A comparative study of airway resistance, conductance and residual volume in first year MBBS day scholars and hostelites from rural areas of BMCRI

 

Bhanu Priya H^1*, Kusuma Devi M S²

 

¹Assistant Professor, Department of Physiology, Akash Institute Of Medical Sciences and Research Centre, Prasannahalli road, Devanahalli

Near Kempegowda International Airport, Bangalore – 562110, Karnataka, INDIA.

²Professor, Department of Physiology, Bangalore Medical College and Research institute, Fort, K. R. Road, Bangalore -560002, Karnataka, INDIA.

Email: bhanupriyah28@gmail.com

 

Abstract               Background: Literature states that exposure to automobile pollution is a proposed marker for future development of acute or chronic respiratory disease. Hence the current study was undertaken with a view to investigate the effect of automobile pollution on pulmonary function parameters of First year MBBS day scholars. The potential health risks in First year MBBS day scholars can be minimised by early identification of abnormalities in Pulmonary Function Test parameters and periodic retesting can detect pulmonary disease in the earliest stages when corrective measures are more likely to be beneficial. Objectives: 1. To record airway resistance, conductance and residual volume in day scholars and hostelites from rural areas (population <20,000) of First year MBBS from Bangalore medical college and research institute. 2. To test the hypothesis that there is decline in above parameters in First year MBBS day scholars due to long term exposure to air pollutants after comparing 2 groups. Materials and Methods: This is a comparative study done in 100 First year MBBS students from BMCRI. Group A: 50 healthy non-smoking day scholars of First year MBBS residing in Bangalore for 5yrs or more. Group B: 50 healthy non-smoking hostelites of First year MBBS from rural areas (population <20,000) are included for the study. Pulmonary function test was carried out, parameters like FEV1, FVC, FEV1/FVC, PEFR, FEF_25-75 were measured using MEC PFT and RAW and sGAW were measured using body plethysmograph in both the groups. Results: It was found that Group A showed significant decrement in pulmonary function parameters like FEV1, FEV1/FVC, PEFR, FEF25-75, sGAW and significant increase in RAW(p value < 0.001) in First year MBBS day scholars when compared with hostelites counterparts. Conclusion: Results of our study showed that obstructive type of pulmonary abnormality is observed in First year MBBS day scholars exposed to automobile pollution for longer duration.

Key Words: Airway resistance, Automobile pollution, Plethysmograph, Specific airway conductance.

 

 

INTRODUCTION

Air pollution is one of the present day health problems throughout the world. Outdoor air pollution caused 3.7 million deaths every year, according to report by WHO¹. Deterioration of air quality in Bangalore is mainly due to transportation sectors and construction activity. Health impact of air pollution depends on the pollutant type, its concentration in the air, length of exposure, other pollutants in the air and individual susceptibility. Poor people, undernourished people, very young and very old, and people with pre-existing respiratory disease and other ill health are more at risk^2,3. Air pollutants when inhaled, cause damage to the airways and the lungs, leading to derangement of respiratory physiology and incurring loss of man power hours. Bangalore has been identified as one of the city with highest particulate matter. Pollution hot spots in the Bangalore city are Graphite India Whitefield, Victoria road, Domlur, Peenyaand Yeshwanthpur Police Station. So it is important to assess the effect of air pollution on lung function of adolescents of urban population, because chronic exposure to air pollution can cause early developmental change in lung leading to various diseases in adult life. Hence the present study is undertaken to test hypothesis that there is detrimental effect on airway resistance, conductance and residual volume in First year MBBS day scholars who are exposed to air pollution for longer duration when compared to First year MBBS hostelites from rural areas.
MATERIALS AND METHODS:

Source of Data: This is a comparative study done on 100 apparently healthy day scholars and hostelites of First year MBBS from Bangalore medical college and research institute. Day scholars were from Graphite India, White Field, K.H.B Industrial Area, Yelahanka, K.R. market area, Yeshwanthpura Police Station of Bangalore city where they are exposed to a high concentrations of ambient air pollutants. Hostelites were from rural areas like Gubbi, Haveri, Havanoor with lower concentration of ambient air pollutants. Study period was from October 2014 – August 2016.

Inclusion Criteria

• Healthy non-smoking dayscholars and hostelites from rural areas (population <20,000) of Istyear MBBS,BMCRI in the age group of 18-20 years were included for the study.

Exclusion Criteria

• Subjects with gross clinical abnormalities of the vertebral column, thoracic cage and neuromuscular diseases.
• Known cases of respiratory diseases, allergic disorders and endocrine disorders.
• Non co-operation or inability to perform pulmonary function tests.

Recording of Pulmonary Function Test⁴:

Pulmonary function Tests were recorded in both the groups using M.E.C PFT body plethysmograph station in life style laboratory. PFT measurements included FVC, FEV₁, PEFR, FEV₁/FVC, FEF_25-75, RAW and sGAW. Procedure was explained and subjects were made to sit in the body box and they were made comfortable and familiarized with the procedure. Nose clip was applied. Forced spirometry was performed in MEC PFT system with door open; total 3 recordings were taken with the interval of 5 minutes. Best of the 3 recording was selected. After 15 minutes of rest, subjects were made to perform panting maneuver in body plethysmography with door closed to measure airway resistance and specific airway conductance. Minimum of 3 recordings were taken at the interval of 5 minutes and best of the 3 was selected.

Statistical Analysis: Data are presented as mean ± standard deviation (SD) and the difference between two means was compared by Student’s t-test. A p value less than 0.05 (p <0.05) was considered to be statistically significant.

RESULTS

 

Table 1: Anthropometric parameters of subjects (Values expressed in Mean± SD)

Table 1 shows that both groups are age matched and have no statistically significant difference in their height, weight and body surface area.

 

Table 2: Comparison of Pulmonary Function test in study and Control group

Pulmonary Function test	Group A	Group B	P value
FVC	3.03±0.6	2.94±0.5	0.07
PEFR	5.42±1.62	6.2±1.2	<0.001**
FEV1	2.45±0.5	2.65±0.52	0.05*
FEV1/FVC	0.84 ±0.07	0.91 ±0.06	<0.001**
FEF25-75%	3.05±0.93	3.54±0.56	<0.001**

 

 

 

 

 

 

 

 

 

 

 

 

Table 2 shows the comparison of mean values of FEV₁, FVC, FEV₁/FVC, PEFR, FEF_25-75% between 2 groups. In the table we can see that FEV₁, FEV₁/FVC, PEFR, FEF_25-75% was significantly reduced in group A.

 

Table 3: An evaluation of RAW, sGAW and Residual volume in both groups

Table 3 shows that Raw is increased, sGaw is reduced significantly in group A and there is no significant change in residual volume between two groups.

 

DISCUSSION

In this present comparative study, the extent of damage ambient air pollution has done to the lung parenchyma and airways is estimated by comparing the results of the ventilatory function tests of the First year MBBS day scholars with those of hostelites of BMCRI. The factors that affect the normal values for ventilatory lung function are ethnic variation, physical activity, altitude of the dwelling, environmental conditions and tobacco smoking⁵.In our study, both the groups included subjects from the same ethnic South-Indian origin, residing at the same altitude, besides being non-smokers but differing only in the environmental exposure to varying concentration of ambient air pollutants. This difference in exposure to varying concentrations of ambient air pollutants is the only factor, which may be responsible for the decline in the results of the ventilatory function tests of the study group.  Table 1 shows that age (years), height (cm), weight (kg) and Body surface area (m²) were well matched with respect to the mean of the above parameters. Table 2 shows that FEV₁, FEV₁/FVC, PEFR, FEF _25-75, are decreased significantly (p value < 0.001) compared to control. This study is also in agreement with Jafary et al who studied the effects of airborne dust on lung function of the exposed subjects and found significant decrease in FVC and FEV1 with a p value of < 0.001 for both the parameters in cases⁶ and Atosh Kumar et al who studied impact of chronic air pollution exposure on pulmonary function in healthy nonsmoker young men from two different areas of Kanpur City and the long term exposure of pollutant PM₁₀ could reduce the forced vital capacity, Forced expiatory flow _{25-75 %}, Vital capacity and peak expiratory flow(P value < 0.001)⁷. Diesel exhaust particle organic extracts induce reactive oxygen species in macrophages and bronchial epithelial cells, two key cell types targeted by particulate matter in the lung. Reactive oxygen species activate the promoters of cytokines and chemokines involved in allergic inflammation through activator protein-1 and nuclear factor- kappa B signalling pathways^8,9. Chronic inflammation of the respiratory tract may be the reason for decreased PEFR, FEV₁/FVC and FEF_25-75%. Table 3 shows that there is increases airway resistance and decrease in specific airway conductance in study group which is statistically significant (<0.001**). This study is in agreement with study done by Islam MS, Schlipköter HW who examined delta Raw in children between 6-8 years of age living in areas with different air qualities and found small but statistically significant (p less than 0.1) greater delta Raw for children of higher polluted areas. This could indicate that children of polluted areas possessed higher bronchial smooth muscle tone¹⁰. The pollutants which act as irritants stimulate the receptors under the tight junction of bronchial epithelium resulting in an increased parasympathetic discharge to the bronchial smooth muscle via the vagus nerve. Through the release of acetylcholine, which acts on the muscarinic receptors present in the bronchial smooth muscle, there is enhancement of the bronchoconstrictor tone of the smooth muscle in the small airways and increase in resistance¹¹.

 

CONCLUSION

Hence it was concluded that decrease in pulmonary function tests is observed in MBBS day scholars who are exposed to high concentration of ambient air pollution compared to hostelites. Hence people should be made aware of the dangerous consequences of ambient air pollution, and should be motivated to prevent its occurrence in all stages.

 

REFERENCES

1. http://www.who.int/mediacentre/factsheets/fs313/en/ accessed on11/06/ 2016
2. Air pollution and its effects on health – Case studies, India ManasRanjan Ray, TwishaLahiri
3. Jafary ZA, FaridiIA,Qureshi HJ. Effects of airborne dust on lung function of the exposed subjects. Pak J Physiol 2007; 3(1): 30-34.
4. MEC PFT manualhttp://mecrd.eu/ accessed on 11/06/2016
5. Woolcock AJ, Colman MH, Blackburn CR. Factors affecting normal values for ventilatory lung function. Am Rev Respir Dis. 1972 Nov; 106(5):692-709.
6. Jafary ZA, FaridiIA,Qureshi HJ. Effects of airborne dust on lung function of the exposed subjects. Pak J Physiol 2007; 3(1): 30-34.
7. Kumar A, Verma SK, Bhargava V. Impact of Chronic Air Pollution Exposure on Pulmonary Function in Healthy Nonsmoker Young Men from Two Different Areas of Kanpur City. 2012; 2(2).
8. Huisingh JL, Bradow R, Jungers R, et al. Application of bioassay to the characterisation of diesel particle emission. In: Waters MD, Nesnow S, Huisingh JI, et al, eds. Application of short term Bioassays in the Fractionation and Analysis of complex Environmental mixtures, Newyork: Pienum press; 1978. p. 381-418
9. Nel AE, Diaz-Sanchez D, Li N. The role of particulate pollutants in pulmonary inflammation and asthma: evidence for the involvement of organic chemicals and oxidative stress.curropinpul med 2001 Jan; 7(1): 20-6.
10. Islam MS, SchlipköterHW.Reversible fraction of airway resistance in healthy children of areas with different levels of atmospheric pollutants. ExpPathol 1989; 37(1-4):23-26.
11.  A Comparative Study of the Effects of Ambient Air Pollution on Ventilatory Functions Tests in Urban and. 2013; 3(9):9–11.