Table 2.

Gestational urinary phytoestrogen concentrations among mothers of girls with and without earlier age at menarche in the Avon Longitudinal Study of Parents and Children (ALSPAC) nested case-control study population (N = 367 mother-daughter dyads).

	Total		Menarche <11.5 years (N = 172)		Menarche ≥11.5 years (N = 195)		p-value^d
Analyte^a^,^b^,^c	Median	IQR	Median	IQR	Median	IQR
Genistein	62.1	27.1–160.9	60.2	26.6–157.6	65.1	27.2–162.7	0.58
Daidzein	184.8	88.8–383.7	187.8	91.9–369.7	183.0	88.8–423.8	0.79
Equol	4.3	2.8–9.0	4.4	2.8–7.4	4.2	2.6–9.6	0.74
O-DMA	13.0	4.4–34.5	14.0	5.7–43.8	11.7	3.4–31.5	0.06
Enterodiol	76.1	39.1–135.8	69.6	33.6–123.6	84.3	49.4–144.4	0.02
Enterolactone	911.7	448.1–1558.0	901.1	494.8–1478.2	923.8	440.6–1650.9	0.89

Abbreviations: IQR, interquartile range; O-DMA, O-Desmethylangolensin.

Creatinine-corrected concentrations in μg/g creatinine.

There are missing concentrations for genistein (n = 1 where menarche <11.5 years), O-DMA (n = 2 where menarche <11.5 years), and equol (n = 1 where menarche <11.5 years and n = 1 where menarche ≥11.5 years).

The limits of detection (LOD) were 0.3 ng/mL (genistein, daidzein, equol, enterodiol, enterolactone) and 0.2 ng/mL (O-desmethylangolensin). There were no samples below the LOD for daidzein and enterodiol, one sample below the LOD for enterolactone, two samples below the LOD for genistein, 16 samples below the LOD for equol, and 30 samples below the LOD for O-DMA; the number of samples below the LOD did not differ by case-control status. The LOD/√2 was substituted for values below the LOD.

p-value for difference between cases and controls using the Wilcoxon Rank Sum Test.