee notes, however, that whereas typically the rate of acute
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence MI is much greater than (as much as twice as high as) the rate of strokes (Lloyd-Jones et al., 2008), in this study there were more strokes than acute MIs. With respect to the analyses, this was the only study that attempted to account for previously implemented smoking bans; that is important given the large portion of the study population that was previously covered by smoking bans (New York City and several other large jurisdictions had previously implemented smoking bans). The results of the study, however, are sensitive to the assumptions used in the model and to the model choice. A sensitivity analysis showing the effect of model choice on study results might have provided more confidence in the study findings. SASKATCHEWAN, CANADA Smoking Ban and Exposure Information Saskatoon, Saskatchewan, Canada, implemented a smoking ban on July 1, 2004. The ban prohibited smoking in “any enclosed public space that is open to the public or to which the public is customarily admitted or invited.” Smoking was also prohibited in outdoor seating areas of restaurants and licensed premises. Smoking had previously been prohibited in government buildings. Lemstra et al. (2008) conducted the only study to assess whether the smoking ban had an effect on rates of acute MI and also assessed smoking prevalence and public support of the ban. That study provides information directly related to questions about the association between smoking bans and acute coronary events. The authors measured business compliance with the ban by reviewing warnings and tickets issued by public-health inspectors to eligible businesses. Of 924 eligible establishments, 914 (98.9%) were inspected within the first 6 months of the ban. Of the 914, only 13 (1.4%) had to be issued noncompliance warnings (for not posting signs or removing ashtrays); one ticket was issued on reinspection of those 13 that were issued warnings. The committee found no exposure-assessment data. Published Results on Acute Coronary Events Lemstra et al. (2008) obtained information on acute MI from the Strategic Health Information Planning Services. ICD-10 codes, rather than ICD-9 codes, were in use in Saskatoon beginning in 2000, so the analyses used data from July 2000 and later. The authors calculated age-standardized incidences of acute MI per 100,000 people in the first full year of the smoking ban (July 1, 2004–June 30, 2005) and in the previous 4 years (July 1, 2000–June 30, 2004). Data collected on smoking prevalence in 2003 and 2005 by Statistics Canada were used to evaluate changes in smoking pattern.
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence The age-standardized incidence of acute MI decreased from 176.1 cases/100,000 people before the ban to 152.4 cases/100,000 after implementation of the ban. The 13% reduction was statistically significant (rate ratio, 0.87; 95% CI, 0.84–0.90). Smoking prevalence in Saskatoon decreased from 24.1% in 2003 to 18.2% in 2005 but was unchanged in the province of Saskatchewan. The study contained some information available from a survey that determined changes in active smoking status (for example, a decrease in the number of people who actively smoked and a decrease in the number of cigarettes smoked by the people who continued to smoke). In addition, the study had a large sample and comprehensive data. The study accounted for changes in ICD coding for acute MI, choosing its timeframe on the basis, in part, of the coding change. The study has a number of limitations: no information on individual exposure to secondhand smoke was available, the postimplementation study period was brief, and no comparison city was available to permit assessment of trends or of any long-term decline. SCOTLAND Smoking Ban and Exposure Information Scotland prohibited smoking in enclosed public places and workplaces—including bars, restaurants, and cafes—as of March 2006. As described by Haw and Gruer (2007), the exceptions included “residential accommodation and designated rooms in hotels, care homes, hospices, and psychiatric units.” Pell et al. (2008) conducted the only study that assessed the effects of that ban on acute coronary events. The study surveyed participants on smoking status and secondhand-smoke exposure before and after the ban, and it measured serum cotinine. The correlation between self-reported duration of exposure to secondhand smoke and serum cotinine concentrations was similar before (r = 0.33, p < 0.001) and after (r = 0.33, p < 0.001) the implementation of the smoking ban. The number of never-smokers who reported no exposure to smoke increased from 57% before the ban to 78% after implementation (p < 0.001) largely because of reduced exposure to smoke in pubs, bars, and clubs. The geometric mean of individual serum cotinine measurements in never-smokers decreased from 0.68 to 0.56 ng/mL (p < 0.001) after implementation. Participants identified as former smokers showed similar changes before and after implementation. Those data indicate that secondhand-smoke exposure decreased in the study population after implementation. Other published research supports the conclusion that secondhand-smoke exposure decreased in Scotland after implementation of the ban. Semple et al. (2007a) monitored PM2.5 during 53 visits to 41 pubs in
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence Edinburgh and Aberdeen both before implementation of the ban and 2 months after implementation; particulate matter is one component of secondhand smoke. Air samples were collected for a minimum of 30 min; days of the week and times of day of sampling before and after implementation were matched. Before the ban, PM2.5 concentrations were 8–902 μg/m3; after implementation, they were 6–104 μg/m3. With the exception of one bar that had a very low PM2.5 concentration before the ban and only a slightly lower concentration after implementation, PM2.5 concentrations decreased by at least 50% in all establishments; in more than half, concentrations decreased by at least 90%. The researchers also collected information on compliance with the ban while conducting the sampling. Only 1 of the 41 pubs had evidence of smoking after implementation of the ban. Haw and Gruer (2007) measured changes in exposure to secondhand smoke in the 14 regions of Scotland. Using a repeat, cross-sectional design, the researchers interviewed adults (ages 16–74 years) on health behaviors, smoking status, nicotine-replacement therapy use, and reported exposures to secondhand smoke before and after implementation of the ban. They also measured cotinine concentrations in saliva samples. Nonsmokers reported decreased exposure to secondhand smoke after implementation of the ban. When sex, years of education, and deprivation of residence (subjects were categorized according to how affluent or deprived their residences were) were controlled for, self-reported decreases were significant only for public places covered by the ban (including pubs, work, and public transport) and not in private homes and cars. In nonsmokers, the geometric mean cotinine concentration decreased by 39% (p < 0.001), from 0.43 ng/mL before the ban to 0.26 ng/mL after implementation. Nonsmokers not living with any smokers showed a greater reduction than nonsmokers living with at least one smoker, with a 49% reduction (95% CI, 40–56%; p < 0.001) and a 16% reduction (95% CI, −111 to 37%; p < 0.05), respectivel. Menzies et al. (2006) measured serum cotinine concentrations in bar workers in Dundee and Perth, Scotland, and found that concentrations decreased by 1.93 ng/mL (95% CI, 1.03–2.83 ng/mL; p < 0.001), from 5.15 ng/mL before the ban to 3.22 ng/mL 1 month after implementation, and by 2.22 ng/mL (95% CI, 1.34–3.10 ng/mL; p < 0.001), to 2.93 ng/mL 2 months after implementation. They also found that respiratory symptoms had decreased and pulmonary function improved at both 1 and 2 months after implementation relative to 1 month before implementation. Semple et al. (2007b) met with 371 people who worked in 72 bars in Aberdeen, Glasgow, Edinburgh, and small towns in two rural areas of Scotland before implementation of the ban (January–March 2006) and twice after implementation (May–July 2006 and January–March 2007). Salivary cotinine in 301 workers was assayed. The geometric mean salivary cotinine concentration in nonsmokers decreased from 2.9 ng/mL before the ban to
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence 0.7 ng/mL about 2 months after implementation to 0.4 ng/mL about a year after implementation. Pell et al. (2008) measured serum cotinine concentrations in the study that evaluated acute MI. The concentration of cotinine in serum samples validated self-reported smoking status and provided a measure of exposure to secondhand smoke; serum cotinine decreased by 38% in men and by 47% in women after implementation of the ban. For the purposes of the study, current smokers were those who reported being smokers and had serum cotinine greater than 12 ng/mL. Never-smokers reported never having smoked and had serum cotinine of no more than 12 ng/mL. Former smokers reported being former smokers and had serum cotinine of no more than 12 ng/mL. Published Results on Acute Coronary Events Pell et al. (2008) prospectively examined the number of hospital admissions for acute coronary syndrome before and after implementation of smoking ban. Their study had serum cotinine concentrations of patients and analyzed the data according to smoking status on the basis of those concentrations, so it directly addressed the question of the association between secondhand-smoke exposure and acute coronary events. The authors gathered information on cases from nine hospitals during the 10 months before implementation (June 2005–March 2006) and 10 months after (June 2006–March 2007). They used detection of cardiac troponin after emergency admission for chest pain to define an acute coronary syndrome; cardiac troponin is routinely measured in people who are admitted with chest pain. During the pre-implementation and postimplementation periods, there were 3,235 and 2,684 admissions for acute coronary syndrome, respectively, in the nine hospitals (the nine hospitals accounted for 64% of admissions for acute coronary syndrome in Scotland). Pell et al. (2008) used English hospitals’ admissions for acute coronary syndrome as a concurrent control. The number of admissions for acute coronary syndrome decreased by 17% (95% CI, 16–18%). Only a 4% reduction occurred during the same period in England, where no ban was in place. In the 10 years before implementation of the ban, a trend of a 3% mean reduction per year occurred in Scotland. Examination by smoking status showed a 14% reduction in smokers, 19% in former smokers, and 21% in those who never smoked; the data indicate that 67% of the prevented admissions were in nonsmokers. This study was one of the few that used a prospective design to address the question of the effect of a smoking ban on acute coronary events. It has several strengths, including a large sample, laboratory confirmation of MI admissions with cardiac troponin assays, and confirmation that
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Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence there was no concurrent change in the rates of out-of-hospital deaths after implementation of the ban. The authors also conducted a survey of cases and a sample of the general population for secondhand-smoke exposure and smoking status, and they measured cotinine concentrations in these participants. The study did, however, have limitations. Although it was large, it did not include all hospitals in Scotland, it did not have a clearly defined study population, and there could have been changes in the nine hospital catchment areas or a more general population influx or efflux after implementation of the ban. The study had a relatively short followup period (1 year), so the long-term effect of the ban on smokers and nonsmokers is not known. It is unclear whether the ban itself affected smoking status in the general population by changing social norms. Finally, as in all observational trials, other changes—including changes in health-care availability and in the standard of practice in cardiac care, such as new diagnostic criteria for acute MI—during the study period could have confounded the results. REFERENCES Akbar-Khanzadeh, F., S. Milz, A. Ames, S. Spino, and C. Tex. 2004. Effectiveness of clean indoor air ordinances in controlling environmental tobacco smoke in restaurants. Archives of Environmental Health 59(12):677-685. ANRF (American Nonsmokers’ Rights Foundation). 2009. Chronological table of U.S. population protected by 100% smokefree state or local laws. (Accessed July 2, 2009, from http://www.no-smoke.org/goingsmokefree.php?id=519.) Barone-Adesi, F., L. Vizzini, F. Merletti, and L. Richiardi. 2006. Short-term effects of Italian smoking regulation on rates of hospital admission for acute myocardial infarction. European Heart Journal 27(20):2468-2472. Bartecchi, C., R. N. Alsever, C. Nevin-Woods, W. M. Thomas, R. O. Estacio, B. B. Bartelson, and M. J. Krantz. 2006. Reduction in the incidence of acute myocardial infarction associated with a citywide smoking ordinance. Circulation 114(14):1490-1496. Buckley, J., and Y. Shang. 2003. Estimating policy and program effects with observational data: The “Differences-in-differences” Estimator. Practical Assessment, Research & Evaluation 8(24). (Accessed May 21, 2009, from http://PAREonline.net/getvn.asp?v=8&n=24.) Burns, D. M. 2003. Epidemiology of smoking-induced cardiovascular disease. Progress in Cardiovascular Diseases 46(1):11-29. CDC (Centers for Disease Control and Prevention). 2004. Indoor air quality in hospitality venues before and after implementation of a clean indoor air law—western New York, 2003. MMWR—Morbidity & Mortality Weekly Report 53(44):1038-1041. ———. 2007. Reduced secondhand smoke exposure after implementation of a comprehensive statewide smoking ban—New York, June 26, 2003–June 30, 2004. MMWR—Morbidity & Mortality Weekly Report 56(28):705-708. ———. 2009. Reduced hospitalizations for acute myocardial infarction after implementation of a smoke-free ordinance— city of Pueblo, Colorado, 2002–2006. MMWR—Morbidity & Mortality Weekly Report 57(51):1373-1377.
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