TABLE 5.

Subgroup analysis for SMD of dietary beta-carotene in depression vs. control subjects.

Stratification	Number of studies	Pooled SMD	95% CI	P-value	Heterogeneity
All studies	14	−0.34	−0.48, −0.20	P < 0.001	P < 0.001; I2 = 96%
Geographical region
Asia	9	−0.43	−0.67, −0.20	P < 0.001	P < 0.001; I2 = 97%
Non−Asia	6	−0.20	−0.24, −0.16	P < 0.001	P = 0.96; I2 = 0%
Exposure assessment
FFQ	10	−0.41	−0.63, −0.18	P < 0.001	P < 0.001; I2 = 97%
Recall method	4	−0.20	−0.24, −0.16	P < 0.001	P = 0.95; I2 = 0%
Sex
Male	5	−0.63	−1.32, 0.07	P = 0.08	P < 0.001; I2 = 99%
Female	9	−0.16	−0.20, −0.12	P < 0.001	P = 0.33; I2 = 13%
Population
Adolescent	4	−0.33	−0.59, −0.06	P = 0.02	P = 0.01; I2 = 73%
Middle aged and elderly	10	−0.34	−0.50, −0.17	P < 0.001	P < 0.001; I2 = 97%
Sample size
<1,000	5	−0.27	−0.47, −0.07	P = 0.008	P = 0.02; I2 = 65%
>1,000	9	−0.35	−0.52, −0.18	P < 0.001	P < 0.001; I2 = 97%