Appendix Table 9.

Pooled (crude) and common IRR after stratification by the year of enrollment

	Pooled IRR	Common IRR*	Mantel Haenzsel test of homogeneity p-value
Depression
All participants	0.48 (0.34, 0.67)	0.54 (0.34, 0.84)	0.24
Excluding baseline depressed	0.37 (0.20, 0.67)	0.36 (0.20, 0.67)	0.37
Suicidal ideation
All participants	0.42 (0.22, 0.76)	0.40 (0.16, 1.03)	0.122
Excluding baseline suicidal	0.41 (0.19, 0.82)	0.35 (0.11, 1.09)	0.27

IRR = incidence rate ratio

^*The common IRR was produced by combining Mantel Haenzsel-weighted stratum-specific IRRs (the strata combined were the three strata for year of enrollment)