Table 5.

Smoking prevalence and incidence by age group and gender in the PLATINO study: retrospective cohort analyses.

Age (years)	Measure	Sao Paulo		Santiago		Mexico City		Montevideo		Caracas
		Men	Women	Men	Women	Men	Women	Men	Women	Men	Women
0–9	Prevalencea	6.3	1.8	2.8	1.5	3.0	0.3	2.6	0.4	0.9	0.6
	Incidenceb	6.3	1.8	2.8	1.5	3.0	0.3	2.6	0.4	0.9	0.6
10–19	Prevalence	57.6	31.0	58.7	35.9	47.3	12.3	65.3	27.9	61.2	32.0
	Incidence	54.9	29.7	57.6	35.0	45.8	12.1	64.3	27.6	60.9	31.6
20–29	Prevalence	68.5	38.5	69.9	51.8	59.9	20.9	72.9	35.7	73.4	46.0
	Incidence	29.4	12.9	30.0	26.3	27.6	10.2	25.4	11.5	33.3	21.1
30–39	Prevalence	61.9	33.0	63.2	49.7	60.1	23.9	67.1	35.7	65.2	44.8
	Incidence	4.5	2.3	6.6	7.9	8.0	5.3	3.8	5.0	3.7	6.3
40–49	Prevalence	50.1	27.4	57.4	47.2	53.8	23.3	59.2	33.9	56.1	39.5
	Incidence	1.5	1.3	4.9	5.6	5.8	2.2	1.0	5.7	2.7	2.9
50–59	Prevalence	41.6	18.1	46.7	36.0	46.9	18.1	50.2	26.2	47.4	31.7
	Incidence	1.2	2.0	3.4	3.3	2.4	1.8	1.2	0.8	0.0	2.2
≥ 60	Prevalence	39.8	41.5	32.2	20.8	40.4	12.7	37.2	19.2	40.6	26.7
	Incidence	0.0	17.1	3.6	0.0	0.0	1.3	0.0	4.5	0.0	0.0
Median age at starting smoking (years)		16.2	18.3	17.4	20.0	18.2	23.3	16.0	21.1	17.0	19.8

^a Number of subjects who started to smoke during the period plus those who were already smokers at the beginning of the period divided by the total number of subjects in the period.

^b Number of subjects who started to smoke during the period divided by the number of non-smokers at the beginning of the period.