Influence of environmental and genetic factors on CYP1A2 activity in individuals of South Asian and European ancestry

Clin Pharmacol Ther. 2012 Oct;92(4):511-9. doi: 10.1038/clpt.2012.139. Epub 2012 Sep 5.


The drug-metabolizing enzyme CYP1A2 contributes to the metabolism of a number of commonly used medicines and displays wide interindividual variability. The aim of this study was to investigate CYP1A2 activity in a population of South Asian ancestry and compare it with a population of European ancestry. CYP1A2 activity was determined using the 4 h paraxanthine/caffeine saliva concentration ratio following a 100-mg oral dose of caffeine in healthy individuals of South Asian (n = 166) and European (n = 166) ancestry. Participants were surveyed for extrinsic ethnic factors and genotyped for polymorphisms in CYP1A2 and related genes. Significantly lower CYP1A2 activity was observed in South Asian participants (median: 0.42; range: 0.10-1.06) as compared with European participants (0.54; 0.12-1.64) (P < 0.01). Multiple linear regression indicated that 41% of the variability in CYP1A2 activity could be explained by the diet, lifestyle, and genetic factors studied.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Asia, Western / ethnology
  • Asian People / ethnology
  • Asian People / genetics*
  • Australia / ethnology
  • Cross-Sectional Studies
  • Cytochrome P-450 CYP1A2 / genetics*
  • Cytochrome P-450 CYP1A2 / metabolism
  • Environment*
  • Enzyme Activation / physiology
  • Female
  • Humans
  • India / ethnology
  • Life Style* / ethnology
  • Male
  • Prospective Studies
  • Sri Lanka / ethnology
  • White People / ethnology
  • White People / genetics*
  • Young Adult


  • CYP1A2 protein, human
  • Cytochrome P-450 CYP1A2