Characterization of urinary cotinine in non-smoking residents in smoke-free homes in the Korean National Environmental Health Survey (KoNEHS)

Table 3 Multivariate analysis for natural log-transformed urinary cotinine concentrations of non-smoking residents of smoke-free homes^a

	β	Standard error	p-value
Type of housing
Apartment	Reference
Attached housing	0.39	0.17	0.011
Detached housing	0.44	0.17	0.024
Sex
Men	Reference
Women	−0.28	0.16	0.074
Household income (USD/month)
≤ 1000	Reference
1001–2000	−0.06	0.16	0.706
2001–3000	−0.17	0.20	0.384
> 3000	−0.06	0.20	0.769
Former smoker
Never smoked	Reference
> 1 year not smoking	0.47	0.17	0.007
≤ 1 year not smoking	1.24	0.28	<0.001
Frequency of SHS odor (times/week)
None	Reference
1–2	−0.07	0.17	0.655
3–6	0.13	0.20	0.520
Every day	0.60	0.31	0.053

R-squared values from the multivariate regression model were 0.14 after adjusting for all associated factors listed in the table
^aAll estimated data are based on weighted analyses