Cohort Study Baseline	Cohort Study Follow-up	Nested Case-Control Study
Group of CD4 (cells/mm3)	Prevalence Ratio	Prevalence Odds Ratio	Cumulative Incidence Ratio (Risk Ratio)	Cumulative Incidence Odds Ratio	Incidence Rate Ratio	Relative Odds: Odds of Exposure in Cases / Odds of Exposure in Controls (Odds Ratio, OR)
Reference: CD4 < 200	REF	REF	REF	REF	REF	REF
Exposure Group 1: CD4 200 to < 350	0.57	0.38	0.51	0.36	0.42
Exposure Group 2: CD4 350	0.42	0.25	0.32	0.20	0.26	X=

For the nested case-control study, the relative odds of exposure group 1 [CD4 200 to <350 cellsmm³] compared to the reference falls in which interval?

1. [0.30, 0.40]
2. [0.40, 0.50]
3. [1.60, 1.80]
4. [2.30, 2.50]

For the nested case-control study, the relative odds of exposure group 2 [CD4 350 cells/mm³] compared to the reference falls in which interval?

1. [0.30, 0.40]
2. [0.50, 0.60]
3. [1.60, 1.80]
4. [2.30, 2.50]