. Author manuscript; available in PMC: 2011 Dec 6.

Published in final edited form as: Dev Psychobiol. 2010 Oct 28;53(2):196–210. doi: 10.1002/dev.20512

Table 1.

Description of Infants and Their Families by Cultural Site

Infant	Accra (N=49)	Beijing (N =47)	Detroit (N=113)
Prior to testing
Sex (%, n male)	49.0, 24^†	53.2, 25	54.9, 62
Birth weight (kg)	3.4±.4^a^‡	3.4±.5^a	3.2±.4^b
Gestational age (weeks)	38.8±2.0^a	39.6±.8^b	39.7±1.2^b
Breastfed (%,n)	100, 49^a	91, 41^b	46.9, 53^c
Duration of breastfeeding (months)^a	8.8±.8^a	7.2±2.6^b	4.5±3.3^c
Weaned before 9 months (%, n)	12.2, 6^a	43.9, 18^b	75.5, 40^c
Hospitalized (%)	14.3	6.4	8.8
At testing
Age (months)	9.5±.32^a	9.4 ± .29^a	9.7±.38^b
HAZ	.37±1.03^a	.61 ± .80^a	−.42±.98^b
WAZ	−.33 ± .84	−.10 ±2.06	−.16 ±1.09
Hand size (mm)	43.0±5.5^a	37.9±4.6^b	43.1±5.4^a
Head circumference (cm)	44.9±1.3	44.9±1.5	45.0±1.5
Hematology
Hb (g/L)	106.4±19.7^a	112.2 ±17.9	113.3±10.6^b
Hb<110 (% low)	55.3^a	31.8^b	39.8
MCV (fl)	67.5±5.8^a	76.6±3.8^b	75.2±4.8^b
MCV<74 (% low)	91.5^a	22.7^b	35.4^b
RDW	17.2±1.8^a	13.7±1.4^b	13.8±1.3^b
RDW ≥14 (% high)	97.9^a	38.6^b	38.1^b
Iron status (composite)	−1.64± 1.3^a	.59 ± 1.0^b	.45 ± 1.0^b
Family
Mother smokes (%)	0^a	0^a	16.8^b
Mother drinks (%)	6.1	0	2.7
Mother’s education (%)	^a	^b	^c
Level 1 (elementary)	16.3	8.7	0
Level 2 (junior high)	38.8	17.4	0
Level 3 (high school)	22.4	26.1	51.3
Level 4 (beyond HS)	18.4	47.8	48.7
Single mother (%)	10.2^a	.0^b	87.8^c
Below poverty level (%)	92.9^a	21.7^b	56.4^c

HAZ, height-for-age Z-score (CDC, 2000); WAZ, weight-for-age Z-score (CDC, 2000); Hb, hemoglobin; MCV, mean corpuscular cell volume; RDW, red cell distribution width.

Values computed for those infants who were breastfed.

^†

Values are mean ± SD for continuous variables and % for categorical variables.

^‡

Different superscripts (a, b, c) indicate statistically significant differences between cultural sites for a given variable(p < .05)