
==== Front
BMJ Open
BMJ Open
bmjopen
bmjopen
BMJ Open
2044-6055
BMJ Publishing Group BMA House, Tavistock Square, London, WC1H 9JR

39299791
10.1136/bmjopen-2024-086266
bmjopen-2024-086266
Original Research
Smoking and Tobacco
1734
1506
Tobacco use, secondhand exposure and knowledge of secondhand and third-hand smoke among medical college students in Western Nepal: a cross-sectional study
Sagar Surabhi sagarsurabhi1996@gmail.com
1
Bhattarai Dikshya dikshya0001@gmail.com
1
Ghimire Srijana srijanaghimire055@gmail.com
1
Bhattarai Apeksha bhattaraiapeksha@gmail.com
1
Wagle Anupa Wagleanupa.7@gmail.com
1
http://orcid.org/0000-0001-5409-1751
Subedi Krishna drkrishnasubedimdsphd@gmail.com
1
1 Department of Community Dentistry, Gandaki Medical College Teaching Hospital and Research Center Pvt Ltd, Pokhara, Kaski, Nepal
Dr; drkrishnasubedimdsphd@gmail.com
None declared.

2024
18 9 2024
14 9 e08626610 3 2024
29 8 2024
Copyright © Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

Abstract

Objectives

This study was conducted to assess the prevalence of tobacco use, secondhand smoke (SHS) exposure and knowledge about SHS and third-hand smoke (THS) exposure among students in a medical college in Western Nepal.

Design

This is a cross-sectional study.

Setting

Data collection was done from 8 July 2023 to 8 August 2023 in a medical college in Nepal.

Participants

This study was conducted on undergraduate students studying in a medical college in Western Nepal using a census (whole population) sampling technique.

Main outcome measures

Prevalence of tobacco use was assessed by asking a question, ‘Did you use tobacco products within the last 30 days?’. Secondhand smoke exposure and knowledge about SHS and THS exposure were assessed by using structured questionnaires. The χ2 test was used to compare the group exposed and non-exposed to tobacco, SHS and THS by sociodemographic variables (sex, residence, year of study and academic stream).

Results

The response rate was 96.43% (n=595/617). The overall prevalence of tobacco use was found to be 16.30%. A total of 88.83% of students from clinical years knew about SHS which was more than preclinical students (p <0.001). The Bachelor of Medicine and Bachelor of Surgery students have higher knowledge of SHS as compared with others (p =0.003). More than 95% of students favoured banning smoking in public places. Nearly half of the participants (45.45%) experienced SHS exposure in the last 7 days. More than half proportion of the clinical students knew about THS, which was higher than preclinical students and interns (p <0.001).

Conclusions

Tobacco use prevalence among the participants was found to be lower in comparison to other studies including medical students in several Asian countries. Despite more than three-fourths of students knowing the harmful effects of SHS exposure, almost one-half of them were exposed to SHS. The proportion of students who knew about THS exposure was comparably lower.

Knowledge
Tobacco Use
Epidemiology
Cross-Sectional Studies
==== Body
pmcSTRENGTHS AND LIMITATIONS OF THIS STUDY

The participants were clearly instructed to complete the questionnaire, and the response rate was high, 96.43% (n=595/617).

The study was a cross-sectional study so the causal relationship could not be explained.

The data was collected from a single medical college; hence, the results of this study cannot be generalised. Even though the participation of the study was completely voluntary and anonymity of the participation was ensured, the data were collected based on self-reporting answers of the selected participants, and therefore the study may be subjected to information bias. As the response rate was high, selection bias may have been minimised.

Due to social desirability bias, the study may have been prone to under-reporting of tobacco use by some students.

Introduction

Tobacco use is a leading preventable cause of morbidity and mortality worldwide.1 There are three types of tobacco smoke: mainstream smoke (first-hand smoke (FHS)), secondhand smoke (SHS) and third-hand smoke (THS)2. SHS is also known as passive smoking or environmental tobacco smoke. It is a synthesis of the smoke exhaled by a smoker and the smoke that comes from the end of a burning cigarette or other smoked tobacco products.2 THS is an adhering pollutant caused by smoke that gets attached or adhered to the clothing, hair, skin, wall, carpet, etc. It is also called a secondary pollutant which is formed by the reaction of nicotine with SHS.3

SHS and THS both play an important role in the exposure of tobacco to non-smokers.4 According to the WHO, exposure to SHS is never safe at any level. SHS exposure causes many serious diseases such as lung cancer and coronary heart disease and kills approximately 1.3 million people prematurely each year.5 THS is emerging as a new health risk, posing a potential threat to well-being.6

Nepal became a Party to the WHO Framework Convention on Tobacco Control on 5 February 2007, leading to the formation of several tobacco control regulations. Smoking is prohibited on public transport and in most public places, including workplaces. However, designated smoking areas are allowed in airports, prisons and hotels.7 Although the smoke-free legislation on tobacco smoking in public places was implemented across Nepal in 2014,8 however, its monitoring is quite challenging.

According to the Nepal Demographic and Health Survey (2022), overall 50% of men and 7% of women use any form of tobacco.9 According to the previous study, medical students have a higher rate of use of tobacco products as compared with the general adult population in Southeast Asia.10 Medical students’ smoking is not only harmful to their health but also affects negatively providing effective anti-tobacco counselling to the patients.11 Medical school life can be a transitional period where students may begin smoking, drinking alcohol or using other substances. The accessibility of these substances and the psychological stress from academic and clinical activities contribute to substance misuse among medical students.12

There are various studies done related to FHS. However, there is a paucity of data on the prevalence of SHS exposure and knowledge about SHS and THS exposure in Nepal. Therefore, this study was conducted to assess the prevalence of tobacco use, SHS exposure and knowledge about SHS and THS exposure among the students studying at Gandaki Medical College, Pokhara, Nepal.

Materials and methods

Public and patient involvement

Patients or the public were not actively engaged in the design of the study. The students filled out the questionnaire that they were provided. They did not have any other role except responding to the questionnaire.

Ethics approval and consent to participate

This study was approved by Gandaki Medical College, Institutional Review Committee, Pokhara, Nepal (Reference No: 289/079/080). Written informed consent was obtained from study participants.

Study design and setting

This was an analytical cross-sectional study conducted on the medical and paramedical undergraduate students studying at Gandaki Medical College Teaching Hospital and Research Centre, Pokhara, Nepal (Western Nepal). Data collection was done from 8 July 2023 to 8 August 2023.

Eligibility criteria

All the medical and paramedical students of Gandaki Medical College who were present during the day of data collection and those who provided written consent were included in this study. The students who were absent during the day of data collection were excluded from the study.

Sample size

Sample size calculation was done by using the formula n= ((Zα/2) 2 pq/l2) where n = required sample size, Zα/2 = 1.96 at 95% CI, p = exposure of SHS at home with 21%,13 q = 1, p and l = absolute precision with 4%. Considering a 10% nonresponse rate, the calculated sample size was 440. However, all the students present during the data collection time were included.

Data Collection

Data collection was done using structured questionnaires. The questionnaires were prepared from previous studies,1416 and some of them were self-prepared which was designed in English. The students can easily understand as their academic language is English. Before the study, the students were informed about the objectives of the study, and written informed consent was obtained from each participating student. The questionnaires were distributed to all of the students during the break time in regular classroom settings. The confusion regarding the questionnaires raised by the students during data collection was cleared by one of the researchers during the data collection.

The prepared questionnaire consists of demographic and personal characteristics including sex, age, academic year, programmes (Bachelor of Dental Surgery (BDS), Bachelor of Medicine and Bachelor of Surgery (MBBS), Bachelor of Public Health (BPH), Bachelor of Pharmacy (B pharma), Bachelor of Nursing Science (BNS), Bachelor of Science in Nursing (BSC Nursing), Bachelor of Science in Medical Imaging Technology (BSc MIT), Bachelor of Medical Laboratory Technology (BMLT)), living with parents (yes, no) and residents (rent, home, hostel). Dependent variables were the prevalence of tobacco use, SHS exposure and knowledge about SHS and THS exposure. Independent variables were age, sex, academic status, living with parents and living with any smokers. Respondents indicated their academic status with six options for ‘first-year undergraduate’ through ‘fifth-year undergraduate’ and intern. First and second-year students were combined to form ‘preclinical students’ and third-, fourth- and fifth-year students were categorised as ‘clinical students’, and interns were categorised as ‘interns’ as clinical students and interns learnt about tobacco, SHS and THS in their clinical posting.

Prevalence of tobacco use was assessed by asking a question, ‘Do you use tobacco products within the last 30 days?’. Those who were using tobacco products within the last 30 days were considered tobacco users.

The knowledge and attitude about the SHS questionnaire consist of the following: (1) Do you know about SHS exposure? (yes, no), (2) Do you know that SHS has a direct effect on health? (yes, no), (3) Do you know the health problems caused by SHS exposure? (yes, no), (4) Do you know smoking is harmful not only for your health but also for the people you surround? (yes, no), (5) Are you aware of the ban on smoking in public places in Nepal? (yes, no) and (6) Are you in favour of banning smoking in public places?

Exposure to SHS consists of ‘Are you exposed to secondhand smoke? (yes, no)’.

The knowledge about the THS questionnaire consists of the following: (1) Do you know about THS exposure? (yes, no), (2) What is THS? ((a) Smokers inhale directly into their lungs, (b) Breathing in other people smoke, (c) Non-smokers getting smoke directly from the smokers, (d) Smoke pollutant remains on the surfaces (e) Don’t know), and (3) Do you know THS has harmful effects on our health? (yes, no).

Statistical analysis

After completion of the survey, data obtained were entered in Microsoft Excel Sheet V.2007 and were analysed using the Statistical Package for Social Sciences (SPSS V.22.0). The χ2 test was used to compare the group exposed and non-exposed to tobacco, SHS and THS by sociodemographic variables (sex, residence, year of study and academic stream). The level of significance was set at p < 0.05.

Results

A total of 617 students from Gandaki Medical College Teaching Hospital and Research Centre in Pokhara, Nepal, were chosen to take part. Of these, 595 students completed the study questionnaires, yielding a response rate of 96.43% (n=595/617). As the data collection took place during college hours, one reason for non-response could be students being absent at that time. Another reason might be that students are unable to submit their responses due to exams coinciding with the data collection period. Non-responders were not included in the study for analysis. The majority of students were female (62.86%, 374). The mean age of the participants was found to be 21.36±2.24, ranging from 18 to 31 years. More than half of the participants were from MBBS background (51.76%, 308). A larger number of participants (45.04%, 268) were in the first year. This was due to the presence of two concurrent batches in the same year (newly admitted first-year and first-year students taking final exams). Less than one-third (31.76%, 189) of the participants were living with their parents, and almost a similar proportion (31.09%, 185) were living in their home. The overall prevalence of tobacco use was found to be (16.30%, 97) with high prevalence among the students who were currently living with smokers (51.16%, 44) as compared with those who were not (10.41%, 53) and differences being statistically significant (p <0.001). Almost one-fifth of the participants (18.97%, 77) who were not living with their parents had used tobacco products (table 1).

Table 1 Association of tobacco use with demographic characteristics (n=595)

Variables	Tobacco users	Non-tobacco users	Total	χ2 value	P value	
Total	97 (16.30%)	498 (83.70%)	595 (100.00%)			
Sex						
 Male	63 (28.51%)	158 (71.49%)	221 (37.14%)	38.37	<0.001	
 Female	34 (9.09%)	340 (90.91%)	374 (62.86%)			
Academic year						
 First	25 (9.33%)	243 (90.67%)	268 (45.04%)	32.83	<0.001	
 Second	12 (12.90%)	81 (87.10%)	93 (15.63%)			
 Third	20 (26.67%)	55 (73.33%)	75 (12.61%)			
 Fourth	13 (23.64%)	42 (76.36%)	55 (9.24%)			
 Fifth	10 (17.24%)	48 (82.76%)	58 (9.75%)			
 Intern	17 (36.96%)	29 (63.04%)	46 (7.73%)			
Programme						
 MBBS	64 (20.78%)	244 (79.22%)	308 (51.76%)	Fisher exact value=9.08	0.197	
 BDS	13 (12.26%)	93 (87.74%)	106 (17.82%)			
 BSC Nursing	11 (13.41%)	71 (86.59%)	82 (13.78%)			
 B pharma	6 (8.96%)	61 (91.04%)	67 (11.26%)			
 BMLT	1 (7.69%)	12 (92.31%)	13 (2.18%)			
 BPH	1 (12.50%)	7 (87.50%)	8 (1.34%)			
 BSc MIT	1 (12.50%)	7 (87.50%)	8 (1.34%)			
 BNS	0	3 (100.0%)	3 (0.50%)			
Living with parents						
 Yes	20 (10.58%)	169 (89.42%)	189 (31.76%)	6.64	0.010	
 No	77 (18.97%)	329 (81.03%)	406 (68.24%)			
Residence						
 Rent	48 (18.90%)	206 (81.10%)	254 (42.69%)	4.88	0.08	
 Home	21 (11.35%)	164 (88.65%)	185 (31.09%)			
 Hostel	28 (17.95%)	128 (82.05%)	156 (26.22%)			
Currently living with smokers around						
 Yes	44 (51.16%)	42 (48.83%)	86 (14.45%)	89.53	<0.001	
 No	53 (10.41%)	456 (89.59%)	509 (85.55%)			
BDSBachelor of Dental SurgeryBMLTBachelor of Medical Laboratory TechnologyBNSBachelor of Nursing ScienceBPHBachelor of Public Health B pharmaBachelor of PharmacyBSc MITBachelor of Science in Medical Imaging TechnologyBSC NursingBachelor of Science in NursingMBBSBachelor of Medicine and Bachelor of Surgery

More than four-fifths of the students from clinical years (88.83%) knew about SHS which was more as compared with preclinical students and statistically significant (p <0.001). MBBS students have higher knowledge of SHS than other programmes which was statistically significant (p =0.003). Regarding the direct effect of SHS on health, more clinical students and interns provided correct responses as compared with preclinical students, and this pattern was almost similar in MBBS and BDS students as compared with other stream students. Almost all of the participants provided the correct response that smoking is not harmful for smokers only but for the people who were surrounded by smokers. More than 95% of students were in favour of banning smoking in public places (table 2).

Table 2 Knowledge of SHS by academic status and academic programmes (n=595)

Variables	Academic years		P value	Programmes		P value	
Preclinical	Clinical	Intern	Total	MBBS	BDS	Others	Total	
Do you know about SHS exposure?	
Yes	232 (64.27%)	167 (88.83%)	40 (86.96%)	439 (73.78%)	<0.001	242 (78.57%)	80 (75.47 %)	117 (64.64 %)	439 (73.78%)	0.003	
No	129 (35.73%)	21 (11.17%)	6 (13.04%)	156 (26.22%)	66 (21.43%)	26 (24.53 %)	64 (35.36 %)	156 (26.22%)	
Do you know SHS has a direct effect on health?	
Yes	259 (71.75%)	169 (89.89%)	41 (89.13%)	469 (78.82%)	<0.001	255 (82.79%)	86 (81.13%)	128 (70.72 %)	469 (78.82%)	0.006	
No	102 (28.25%)	19 (10.11%)	5 (10.87%)	126 (21.18%)	53 (17.21%)	20 (18.87 %)	53 (29.28 %)	126 (21.18%)	
Do you know the health problems caused by SHS exposure?	
Yes	214 (59.28%)	167 (88.83%)	41 (89.13%)	422 (70.92%)	<0.001	230 (74.68%)	76 (71.70%)	116 (64.09%)	422 (70.92%)	0.044	
No	147 (40.72%)	21 (11.17%)	5 (10.87%)	173 (29.08%)	78 (25.32%)	30 (28.30 %)	65 (35.91 %)	173 (29.08%)	
Do you know smoking is harmful not only for your health but also for the people you surround?	
Yes	352 (97.51%)	184 (97.87%)	46 (100%)	582 (97.82%)	NA	303 (98.38%)	106 (100%)	173 (95.58%)	582 (97.82%)	NA	
No	9 (2.49%)	4 (2.13%)	0	13 (2.18%)	5 (1.62%)	0	8 (4.42%)	13 (2.18%)	
Are you aware of ban on smoking in public places in Nepal?	
Yes	298 (82.55%)	157 (83.51%)	42 (91.30%)	497 (83.53%)	0.321	257 (83.44%)	90 (84.91%)	150 (82.87%)	497 (83.53%)	0.903	
No	63 (17.45%)	31 (16.49%)	4 (8.70%)	98 (16.47%)	51 (16.56%)	16 (15.09%)	31 (17.13%)	98 (16.47%)	
Are you in favour of banning smoking in public places?	
Yes	350 (96.95%)	178 (94.68 %)	42 (91.30%)	570 (95.80%)	0.130	291 (94.48)	104 (98.11%)	175 (96.69%)	570 (95.80%)	0.213	
No	11 (3.05%)	10 (5.32%)	4 (8.70%)	25 (4.20%)	17 (5.52%)	2 (1.89%)	6 (3.31%)	25 (4.20%)	
BDSBachelor of Dental SurgeryMBBSBachelor of Medicine and Bachelor of SurgerySHSsecondhand smoke

Slightly less than half (45.45%, 270) of the participants were exposed to SHS in the last 7 days. More than one-half of students from both MBBS and clinical year were exposed to SHS in the last 7 days. The proportion of interns who were exposed to SHS was significantly higher as compared with preclinical and clinical students (p<0.001). A higher proportion of MBBS students were exposed to SHS as compared with BDS and other streams (p=0.011) (table 3).

Table 3 Exposure to SHS within the last 7 days by academic years and academic programmes (n=595)

Variables	Are you exposed to SHS?	χ2 value	P value	
Yes	No	
Academic years	Preclinical	134 (37.12%)	227 (62.88%)	26.87	<0.001	
Clinical	106 (56.68%)	81 (43.32%)	
Intern	30 (65.22%)	16 (34.78%)	
Total	270 (45.45%)	324 (54.45%)	
Programmes	MBBS	157 (50.97%)	151 (49.03%)	9.08	0.011	
BDS	37 (35.24%)	68 (64.76%)	
Others	76 (41.99%)	105 (58.01%)	
BDSBachelor of Dental SurgeryMBBSBachelor of Medicine and Bachelor of SurgerySHSsecondhand smoke

Overall, 29.42% (175) of the participants indicated that they knew about THS exposure. However, almost two-fifths of the participants (39.49%, 235) provided the correct answers to the question, ‘What is third-hand smoke?’. More than half proportion of the clinical students knew about THS, which was higher than preclinical students and interns, which was statistically significant (p<0.001). More than two-thirds of students in the clinical year knew about the harmful effects of THS on our health, which was higher as compared with the two other groups and statistically significant (p<0.001). There were no significant differences among students from each programme about knowledge of the harmful effects of THS on our health (table 4).

Table 4 Knowledge of THS among medical college students in Western Nepal by academic years and academic programmes (n=595)

Variables	Academic years		P value	Programmes		P value	
Preclinical	Clinical	Intern	Total	MBBS	BDS	Others	Total	
Do you know about THS exposure?	
Yes	59 (16.34%)	100 (53.19%)	16 (34.78%)	175 (29.42%)	<0.001	97 (31.49%)	27 (25.47%)	51 (28.18%)	175 (29.42%)	0.456	
No	302 (83.66%)	88 (46.81%)	30 (65.22%)	420 (70.58%)	211 (68.51%)	79 (74.53%)	130 (71.82%)	420 (70.58%)	
What is THS?	
Don’t know	243 (67.31%)	55 (29.26%)	24 (52.17%)	322 (54.12%)	NA	154 (50.00%)	64 (60.38%)	104 (57.46%)	322 (54.12%)	NA	
Smoke pollutant remain on the surfaces	96 (26.59%)	121 (64.36%)	18 (39.13%)	235 (39.49%)	137 (44.49%)	36 (33.96%)	62 (34.25%)	235 (39.49%)	
Non-smokers getting smoke directly from smokers	17 (4.71%)	5 (2.66%)	4 (8.70%)	26 (4.37%)	11 (3.57%)	2 (1.89%)	13 (7.18%)	26 (4.37%)	
Breathing in other people smoke	3 (0.83%)	4 (2.13%)	0 (0%)	7 (1.18%)	3 (0.97%)	3 (2.83%)	1 (0.55%)	7 (1.18%)	
Smokers inhale directly into their lungs	2 (0.55%)	3 (1.60%)	0 (0%)	5 (0.84%)	3 (0.97%)	1 (0.94%)	1 (0.55%)	5 (0.84%)	
Do you know THS has harmful effects on our health?	
Yes	135 (37.40%)	130 (69.15%)	23 (50.00%)	288 (48.40%)	<0.001	152 (49.35%)	48 (45.28%)	88 (48.62%)	288 (48.40%)	0.76	
No	226 (62.60%)	58 (30.85%)	23 (50.00%)	307 (51.60%)	156 (50.65%)	58 (54.72%)	93 (51.38%)	307 (51.60%)	
BDSBachelor of Dental SurgeryMBBSBachelor of Medicine and Bachelor of SurgeryTHSthird-hand smoke

Discussion

This study analysed the use of tobacco products, exposure to SHS and knowledge of SHS and THS among undergraduate students at Gandaki Medical College of Nepal. The overall prevalence of tobacco use was 16.30%. SHS exposure was reported by 45.45% of participants. Additionally, 73.78% were aware of SHS, and 29.42% knew about THS.

The overall prevalence of participants who had ever used tobacco products was found to be 16.30% which was quite similar to the studies done by Bartwal et al17 in Uttarakhand, India (14.5%); Chatterjee et al18 in Kolkata, India (18.3%); and Shrestha et al19 in Chitwan, Nepal (16.3% were current smokers). The prevalence of tobacco use in our study is lower in comparison to the studies done by Ramakrishna et al20 in Orissa (24.1%), Patel et al21 among private in Belgaum (27.1%), Imam et al22 among Pakistani medical students (21.5%), Kushwaha et al12 among undergraduate students of BPKIHS, Nepal (28.1%). These discrepancies may be attributed to different studies done in various locations and countries resulting in variation in the study population and their sociodemographic status. All of these studies were medical college-based studies and were comparable with our study. A study done by Pokharel et al23 among health professionals in Nepal showed the overall prevalence of tobacco use to be 33.2% which was higher in comparison to our study. This may be attributed to the mean age of participants in this study being higher than our study (21.36 vs 36.0). This highlights that tobacco consumption increased with an increase in age group as per the STEPS surveys conducted in Nepal.24

This study reports significantly higher proportions of students from clinical years who knew about SHS exposure (88.83%) as compared with preclinical years. However, there were no significant differences among students from clinical years and interns about knowledge of SHS exposure. This may be attributed to advanced medical curriculums in clinical years as well as students from clinical years and interns having firsthand experiences working in medical environments among patients and medical faculties. Medical students may have opportunities to learn about the harms of tobacco in clinical medicine or clinical practice courses. However, it would be beneficial to include tobacco education in preclinical courses as well. This early education can help prevent students from starting to smoke themselves and enhance their ability to counsel patients effectively about tobacco use. Knowledge about SHS can be lower among the general population. Therefore, public education campaigns about tobacco use are essential and should be prioritised.

The number of students who are in favour of banning smoking in public places is likely to be smaller along with higher academic status. The reason may be that smokers tend not to approve of banning smoking in public places. There is a high number of interns who are using tobacco as compared with others.

This study shows that 78.82% of overall participants were aware of the harmful effects on health caused by SHS exposure which was lower in comparison to the study done by Das et al25 among undergraduate medical students in Assam, India (92.8%). This discrepancy might be due to differences in level of education as the latter study was conducted on second-year, third-year and final-year MBBS students. Almost all of the participants in our study correctly reported that SHS exposure was also harmful to other people surrounded by smokers which was quite similar to the studies done by Bahadur et al26 among high school students in Kathmandu, Nepal, and Gharaibeh et al27 among non-smoking women employees in Jordan. A total of 95.8% of the participating students in our study supported a ban on smoking in public places which is higher compared with the result obtained from Global Youth Tobacco Surveys (GYTS) (76.1%).28 This difference might be due to data from GYTS being applied only to youth aged 13–15 years attending school with a lack of awareness about risks of SHS exposure and the participants from our study having a higher level of education which contributes to their positive attitudes on banning of smoking in public places. Although the target populations differ, the goal remains the same: health education about tobacco is necessary for both medical students and the general population to protect people from the direct and indirect effects of tobacco smoke.

In this study, 45.38% of total students reported exposure to SHS within 7 days which was quite higher compared with the study done by Al-Zalabani et al29 in Saudi Arabia (25%). This may be attributed to a lack of compliance by the general public with smoke-free legislation banning tobacco smoking in public places and ineffective enforcement of strategies and policies regarding tobacco control measures in Nepal.8 30 The result obtained from the study done by Nan et al31 among women in Inner Mongolia, China, who were exposed to SHS during the last 7 days was reported to be 64.20% which was higher than the result obtained from this study. The discrepancy may be attributed to women being frequently exposed to SHS at home and their work environments in China. It was also reported that it might be due to a lack of awareness about the risks of SHS among women in China as per the study done by Jin et al.32 In this study, SHS exposure occurred in the home, workplace or public places. Any exposure to SHS is unsafe.

The proportion of interns exposed to SHS was significantly higher than preclinical and clinical students. This might be because as people age, smoking prevalence tends to increase, which can lead to more exposure to SHS. In this study, also higher percentage of interns are tobacco users. A study among medical students in India showed that tobacco smoking in students increased with age and professional years.33

A higher proportion of MBBS students were exposed to SHS as compared with BDS and other streams. This could be because a higher percentage of MBBS students were using tobacco.

More than two-thirds of the students in our study were not well informed on THS which was quite similar to the multinational study done by Quispe-Cristóbal et al34 where almost two-thirds of health professionals were unaware of THS. A study done by Salimoğlu et al35 in Turkey reported that the proportion of students who knew about THS was 15.5% which is comparably lower than our study (29.4%). The discrepancy may be attributed to the different levels of students as the Turkish study included students of the vocational school of health sciences. However, this study included students from medical college ranging from first year to interns. Two-fifths of the students gave correct responses on what THS is and almost one-half knew its harmful effects on our health. The results obtained from this study underscore significantly lesser knowledge about THS exposure among the students contrary to their knowledge on SHS exposure. This may be attributed to THS not being implicated as the fundamental topic of discussion in schools/universities, communities and homes. As future medical professionals, it is essential for medical students to stay updated on all knowledge related to THS to effectively provide health services to the public.

More than two-thirds of students in the clinical year knew about the harmful effects of THS on our health, which was higher as compared with the two other groups (preclinical and interns) and statistically significant. Clinical students may have more knowledge about THS compared with interns because THS is a relatively new concept that might not be covered during intern clinical postings, whereas clinical students have been taught about it. Additionally, clinical students may have more curiosity and interest in learning about THS.

There is a variation in the answers provided particularly for the question do you know SHS and THS with the correct answers provided for what is SHS and THS. The reason for this may be the fact that this study used multiple-choice questions (MCQs) for assessing knowledge. The disadvantage of MCQS is that participants might guess the answers, which can undermine the accuracy of the assessment.36

Limitations of the study

The study was a cross-sectional study so the causal relationship could not be explained. The data were collected from a single medical college; hence, the results of this study cannot be generalised. Even though the participation of the study was completely voluntary and anonymity of the participation was ensured, the data were collected based on self-reporting answers of the selected participants, and therefore the study may be subjected to information bias. Due to social desirability bias, the study may have been prone to under-reporting of tobacco use by some students. The majority of the participants were first-year students, which might explain the lower level of knowledge and lower prevalence of tobacco use.

Conclusions

In this study, the prevalence of tobacco use was reported to be low (16.30%) as compared with the general population in Nepal. Despite more than three-fourths of students knowing the harmful effects of SHS exposure, almost one-half of them were exposed to SHS in the last 7 days. The proportion of students who knew about THS exposure was comparably lower which serves as a baseline to include discussions regarding knowledge on THS exposure in their course curriculum.

Although the smoke-free legislation on tobacco smoking in public places was implemented across Nepal in 2014,8 the exposure of students to SHS was still prevalent in our study with more than four-fifths of students being aware of the ban of smoking in public places in Nepal. This underlines the urgent need to design appropriate and effective education interventions in colleges on ‘no smoking’ laws and policies to reduce SHS as well as THS exposure.

Acknowledgements

We are grateful to all the participating undergraduate students for their time and support at the time of data collection without whom our research would not be possible.

Data availability statement

Data are available upon reasonable request.

Review Process File
18 09 2024

Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Prepublication history for this paper is available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2024-086266).

Patient consent for publication: Consent obtained directly from patient(s).

Ethics approval: This study involves human participants and was approved by Gandaki Medical College, Institutional Review Committee, Pokhara, Nepal (Reference No: 289/079/080) Participants gave informed consent to participate in the study before taking part.

Provenance and peer review: Not commissioned; externally peer reviewed.

Patient and public involvement: Patients and/or the public were not involved in the design or conducting, reporting or dissemination plans of this research.
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