Myocardial Infarction and Sudden Cardiac Death in Olmsted County, Minnesota, Before and After Smoke-Free Workplace Laws

Jon O. Ebbert, MD, MSc; Richard D. Hurt, MD; Susan A. Weston, MS; Sheila M. McNallan, MPH; Ivana T. Croghan,

PhD; Darrell R. Schroeder, MS; Véronique L. Roger, MD, MPH

Mayo Clinic

Disclosures

• Consultant for GSK, maker of Nicorette™ gum & Nicorette™ lozenge

• Received medication for clinical trialsfrom Pfizer, maker of Chantix™

• Off-Label Use: None

• Sponsor: ClearWay

Whincup PH, et al. BMJ. 2004 Jul 24;329(7459):200-5.

Pregnancy

Low birth weight infantsPre Term Delivery

24,500 71,900

Children

Asthma Episodes 202,300

Lower Respiratory Illness 150,000-300,000

Otitis Media Office Visits 790,000

SIDS 430

Adults

Cardiac Deaths 46,000 (22,700-69,600)

Lung Cancer Deaths 3,400

California EPA Report on Environmental Tobacco Smoke – 2006Excess Morbidity and Mortality in USA

Smoke-Free Legislation Reduces Coronary Events

• Meta-analysis assessing smoke-free legislation and acute coronary events

• 17 eligible studies

• 10 from North America

• 6 from Europe and 1 from Australasia provided 35 estimates of effect size.

• Pooled RR = 0.90 (95% CI 0.86 to 0.94)

Goals of Project

• To evaluate the population impact of smoke-free laws on the incidence of Myocardial Infarction (MI) and Sudden Cardiac Death (SCD) in Olmsted County during the 18-month calendar period before and after implementation of each smoke-free ordinance.

Olmsted County, MN

• Smoke free ordinances implemented on two different dates

• January 1, 2002: smoke-free restaurant law (Ordinance 1)

• October 1, 2007: all workplaces became smoke-free (Ordinance 2)

Methods

• The Rochester Epidemiology Project (REP)

• Medical records linkage system

• Links and archives medical records of virtually all persons residing in Olmsted County, Minnesota

• Identifies patients through their outpatient (office, urgent care, or emergency department) and hospital contacts across all local medical providers

Methods (Cont.)

• Myocardial infarction (MI)

• International Classification of Disease, Ninth Revision code 410 (acute MI)

• Standard algorithms integrating cardiac pain, electrocardiographic (ECG) and biomarker data

• CK & CKMB until 2000, troponin thereafter

• Sudden cardiac death

• Out-of-hospital deaths with the primary cause of death classified as coronary heart disease on the death certificate

• International Classification of Diseases, Ninth Revision codes 410-414

Methods (Cont.)

• Medical records were abstracted at time of event

• Clinical diagnoses used for hypertension, hyperlipidemia, diabetes, familial coronary heart disease, and smoking status.

• Statistics:

• Age-and-sex-adjusted incidence rates of MI and SCD were calculated for the 18 months before and 18 months after law implementation

• Events were numerators & denominators were Olmsted County population as determined by census data for the year 2000 and extrapolated

• Rates were standardized to the age distribution of the 2000 US population

Results: Patient Characteristics MI

(N=768)

SCD

(N=570*)

Age (years), mean (SD) 67.7 (15.2 77.7 (14.9)

Female, n(%) 285 (37.1) 252 (44.2)

Hypertension

n(%) 513 (66.8) 371 (72.6)

Current smoking

n(%) 469 (61.1) 270 (52.8)

Diabetes mellitus

n(%) 175 (22.8) 76 (15.0)

Body mass index (kg/m2) 173 (22.5) 127 (25.0)

Normal (<25), n(%) 208 (27.1) 203 (40.3)

Overweight (25-30), n(%) 289 (37.6) 163(32.3)

Obese (≥30), n(%) 271 (25.3) 138 (27.4)

Familial Coronary Heart Disease n(%)

61 (21.2) 62 (12.4)

*Age and sex were obtained from the death certificates. For all other characteristics, data are missing for 52 patients who did not provide consent for the use of their medical records for research purposes.

Results: Incidence Rates & Relative Risks of MI Prior and Post Smoke-free Laws

Prior Post

N Rate per 100,000 (95% CI)*

N Rate per 100,000 (95% CI)

Adjusted RR* (95% CI), P

MIOrdinance #1 233 186.7 (162.5-210.8) 215 167.9 (145.3-190.5) 0.89 (0.74-1.08), 0.24

Ordinance #2 177 129.4 (11.02-148.5) 143 102.2 (85.3-119.0) 0.79 (0.63-0.98), 0.04

Pre-Ordinance #1 vs.

Post –Ordinance #2 233 186.7 (162.5-510.8) 143 102.2 (85.3-119.0) 0.54 (0.44-0.67), <0.01

Results: Incidence Rates & Relative Risks of SCD Prior and Post Smoke-free Laws

Prior Post

N Rate per 100,000 (95% CI)*

N Rate per 100,000 (95% CI)

Adjusted RR* (95% CI), P

SCDOrdinance #1 199 152.5 (131.1-174.0) 148 112.2 (93.9-130.4) 0.72 (0.58-0.89), <0.01

Ordinance #2 111 78.0 (63.4-92.7) 112 76.6 (62.2-91.0) 0.99 (0.76-1.28,) 0.91

Pre-Ordinance #1 vs.

Post –Ordinance #2 199 152.5 (131.100-174.0) 112 76.6 (62.2-91.0) 0.50 (0.40-0.63), <0.01

*Adjusted for age and sex

Prevalence of self-reported high cholesterol, diabetes, hypertension and obesity in Minnesota, 1999-2010 from Behavioral Risk Factors Surveillance System (BRFSS)

05

10152025303540

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Pre

vale

nce

(%)

High Cholesterol

0

5

10

15

20

25

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Pre

vale

nce

(%)

Hypertension

012345678

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Pre

vale

nce

(%)

Diabetes*

0

5

10

15

20

25

30

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Pre

vale

nce

(%)

Obesity (BMI ≥ 30 kg/m2)

Prevalence of Self-Reported Current Smoking in Minnesota, 1999-2010 from Behavioral Risk Factors

Surveillance System (BRFSS)

0

5

10

15

20

25

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

Pre

vale

nce

(%)

Current Smokers

Conclusions

• The implementation of smoke-free ordinances was associated with significant decreases in MI (46% reduction) and SCD (50% reduction)

• The magnitude is not explained by community co-interventions or changes in known cardiovascular risk factors.

• SHS exposure should be considered a modifiable risk factor for MI and SCD.