... 7:45http://www.aidsrestherapy.com/content/7/1/45Page 3 of 6to stratif y the data using a cut-off of 50 years. Althoughthere were more than enough individuals for additionalstratification at younger ages, additional str atification atolder ... 111-494‡P-values calculated using Cochran-Armitage test for categorical variables or Cuzick’s test for continuous variables.Althoff et al. AIDS Research and Therapy 2010, 7:45http://www.aidsrestherapy.com/content/7/1/45Page ... Stephen J. Gange,Mari M. Kitahata, Rosemary G. McKaig, Aimee FreemanEpidemiology/Biostatistics Core: Stephen J. Gange, Alison G. Abraham,Bryan Lau, Keri N. Althoff, Jinbing ZhangData Management...