VENTILATORY CAPACITY INDICES IN MALAWIAN CHlLDREN

Abstract

Objective: To compare ventilatory capacity indices in healthy Malawian school children with
those of other ethnic Africans and Caucasians.
Design: Forced vital capacity (FVC), forced expiratory volume in one second (FEV,), peak
expiratory flow rate (PEFR), FEV, expressed as a percentage of FVC (FEV%), weight and
height.
Setting: Two primary schools in urban Blantyre, Malawi.
Subjects: Five hundred and fourteen apparently healthy school children (230 boys and 284
girls) aged six to 17 years.
Results: Ventilatory capacity indices (FEV,, FVC and PFFR) strongly and significantly
correlated to body size and age of children of both sexes. The mean value of FEV % was 88.3 %
and it did not change significantly with increasing body size and age of children. The mean
values of FEV, and FVC were 9.8 % and 10.8 % higher in bo 6 s than in girls, respectively. The
1.4 '% gender difference in PEFR values was statistically norl-significant. For FEV, and FVC
values, the average differences between Malawian and Eelropean children were between
20.5% and 23% while for F'EFR the ethnic difference was about 12%. The Malawian
children have similar ventilatory capacity indices to those of Nigerian, Jamaican and
Tanzanian children.
Conclusion: Prediction equations calculated in this study should be used for interpretation
of ventilatory capacity indices in Malawian children instead of reference values for Caucasians
or ethnic scaling factors. Cornputation of regional reference values for ventilatory capacity
indices shall be continued. It shall embrace additional factors contributing to variance in
respiratory functions such as customary physical activity, local environmental conditions,
altitude of residence, nutritional status and smoking.