Peak expiratory flow in rural residents of Tamil Nadu, India.

BACKGROUND In a country such as India that covers several latitudes, climatic zones, ethnic groups, and dietary habits lung function within the normal population would be expected to vary. Several studies have looked at normal values of peak expiratory flow (PEF) in different regions of urban India but none has looked at rural South India. A study of PEF has now been carried out in a rural population of Tamil Nadu. METHODS All subjects were of Dravidian stock and lived at sea level with rice as their staple food. Ten five year age groups from 10 to 59 years with 100 males and 100 females in each were studied. Peak flow was measured by mini-Wright peak flow meter, and height was also measured. Regression equations for predicting normal PEF were calculated. RESULTS Peak flow ranged from 150 to 680 l/min in males and from 150 to 500 l/min in females. Maximum values of PEF were attained at the age of 32.5 years in men and 35.6 years in women. There was a significant linear correlation between height and PEF and a curvilinear relation between age and PEF in both sexes. CONCLUSION Regression equations are now available for PEF values in normal subjects from rural South India. PEF was related to age and height and values were greatest in the fourth decade.