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ORIGINAL ARTICLE
Year : 2019  |  Volume : 22  |  Issue : 2  |  Page : 221-226

Profile of patients with chronic obstructive pulmonary disease in Ilorin who were never-smokers


Pulmonology Unit, Department of Internal Medicine, University of Ilorin Teaching Hospital, Ilorin, Kwara State, Nigeria

Date of Acceptance16-Nov-2018
Date of Web Publication7-Feb-2019

Correspondence Address:
Dr. O B Ojuawo
Pulmonary Unit, Department of Medicine, University of Ilorin Teaching Hospital, Ilorin, Kwara State
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njcp.njcp_344_18

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   Abstract 


Background: The most recognized risk factor for chronic obstructive pulmonary disease (COPD) worldwide is cigarette smoking. However, recent surveys have revealed an increasing trend from nonsmoking causes especially from biomass exposure. This study, therefore, aimed to determine the proportion of patients and the clinical pattern of COPD among never-smokers in Ilorin. Subjects and Methods: This is a retrospective study in which case records of patients with clinical diagnosis of COPD from January 2013 to December 2017 were reviewed. Data were collected with respect to their sociodemographic characteristics, clinical details, comorbid illnesses, and severity of the disease. Results: A total of 135 case records of patients with COPD were reviewed, of which 66 had spirometric confirmation of the disease. In all, 38 (57.6%) of them were never-smokers with a male-to-female ratio of 1:1.1. The mean age of the subjects was 64.5 ± 11.7 years. Cough and exertional dyspnea were the most common symptoms (89.5% each), and systemic hypertension was the most common comorbid illness. Firewood exposure constituted the most common nonsmoking risk factor (47.4%), and the majority of the patients had mild COPD. When compared with ever-smokers, the mean post bronchodilator lung function parameters were found to be significantly better in never-smokers. Conclusion: Over half of COPD cases in Ilorin were never-smokers with firewood exposure as the main risk factor. This study has further highlighted the need for increased awareness of the hazards of biomass fuel exposure in our setting.

Keywords: Biomass, chronic obstructive pulmonary disease, never-smokers


How to cite this article:
Ojuawo O B, Aladesanmi A O, Opeyemi C M, Desalu O O, Fawibe A E, Salami A K. Profile of patients with chronic obstructive pulmonary disease in Ilorin who were never-smokers. Niger J Clin Pract 2019;22:221-6

How to cite this URL:
Ojuawo O B, Aladesanmi A O, Opeyemi C M, Desalu O O, Fawibe A E, Salami A K. Profile of patients with chronic obstructive pulmonary disease in Ilorin who were never-smokers. Niger J Clin Pract [serial online] 2019 [cited 2019 Oct 14];22:221-6. Available from: http://www.njcponline.com/text.asp?2019/22/2/221/251788




   Introduction Top


Chronic obstructive pulmonary disease (COPD) is an increasing cause of morbidity and mortality, accounting for 6% of global deaths, the majority of which are from low- and middle-income countries.[1] It is a preventable disease projected to rank third among all the medical causes of death by 2030. The condition also affects about 10% of people older than 40 years of age.[2]

COPD is characterized by progressive airflow limitation and lung parenchymal damage occurring as a result of chronic exposure of genetically susceptible individuals to noxious gases and particles.[3] Generally, the most recognized risk factor for COPD in both developing and developed world is cigarette smoking, and the overwhelming interest in it has overshadowed the nonsmoking causes.[4] However, in recent periods, emerging facts have demonstrated an increasing trend of nonsmoking risk factors especially in developing countries.[5] These include, but are not limited to, exposure to chemical pollutants, fumes from burning fuels and automobile exhaust, organic and inorganic dusts, genetic disorders such as alpha-1- antitrypsin deficiency, low birth weight, recurrent respiratory illnesses in childhood, and atopy.[6]

Indeed, never-smokers (persons who have never smoked or smoked less than 100 sticks in their entire lifetime) now constitute about one-fourth to one-third of all COPD cases.[7] This may be linked to the fact that about half of the world's population are exposed to fumes from biomass, making it a potentially bigger risk factor when compared with cigarette smoking.[8]

There have been a number of surveys evaluating the risk factors, clinical, and spirometry pattern of COPD in never-smokers.[9],[10],[11],[12],[13] However, there is dearth of information in that regard in this locality. This study is, therefore, aimed at evaluating the proportion of patients with COPD among never-smokers in Ilorin as well as the pattern of the disease.


   Materials and Methods Top


Study setting

The study was conducted at the University of Ilorin Teaching Hospital (UITH), Ilorin, Kwara State, Nigeria, which is a 600-bed tertiary hospital in north central Nigeria. The hospital receives patients from Ilorin and the surrounding states including Oyo, Osun, Kogi, and Niger states. The subjects were patients being followed up at the respiratory outpatient clinic of the hospital.

Study design

Data were retrieved retrospectively from the case notes of adult patients age 18 years and above with a physician's diagnosis of COPD based on symptomatology and spirometric confirmation seen at the pulmonology outpatient clinic between January 2013 and December 2017. This included subjects with exertional dyspnea, chronic cough, sputum production, and wheezing who had a history of exposure to a risk factor for COPD in the absence of obvious alternative diagnosis such as tuberculosis or other lung infections, asthma, bronchiectasis, and so on.

Data collection

Data were collected with respect to their age, gender, occupation, symptomatology (presence of cough, difficulty in breathing and wheezing), risk factors (smoking history, exposure to biomass fuels), comorbid and previous respiratory illnesses, anthropometric parameters, and severity of the disease.

Disease severity was assessed retrospectively based on the Global Initiative for Obstructive Lung Disease (GOLD) spirometric classification documented by the attending respiratory physician. The classification was divided into four stages based on the post bronchodilator forced expiratory volume in the first second (FEV1) after a baseline post bronchodilator forced expiratory volume in first second/forced vital capacity (FEV1/FVC) ratio of less than 70%.

The 2010 GOLD staging used is as follows:

  • GOLD stage 1: mild COPD: FEV1/FVC <70% with FEV1 >80% predicted
  • GOLD stage 2: moderate COPD: FEV1/FVC <70% with FEV1 of 50%–79% predicted
  • GOLD stage 3: severe COPD: FEV1/FVC <70% with FEV1 of 30%–49% predicted
  • GOLD stage 4: very severe COPD: FEV1/FVC <70% with FEV1 <30% predicted or <50% with chronic respiratory failure.


The smoking definitions used were according to the Centre for Disease Control and Prevention [14] and are as follows:

  • Never-smokers – Adults who have never smoked a cigarette or who smoked fewer than 100 cigarettes in their entire lifetime
  • Past/former smokers – Adults who have smoked at least 100 cigarettes in their lifetime, but say they currently do not smoke
  • Nonsmokers – Adults who currently do not smoke cigarettes, including both former smokers and never-smokers
  • Current smokers – Adults who have smoked 100 cigarettes in their lifetime and currently smoke cigarettes every day (daily) or some days (nondaily).
  • Ever-smokers – a combination current smokers and past smokers.


Inclusion criteria

  • Cases with a physician's diagnosis of COPD from a consultant pulmonologist based on symptomatology and spirometric confirmation.


Exclusion criteria

  • Patients with other confirmed respiratory conditions that mimic COPD such as asthma, pulmonary tuberculosis, bronchiectasis, and heart failure were excluded.


Data analysis

Data were analyzed using SPSS version 20.0 for Windows. Descriptive statistics of sociodemographic variables (such as age, sex, level of education, and occupation), symptomatology, risk factors, comorbid illnesses, and severity of the disease were stated in the form of frequencies, percentages, means, standard deviation, and range. Student's T-test was used to assess the relationship between smoking status and age, body mass index, post bronchodilator FEV1/FVC, and the percentage predicted values of the post bronchodilator FEV1. Statistical significance was set at P value <0.05.

Ethical approval

Ethical approval for the study was obtained from the Ethical Review Board of the UITH.


   Results Top


Smoking pattern and socio demographic characteristics

A total of 135 case records of patients with clinical diagnosis of COPD were evaluated, of which 36 (48.9%) of them had spirometric confirmation of COPD. In all, 38 (57.6) were never-smokers, whereas 28 (42.4%) of them were ever smokers [Table 1]. Among the never-smokers, 18 (47.4%) were males and 20 (52.6%) were females. The age range of the subjects was from 40 to 100 years with a mean age of 64.5 ± 11.7 years. The majority of the patients (55.3%) had some degree of formal education and petty trading constituted the most common occupation (42.1%) [Table 2].
Table 1: Smoking status of patients with clinical diagnosis of COPD

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Table 2: Sociodemographic characteristics of patients with COPD who were never-smokers

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Symptomatology and comorbid illnesses

[Table 3] shows that cough and exertional dyspnea were the most common symptoms; each occurring in 34 (89.5%) of the never-smokers with COPD. Thirty (78.9%) had chronic sputum expectoration and 11 (28.9%) had presenting complaints of wheezing. The most common comorbid illness was systemic hypertension (14; 36.8%) followed by echocardiography confirmed cor-pulmonale (5; 13.2%) which is possibly a complication of the disease. Twelve (31.6%) of the patients did not have any comorbid illness.
Table 3: Symptomatology and documented comorbid illness of patients with COPD who were never-smokers

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Risk factors for COPD in never-smokers

[Table 4] demonstrates that firewood exposure from cooking constituted the most common nonsmoking risk factor (18; 47.4%). This was followed by exposure to fumes from household charcoal use (7; 18.4%) as well as exposure to fumes from prolonged use of kerosene stove (6; 15.8%).
Table 4: Risk factors for COPD in never-smokers

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Spirometric staging of never smoking COPD patients

Half of the patients with COPD who had never smoked were in GOLD stage 1, three (7.9%) were in GOLD stage 2, seven (18.4) were in GOLD stage 3, and nine (23.7%) were in GOLD stage 4 [Table 5].
Table 5: GOLD staging of patients with COPD who were never-smokers

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Comparison of mean spirometric parameters in never- and ever-smokers

[Table 6] reveals that the mean age of ever smokers was more than that of never-smokers (68.4 ± 11.0 vs. 64.5 ± 11.7) though the difference was not statistically significant. However, the mean body mass index (BMI), post bronchodilator FEV1/FVC, and percentage predicted post bronchodilator FEV1 were significantly higher in the never-smokers when compared with ever-smokers.
Table 6: Comparison of mean spirometric parameters in never and ever smokers

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   Discussion Top


Never-smokers constituted 57.6% of patients with COPD in Ilorin in the 5-year period. This figure is higher than that reported by Bakr and Elmahallawy [9] in Egypt and Ehrlich et al.[15] in South Africa which revealed a prevalence of 40.0% and 47.6%, respectively. It is also higher compared with other studies done in Europe and Asia.[7],[10],[13],[16] This may be due to the fact that a fewer number of subjects were used in our study when compared with the other surveys. However, in general, these figures demonstrate that never-smokers constitute a significant proportion of COPD cases globally. The higher prevalence of nonsmoking-related COPD in this report may be as a result of a lower rate of smoking in our settings compared with smoking rates in other parts of Africa, Asia, and Europe. Despite this finding, 42.4% of the patients had varied degrees of smoking exposure in our survey which further emphasizes the major impact of smoking on the disease.

The proportion of patients with COPD who were never-smokers in this study was also noted to be higher when compared with figures from a previous survey [17] done in this center to determine the incidence and pattern of COPD over a 10-year period (2001–2010) which reported 30.2% of subjects as never-smokers. This can be attributed to increasing awareness of physicians to probe exposure of patients to biomass and an increasing campaign worldwide against tobacco smoking.

Almost two-thirds of the subjects were above 60 years of age which was consistent with previous findings by Bakr and Elmahallawy,[9] Lamprecht et al.,[7] and Celli et al.[18] This is most likely a result of the natural decline in lung function with increasing age which may be associated with airflow limitation. In addition, most of the subjects who were never-smokers were women as reported by many previous authors [7],[10],[16] who demonstrated a strong relationship between female sex and COPD in never-smokers. This can be attributed to the fact that a majority of smokers worldwide are males with a wider gender gap with regard to cigarette smoking in developing countries when compared with the developed world.[19] Another very important reason for this trend is the fact that women in our environment are more exposed to smoke and fumes from firewood, charcoal, and kerosene stove while cooking.

Our study also revealed that a number of nonsmoking subjects had domiciliary or occupational exposure to fumes and irritant gases which constituted risk factors for the disease. This mirrors a previous report by Celli et al.[18] who revealed that occupational exposure to dust and irritant gases was a recognized risk factor for COPD after cigarette smoking in a survey of airway obstruction in never-smokers. Furthermore, other surveys also documented independent associations with airflow limitation among occupational groups such as farmers, textile workers employed in dyeing cotton and wool fibres, and those exposed to quartz and metal dust.[20],[21],[22]

Petty trading constituted the most common occupation in patients with COPD who had never smoked in our locality and this may be as a result of constant exposure to outdoor dust and fumes while plying their trade. Firewood usage was found, in this study, to be the most common source of biomass exposure with 47.4% of the subjects implicated. This is consistent with reports that biomass exposure is significantly associated with occurrence of COPD in never-smokers as documented by Lamprecht et al.[7] and Bakrand Elmahallawy.[9]

The most common symptoms observed among the subjects were chronic cough, exertional dyspnea, and chronic sputum production. The pattern of the symptoms is also in accordance with the general COPD pattern reported in Ilorin and Ile-Ife.[17],[23]

Spirometric confirmation of disease was done in less than half (48.9%) of our patients with clinical diagnosis of COPD. This demonstrates the improving though still low utilization of this investigatory modality in our setting. The majority of patients were classified as GOLD stage 1 which is in contrast to a previous study in Egypt,[9] which had a majority of never-smoking COPD subjects in GOLD stage 2.

Our data also showed that never-smokers had a lower mean age, higher BMI, and better mean post bronchodilator spirometric parameters when compared with ever-smokers. This is consistent with reports by Celli et al.[18] who demonstrated that airflow limitation was associated with increasing age and lower BMI.

A major limitation to generalizability of the results of this work is the relatively small number of patients analyzed which are likely due to many factors. First is the retrospective nature of this work which most probably would have led to nonretrieval of data from cases of COPD treated but whose records have been lost due to poor health record keeping. Another major factor is the fact that our analysis was restricted to less than half of the total diagnosed patients who had spirometric confirmation of their COPD diagnosis. Furthermore, since this is a tertiary hospital–based study, we only captured those patients who presented to us. It is possible that more patients had presented to other healthcare facilities.


   Conclusion Top


Despite the limitations associated with the relatively small number of subjects in this study compared with other reports, the findings from this survey have demonstrated that never-smokers constitute a significant fraction of COPD cases in Ilorin with exposure to biomass as the major risk factor. The study has also further established the need for healthcare facilities to adopt computerized storage of patient's information to prevent loss of data. We advocate for increased sensitization of the population of the risks of prolonged exposure to biomass fuel.

Acknowledgement

The authors appreciate the efforts of the record staff at the pulmonary outpatient clinic of the hospital for retrieving and providing them with the case folders required for the research.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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