TABLE 3.

Subgroup analysis for SMD of dietary vitamin A intake in depression vs. control subjects.

Stratification	Number of studies	Pooled SMD	95% CI	P-value	Heterogeneity
All studies	14	−0.13	−0.18, −0.07	P < 0.001	P = 0.005; I2 = 53%
Geographical region
Asia	7	−0.13	−0.20, −0.06	P < 0.001	P = 0.03; I2 = 51%
Non−Asia	7	−0.14	−0.25, −0.02	P = 0.02	P = 0.02; I2 = 59%
Exposure assessment
FFQ	8	−0.07	−0.11, −0.03	P < 0.001	P = 0.03; I2 = 50%
Recall method	6	−0.20	−0.26, −0.14	P < 0.001	P = 0.82; I2 = 0%
Sex
Male	5	−0.06	−0.12, 0.01	P = 0.10	P = 0.16; I2 = 38%
Female	9	−0.11	−0.20, −0.03	P = 0.007	P = 0.02; I2 = 56%
Population
Adolescent	4	−0.20	−0.38, −0.03	P = 0.02	P = 0.07; I2 = 58%
Middle aged and elderly	12	−0.12	−0.18, −0.06	P < 0.001	P = 0.01; I2 = 54%
Sample size
<1,000	8	−0.13	−0.22, −0.05	P = 0.002	P = 0.11; I2 = 39%
>1,000	6	−0.11	−0.18, −0.05	P < 0.001	P = 0.004; I2 = 66%