Table 2. Comparison of Oral Bacteria Within-Sample (Alpha) Diversity by Betel Nut Chewing History^a.

	Shannon				Chao1				Observed Species				PD Whole Tree
Betel Nut Status	mean	std	t stat	p-value	mean	std	t stat	p-value	mean	std	t stat	p-value	mean	std	t stat	p-value
Long-term chewers (≥10 yr)	4.00	0.78	-3.173	0.002	129.08	47.35	-2.695	0.011	37.85	9.96	-3.454	0.002	3.80	1.17	-2.236	0.028
Never Chewers	4.67	0.74			169.40	65.37			47.98	11.83			4.52	1.18
Current chewers with Oral Lesions	3.71	0.51	-1.029	0.322	123.14	50.99	0.626	0.544	32.60	7.08	-1.023	0.307	4.71	1.19	-1.925	0.047
Chewers & Non-Chewers without Oral Lesions	3.96	0.71			113.80	41.89			35.72	8.85			5.49	1.16
Current chewers without added tobacco	4.17	0.78	-2.077	0.041	118.29	33.23	-3.888	0.002	39.95	9.16	-2.735	0.007	4.05	1.08	-3.461	0.001
Current chewers with added tobacco	4.63	0.93			176.27	74.94			48.19	13.60			5.29	1.63
Nonsmoking current chewer without tobacco	3.81	0.80	-2.850	0.012	108.40	35.49	-3.242	0.001	35.37	9.14	-3.197	0.007	3.12	0.81	-2.987	0.008
Nonsmoking never chewer	4.58	0.75			152.69	45.14			46.57	11.51			4.12	1.16
Never chewer current smoker	4.24	0.50	-0.121	0.908	141.33	63.24	0.646	0.524	40.52	7.82	-0.026	0.982	2.86	0.74	-0.382	0.698
Never chewer non-smoker	4.28	0.78			123.96	48.22			40.63	9.40			3.01	0.80

^a 4 subjects with fewer than 100 sequences not included