May 1988, Volume 38, Issue 5

Original Article

A CORRELATION BETWEEN VARIOUS SPLROMETRIC VARIABLES AND PERIPHERAL LEUCOCYTE COUNT

Alam Sher  ( Deptt. of Physiology, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. )
Asmat Kamal  ( Deptt. of Physiology, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. )
Ahmed Kamal  ( Deptt. of Physiology, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. )
Salimuddin Aziz  ( PMRC Research Centre, Jinnah Postgraduate Medical Centre, Karachi. )

Abstract

An inverse correlation between peripheral leucocyte count and various spirometric variables, i.e. vital capacity (V.C.), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory ratio (FEV1%), forced mid-expiratory flow rate (FEF 25% — 75% or MMFR), maximum ex­piratory flow rate (FEF.2—1 .2m1 or MEFR), was found among 60 smokers of various age groups when compared with matched controls. Results suggest that peripheral leucocyte count can be used as another determinant of lung function besides various spirometric variables used in routine assessment of lung function (JPMA 38 132, 1988).

INTRODUCTION

Peripheral leucocyte count and the pulmo­nary function in smokers have been studied for many years. It has been reported by Sparrow1 and co-workers that the peripheral as well as lung leucocyte count tend to be higher in cigarette smokers which could reflect a probable increase in the elastinolytic burden on the lung. Cigarette smoking has also been shown to produce changes in various spirometric variables including FEV2, MMFR3, MEFR4 and FVC5. In the present study, changes in various spirometric variables and the leucocyte count in smokers have been investigated In order to explore possible correlation between the spirometric variables and leucocyte count and to assess whether peripheral leucocyte count can be used as another determinant of lung function.

PATIENTS AND METHODS

Sixty males with a smoking history of at least one year were selected from the general population. Smokers practising vigorous exer­cises, and those who were unusually exposed to various dusts, fumes, or having gross abnormalities of vertebral column, thoracic cage, or suffering from neuromuscular diseases, acute febrile illness, disabling cardiac disease and gross anaemia were excluded. Control subjects included 40 healthy subjects who had never smoked. Control subjects as well as smokers had differential leucocyte count within normal range and body mass index below 30. The subjects were divided into 4 age groups with the age range of 21 to 30, 31 to 40, 41 to 50 and 51 to 60 years. Expiratoiy spirometry was performed on an S-model vitalograph spirometer at Pakistan Medical Research Council Laboratory, Karachi. Six seconds Vitalogram charts and disposable safety mouth pieces were used for recording forced expiratory spirogram. Total leucocyte count were estimated by ERMA blood cell counter P,C—604 at the main Clinical Laboratory of Jinnah Postgraduate Medical Centre, Karachi.

RESULTS

The values of all the spirometric variables were lower in smokers as compared to the control subjects, and the difference was statistically significant for all the variables in the age range of 31-40 years with the exception of MEFR (Table I).

Higher values of peripheral leucocyte count were observed in smokers in all age groups, as compared to the control subjects; the difference was significant in age groups 1, 2 and 3.

Table II shows the variation in the spiro-metric variables with increasing peripheral leuco­cyte count in the smokers. All the spirometric variables appeared to decrease with the increasing peripheral leucocyte count. Table III shows correlation co-efficient for various spirometric counts in 60 smokers. An inverse correlation was observed between peri­pheral leucocyte count and all the spirometric variables studied.

DISCUSSION

The present work which is concerned with the study of the effect of smoking on leucocyte count and spirometric variables in our population, confirms the finding of previous studies6-8 that cigarette smoking leads to elevation of leucocyte count and reduction of spirometric variables. In the present study leucocyte count in smokers was higher than in the non-smokers (Table I). The mechanism of increase is unknown. One postulate is that nicotine induces the release of cata­cholamines that can raise the leucocyte count, the other being irritant effect of smoke on the respira­tory tree with resultant inflammation. Lung function studies, i.e., vital capacity, forced vital capacity, forced expiratory volume in one second, forced expiratory ratio, forced mid expiratory flow rate and peak flow rate all showed reduction in these spirometric variables compared to age­matched non-smoking controls. The values of spirometric variables show a decline as the leucocyte count increases, which is suggestive of pulmonary damage induced by elevated leucocyte count. This is further supported by the values of correlation coefficient calculated to relate spirometric variables with leucocyte count in smokers. All the spirometric variables are inversely correlated with the peripheral leucocyte count. Since our data shows relationship between leucocyte count and the spirometric variables in smokers, we are of the view that leucocyte count can be used as another determi­nant of lung function.

REFERENCES

1. Sparrow, D., Glynn, R.J., Cohen, M. and Weiss, S.T. The relationship of the peripheral leucocyte count and cigarette smoking to pulmonary func­tion among adult men. Chest, 1984; 86 : 383.
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3. Mcfadden, E.R. and Linden, D.A. A reduction in maximum mid-expiratory flow rate; a spiro-graphic manifestation of small airway disease. Am.J.Med.,1972;52 :725.
4. Williams, D.E., Miller, RD. and Taylor, W.F. Pulmonary function studies in healthy Pakistani adults. Thorax, 1978; 33 : 243.
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6. Corre, F., Leilouch, J. and Schwartz, D. Smoking and leucocyte counts. Results of an epidemio­logical survey. Lancet, 1971; 2 :632.
7. Friedman, G.D., Singelaub, A.B., Seltzer, C.C., Feldman, R. and Colien, M.F. Smoking habits and the leucocyte count. Arch. Environ. Health, 1973;26 :137.
8. Yeung, M.C. and Buncio, AD. Leucocyte count, smoking, and lung function. Am. J. Med., 1984; 76: 31.

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