CD4 and osteogenesis imperfecta: Another cohort study also showed that higher CD4 cell count was associated with a reduction of risk of new OI progression and with a hazard ratio compared to 100 cells/mL of 0.35 for counts 200 cells/mL, 0.81 for counts 200 to 350 cells/mL, 0.74 for counts 350 to 500 cells/mL, and 0.96 for counts 500 cells/mL or above [22].