Environmental exposure as an independent risk factor of chronic bronchitis in northwest Russia

Figures & data

Fig. 1.  Murmansk region in the northwest Russia.

Table I. Distribution of chronic cough with sputum production by dwelling place, smoking status, age and sex

Variable	Chronic cough with sputum production			p-Value of chi-square test
	No	Yes	Total
	n (%)	n (%)	n
Dwelling place				0.006
Murmansk	82 (82.0)	18 (18.0)	100 (100)
Monchegorsk	65 (65.0)	35 (35.0)	100 (100)
Smoking status				0.023
Never a smoker	79 (81.4)	18 (18.6)	97 (100)
Ex-smoker	29 (72.5)	11 (27.5)	40 (100)
Current smoker	39 (61.9)	24 (38.1)	63 (100)
Sex				0.078
Female	68 (68.0)	32 (32.0)	100 (100)
Male	79 (79.0)	21 (21.0)	100 (100)
Age				0.414
10–30 years	36 (81.8)	8 (18.2)	44 (100)
31–49 years	47 (74.6)	16 (25.4)	63 (100)
50–59 years	34 (70.8)	14 (29.2)	48 (100)
60–89 years	30 (66.7)	15 (33.3)	45 (100)
All	147 (73.5)	53 (26.5)	200

Fig. 2.  The percentage distribution of sputum production according to smoking status and dwelling place.

Table II. Important variables, unadjusted and adjusted odds ratios with 95% confidence interval estimates predicting the probability of chronic cough with sputum production using logistic regression analysis

Variable	Unadjusted OR (95% CI)	Adjusted OR (95% CI)
Dwelling place
Murmansk (reference)	1	1
Monchegorsk	2.45 (1.27–4.72)	2.16 (1.07–4.35)
Smoking status
Never smoker (reference)	1	1
Ex-smoker	1.67 (0.70–3.94)	1.89 (0.70–5.07)
Current smoker	2.70 (1.31–5.56)	3.39 (1.40–8.21)
Sex
Female (reference)	1	1
Male	1.77 (0.93–3.35)	1.18 (0.56–2.47)
Age
10–30 years (reference)	1	1
31–49 years	1.53 (0.59–3.97)	1.67 (0.62–4.54)
50–59 years	1.85 (0.69–4.97)	2.69 (0.92–7.90)
60–89 years	2.25 (0.84–6.03)	4.47 (1.45–13.83)