Excess risk of preterm birth with periconceptional iron supplementation in a malaria endemic area: analysis of secondary data on birth outcomes in a double blind randomized controlled safety trial in Burkina Faso

Table 3 C-reactive protein concentration at baseline, ANC1, or ANC2, for preterm/term or SGA/AGA outcomes

Parameter mg/l	n	Outcome^a		Difference or Relative risk^a (95% CI)	P	Adjusted difference or relative risk^b (95% CI)	P ^c_adj
Parameter mg/l	n	Term	Preterm	Difference or Relative risk^a (95% CI)	P	Adjusted difference or relative risk^b (95% CI)	P ^c_adj
Baseline
Log CRP, ± SD	280	− 0.2 ± 0.7	− 0.09 ± 0.7	1.18 (0.85; 1.63)	0.32	1.20 (0.87; 1.65)	0.26
CRP > 5, n/N (%)	280	20/221 (9)	6/59 (10)	1.11 (0.53; 2.33)	0.79	1.14 (0.55; 2.35)	0.74
CRP > 10, n/N (%)	280	8/221 (4)	4/59 (7)	1.62 (0.70; 3.75)	0.31	1.65 (0.73; 3.74)	0.31
ANC1
Log CRP, ± SD	282	0.6 ± 0.7	0.7 ± 0.7	1.28 (0.91; 1.80)	0.15	1.33 (0.94;1.89)	0.097
CRP > 5, n/N (%)	282	104/223 (47)	36/59 (61)	1.59 (0.99; 2.54)	0.049	1.60 (1.00; 2.55)	0.044
CRP > 10, n/N (%)	282	69/223 (31)	26/59 (44)	1.55 (0.99; 2.44)	0.062	1.63 (1.04; 2.56)	0.036
ANC2
Log CRP, ± SD	239	0.5 ± 0.7	0.9 ± 0.6	2.11 (1.25; 3.58)	0.004	1.78 (1.05; 3.00)	0.023
CRP > 5, n/N (%)	239	74/208 (36)	19/31 (61)	2.49 (1.26; 4.90)	0.007	2.06 (1.04; 4.10)	0.034
CRP > 10, n/N (%)	239	49/208 (24)	12/31 (38)	1.84 (0.95; 3.58)	0.082	1.48 (0.75; 2.91)	0.26

Parameter mg/l	n	Outcome^a		Difference or relative risk^a (95% CI)	P	Adjusted difference or relative Risk^b (95% CI)	P ^c_adj
Parameter mg/l	n	AGA	SGA	Difference or relative risk^a (95% CI)	P	Adjusted difference or relative Risk^b (95% CI)	P ^c_adj
Baseline
Log CRP, ± SD	271	− 0.2 ± 0.7	− 0.1 ± 0.7	1.06 (0.83; 1.35)	0.67	1.10 (0.86; 1.4)	0.51
CRP > 5, n/N (%)	271	15/183 (8)	11/88 (13)	1.35 (0.83; 2.19)	0.27	1.37 (0.86; 2.17)	0.23
CRP > 10 n/N (%)	271	7/183 (4)	5/88 (6)	1.30 (0.65; 2.61)	0.50	1.41 (0.76; 2.63)	0.37
ANC1
Log CRP, ± SD	273	0.7 ± 0.7	0.4 ± 0.7	0.75 (0.60; 0.94)	0.012	0.77 (0.61; 0.96)	0.018
CRP > 5, n/N (%)	273	103/185 (56)	33/88 (38)	0.60 (0.42; 0.87)	0.005	0.62 (0.44; 0.09)	0.009
CRP > 10, n/N (%)	273	70/185 (38)	23/88 (26)	0.68 (0.46;1.03)	0.054	0.71 (0.47; 1.07)	0.086
ANC2
Log CRP, ± SD	236	0.5 ± 0.7	0.6 ± 0.7	1.08 (0.83; 1.41)	0.58	1.10 (0.84; 1.44)	0.51
CRP > 5, n/N (%)	236	61/155 (39)	32/81 (40)	1.00 (0.70; 1.44)	0.98	1.02 (0.70; 1.47)	0.92
CRP > 10, n/N (%)	236	40/155 (26)	21/81 (26)	1.00 (0.67; 1.50)	0.98	1.02 (0.68; 1.54)	0.91

Antenatal clinic visits: ANC1 scheduled at 13–16 weeks gestation; ANC2 at 33–36 weeks gestation
AGA appropriate for gestational age, SGA small for gestational age
^aN(%) for categorical variables; mean ± SD for log(CRP)
^bRelative risk for the categorical variables; difference in log₁₀ CRP
^cAdjusted for assessment month

ISSN: 1475-2875