Table 5B.

Effect of vitamin D3 or omega-3s, compared to their matching placebos, on mean difference in change in PHQ-9 score over 2 years by quartiles of serum BDNF at baseline.

	Vitamin D3 vs. placebo		Omega-3s vs. placebo
	Mean difference (95% CI)	P-interaction	Mean difference (95% CI)	P-interaction
Quartiles of serum BDNF		0.89		0.42
Lowest (Q1) (n=72)	0.99 (0.53 to 1.85)		0.91 (0.50 to 1.65)
Second (Q2) (n=72)	0.87 (0.42 to 1.79)		1.37 (0.71 to 2.66)
Third (Q3) (n=72)	1.25 (0.66 to 2.36)		1.48 (0.77 to 2.83)
Highest (Q4) (n=72)	0.69 (0.38 to 1.25)		1.25 (0.69 to 2.26)

Abbreviation: BDNF, brain-derived neurotrophic factor; PHQ, patient health questionnaire; CI, confidence interval Analyses were from repeated measures negative binomial regression models, with follow-up time modeled as an indicator. Results show RR and 95% CI, which reflect differences in the change in serum BDNF over 2 years comparing treatment agents and placebos. Models were controlled for age, sex, and concurrent randomization group. P-interaction is from the test of the BDNF quartile category-x-treatment-x-time interaction term in the model.