Indmedica Home | About Indmedica | Medical Jobs | Advertise On Indmedica
Search Indmedica Web
Indmedica - India's premier medical portal

Indian Journal of Community Medicine

Peak Expiratory Flow Rate and Cardio-Respiratory Fitness of Bengali Workers Exposed to Dust and Plant Source Particulate Matters

Author(s): Parthasarathi Debray, Jaydeb Misra, Chandradipa Ghosh

Vol. 27, No. 4 (2002-10 - 2002-12)

Deptt. of Human Physiology with Community Health, Vidyasagar University, Medinipur, West Bengal - 721102

Abstract:

Research question: What is the effect of exposure to 'dust and plant source particulate matter' on lung capacity and cardio-respiratory fitness of workers from different occupations?

Objective: Examination and comparative analysis of the effects of exposure to 'dust and plant source particulate matter' on lung capacity and cardio-respiratory fitness of workers from different occupational activities.

Study design: Cross-sectional.

Setting: Medinipur and Bankura districts of West Bengal.

Participants: 113 Bengali male workers including 28 stone grinders, 25 jute mill workers, 29 agricultural workers and 31 healthy normal individuals (control) participated in the study.

Results: Peak expiratory flow rate (PEFR), physical fitness index (PFI) and maximum oxygen consumption (VO2 max) of control subjects were significantly higher than stone grinding, jute mill and agricultural workers. Among the three groups exposed to 'dust and plant source particulate matter', the mean values of PEFR and VO2 max of stone grinders were significantly lower than jute mill and agricultural workers.

Conclusions: Based on the present study it is concluded that occupational activities which involve exposure to 'dust and plant source particulate matter' such as stone griding, jute mill and agricultural works affect the lung capacity and cardio-respiratory fitness of workers and the maximum deterioration of these parameters have been observed in the stone grinders.

Keywords: Peak expiratory flow rate, Physical fitness index (PFI), Maximum oxygen consumption (VO2 max), Workers, Dust, Particulate matter, Cardio-respiratory fitness

Introduction:

Environmental pollution is a worldwide phenomenon. It is increasing day by day due to effluents and emissions from industries, solid waste disposal, automobile exhaust and degradation of soil by removing the green belt and high use of pesticides. The particulate matter that remains in a suspension state in trophosphere, such as solid particles (from combustion processes, industrial activities and natural sources), liquid droplets etc. floating in the air are referred to as particulate pollutants.

Of greatest concern to the public health are the particles small enough to be inhaled into the deepest parts of the lung. These particles are less than 10 microns in diameter about 1/7th the thickness of a human hair and are known as PM10. This includes fine particulate matter known as PM2.5. PM10 is a major component of air pollution that threatens both our health and environment. A large number of epidemiological studies have shown that day-to-day variations in concentrations of particles are associated with adverse effects on health. These include increased daily deaths, increased admissions of patients to hospitals suffering from heart and lung disorders and a worsening of the condition of those with asthma1.

Tiittanen et al, 19992 observed that PM10 were mainly resuspended soild and street dust in Finland and they examined the effect of various particulate matters on peak expiratory flow rate (PEFR) and respiratory symptom in children (8-13 years) and showed that PM10, PM2.5-10, PM2.5 and resuspended PM10 were significantly associated with increased risk of cough. Gupta et al 19983 showed on rubber factory workers in India that a significant positive correlation existed between the decrement in values of FEV1/FVC% and a rise in the ratio of RV/TLC with the increasing inhaled concentrations of the particulate load. Gold et al, 19994 assessed the contributions of particulate matter (PM2.5 and PM10) and ozone (O3) to peak expiratory flow (PEF) and respiratory symptoms in 40 school children 8-11 years of age for 59 days during three periods in 1991 at a school in southwest Mexico City and observed role for both particles and O3 in the reduction of peak expiratory flow. Occupational exposure to combustion particulates in boilermaker construction workers showed association between working at gas, coal and oil-fired plants and annual lung function loss5.

Numerous epidemiological studies have reported increases in the daily incidence of cardiovascular mortality and morbidity associated with increase in daily levels of particulate matter in air6. The aim of the present study, therefore, is to examine the effects of 'dust and plant source particulate matter' on lung capacity and cardio-respiratory fitness of stone grinding, jute mill and agricultural Bengali workers in West Bengal. 

Material and Methods:

Selection of the subject: Data were collected from Bengali male subjects in different places of Medinipur and Bankura districts of West Bengal. The study populations were mainly individuals who remain exposed directly to 'dust and plant source fine particulate matter' during their occupational activities. The average time period of working was 13.56±6.58 years for these individuals. These workers were again sub-divided according to their type of work i.e., (a) Stone grinders - those directly exposed to dust from stone during grinding of stone, (b) Jute mill workers - those directly exposed to plant source and dust particulate matter at the time of making jute bags, (c) Agricultural workers - those directly exposed to plant source and dust particulate matter during the paddy thrashing. Besides these another group of healthy normal individuals not directly exposed to dust and plant source particulate matter during occupational activities except their regular exposure to ambient particulate matter pollution were treated as controls. The controls were selected from the type of occupations where activities were quite similar to stone grinding, jute mill and agricultural activities as classified by ICMR expert group of 1988 on the basis of the activities in the occupation7.

Prior to initial testing all selected subjects were given a complete explanation of the purposes, procedures and potential risks and benefits involved in the study and their consent was taken in this regard.

Age was computed from date of birth and date of tests. Body weight was taken using a weighing machine when subjects were without shoes and wearing minimum clothes. Height was measured by standard procedure. Blood pressure was measured in sitting posture as per recommendation of WHO, 19898.

Measurement of Peak Expiratory Flow Rate (PEFR):

Peak expiratory flow rate was examined with an Airmed peak-flow meter. The test was performed in standing position holding the peak flow meter horizontally. A tight fitting disposable cardboard mouthpiece was inserted in the inlet nozzle. After proper rest, subject was requested to take a deep breath and exhale as forcefully as possible in one single blow into the instrument. The procedure was repeated three times and best of the three was recorded.

Measurement of Physical Fitness Index (PFI):

PFI was measured by Harvard step test9. The standard procedure for the original step test was modified and used with a difference that the stepping height was reduced from 20 inches to 18 inches in the line of originator of the tests who suggested that for evaluating subjects with body surface area below 1.85 m2, an 18 inches stool should be appropriate10. The subjects stepped up and down on a stool at the rate of 30 complete steps per minute keeping time to a metronome for duration of 5 minutes unless one stepped before from exhaustion. The recovery pulse counts were measured at 1 to 1-1/2, 2 to 2-1/2, 3-1/2 minutes recovery. Physical fitness was scored as PFI = [Duration of exercise in sec x 100] / [2 x (sum of 1 to 1-1/2 min., 2 to 2-1/2 min., 3-1/2 minutes recovery)].

Measurement of Maximum Oxygen Uptake (VO2 max:

VO2 max was measured indirectly by queen's College step test11. Subject stepped up and down on 16.25 inch stool for three minutes with a cadense of 24 beats per minute. A metronome maintained the cadense. After three minutes of exercise, recovery pulse rate was taken for 5 to 20 second i.e. 15 seconds. Following equation was used for calculating the VO2 max (ml.kg-1.min-1.): 111.33-0.42 (pulse count in 15 sec x 4).

Statistical analysis:

The statistical analysis was done using statistical package (SPSS, version 6.0). Mean, standard deviation and range of values were obtained. Overall comparison of selected values was performed by one way ANOVA. Scheffe's multiple comparison tests were performed to compare means of selected physiological parameters where overall comparison by one way ANOVA was significant.

Results:

Table I: Characteristics of various groups of subjects.

Variable Mean SD Minimum value Maximum value
Stone grinders (n=28)
Age (years) 31.4 10.85 20.0 55.0
Height (cm) 157.5 6.74 146.0 175.0
Weight (kg) 47.4 4.82 37.0 56.0
Systolic blood pressure (mmHg) 118.2 7.87 104.0 140.0
Diastolic blood pressure (mmHg) 73.6 6.18 60.0 82.0
Jute mill workers (n=25)
Age (years) 33.0 9.75 21.0 56.0
Height (cm) 155.2 4.11 147.0 163.0
Weight (kg) 50.9 4.08 45.0 57.0
Systolic blood pressure (mmHg) 116.3 5.67 106.0 122.0
Diastolic blood pressure (mmHg) 71.3 4.21 62.0 80.0
Agricultural workers (n=29)
Age (years) 35.4 10.82 21.0 53.0
Height (cm) 163.4 5.38 153.0 174.0
Weight (kg) 55.4 5.35 48.0 67.0
Systolic blood pressure (mmHg) 124.0 10.68 106.0 144.0
Diastolic blood pressure (mmHg) 75.7 5.60 64.0 84.0
Controls (n=31)
Age (years) 33.5 10.26 20.0 54.0
Height (cm)   5.89 152.0 174.0
Weight (kg) 55.7 5.95 46.0 68.0
Systolic blood pressure (mmHg) 125.8 8.99 108.0 142.0
Diastolic blood pressure (mmHg) 77.9 6.07 68.0 88.0

SD - Standard deviation.

Characteristics including age, height, weight and blood pressure of the subjects of four groups such as stone grinders, jute mill workers, agricultural workers and controls (healthy subjects of moderate working in occupation) are presented in Table I.

Table II: Comparison of selected physiological parameters of different groups.

Variable* Stone grinder1 Jute mill worker2 Agricultural worker3 Control4 Trend for
linearity
Significant F#
Peak expiratory flow rate 363.1± 67.67 420.4± 48.36 406.9± 52.91 504.8± 41.14 p<0.01
(PEFR) (Lmin-1)abcef (230.0-480.0) (320.0-490.0) (310.0-480.0) (430.0-580.0)  
Physical Fitness Index 43.7± 2.42 44.6± 2.04 47.4± 2.41 50.1± 1.67 p<0.01
(PFI)bedef (38.7-47.1) (41.2-50.3) (41.6-50.3) (46.3-57.4)  
VO2 max 30.6± 3.24 37.0± 2.30 36.5± 2.79 42.7± 2.36 p<0.01
(ml.kg-1.min-)abcef (25.7-35.7) (34.0-42.8) (32.4-40.8) (39.1-45.8)  

Values are Mean±standard deviation (Minimum value-Maximum value)
#Overall difference is based on one way ANOVA, **p<0.01, *Scheff's F tests were performed for multiple comparisons of selected variables for significance of differences in each pair of groups where F values in one way ANOVA were significant. Significant differences at p<0.05 by Scheff's multiple comparison test, where significant differences are denoted as a1 vs 2; b1 vs 3; c1 vs 4; d2 vs 3; e2 vs 4; f3 vs 4.

Comparison of peak expiratory flow rate, physical fitness index (PFI) and VO2 max among the groups are presented in Table II.

Peak expiratory flow rate (PEFR), physical fitness index (PFI) and VO2 max differed significantly (p<0.01) among the groups. PEFR, PFI and VO2 max of controls was significantly higher than stone grinding, jute mill and agricultural workers. It is also evident that the mean value of PEFR and VO2 max of stone grinders were significantly lower than jute mill and agricultural workers. Like PEFR and VO2 max, the mean value of PFI was also lower in stone grinders than jute mill and agricultural workers, although the differences were statistically significant only with agricultural workers.

Discussion:

The prevalence of occupational health hazards and mortality has been reported to be unusually high among people of India. Although developed countries are very much careful about the health in occupations it is quite neglected in the developing countries like India. There is a widespread misconception that occupational health is mainly concerned with industry and industrialized countries. But in a country like India, millions of people work as daily wages labour like stone grinding, paddy thrashing, weaving etc. These workers often face health hazards during occupational activities. For example in agricultural fields with increasing use of chemicals either as fertilizers, insecticides, pesticides agricultural workers are exposed to toxic hazards from these chemicals and particulate pollutants and thus face a multitude of health problems. In different occupations different hazardous substances contaminate the work environment. The inhalation of this atmospheric air of work environment is by far the commonest route of entry of most of the hazardous substances. Lungs by virtue of direct contact with the atmospheric air are naturally first to bear the onslaught of air contaminants. In different industries and mines the nature of the small inhalable particles are different and causing different types of occupational diseases.

The findings of the present study i.e. mean values of peak expiratory flow rate (PEFR) of control subjects were quite similar to the values of other Bengali male subjects observed by Dey, 198812. In contrast the PEFR values of stone grinders, jute mill workers and agricultural workers were much lower than the values observed in Bengali males12.

The mean physical fitness index (PFI) of stone grinders, jute mill workers, agricultural workers and control subjects in the present study were 43.7, 44.6, 47.4 and 50.1, respectively. Banerjee et al 197413 worked on Indian sedentary people (18-23 years) and observed the mean PFI value to be 56.5±15.44. Dey 198812 also studied Bengali sedentary individuals (20-59 years) and found the mean PFI values for non-smokers and smokers to be 54.02±12.62 and 50.56±12.39 respectively. In both studies, 18 inches stool height was used. In the present study, stool height was also 18 inches and mean PFI values were well corroborated with the observation of Dey, 198812. It is also evident that the mean PFI values in the present study were poor according to the standard PFI classification.

Mean maximal oxygen consumption (VO2 max) of stone grinders, jute mill workers, agricultural workers and controls in the present study were 30.6, 37.0, 36.5 and 42.7 ml.kg-1.min-1 respectively. Sengupta et al 197414 reported that VO2 max of active Indians of various age groups were 42.1 ml.kg-1.min-1 corresponding to the age groups of 31-40 years, 41-50 years and 51-56 years, respectively. Chatterjee et al 198715 have also reported that the average VO2 max 37.3 ml.kg-1.min-1. in smokers (36.2±10.27 years) and non-smokers (35.2±10.14 years) of Bengali males (20-59 years). It is evident that mean values of VO2 max in the present study were in general agreement with published values of Sengupta et al, 197414 and Chatterjee et al, 198715, except the values of stone grinders which were much below the published data.

Present study reveals that PEFR and VO2 max of stone grinders were significantly lower than jute mill and agricultural workers. Like PEFR and VO2 max, PFI was also lower in stone grinders than jute mill and agricultural workers, although the differences were statistically significant only with agricultural workers.

It is clear from the present study that 'dust and plant source fine particulate matter' exposed workers had lower PEFR, PFI and VO2 max values than controls and stone grinders having least values for all the selected physiological parameters. So, it seems that inhalation of the 'dust and plant source fine particulate matter' during work cause deposition of small particles along the lining of alveoli that decreases the ventillation- perfusion ratio and thus reduces the maximum oxygen uptake. This deposition may also be the cause of lower lung capacity. The present findings are well in line with the findings of Tiittanen et al, 1999 that resuspended soil and street dust in Finland affected peak expiratory flow rate (PEFR) and respiratory symptoms in children (8-13 years) and significantly associated with increased risk of cough.

In the present study, the composition of the 'dust and plant source fine particulate matter' was not analyzed. So, it is difficult to explain the agent responsible for the deterioration of lung capacities and cardio-respiratory fitness in the 'dust and plant source fine particulate matter' exposed groups and observed least values of lung capacity and cardio-respiratory fitness of stone grinders than jute mill and agricultural workers. It seems that stone grinders were worst affected by the exposure to stone grinding dust in terms of lung capacity and VO2 max.

Conclusion:

It is concluded from the present study that 'dust and plant source particulate matter' exposed work such as stone grinding, jute mill and agricultural work affects the lung capacity and cardio-respiratory fitness of Bengali male workers. It is also interestingly noted that among the 'dust and plant source particulate matter' exposed workers, stone grinders were worst affected by the exposure to stone grinding dust.

Acknowledgements:

The authors express their sincere gratitude to authorities of Vidyasagar University for providing facilities and the subjects those who volunteered for the present study.

References:

  1. HMSO. Committee on the Medical Effects of Air Pollutants. Non-Biological Particles and Health. London, 1995.
  2. Tiittanen P, Timonen KL, Ruuskanen J, Mirme A, Pekkanen J. Fine particulate air pollution, resuspended road dust and respiratory health among symptomatic children. Eur Respir J 1999; 13: 266-73.
  3. Gupta P, Makhijani SD, Meenakshi C. Pulmonary function tests on rubber factory workers exposed to polynucelar aromatic hydrocarbons. Ind J of Physiol, 1988; 52(2): 71-5.
  4. Gold DR, Damokosh AI, Arden Pope C, Dockery DW, McDonnell WF, Serrano P, Retama A, Castillejos M. Particulate and Ozone Pollutant Effects on the Respiratory Function of Children in Southwest Mexico City. Epidemiology (Cambridge, Mass), 1999; 1(10): 8-16.
  5. Hauser R, Eisen EA, Pothier L, Christiani DC. A prospective study of lung function among boilermaker construction workers exposed to combustion particulates. Am J of Industrial Med, 2001; 5(39): 454-62.
  6. Levy D, Sheppard L, Checkoway H, Kaufman J, Lumley T, Koenig J, Siscovick D, Levy D. A case-crossover analysis of particulate matter air pollution and out of hospital primary cardiac arrest. Epidemiology (Cambridge, Mass), 2001; 2(12): 193-9.
  7. Gopalan C, Rama Sastri BV, Balasubramanian SC. Nutritive Value of Indian Foods. National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, 1989.
  8. WHO. Measuring obesity-classification and description of anthropometric data. EUR/ICP/NUT 125. World Health Organization, Regional office for Europe, Copenhagen, 1989.
  9. Brouha L, Health CW, Graybiel A. Step test simple method of measuring physical fitness for hard muscular work in adult men. Rev Canadian Biol, 1943; 2: 86.
  10. Gallagher JR, Brouha L. Yale J Biol Med, 1943; 15: 657.
  11. McArdle WD, Katch FI, Katch VL. Exercise Physiology: Energy, Nutrition, and Human Performance. Williams and Wilkins, Baltimore, Maryland, 1996.
  12. Dey SK. Experimental study of aerobic capacity in smokers and non-smokers of different groups. Ph.D. Thesis, Calcutta University, 1988.
  13. Banerjee PK, Chatterjee S, Maitra SR. Aerobic capacity in Bengali young men trained and untrained. Ind J Physiol and Allied Sci, 1974; 28: 91-9.
  14. Sengupta J, Srinivasulu N, Sampat Kumar T et al. Influence of age on maximum oxygen uptake and maximum heart rate of Indians during work. Ind J Med Res, 1974; 62: 8.
  15. Chatterjee S, Dey SK, Nag SK. Maximum oxygen uptake capacity of smokers of different age groups. Jap J Physiol, 1987; 37: 837-50.

Parthasarathi Debray, Jaydeb Misra, Chandradipa Ghosh

Deptt. of Human Physiology with Community Health, Vidyasagar University, Medinipur, West Bengal - 721102

Access free medical resources from Wiley-Blackwell now!

About Indmedica - Conditions of Usage - Advertise On Indmedica - Contact Us

Copyright © 2005 Indmedica