Pulmonary effects of active smoking and secondhand smoke exposure among adolescent students in Juárez, Mexico

Figures & data

Table 1 Sociodemographic variables by smoking status

Sociodemographic variables	Smoking status
	Nonsmokers/nonexposed to SHS n=64 (21.3%)	Nonsmokers/exposed to SHS n=147 (49.1%)	Smokers n=89 (29.6%)	Total n=300 (100%)	P-value*
					A	B	C
Age					<0.045	<0.350	<0.268
13 years old	10 (15.6)	4 (2.7)	9 (10.1)	23 (7.7)
14 years old	49 (76.6)	133 (90.5)	72 (80.9)	254 (84.6)
15 years old	5 (7.8)	10 (6.8)	8 (9.0)	23 (7.7)
Sex					<0.001	<0.001	<0.378
Male	18 (28.1)	94 (63.9)	51 (57.3)	137 (45.7)
Female	46 (71.9)	53 (36.1)	38 (42.7)	163 (54.3)
School setting					<0.001	<0.001	<0.484
Public	26 (40.6)	87 (59.2)	55 (61.8)	168 (56.0)
Private	38 (59.4)	60 (40.8)	34 (38.2)	132 (44.0)
Socioeconomic status					<0.001	<0.001	<0.325
Low (<10,000 Mexican pesos)	13 (20.3)	81 (55.1)	53 (59.5)	147 (49.0)
Middle (10,001–25,000 Mexican pesos)	21 (32.8)	45 (30.6)	22 (24.7)	88 (29.3)
High (>25,000 Mexican pesos)	30 (46.9)	21 (14.3)	14 (15.8)	65 (21.7)

Notes:

* Sociodemographic distributions are significantly different at P<0.05 level using χ² tests. A, Test between nonsmokers/nonexposed to SHS and nonsmokers/exposed to SHS groups; B, test between nonsmokers/nonexposed to SHS and smokers groups; C, test between nonsmokers/exposed to SHS and smokers groups.

Abbreviation: SHS, secondhand smoke.

Table 2 Pulmonary function test variables by smoking status†

Pulmonary variables	Smoking status
	Nonsmokers/nonexposed to SHS n=64	Nonsmokers/exposed to SHS n=147	Smokers n=89	P-value*
				A	B	C
FEV1	79.14±13.61	69.41±11.35	62.88±10.25	<0.010	<0.001	<0.255
FEV1/FVC	94.88±21.88	88.75±15.75	83.50±14.15	<0.290	<0.010	<0.350
FEF25%–75%	87.36±17.02	78.90±14.65	66.35±12.55	<0.010	<0.001	<0.040

Notes:

† Mean ± standard deviation.

* Pulmonary function test distributions are significantly different at P<0.05 level using χ² tests. A, Test between the nonsmokers/nonexposed to SHS and nonsmokers/exposed to SHS groups; B, test between the nonsmokers/nonexposed to SHS and smokers groups; C, test between the nonsmokers/exposed to SHS and smokers groups.

Abbreviations: SHS, secondhand smoke; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; FEF_25%–75%, forced mid-expiratory flow rate.

Table 3 Respiratory symptom variables by smoking status†

Respiratory variables	Smoking status
	Nonsmokers/nonexposed to SHS n=64	Nonsmokers/exposed to SHS n=147	Smokers n=89	P-value*
				A	B	C
Morning cough	1.92±1.12	3.64±1.34	4.38±1.42	<0.001	<0.001	<0.040
Daytime cough	2.25±1.50	3.15±1.55	4.10±1.26	<0.180	<0.001	<0.020
Wheezing	1.45±0.46	2.74±1.08	3.20±1.24	<0.010	<0.001	<0.180
Phlegm production	2.02±1.17	3.00±0.92	3.26±1.34	<0.120	<0.010	<0.258
Shortness of breath when walking	1.28±0.98	3.10±1.25	3.90±1.38	<0.001	<0.001	<0.010
Shortness of breath during exercise	1.64±0.79	3.25±1.10	4.36±1.26	<0.001	<0.001	<0.010
Getting tired easily	1.40±0.88	3.10±1.28	3.60±1.16	<0.001	<0.001	<0.145
Pain in the chest	1.20±0.85	1.34±0.78	1.50±0.90	<0.380	<0.160	<0.320

Notes:

† Mean ± standard deviation (1= Never, … < 5= Every day).

* Respiratory symptoms distributions are significantly different at P<0.05 level using χ² tests. A, Test between the nonsmokers/nonexposed to SHS and nonsmokers/exposed to SHS groups; B, test between the nonsmokers/nonexposed to SHS and smokers groups; C, test between the nonsmokers/exposed to SHS and smokers groups.

Abbreviation: SHS, secondhand smoke.

Table S1 Adaptation of the Global Youth Tobacco Survey questionnaire

Demographic characteristics
How old are you?						_______ years old
What is your sex?						a. Male	b. Female
What kind of school do you attend?						a. Public	b. Private
Smoking behaviors
Ever smoked a full cigarette?						a. Yes	b. No
Started smoking at or before 10 years old?						a. Yes	b. No
If yes, how old were you when you started?						_______ years old
Currently smoke?						a. Yes	b. No
Have you smoked a cigarette, even if only one puff, in the last 30 days?						a. Yes	b. No
Secondhand smoke exposure
Do you have one or more parents who smoke?
If yes, who?						a. Yes	b. No
a. Father
b. Mother
c. Both
Do you have one or more close friends who smoke?						a. Yes	b. No
Do you live in a home where in the last 30 days others smoked in your presence?						a. Yes	b. No
In the last 30 days, were you around others who smoked in places outside your home?						a. Yes	b. No
Respiratory symptoms*
In the last 30 days, have you experienced one of the following?
	Never (1)	Rarely (2)	Sometimes (3)	Often (4)	Everyday (5)
Morning cough
Daytime cough
Wheezing
Phlegm production
Shortness of breath when walking
Shortness of breath during exercise
Getting tired easily
Pain in the chest

Notes:

* All items are weighted equally. Mean score is calculated across all items within each domain.