TABLE 2.

Results of mixed linear regression analysis (degrees of freedom, F statistic and P value; described in Methods) assessing effect of vitamin A treatment group on Bifidobacterium relative abundance measured in early infancy¹

Effect	F value	P value
Group	0.43	0.513
Sex	8.75	*0.003
BWM	2.51	0.114
Type	3.28	*0.071
Age	1.72	0.182
BF	19.81	*<0.0001
Group × sex	5.46	*0.020
Group × BWM	0.10	0.755
Group × type	5.43	*0.021
Group × age	0.12	0.889
Sex × BWM	0.03	0.854
Sex × type	0.81	0.368
Sex × age	2.44	*0.089
BWM × type	0.08	0.784
BWM × age	1.46	0.233
Type × age	1.54	0.216
Group × sex × BWM	0.00	0.980
Group × sex × type	0.00	0.971
Group × sex × age	0.22	0.805
Group × BWM × type	1.58	0.209
Group × BWM × age	0.00	0.999
Group × type × age	2.86	*0.059
Group × sex × BWM × type	0.13	0.877
Group × sex × BWM × age	1.34	0.256
Group × sex × type × age	0.60	0.664
Group × BWM × type × age	0.78	0.537
Group × sex × BWM × type × age	1.18	0.322

¹ P values indicated by an asterisk (*) are <0.10. Bifidobacterium relative abundance during early infancy was measured at ages 6 wk (n = 280), 11 wk (n = 281), and 15 wk (n = 279). Group, vitamin A or placebo treatment groups; BWM, birthweight median category (above/below); type, type of delivery (cesarian/vaginal); and BF, breastfeeding status (1 = exclusive/0 = nonexclusive) at 6, 10, and 15 wk of age. The overall model chi-squared value was 41.21 (P < 0.0001).