The influence of age, height, and body weight on cerebrospinal fluid amine metabolites and tryptophan in women

Cerebrospinal fluid 5-hydroxyindoleacetic acid (CSF 5HIAA), homovanillic acid, and tryptophan were measured in 33 depressed, 36 alcoholic, and 32 neurological control female patients selected by strict operational criteria and investigated under controlled circumstances. Plasma total tryptophan was also measured in blood samples taken simultaneously with lumbar punctures. A multivariate regression analysis was done to discover the effect of age, height, and body weight on these four biochemical measures. Only CSF 5HIAA was significantly dependent on the nonspecific patient variables: height, but neither age nor weight, accounted for more than 10% of the variance of 5HIAA. The same analysis was carried out in all three separate patient groups: the relationship between height and CSF 5HIAA was present throughout, and only 2 of 12 correlations proved to be non-homogeneous. To demonstrate the significantly of these clinical parameters a multivariate analysis of covariance was done to eliminate their effect on the four biochemical variables. As a result significant differences emerged in CSF 5HIAA and total plasma tryptophan for some of the patient groups which were not demonstrable without this correction.