Figure 2: Distribution of smoking types among participants

Table 4: Association between smoking type and respiratory diseases/symptoms

 
Among e-cigarette users, 86.1% reported obstructive lung diseases and 13.8% reported restrictive lung diseases, both with statistically significant p-values of 0.001, indicating a strong association between e-cigarette use and these conditions. Cough and shortness of breath were universal symptoms among e-cigarette users, both at 100% prevalence and significant p-values of 0.001. Wheezing was reported by 87.5% of e-cigarette users, but with a p-value of 0.109, this was not statistically significant. COPD was present in 25% of e-cigarette users, and asthma in 13.8%, both with significant p-values of 0.001.

For traditional smokers, 50% had obstructive lung diseases and 25% had restrictive lung diseases, both with significant p-values of 0.001. Cough and shortness of breath were prevalent in 100% and 75% of traditional smokers, respectively, with significant p-values of 0.001. Wheezing was reported by 75% of traditional smokers, also with a significant p-value of 0.001. COPD was found in 50% and asthma in 9.2% of traditional smokers, both with significant p-values of 0.001.

In contrast, non-smokers exhibited much lower rates of respiratory diseases and symptoms. Only 14.8% had obstructive lung diseases and 23.4% had restrictive lung diseases, with p-values of 0.232 and 0.321, respectively, indicating no significant association. Cough was reported by 25.9% and wheezing by 33.3% of non-smokers, with p-values of 0.091 and 0.072, respectively, showing no statistical significance. Shortness of breath was present in 16% of non-smokers with a p-value of 0.231, COPD in 11.1% with a p-value of 0.121, and asthma in 16% with a p-value of 0.111, none of which were statistically significant.

Overall, these results indicate a strong and significant association between smoking, particularly e-cigarette and traditional cigarette use, and various respiratory diseases and symptoms. Non-smokers had much lower and non-significant prevalence rates for these conditions, highlighting the negative impact of smoking on pulmonary health. (Table 4) ( Figure 3).

Figure 3: Association between smoking type and respiratory diseases/symptoms

Table 5: Occupation-Based analysis of smoking habits, e-cigarette preferences, and socioeconomic status

The occupation-based analysis reveals distinct patterns in smoking habits, e-cigarette preferences, and socioeconomic status among different occupational groups. Students predominantly favor e-cigarette use, with disposable e-cigarettes being the most common choice, often associated with higher socioeconomic status. Employees in corporate or other jobs also lean towards e-cigarette use, similarly preferring disposable options, typically placing them in middle socioeconomic brackets. Laborers show a preference for traditional smoking habits, aligning with lower socioeconomic standings. In contrast, professionals such as professors, lecturers, and doctors prefer e-cigarettes, particularly pod-based varieties, reflecting a mix of higher and middle socioeconomic statuses. Those who are jobless or unemployed are more likely to be non-smokers with exposure to environmental tobacco smoke, often associated with lower socioeconomic status. This analysis underscores the varying smoking behaviors and preferences across occupational categories, influenced by socioeconomic factors, and highlights potential targets for tailored interventions aimed at promoting healthier behaviors and reducing smoking-related disparities (Table 5).

Discussion

This study aimed to determine the prevalence of respiratory symptoms and conditions among users of emerging e-cigarette technologies, compare pulmonary function between e-cigarette users, traditional cigarette smokers, and non-smokers, and assess the characteristics of various e-cigarette devices. Conducted at the University of Peshawar, the study included a diverse sample of participants aged 18 and above. The demographic analysis revealed a mean participant age of 30.67 years, with a notable gender disparity: 80% of participants were male, and e-cigarette use was most prevalent among them.

The distribution of smoking types showed that e-cigarette use was the most common at 53.3%, followed by traditional smoking at 26.7%, and non-smoking at 20%. This indicates a shift towards e-cigarette use within the study population. Analysis of respiratory symptoms and diseases revealed significant health risks for all groups. E-cigarette users had a high prevalence of cough (100%), shortness of breath (100%), and obstructive lung diseases (86.1%), with notable incidences of COPD (25%) and asthma (13.8%). Traditional smokers also exhibited high rates of cough (100%), wheezing (75%), and shortness of breath (75%), along with significant occurrences of obstructive lung diseases (50%) and COPD (50%). Non-smokers exposed to environmental tobacco smoke showed substantial rates of cough (100%), shortness of breath (71.6%), and restrictive lung diseases (50%). These findings, with a strong statistical significance (p-value = 0.001), underscore the health risks associated with different smoking behaviors.

An occupation-based analysis revealed that smoking habits and e-cigarette preferences vary by socioeconomic status and occupation. Students and professionals favored e-cigarettes, particularly disposable and pod-based forms, often associated with higher socioeconomic status. Laborers preferred traditional smoking, linked to lower socioeconomic status, while jobless individuals were more likely to be non-smokers exposed to environmental tobacco smoke. These results highlight the need for targeted public health interventions to reduce smoking prevalence and mitigate associated health risks. The distinct patterns of e-cigarette use and traditional smoking across different demographic and occupational groups emphasize the importance of tailored strategies to address specific needs and behaviors within these populations. This study underscores the urgent need for continued research and proactive measures to combat the rising trends in e-cigarette use and improve respiratory health outcomes.

The findings from our study align closely with those reported in three case series from the US, which highlight the clinical presentation and management of respiratory illnesses associated with e-cigarette use. In our study, 100% of e-cigarette users reported experiencing cough, which is consistent with the 80% reported in the US studies. Similarly, the US data indicated that 33% had a productive cough, although our study did not specifically differentiate between productive and non-productive coughs²⁰.

Dyspnea was another common symptom observed in both studies, with 86% of the US patients and a significant portion of our participants reporting this symptom. Our findings of 100% of e-cigarette users experiencing shortness of breath strongly echo the US study's findings. Additionally, the US studies reported a high incidence of hypoxemia (77%), defined as peripheral capillary oxygen saturation (spO2) < 95% on room air. While our study did not measure hypoxemia directly, the high prevalence of shortness of breath and other respiratory symptoms suggests a similar trend of impaired pulmonary function among e-cigarette users.

Both studies underscore the significant respiratory health risks associated with e-cigarette use, particularly regarding decreased pulmonary gas exchange and the resulting hypoxemia. The strong parallels between our findings and those from the US studies reinforce the growing body of evidence indicating the adverse effects of e-cigarette use on respiratory health. These comparisons highlight the need for targeted public health interventions and further research to address and mitigate these risks effectively.

Our study's findings are consistent with broader research on e-cigarette use and respiratory health, as evidenced by a review of 45 studies involving 1,465,292 subjects aged 12 to 99 years. This review included 14 randomized experiments, 7 nonrandomized experiments, 6 cohort studies, and 18 cross-sectional studies, with 35.6% of these studies conducted in the United States. These studies found a significant link between e-cigarette (EC) use and respiratory issues such as lung symptoms, asthma, and chronic obstructive pulmonary disease (COPD)²¹.

Our study similarly found that e-cigarette users reported high rates of cough (100%) and shortness of breath (100%), paralleling the broader findings of increased lung symptoms associated with EC use. The review also noted that while EC use resulted in poorer outcomes compared to non-smoking, it led to better outcomes than traditional cigarette smoking. This aligns with our comparative analysis, which showed that e-cigarette users had a higher prevalence of respiratory symptoms compared to non-smokers but a lower prevalence compared to traditional smokers.

Overall, both our study and the broader research highlight the significant respiratory risks of e-cigarette use, particularly in comparison to non-smoking, while also suggesting a relative reduction in harm compared to traditional cigarette use and compare it briefly.

In our study, we found significant respiratory symptoms among e-cigarette users, which aligns with experimental findings from other research. For instance, using an e-cigarette for just 5 minutes caused an immediate drop in fractional exhaled nitric oxide (FeNO) by 2.14 parts per billion (ppb) in the experimental group (P = .005), with no significant change in the control group (P = .859). Additionally, the experimental group experienced an increase in total respiratory impedance at 5 Hz by 0.033 kilopascals per liter per second (kPa/[L/s]) (P < .001) and increased flow respiratory resistance at 5 Hz, 10 Hz, and 20 Hz. Regression analyses controlling for baseline measurements revealed significant decreases in fractional exhaled nitric oxide (FeNO) and increases in respiratory impedance and resistance across multiple frequencies, with an overall increase in peripheral airway resistance (β, 0.042 kPa/[L/s]; P = .024)²².

Comparatively, our study also noted high rates of cough and shortness of breath among e-cigarette users, suggesting impaired respiratory function. These experimental results corroborate our findings by demonstrating the immediate adverse effects of e-cigarette use on respiratory parameters, such as increased airway resistance and reduced nitric oxide levels, indicative of airway inflammation. Both studies highlight the significant impact of e-cigarette use on respiratory health, reinforcing the need for public health measures to address these risks.

Our study's findings align with those of Bircan et al., who found significant associations between e-cigarette (EC) use and self-reported diagnoses of asthma, chronic obstructive pulmonary disease (COPD), and asthma-COPD overlap syndrome in a cross-sectional study of 18-24-year-olds using data from the Behavioral Risk Factor Surveillance System (BRFSS). By excluding participants with a history of smoking, Bircan et al. minimized the confounding effects of traditional smoking on chronic respiratory disorders, enhancing the validity of their findings. However, they noted potential issues with diagnostic mislabeling and a reliance on a small number of patients, with their propensity score reflecting only demographic factors rather than the actual likelihood of developing COPD²³.

In comparison, our study also demonstrated high rates of respiratory symptoms such as cough and shortness of breath among e-cigarette users, supporting the association between EC use and respiratory issues. Both studies emphasize the importance of considering confounding factors and potential biases in research on e-cigarette use and respiratory health, highlighting the consistent evidence of respiratory risks linked to e-cigarette use.

Limitations

Despite the valuable insights gained from our study, several limitations should be noted. Firstly, the study was confined to a single institution, the University of Peshawar, which may limit the generalizability of our findings to a broader population. The sample, while diverse, may not fully represent the varied demographics and smoking behaviors of other regions. Secondly, our research focused exclusively on respiratory symptoms and conditions, potentially overlooking other significant health impacts of e-cigarette use, such as cardiovascular or neurological effects. Future studies should aim to include multiple institutions and a broader range of health outcomes to provide a more comprehensive understanding of the long-term health effects of emerging e-cigarette technologies

Conclusion

In conclusion, our cross-sectional study at the University of Peshawar reveals significant respiratory health risks associated with the use of emerging e-cigarette technologies. Our findings show a high prevalence of respiratory symptoms, such as cough and shortness of breath, among e-cigarette users, with notable incidences of obstructive lung diseases, COPD, and asthma. Comparatively, traditional cigarette smokers also exhibited high rates of respiratory conditions, while non-smokers though somewhat lesser, respiratory issues.

The comparison with broader research underscores the consistency of our results with existing literature, highlighting the adverse effects of e-cigarette use on pulmonary health. Our study further identifies distinct patterns of smoking behaviors influenced by socioeconomic and occupational factors, emphasizing the need for targeted public health interventions.

However, the study's limitations, including its confinement to a single university and its exclusive focus on respiratory outcomes, suggest that further research is necessary. Expanding the scope to include multiple institutions and a wider array of health impacts will provide a more comprehensive understanding of the long-term consequences of e-cigarette use.

Overall, our study contributes valuable data to the growing body of evidence on the health implications of e-cigarettes, underscoring the urgent need for continued research and proactive public health strategies to mitigate these risks.

Acknowledgements: We extend our gratitude to the Ethical Review Board of KMC (IREB KMC) for granting us the necessary permissions to conduct our data collection. We are also thankful to Kashif Ur Rehman who helped us with data analysis. Additionally, we appreciate the contributions of our colleagues Arsalan khan, Muneeb Ali and Nida Gul who assisted with data collection. All authors contributed equally to this research. All authors are considered as first authors.

Author’s contribution: All authors have contributed equally so all are considered as 1^st author.

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