Table 2. Control–case differences in Shannon index and number of unique species-level operational taxonomic units (OTUs) in the fecal samples of 13 twin pairs, discordant for Hodgkin lymphoma.

Twin pairs	Zygosity	Difference in Shannon indexa	Difference in number of unique OTUsa
1	DZ	0.92	71.7
2	DZ	1.68	66.3
3	DZ	−0.17	−5.2
4	DZ	−0.31	−4.1
5	DZ	0.49	37.1
6	DZ	−0.72	−51.5
7	DZ	0.93	48.5
8	DZ	−0.12	34.9
9	MZ	−0.36	34.6
10	MZ	−0.09	−10.6
11	MZ	0.08	80.7
12	MZ	0.15	67.4
13	MZ	0.25	26.8
Mean within-pair differenceb		0.48	41.5
Mean between-pair differencec		0.75	77.2
P-valued		0.02	0.0004

Abbreviations: DZ=dizygotic; MZ=monozygotic.

^aControl value−case value.

^bMean of absolute differences within twin pairs.

^cEstimated mean of the absolute difference between values from two members chosen at random from different twin sets.

^dAnalysis of variance to test whether values are more similar within vs between twin pairs.