Table 3

Distribution of age at initiation of smoking and betel quid chewing among those with both habits at two year intervals* (n = 1387)

Initiation age of smoking	Initiation age of betel quid chewing, showing number with both habits
Initiation age of smoking	10–12	13–14	15–16	17–18	19–20	21–22	23–24	25–26	27–28	29–30	⩾31	Total
*When one year interval was used, those starting smoking first became 764 (55.1%), same year 538 (38.8%), and betel quid chewing first 85 (6.1%).
Data source: National Health Interview Survey (NHIS) 2001.
10–12	19	6	8	4	5	0	1	2	1	1	2
13–14	4	30	17	15	11	3	1	3	0	1	6
15–16	6	6	101	40	38	12	16	11	4	12	7
17–18	2	3	7	160	57	19	33	29	8	14	30
19–20	3	0	2	7	142	17	22	35	3	31	43	728 (52.5%)
21–22	0	2	0	5	6	46	14	15	8	11	21
23–24	1	0	1	4	2	1	33	8	7	12	10
25–26	0	0	0	0	1	0	4	15	1	12	22
27–28	0	1	0	0	2	0	0	1	5	4	7
29–30	0	0	0	0	0	0	0	0	0	13	8
⩾31	0	0	0	0	2	1	0	2	0	3	16
Total					79 (5.7%)							580 (41.8%)