TABLE 4.

Associations between CES-D score (continuous) and dietary intake of folate and dietary quality (raw values), stratified by sex: mediating effect of plasma folate (raw values) (HANDLS study)

	Men, n = 734				Women, n = 947
	β	±SE	P	Sobel-Goodman Test (Z); % total effect mediated2	β	±SE	P	Sobel-Goodman Test (Z); % total effect mediated2
MODEL 1: HEItotal
Adjusted model 1a
Y = CES-D vs. X = HEItotal	−0.045a	±0.024	0.063	Z = −2.00c; 17.4%	−0.083b	±0.023	<0.001	Z = −1.64;9.9%
Adjusted model 1b: Model 1a + plasma folate,1μg/L
X = HEItotal	−0.037	±0.024	0.127		−0.075b	±0.024	0.002
M = plasma folate	−0.085b	±0.038	0.024		−0.075a	±0.044	0.094
Adjusted model 1c
Y = plasma folate vs. X = HEItotal	0.092b	±0.023	<0.001		0.110b	±0.017	<0.001
MODEL 2: dietary folate, μg/d
Adjusted model 2a
Y = CES-D vs. X = dietary folate	−0.002a	±0.001	0.055	Z = −2.03c; 19.8%	−0.001	±0.001	0.409	___d
Adjusted model 2b: Model 2a + plasma folate,1μg/L
X = dietary folate	−0.001	±0.001	0.128		−0.000	±0.001	0.764
M = plasma folate	−0.084b	±0.038	0.028		−0.101b	±0.045	0.025
Adjusted model 2c
Y = plasma folate vs. X = dietary folate	0.004b	±0.001	<0.001		0.007b	±0.001	<0.001

¹1 ng/mL = 2.266 nmol/L.

²Percent of total effect that is mediated is obtained using Sobel-Goodman test, specifying diet as the independent variable and plasma folate as the potential mediator. All models controlled for sociodemographic and lifestyle factors: age, ethnicity, marital status, education, poverty status, smoking status, illicit drug use, and BMI. ^aP < 0.10; ^bP < 0.05 for null hypothesis that β = 0 for each stratum-specific analysis; ^cP < 0.05 for Sobel-Goodman test (Z-score); ^dSobel-Goodman test and percent total effect mediated not applicable because total effect in Model 2a was not significant.