Peak expiratory flow rate variability in apparently healthy school children aged 10-15 years in Oredo, Nigeria

To study the peak expiratory flow rate variability (PEFRVar) in apparently healthy school children in Oredo, Nigeria. We carried out a cross-sectional study of 438 subjects (10-15 years), attending the public junior secondary schools, between March and November 2005. The study took place in the Oredo Local Government Area. The age and anthropometry were taken and PEFRVar was determined using values obtained at 6 AM, 2 PM, and 10 PM over a 14-day period, using a mini-Wright peak expiratory flow meter. Peak expiratory flow rate variability (mean+/-SD) was 4.5+/-1.3% for all subjects (4.4+/-1.0% for males, and 4.6+/-1.6% for females). Females had higher PEFRVar. The upper limits of 95% CI were 7.1% for all subjects (6.4% for males, and 7.8% for females). The PEFRVar showed an inverse relationship with height, age, and weight. Regression equations for PEFR and PEFRVar were derived for age, height, and weight. Based on upper limit of 95% CI for all subjects, a PEFRVar cut-off of 7.1% is recommended for diagnosis of significant airway obstruction as in asthma in the age bracket under review in Oredo and perhaps other areas, sharing similar geo-physical and social characteristics.