No Relationship between Maternal Iron Status and Postpartum Depression in Two Samples in China

Table 2

Background characteristics of the two samples in China^a.

	Sample
	Pilot	Confirmatory	𝑃^b
	(𝑛=137)	(𝑛=567)
Mother and family
Mother age, years	27.0±2.9	24.6±3.7	<0.001
Mother high school graduate %  (𝑛)	66.2 (90/136)	31.5 (174/552)	<0.001
Annual household income %  (𝑛)			<0.001
<5000, ¥^c	46.5 (59/127)	87.1 (481/552)
>5000, ¥	53.5 (68/127)	12.9 (71/552)
Infant
Gender, %male (𝑛)	53.3 (73/137)	54.5 (305/560)	0.44
Gestational age, weeks	39.6±0.9	39.7±1.2	0.36
Birth weight, g	3420.1±452.8	3375.6±426.4	0.28

^a𝑛 varies slightly due to occasional missing data for some measures. Values are expressed as means ± SD or %  (𝑛) for categorical variables.
^b𝑃 values are based on 𝑡-tests for continuous variables and Fisher’s exact analyses for categorical variables.
^cYuan Renminbi, sign ¥, is the official currency of China. Approximate exchange rate 1$ = 6.31¥.