Respiratory health and quality of life in young exclusive, habitual smokers - a comparison of waterpipe smokers, cigarette smokers and non-smokers

Figures & data

Table 1 Descriptive tobacco-related measures among waterpipe (WP), cigarette and non-smokers

	WP smokers (N=135)	Cigarette smokers (N=303)	Non-smokers (N=300)	Between-group comparisons*
Mean age in years (median, standard deviation)	21.5 (21.4, 1.8)	21.7 (21.5, 1.99)	21.6 (21.6, 1.99)	No significant overalldifference (p=0.77)
Gender, % male	70.9%	95.0%	50.3%	WP vs NS (p=0.000) WP vs CS (p=0.000) CS vs NS (p=0.000)
Age of initiation of tobacco use in years, (median, standard deviation)	16.3 (16.5, 2.4)	15.7 (16.0, 2.8)	–	No significant overalldifference (p=0.058)
Weekly sessions of WP
3–4	47.4%	–	–
5–6	24.8%	–	–
7–8	13.5%	–	–	-
9–10	6.8%	–	–
>10	7.5%	–	–
WP session length
<30 min	12.6%	–	–
30–60 min	53.3%	–	–
61–90 min	19.3%	–	–	-
91–120 min	6.7%	–	–
>120 min	8.2%	–	–
WP heads per session
<1	19.6%	–	–
1–2	61.7%	–	–	-
3–4	15.0%	–	–
>4	3.8%	–	–
Proportion usually share WP	67.6%	–	–
Daily cigarettes
≤10	–	27.7%	–
11–20	–	43.2%	–
21–30	–	17.2%	–	-
31–40	–	6.3%	–
>40	–	5.6%	–
Ever attempted to quit	50.4%	72.5%	–	p=0.000
Average number quit attempts (median,standard deviation)	0.41 (0, 0.96)	1.6 (0.2, 0.98)	–	p=0.001
Intention to quit within 1–6 months	25.2%	44.6%	–	p=0.001
Daily secondhand smoke exposure	65.2%	61.4%	38.7%	WP vs NS (p=0.000) CS vs NS (p=0.000) WP vs CS (p=0.450)
Daily censer smoke exposure	12.6%	9.6%	11.0%
Cigarettes perceived harmful (yes)	93.3%	86.1%	93.3%	WP vs CS (p=0.03) CS vs NS (p=0.004)
WP perceived harmful (yes)	81.5%	83.2%	96.0%	WP vs NS (p=0.000) CS vs NS (p=0.000) WP vs CS (p=0.670)
WP perceived relative harm: less harmful than cigarettes	35.6%	13.2%	8.3%	WP vs NS (p=0.000) CS vs NS (p=0.054) WP vs CS (p=0.000)
WP perceived relative harm: more harmful than cigarettes	37.0%	53.8%	65.7%	WP vs NS (p=0.000) CS vs NS (p=0.003) WP vs CS (p=0.001)
Country
Jordan	46%	45%	46%	No significant overall difference (p=0.80)
Egypt	25%	27%	22%
Morocco	17%	17%	18%
Oman	12%	11%	13%

Note: *Significance cut-off for Šidák-Holm adjusted p-value <0.004.

Table 2 Descriptive lifestyle and academic characteristics of the sample (column percentages reported)

	Waterpipe smokers (N=135)	Cigarette smokers (N=303)	Non-smokers (N=300)	Between-group comparisons*
Body mass index: mean (median, standard deviation)	24.3 (23.7, 3.9)	24.2 (23.6, 4.1)	22.9 (22.4, 3.5)	WP vs NS (p=0.0003) CS vs NS (p=0.0001)
Eating vegetables atleast once a day	52.6%	47.5%	50.3%	No significant overall difference (p=0.59)
Eating fruits atleast once a day	58.5%	48.5%	47.0%	No significant overall difference (p=0.07)
Eating fish atleast twice a week	20.7%	22.8%	19.0%	No significant overall difference (p=0.52)
Eating sugary snacks, sodas or chips daily	68.2%	61.7%	49.3%	WP vs NS (p=0.000) CS vs NS (p=0.002)
Eating breakfast daily or almost daily	54.8%	55.8%	64.3%	No significant overall difference (p=0.055)
Regular exercising^¶	25.9%	36.0%	30.0%	No significant overall difference (p=0.13)
Academic rank “very good” or higher	32.6%	30.0%	48.0%	WP vs NS (p=0.003) CS vs NS (p=0.000)
High pocket money group	47.4%	46.5%	32.7%	WP vs NS (p=0.003) CS vs NS (p=0.000)

Notes: ^¶Defined as performing strenuous exercise atleast 2 to 3 times weekly, for a weekly total of atleast 2 to 3 hrs. *Significance cut-off for Šidák-Holm adjusted p-value <0.004.

Figure 1 Proportions reporting each respiratory symptom across waterpipe smokers (WP), cigarette smokers (CS), and non-smokers (NS).

Notes: Please see separate image. *p-value for chi-square statistic comparing waterpipe smokers to non-smokers or cigarette smokers to non-smokers <0.015 (significance cut-off for Šidák-Holm adjusted p-value). ^¶p-value for chi-square statistic comparing waterpipe smokers to cigarette smokers <0.015. ^§p-value for chi-square statistic comparing waterpipe smokers to cigarette smokers <0.05 but >0.015. ^ǂp-value for chi-square statistic comparing cigarette smokers to non-smokers <0.016; p-value for chi-square statistic comparing waterpipe smokers to non-smokers <0.05 but >0.016.

Table 3 Multivariable negative binomial regression model of count of respiratory symptoms in waterpipe smokers (WP), cigarette smokers (CS) compared to non-smokers (incidence rate ratios presented)

	Incidence rate ratio(95% confidence interval)
Smoking status
Non-smoker	Reference group (1.0)
Waterpipe smokers*	1.6 (1.4–1.9)
Cigarette smokers	1.9 (1.7–2.2)
Daily second hand smoking exposure (versus less than daily)*	1.2 (1.1–1.4)
Daily censer smoke exposure (versus less than daily)	1.1 (0.95–1.4)
Living near a factory (versus not living near one)*	1.3 (1.1–1.6)
Being overweight or obese(versus having a BMI <25)	1.1 (0.93–1.2)
Active lifestyle (versus not performing regular exercise)*	0.88 (0.78–0.99)

Note: *Incidence rate ratio (95% confidence interval) for waterpipe smokers when using positive controls (cigarette smokers) as the reference group: 0.87 (0.75–1.0).

Table 4 Quality of life mean scores reported by waterpipe smokers (WP), cigarette smokers (CS) and non-smokers (NS)

	Waterpipe smokers (N=135)	Cigarette smokers (N=303)	Non-smokers (N=300)	Pairwise comparisons* ¶
General health: mean(median, standard deviation)	61.8 (62.5, 25.4)	57.0 (50.0, 28.3)	68.1 (75.0, 25.1)	CS vs NS (p=0.0001) WP vs NS (p=0.0127) WP vs CS (p=0.085)
Physical health: mean(median, standard deviation)	65.6 (75.0, 32.9)	61.6 (75.0, 32.1)	69.9 (75.0, 31.9)	CS vs NS (p=0.0007) WP vs NS (p=0.180)
Social health: mean(median, standard deviation)	69.7 (75.0, 30.9)	67.6 (75.0, 29.9)	69.6 (75.0, 29.0)	No significant overall difference (p=0.610)
Mental health: mean(median, standard deviation)	62.1 (60.0, 19.6)	58.0 (60.0, 21.7)	59.9 (60.0, 20.7)	No significant overall difference (p=0.290)
Emotional limitations: mean(median, standard deviation)	60.9 (100, 44.1)	54.1 (50.0, 43.1)	48.4 (50.0, 45.1)	WP vs NS (p=0.007) WP vs CS (p=0.140) CS vs NS (p=0.123)
Physical limitations: mean(median, standard deviation)	69.0 (100, 41.5)	59.5 (50.0, 42.6)	68.0 (100, 42.3)	CS vs WP (p=0.023) CS vs NS (p=0.008)
Vitality: mean (median, standard deviation)	56.6 (60.0, 26.4)	56.6 (60.0, 27.0)	56.4 (60.0, 24.6)	No significant overall difference (p=0.993)
Pain: mean (median, standard deviation)	79.7 (75.0, 21.8)	77.9 (75.0, 22.4)	79.2 (75.0, 23.2)	No significant overall difference (p=0.570)

Notes: *Pairwise ANOVA (if normally distributed) or medians/rank-sum (if failing the normality assumption). ^¶Significance cut-off for Šidák-Holm adjusted p-value <0.008.