Body mass index and asthma severity in a population of Nigerian asthmatics

Asthma and obesity have considerable impact on public health. There is increase prevalence of both conditions worldwide. This study was undertaken to determine the prevalence of obesity among asthma patients as well as determine the effect of body mass index (BMI) on asthma severity and pulmonary functions.

The study was conducted at the asthma clinic of the medical outpatient of Lagos State University Teaching Hospital, Ikeja. Ethical clearance was obtained from the hospital's research and ethics committee. Non probability sampling method was used with consecutive asthma patients diagnosed by the respiratory physicians according to NHLBI guideline recruited into the study. The weight, height and pulmonary function tests were carried out using standard methods. Acarefully designed interviewer administered questionnaire were used to collect information on the socio demographic characteristics of the patient, asthma symptoms, control use of rescue medications and emergency visits.

One hundred and fifty eight (158) asthma patients participated in the study. There were 63 (39.9%) males and 95 (60.1%) females. The prevalence of obesity was 53.8%. The mean age of respondents was 46.48 +/- 17.16 years. Age, educational level and employment status were related to the body mass index while gender and duration of asthma were not. There was no difference in the severity of asthma and utilization of emergency services across the BMI categories. The obese asthmatics generally recorded lower lung function volumes compared with the non-obese asthmatic groups.

Prevalence of obesity is high among the asthmatics studied. There is no difference in asthma severity across the BMI categories. Pulmonary functions are lower in obese asthmatics.