Table 5.

Percent of Infants by Risk Category in the US and South American Samples Age (in Months) Risk Category

Age (in Months)	Risk Category	US (%)	South American (%)	χ 2
3 a	Low	58	78
	Moderate	31	20	p<0.001
	High	11	2
6	Low	54	44
	Moderate	31	46	p<0.039
	High	15	10
9	Low	58	51
	Moderate	31	42	p<0.187
	High	11	7
12	Low	39	49
	Moderate	51	49	p<0.015
	High	10	2
18	Low	48	51
	Moderate	43	47	p<0.121
	High	9	2
24	Low	59	70
	Moderate	31	25	p<0.203
	High	10	5

^aSouth American distribution involved interpolating data for infants aged 2.5 to 3.0 month olds and combining that distribution with the observed distribution for 3.0 to 3.5 month olds.