Abstract
Multiple dependent and independent variables affect lung function tests. Hence univariate analysis is not appropriate. The main objectives of the study were to show the appropriateness of multivariate analysis for these types of studies, to know the exact quantification effects of factors on study variables and to study the interaction effects of factors. Eighty individuals between 29-59 years formed the study group. Using computerized spirometer, 3 study variables - Forced Expiratory Volume in 1st sec / Forced Vital Capacity , Forced Expiratory Flow rate 25-75% and Peak Expiratory Flow Rate, were determined and correlated to 3 factors - age, gender and height. Seven Models were formulated by different combinations of factors. Each Model was analysed by Multivariate analysis of Variance (MANOVA) which resulted Wilks’ Lamda (λ), Univariate ANOVA with full Factorial Experiments (2n) and K-matrix with Bonferoni’s confidence interval. Geometric Mean was calculated from partial values. This methodology is superior and exact compared to univariate analysis. Overall contribution of age in influencing study variables simultaneously is 67.4%, gender 88.3%, height 63.2%, age-gender 30.9%, age-height 28.2% and gender-height 31.5%. This effect quantification information is not available in literature as their analysis was by univariate analysis. All main effects and second order interaction effects of factors are significantly influencing study variables. It is concluded that multivariate analysis is preferred over univariate analysis in lung function studies.
Keywords: Wilks Lamda, MANOVA, K -matrix, partial .
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Corresponding Author
Dr Kalavathi Lakshmipathy
MD (Physiology), Director – Professor, Department of Physiology,
ESIC Medical College & Post Graduate Institute of Medical Sciences & Research,
Rajajinagar, Bangalore-560010, Karnataka, India.
Landline: +91 080 23125572 (Dean), +91 080 23003604 (Chamber)
Mobile No: (+91) 9448259303, Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
DOI: https://dx.doi.org/10.18535/jmscr/v6i3.50
