THC and THC-COOH hair concentrations: Influence of age, gender, consumption habits, cosmetics treatment, and hair features
Fabio Vaiano, Lapo Scuffi, Alessio Lachi, Claudia Trignano, Antonina Argo, Francesco Mari, Elisabetta Bertol
Abstract
1 M) of 25 mg of hair. A liquid chromatograph - tandem mass spectrometer (LC-MS/MS) equipped with a C18 column was used. The acquisition was in multiple reaction monitoring for the following transitions: 315→259, 193 m/z, for THC; 318→196, 123 m/z, for THC-d3; 345→299, 193 m/z for THC-COOH; 348→196, 302 m/z for THC-COOH-d3. Correlation between THC and THC-COOH hair concentrations was analyzed by Spearman's rank correlation coefficient. In order to study the influences of several variables, a new value, Sqrt(THC*THCCOOH), was adopted. Its effectiveness and reliability were proved by the Principal Component Analysis. Relationships between the Sqrt(THC*THCCOOH) and the variables were studied through the Stepwise regression (p = 0.05). The normality of data distribution was tested by the Shapiro-Wilk test. The Lower limits of quantification were 10.0 (THC) and 0.2 (THC-COOH) pg/mg. Accuracy and precision always met the acceptable criteria. Recoveries were > 78% and ion suppression was observed for both the compounds. Data from 126 hair samples were included in this study: 54 subjects(42.9%) were positive both for THC and THC-COOH; none of the samples was positive for a single substance. Concentrations ranged from 0.18 to 1.75 ng/mg (median: 0.78 ng/mg) for THC and from 0.04 to 0.85 ng/mg (median: 0.31 ng/mg) for THC-COOH. Cannabinoids levels seemed to decrease with the age, with lower amounts in the subjects aged > 40 years (p < 0.05). Also years of consumption seemed to have a significant impact on hair concentrations, as higher levels were observed in consumers from > 10 years (p = 0.013). Moreover, this study further provided evidences of a significant reduction of THC and THC-COOH in bleached hair (p = 0.042).