Table 5.

Multivariable analysis: Logistic regression taking the presence/absence of acne as the dependent variable

Variable	p	aOR	95% CI
Gender (females vs males*)	0.001	4.39	1.80–10.68
Age	< 0.001	1.05	1.03–1.08
Use of hydrating cream (yes vs no*)	0.002	4.30	1.70–10.85
Passive smoking (yes vs no*)	0.069	1.64	0.96–2.79
Working near a power plant (yes vs no*)	0.039	3.07	1.06–8.88
NO2 exposure categories (vs no exposure*)	0.105
Mild	0.149	2.28	0.74–7.02
Moderate	0.436	1.53	0.53–4.43
Severe	0.022	8.24	1.36–49.90
Number of family members with acne or history of acne	0.035	1.48	1.03–2.13
Skin type	< 0.001
Normal		1
Dry	< 0.001	0.20	0.09–0.44
Mixed	0.103	0.41	0.14–1.20
Oily	0.149	0.61	0.31–1.20

*Reference group; CI Confidence Interval; aOR Adjusted odds ratio; Nagelkerke R2 = 35.6%; numbers in bold indicate significant p-values. Variables entered in the model: gender, age, use of hydrating cream, passive smoking, working near a power plant, NO2 exposure categories, number of family members with acne or history of acne, skin type