title: The amplitude of circadian FEV1 variation suitable for phase determination by cosinor analysis in stable asthmatic children.
abstract: To elucidate the criterion for amplitude of circadian FEV1 variation suitable for phase analysis, six FEV1 measurements within a day were made on 346 days in 125 stable asthmatic children aged 8 to 12 years. Since coefficient of variation (CV) of FEV1 within a day in nonasthmatic children in our laboratory is less than 5 percent, circadian FEV1 variations were divided into CV greater than or equal to 5 percent and CV less than 5 percent groups. Forty-two (12 percent) variations with significant fit of cosinor rhythm were CV greater than or equal to 5 percent. Troughs in 32 (76 percent) variations of the 42 were distributed between 12 PM and 6 AM, and the deviation was highly significant against a uniform distribution (p less than 0.001). This was consistent with nocturnal asthma. Thirty-five (10 percent) variations with significant fit of cosinor rhythm were CV less than 5 percent. Troughs in 12 (34 percent) variations of the 35 were distributed between 12 PM and 6 AM, and the deviation from a uniform distribution was nonsignificant. These suggest that 5 percent or more of CV of FEV1 may be clinically suitable for analysis of circadian FEV1 variation.
authors.affiliation: Children's Asthmatic Center, Kawasaki City Ida Hospital, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kondo
mesh_terms: D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D013147:Spirometry