|BRIEF RESEARCH ARTICLE
|Year : 2014 | Volume
| Issue : 1 | Page : 45-49
Prevalence of chronic obstructive pulmonary disease and its association with tobacco smoking and environmental tobacco smoke exposure among rural population
BG Parasuramalu1, N Huliraj2, SP Prashanth Kumar3, Gangaboraiah4, NR Ramesh Masthi5, CR Srinivasa Babu6
1 Professor and Head, Department of Community Medicine, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India
2 Professor and Head, Department of TB & Chest Diseases, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India
3 PG cum Tutor, Department of Community Medicine, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India
4 Professor of Statistics, Department of Community Medicine, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India
5 Associate Professor, Department of Community Medicine, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India
6 Professor & Head, Department of Radiodiagnosis, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India
|Date of Web Publication||5-Mar-2014|
B G Parasuramalu
Professor and Head, Department of Community Medicine, Kempegowda Institute of Medical Sciences, Banashankari 2nd Stage, Bengaluru - 560 070, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
A field survey was conducted for chronic obstructive pulmonary disease (COPD) epidemiology in the rural field practice area of Kempegowda Institute of Medical Sciences, Bangalore, India, which covers a population of 44,387 to find out the prevalence of COPD in adult subjects of 35 years and above using cluster sampling technique and to determine the association of tobacco smoking, environmental tobacco smoking (ETS) exposure and type of cooking fuel used with COPD. The overall prevalence of COPD was 4.36%. The prevalence among males and females were 5.32% and 3.41% respectively. The prevalence was found to be increasing with an increase in age. The tobacco smoke and exposure to ETS was significantly associated with higher odds of COPD with adjusted odds ratio 2.97 and 2.67 respectively. Thus, there was a significant association between tobacco smoking and ETS exposure with COPD.
Keywords: Chronic obstructive pulmonary disease, Prevalence, Questionnaire, Spirometry, Tobacco smoking
|How to cite this article:|
Parasuramalu B G, Huliraj N, Prashanth Kumar S P, Gangaboraiah, Ramesh Masthi N R, Srinivasa Babu C R. Prevalence of chronic obstructive pulmonary disease and its association with tobacco smoking and environmental tobacco smoke exposure among rural population. Indian J Public Health 2014;58:45-9
|How to cite this URL:|
Parasuramalu B G, Huliraj N, Prashanth Kumar S P, Gangaboraiah, Ramesh Masthi N R, Srinivasa Babu C R. Prevalence of chronic obstructive pulmonary disease and its association with tobacco smoking and environmental tobacco smoke exposure among rural population. Indian J Public Health [serial online] 2014 [cited 2019 Oct 18];58:45-9. Available from: http://www.ijph.in/text.asp?2014/58/1/45/128166
| Introduction|| |
Chronic respiratory disease (CRD) is one of the most common causes of disease burden both globally and in India. CRD includes asthma and chronic obstructive pulmonary disease (COPD) which together may account for an estimated burden of about 100 million individuals in India. Prevalence rates varying from 2% to 22% in men and from 1.2% to 19% in women have been shown in different reports.  Tobacco smoking and environmental tobacco smoking (ETS) are associated risk factor for COPD. ,, Only Very few studies have been conducted in rural areas of India to find out the prevalence of COPD and its relationship with tobacco smoking, ETS and type of fuel used for cooking. Hence the present study was undertaken with the following objectives: The primary aim is to find out the prevalence of COPD in adult subjects of 35 years and above. The secondary aim is to determine the association of tobacco smoking, ETS and type of fuel used with COPD.
A cross sectional field survey for asthma and COPD epidemiology was conducted among adults in the rural field practice area of Kempegowda Institute of Medical Sciences, Bangalore (K. Gollahally and Sulikere Primary Health Centers, Bangalore Rural district, covering a population of 44,387 residing in 71 villages) from January to December 2008 after obtaining the Institutional Ethics Committee approval. The sample size was calculated using the formula n = Z α/2 2pq/L2 (At 5% level of significance and 95% confidence interval (CI), Z α/2 = 1.96, prevalence of 11%  and error allowable margin of 10%, i.e. 10% of prevalence 11% = 1.1%). The sample size was found to be 3108 which was rounded off to 3120. The study population was selected from 30 clusters/villages using a cluster sampling technique with 104 individuals in each cluster/village.  However, for COPD epidemiology, subjects above 35 years i.e., 1400 subjects out of 3120 were considered and analyzed as it was common after the age of 35 years. Validated questionnaire used by Jindal et al.  translated to Kannada (local language) version 1.0 dated 15 th November 07 was used to diagnosis of COPD in all 1400 subjects.
The definition of COPD according to the structured questionnaire was based on the following factors:
- Age above 35 years,
- Presence of cough with expectoration for three or more months in a year, for two or more years. ,
COPD cases were identified by both COPD questionnaire and spirometry. Spirometry was performed and the COPD patients were classified according to the global initiative for chronic obstructive lung disease (GOLD) criteria  into following stages:
Stage I: Forced expiratory volume in 1 second (FEV 1 ) >80% with FEV 1 /forced vital capacity (FVC) <70%;
Stage II: FEV 1 50-80% predicted, FEV 1 /FVC <70% with or without symptoms;
Stage III: FEV 1 30-49%, FEV 1 /FVC <70% with or without symptoms; and
Stage IV: FEV 1 <30% predicted, FEV 1 /FVC <70% or FEV1 <50% with chronic respiratory failure. Other diseases were diagnosed with appropriate investigations. Asthma was diagnosed according to global initiative for asthma  criteria.
Smoking was assessed in detail and smoking was considered in three classes: Current smokers, ex-smokers and non-smokers. Current smokers were defined as subjects who reported smoking cigarettes beedis, or hookah daily at the time of the survey. Ex-smokers were subjects who had smoked daily and given up ≥1 month before the survey. Non-smokers were those who had never smoked.  The age of starting smoking was asked and ex-smokers were asked at what age they had stopped and how much they smoked before stopping. Current smokers were asked how much they are smoking currently (less than 5 cigarettes/beedis/hookah daily, 5-9, 10-14, 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, 45-49 or 50 or more). 
Statistical tests used for analysis in the present study were Pearson's Chi-square for trend, Odds Ratio, Mann-Whitney U tests, univariate and multivariable logistic regression. Student t-test was used to analyze the difference in the mean percentage of FEV1 and FVC values of spirometry.
In the present study, out of 1400 subjects, 693 (49.5%) were males and 707 (51.5%) were females. Most of the subjects i.e., 599 (42.79%) were in the age group of 35-44 years. The mean age of males was 47.36 ± 10.28 years and of females was 47.41 ± 10.25 years. The mean age of the total population was 47.39 ± 10.28 years. The youngest and oldest subject in this study was 35 years and 70 years respectively. 721 (51.50%) were illiterates, 506 (36.14%) were housewives. A total of 61 subjects were found to be COPD cases as per questionnaire and spirometry. The overall prevalence of COPD was found to be 4.36%. The prevalence was increasing with an increase in age, i.e., 2.5%, 3.85%, 6.72% and 9.52% in 35-44 years, 45-54 years, 55-64 years and 65-74 years respectively which was found to be statistically significant (χ2 = 29.88, P = 0.0001).
The univariate analysis was carried out with COPD as the dependent variable and age, sex, occupation, educational status, standard of living index (SLI), cooking fuel used, smoking habits and ETS exposure as exposure variables. Smoking habits, medium and high SLI, kerosene and ETS exposure were significantly associated with COPD in the univariate analysis [Table 1]. In multivariable analysis age, smoking and ETS exposure was significantly associated with COPD. The odds of having COPD were significantly associated with advancing age (adjusted odds ratio [AOR] = 1.07, 95% CI: 1.04-1.09). The tobacco smoke was significantly associated with higher odds of COPD (AOR = 2.97, 95% CI: 1.45-6.06). Similarly, exposure to ETS was significantly associated with higher odds of COPD in this study (AOR = 2.67, 95% CI: 1.31-5.42). All 61 subjects with COPD were classified for severity as per GOLD criteria based on spirometry. The prevalence of stage II was 42.6% followed by stage I 36.1%, stage III 18.0% and stage IV 3.3% respectively.
|Table 1: Logistic regression for COPD and risk factors-univariate analysis|
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The mean percentage predicted FEV1 and FVC values according to age group and smoking status and according to sex and smoking status were given in [Table 2]. The mean percentage of predicted FEV1 and FVC was less among smokers compared to non-smokers in all the age groups and also among male smokers. Difference in the mean percentage of FEV1 for all the age groups is not statistically significant and difference in the mean percentage of FVC is also not statistically significant for the age groups 35-44 years, 45-54 years between smokers and non-smokers. However, it is statistically significant for the age group 55-64 years (P = 0.045) and for the age group 65-74 years (P = 0.02). However considering all ages, difference in the mean percentage of FEV1 is statistically significant (P = 0.032) as well as that of FVC (P = 0.007). Among males difference in the mean percentage of both FEV1 and FVC were not statistically significant between smokers and non-smokers.
|Table 2: Mean percentage predicted spirometry values according to age group, sex and smoking status|
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Out of 61 COPD subjects, 29 were smokers and 32 were non-smokers. Among 29 smokers, it was observed that the prevalence of COPD cases increased with an increase in the duration of smoking. It was 3.45%, 10.34%, 27.59% and 60.72% among those who were smoking for 0-10 years, 11-20 years, 21-30 years and more than 30 years respectively. The prevalence of COPD among smokers was significantly high (8.31%) compared with non-smokers (3.04%) (P = 0.001).
Further the mean number of years of smoking was 28.79 ± 11.62 years; individuals without COPD had smoked for an average of 22.09 ± 11.38 years, compared with 35.89 ± 12.40 years for those with COPD. This difference is found to be statistically significant (P = 0.001) (Mann-Whitney test).
All questionnaire positive (61) individuals were subjected for acid-fast bacilli (AFB) and chest radiography. None of them were positive for AFB.
In this study, prevalence of COPD was assessed using the validated questionnaire and spirometry which is most reliable in assessing the prevalence of COPD in the field setting though it is difficult and cumbersome to carryout spirometry in the population based surveys. 
In the present study, the overall prevalence of COPD was 4.36%, which was in accordance with the study conducted by Jindal et al.  and INSEARCH multicentric study.  The prevalence of COPD among males and females were found to be 5.32% and 3.41% respectively in our study, which was similar to the multicentric study conducted by Jindal et al.  where the prevalence of COPD was 5% and 3.2% among males and females respectively. In a study by Mahesh et al.  showed a higher prevalence of 11.1% in males and 4.5% in females.
The prevalence of COPD among smokers was significantly high (8.31%) compared to non-smokers (3.04%) which was similar to observations of Mahesh et al., study. 
In the present study, we found among current smokers the number of cigarettes/beedis/hookah smoked daily did not differ (P = 0.16) between individuals without COPD (mean 16.70 ± 15.78) and with COPD (mean 18.21 ± 11.69). Further, the mean number of years of smoking was 28.79 ± 11.62 years; individuals without COPD had smoked for an average of 22.09 ± 11.38 years, compared with 35.89 ± 12.40 years for those with COPD. This difference is found to be statistically significant (P = 0.001). A dose response relationship was also observed by Mahesh et al.  where 9.6% smokers who smoked for less than 20 pack years had COPD. The prevalence increased to 18% in those who smoked for more than 20 pack years.
Exposure to ETS was significantly associated with higher odds of COPD in this study. This finding is in accordance with INSEARCH multicentric study  and a review of the health effects of ETS,  where an increased risk of COPD was found. The excess risk related to ETS exposure was estimated to be from 60% to 400% respectively. Eisner et al.  also found that ETS exposure is an important cause of COPD
In the present study, sex, occupation, educational status, low SLI, cooking fuel used except kerosene were not significantly associated with COPD, which differs from the INSEARCH multicentric study. 
| Limitation of the Study|| |
Since it is a community based study the spirometry was carried out on questionnaire positive cases due to feasibility and financial constraints. Based on the available data from the literature, the error margin was taken as 10%. However based on the actual prevalence from the study, it was found that the error margin is high.
| Conclusion|| |
The prevalence of COPD was 4.36%. There was a significant association between tobacco smoking and ETS exposure with COPD it is recommended to conduct similar studies in different parts of the countries to find out the magnitude of COPD and to avoid of all forms of tobacco consumption to prevent COPD.
| Acknowledgment|| |
The authors would like to acknowledge the support by Dean and Principal, staff and interns of Department of Community Medicine, Kempegowda Institute of Medical Sciences, Bangalore.
| References|| |
|1.||Jindal SK. Indian Study on Epidemiology of Asthma, Respiratory Symptoms and Chronic Bronchitis (INSEARCH): A Multi Centre Study (2006-2009) - Final Report. New Delhi: Indian Council of Medical Research; 2010. |
|2.||Eisner MD, Balmes J, Katz PP, Trupin L, Yelin EH, Blanc PD. Lifetime environmental tobacco smoke exposure and the risk of chronic obstructive pulmonary disease. Environ Health 2005;4:7. |
|3.||Jaakkola MS. Environmental tobacco smoke and health in the elderly. Eur Respir J 2002;19:172-81. |
|4.||Gaur SN, Gupta K, Rajpal S, Singh AB, Rohatgi A. Prevalence of bronchial asthma and allergic rhinitis among urban and rural adult population of Delhi. Indian J Allergy Asthma Immunol 2006;20:90-7. |
|5.||Woodward SH. Description and Comparison of the Methods of Cluster Sampling and Lot Quality Assurance Sampling to Assess Immunization Coverage. Geneva: WHO Department of Vaccines and Biologicals; 2001. p. 7-15. |
|6.||Jindal SK, Aggarwal AN, Chaudhry K, Chhabra SK, D'Souza GA, Gupta D, et al. A multicentric study on epidemiology of chronic obstructive pulmonary disease and its relationship with tobacco smoking and environmental tobacco smoke exposure. Indian J Chest Dis Allied Sci 2006;48:23-9. |
|7.||Mahesh PA, Jayaraj BS, Prahlad ST, Chaya SK, Prabhakar AK, Agarwal AN, et al. Validation of a structured questionnaire for COPD and prevalence of COPD in rural area of Mysore: A pilot study. Lung India 2009;26:63-9. |
|8.||Pauwels RA, Buist AS, Ma P, Jenkins CR, Hurd SS, GOLD Scientific Committee. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: National Heart, Lung, and Blood Institute and World Health Organization Global Initiative for Chronic Obstructive Lung Disease (GOLD): Executive summary. Respir Care 2001;46:798-825. |
|9.||Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention. NHLBI/WHO Workshop Report. Bethesda, MD: National Institutes of Health, National Heart, Lung and Blood Institute; 2002. (NIH Publication No. 02-3659). |
|10.||Siroux V, Pin I, Oryszczyn MP, Le Moual N, Kauffmann F. Relationships of active smoking to asthma and asthma severity in the EGEA study. Epidemiological study on the Genetics and Environment of Asthma. Eur Respir J 2000;15:470-7. |
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[Table 1], [Table 2]
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