TOBACCO AND ASTHMA

1. TOBACCO AND ASTHMA Mini Lecture 3 Module: Effects of Tobacco on the Respiratory System

2. Objectives of the Mini Lecture GOAL OF MINI LECTURE: Provide students with knowledge about the harmful effects of tobacco on asthma and skills for smoking cessation counseling for asthma patients and their parents. LEARNING OBJECTIVES Students will be able to: • Describe the burden of smoking among asthma patients. • Describe the association between smoking and asthma, and the impact of smoking on asthma management and control. • Understand the importance of counseling asthma patients or their parents to quit smoking.

3. Contents Core Slides Optional Slides Global Burden: Childhood Asthma Burden of Asthma in India Asthma in Indonesia Smoking and Steroid Resistance Smoking and Health Care Utilization • Global Burden of Adult Asthma • Active Smoking and Asthma • Secondhand Smoke and Asthma • Smoking and Children with Asthma • Smoking, Cessation, and Asthma Treatment • Cessation Messages: Asthma Patients • Clinical Approach: Smoker Asthma Patient

4. CORE SLIDES Tobacco and Asthma Mini Lecture 1 Module: Effects of Tobacco on the Respiratory System

5. Global Burden of Adult Asthma • Global prevalence of clinical asthma ranges from 0.7% to 18.4% • The highest case-fatality rate of asthma: in China (36.7 deaths per 100,000 population). • Prevalence of clinical asthma in South East Asia: 3.3% 1. Global Initiative for Asthma 2004; 2. WHO 2007

6. Active Smoking and Asthma • Smoking induces bronchial and peripheral airway inflammation. • Smoking influences cytokine and mediator production. • Smoking leads to alteration of mechanical properties of the airway wall. • Smoking might influence immunological response to allergens in asthma. Thomson et al. 2004

7. Secondhand Smoke and Asthma • SHS is a risk factor for asthma development and severe asthma attacks. • SHS exposure doubles prevalence of asthma in children and increases risk of current asthma by 25%. • In-utero smoke exposure (maternal smoking): decreases respiratory function and increases chance of wheezing. Baena-Cagnani et al. 2009

8. Smoking and Children with Asthma Active smoking, children (13–14 years): • Increased chance of current wheeze significantly (3 times) • Increased probability of doctor visit in the last 12 months • Increased chance of asthma interfering with physical education SHS exposure, children (13–14 years): • Increased school absence and impairment of home activities. Austin et al. 2005

9. Smoking, Cessation, andAsthma Treatment • Effects of smoking on asthma treatment: • Reduced therapeutic effects of corticosteroids. • Increased clearance of theophylline. • Harmful effects are reversible with smoking cessation: • Decreased theophylline elimination. • Reversal of corticosteroid resistance. • Improvement of peak expiratory flow (PEF). 1. Thomson et al. 2004; 2. Adis Data Information BV 2006

10. Cessation Messages:Asthma Patients • Smoking cessation: First line therapy for asthma. • The physician should: • Ask all asthmatic patients about smoking. • Advise all asthmatic patients to quit smoking: “Quitting smoking is the most important thing you can do to improve your asthma.” • Assist the patient with information, referrals for cessation help, and medications as available. Haughney et al. 2008

11. Clinical Approach: Smoker Asthma Patient • Assessing and addressing smoking behavior is important in clinical management of asthma patients. • Exclude diagnosis of COPD. • First line therapy: Smoking cessation. • Second line therapy: Pharmacotherapy including theophylline, inhaled corticosteroids, and β-agonists. • Parents of asthmatic children: Home smoking ban and smoking cessation should be strongly encouraged. Haughney et al. 2008

12. OPTIONAL SLIDES Tobacco and Asthma Mini Lecture 1 Module: Effects of Tobacco on the Respiratory System

13. Global Burden: Childhood Asthma • In low-middle income vs. high income countries: • Lower prevalence of current wheeze • Higher prevalence of severe asthma episodes Lai et al. 2009

14. Burden of Asthma in India India • Asthma Prevalence: Adults > 18 yrs (1995–1997)1: • Males > 18 yrs: 3.94% (urban), 3.99% (rural) • Females > 18 yrs: 1.27% (urban & rural) • Children < 18 yrs (1999): 29.5%2 • Age of onset:26% (1 yr), 52% (1–5 yrs), 22% (> 5 yrs)1,2 • Asthma incidence and family history:1,2 • 18.79% (one parent has asthma) • 1.65% (sibling/s have asthma) • 4.12% (grandparent/s have asthma) 1. Murthy and Sastry , accessed April 10, 2010; 2. Paramesh 2002

15. Smoking and Steroid Resistance • Increases mucosal permeability and secretions • Down-regulation of b2-adrenergic receptor function • Inflammatory cell phenotype changes → impaired responses to corticosteroids • Changes in cytokine and mediators levels • Changes in glucocorticoid receptor numbers or binding affinity • Over-expression of pro-inflammatory transcription factor activation • Changes in corticosteroid cell-signalling systems 1. Thomson et al. 2004; 2. Thomson and Spears 2005

16. Smoking and HealthCare Utilization Compared to persistent-asthma patients who did not smoke, patients who smoked are more likely to: • Report night-time symptoms (67% in smokers vs. 58% in non-smokers) • Visit emergency department because of asthma exacerbation (16% in smokers vs. 10% in non-smokers) • Go for hospitalization (18% in smokers vs. 11% in non-smokers) Shavit et al. 2007

17. The most important health message a doctor can give to patients is to quit smoking.