Table 1.

The prevalence of prenatal exposure to firsthand and secondhand tobacco smoke among mothers whose children were aged 3–6 years, rural area of Shanghai, China, 2018 (N=8586)

Variables	Participants (N=8586)		Firsthand smoke (N=81)		Secondhand smoke (N=1785)
	n	(%)a	n	(%)b	n	(%)b
Age (years)c,d
19–25	237	2.76	6	2.53	62	26.16
26–30	2870	33.43	25	0.87	728	25.37
31–35	3858	44.93	29	0.75	730	18.92
36–48	1621	18.88	21	1.30	265	16.35
Educationc,d
Illiterate/Primary	71	0.83	1	1.41	14	19.72
Junior High	795	9.26	14	1.76	181	22.77
Senior High	1613	18.79	25	1.55	373	23.12
College and above	6107	71.13	41	0.67	1217	19.93
Family yearly income (US$)d
<8000	1344	15.65	15	1.12	334	24.85
8000–16000	1206	14.05	9	0.75	273	22.64
16001–24000	1117	13.01	12	1.07	239	21.40
24001–48000	1169	13.62	11	0.94	204	17.45
>48000	3750	43.68	34	0.91	735	19.60
Resident statusc,d
Local	4545	52.94	56	1.23	1094	24.07
Non-local	4041	47.06	25	0.62	691	17.10

^aProportion.

^bPrevalence.

^cThe differences between group on prevalence of prenatal exposure to firsthand sm ke were statistically significant (p<0.01).

^dThe differences between group on prevalence of prenatal exposure to secondhand smoke were statistically significant (p<0.01).