Table 2.

Adjusted Mean Difference in Change in PHQ-9 Score at 2-Year Follow-Up Comparing Vitamin D₃ and Placebo Groups by Risk Group of Indicated and Selective Prevention^a

		Vitamin D3 vs Placebo
Risk Group	Eligible Participants, n	Mean Difference (95% CI)b	P-Interactionc
Subthreshold depression			.86
Yesd	80	−0.02 (−1.26 to 1.21)
No	640	−0.11 (−0.29 to 0.08)
1+ High-risk factors for LLD			.53
Yese	438	−0.14 (−0.45 to 0.17)
No	282	−0.01 (−0.28 to 0.25)

^aFor this coprimary outcome, P < .025 was considered as threshold for statistical significance. The prespecified MCID(minimally clinically important difference) in PHQ-9 score was 0.5 points.

^bResults are from repeated measures model; all participants contributed to the repeated measure analysis at one and/or both time points. Models were controlled for age, sex, and marine omega-3 fatty acids randomization group.

^cP-interaction is from the test of the prevention category × treatment × time interaction term in the model.

^dIndicated prevention targeted participants with subthreshold depression, but who did not meet DSM-IV criteria for current major depressive disorder or dysthymia, at baseline.

^eSelective prevention targeted participants with ≥ 1 high-risk factor for LLD at baseline; see details in Supplementary Appendix 1 (under E. Approach for selective prevention).

Abbreviations: LLD = late-life depression, PHQ-9 = Patient Health Questionnaire-9.