INTRODUCTION
Cigarette smoking poses a major global public health concern worldwide1-5. Several investigations have highlighted the interrelatedness of smoking and hearing loss1,4,6. It has been observed that smokers have a greater likelihood of experiencing hearing loss compared to non-smokers6-8. The auditory system is particularly vulnerable to the harmful effects of smoking6-10. The impact of both cigarette and waterpipe (hookah) smoking on the loss of hearing ability is extensively documented in the literature1,6-10.
The literature states that cigarette smoking is the primary risk factor for tracheal, bronchus, or lung (TBL) cancer, incidence rate of 27.7 per 100000 people, accounting for 80–90% of cases in regions with high smoking prevalence5. While other risk factors exist, smoking is the dominant driver of TBL cancer in many communities. The incidence of TBL-related cancers can potentially be predicted based on smoking rates.
Several studies have established a link between elevated long-term blood pressure and hearing loss8,10-13. More recent research has also found associations between hearing impairments and conditions such as hypertension8,9-13, stroke10,14-16, sleepiness8,17, and cigarette smoking1,3-6,12. However, the precise cause of hearing loss in many stroke patients who smoke cigarettes or waterpipes, remains unidentified8,12,16. Literature findings are showing that a reduction in hearing could significantly happen due to high threshold vitamin D levels17-23, making vitamin D levels a critical consideration in diet. Additionally, MP3 players have been identified as a remarkable danger for hearing loss24. This study aimed to explore the relationship between cigarette smoking, alcohol consumption, sleeping disorder, mental health and hearing loss among stroke patients.
METHODS
Participants
This cross-sectional study was carried out at the outpatient clinics of the Ear, Nose, and Throat (ENT) and Neurology Departments at Istanbul Medipol University Hospitals from January 2024 to March 2025. With a prevalence of 20% for smokers with hearing loss, a 99% confidence interval, and a 3% margin of error12,16, the calculated sample size was 1352 subjects, of which 11140 agreed to participate (response rate of 75%). Ethical approval was obtained from the Istanbul Medipol University Institutional Review Board (IRB) committee (IRB: E-10840098-772.02-1411 and IRB: E-10840098-202.3.02-7291).
Design and smoking history
Smoking was defined as having smoked at least 100 cigarettes in a lifetime and currently smoking. The study compared smokers with and without hearing loss to non-smokers without hearing loss.
Blood pressure and vitamin D assessment
Hypertension was assessed based on ≥140 mmHg systolic blood pressure (SBP) or ≥90 mmHg diastolic blood pressure (DBP), or regular antihypertensive medication use16,19. Serum 25(OH)D (25-hydroxy vitamin D) levels were measured using a competitive radio-immunoassay (RIA), a sensitive immunoassay technique involving antigen-antibody interaction in vitro, aided by radioisotopes (DiaSorin, Stillwater, Minnesota). Participants were categorized into three groups: those with vitamin D deficiency, those with insufficiency, and those with normal/optimal levels16,19,22-23.
Hearing assessment
Hearing sensitivity was assessed using pure-tone audiometry (PTA) with two clinical digital audiometers (Interacoustics AC40 Clinical Audiometer and Garson Stadler GSI 61). Hearing loss was classified as normal (<26 dB) or impaired (≥26 dB)8,12,16,19,21.
Patients Heath Questionnaire - Depression (PHQ-15)
The PHQ-15 is depression disorder screening. The Turkish version of the PHQ-15 has shown satisfactory reliability, with a Cronbach’s alpha of 0.79, pointing fine internal consistency. The total score ranges from 0 to 30, categorized as follows: 0–4 (none), 5–9 (mild), 10–14 (moderate), and 15–30 (severe). A score of 10 is considered the recognized cutoff value for identifying potential depressive symptoms.
Sleepiness assessment
The Epworth Sleepiness Scale (ESS)8,25 was employed to examine sleepiness symptoms. This scale includes eight items evaluating the likelihood of dozing in specific situations (e.g. watching TV, sitting, talking) and is rated from 0 (would never doze) to 3 (high chance of dozing). Total scores span from 0 to 24, categorized into normal (0–7), mild (8–9), moderate (10–15), and severe (16–24) sleepiness8,25.
Depression Anxiety Stress Scale (DASS-21)
The 21-item DASS-21, developed by Lovibond and Lovibond (1995), is used to assess anxiety, depression and stress. In the current study, the internal consistency was high, with Cronbach’s alpha values of α=0.85 for the depression sub-scale, α=0.83 for the anxiety sub-scale, and α=0.81 for the stress sub-scale. Stress was categorized as five levels: normal, mild, moderate, severe, and very severe.
Statistical analysis
Data analysis was performed using SPSS software, version 25. The chi-squared test was applied to evaluate significant differences across categorical variables. To contrast these three group’s means, a one-way analysis of variance (ANOVA) was employed. Additionally, a multivariate stepwise linear regression analysis was conducted to examine the relationship between smoking and hearing loss in stroke patients, considering p<0.05 as significant.
RESULTS
Out of 1140 patients studied, 19.2% were cigarette smokers who experienced hearing loss, while 10.9% were waterpipe smokers who have lost their hearing ability. Table 1 outlines the sociodemographic and clinical characteristics among the three groups: cigarette smokers with hearing loss, cigarette smokers without hearing loss, and non-smokers who did not use waterpipes and had no hearing loss. These dissimilarities were noted in BMI (p<0.001), physical activity (p=0.002), hypertension (p<0.001), MP3 player usage (p<0.001), tinnitus (p<0.001), vertigo (p<0.001), dizziness (p<0.001), and headaches/migraines (p<0.001).
Table 1
The general characteristics and clinical comparison of cigarette smokers with hearing loss versus without, among stroke patients (N=1140)
Table 2 presents the prevalence of mental health symptoms and sleep disorders. It shows that 10% of individuals with sleeping disorders had PHQ-15 scores ≥10, compared to 5% of those without sleeping disorders. The data indicate significant differences between those with and without sleep disorders, with higher prevalences of PHQ-15 scores ≥10 (p<0.001), depression (p<0.001), anxiety (p=0.002), and stress (p<0.001) among individuals with mental health conditions.
Table 2
Prevalence of mental health symptoms by gender (N=1140)
Table 3 displays the clinical biochemical values for cigarette smokers with hearing loss among three stroke groups, showing differences in vitamin D (p<0.001), hemoglobin (p<0.001), calcium (p=0.004), magnesium (p<0.001), fasting glucose (p<0.001), HbA1C (p<0.001), HDL (p=0.009), microalbuminuria (p<0.001), systolic BP (p<0.001), and diastolic BP (p<0.001). Sleepiness was notably higher among cigarette smokers with hearing loss compared to non-smokers without hearing loss (p=0.013).
Table 3
Clinical biochemical variables comparison cigarette smoker with hearing loss patients versus without among stroke patients (N=1140)
Table 4 outlines the multivariate regression analysis for predicting risk factors in cigarette smokers with hearing loss among stroke patients, identifying vertigo (p<0.001), obesity (p<0.001), vitamin D deficiency (<20 ng/mL) (p<0.001), ATP III Metabolic Syndrome (p<0.001), IDF Metabolic Syndrome (p=0.004), calcium (mmol/L) (p=0.008), headaches/migraines (p=0.039), and hypertension (p=0.025) as significant predictors among stroke patients.
Table 4
Multivariate stepwise regression analysis for predictors of hearing impairment associated with cigarette smoking in stroke patients (N=1140)
DISCUSSION
This study revealed a significant association between cigarette smoking, waterpipe use, and hearing loss among stroke patients, consistent with previous studies3-10,12. Exploring the factors related to smoking and hearing loss in stroke patients is crucial for preventing hearing loss. Reducing or quitting smoking could potentially prevent hearing issues3-10,12. Hu et al.5 discovered that individuals who had quit smoking faced a lower risk of hearing loss compared to those who continued to smoke. Recently, Bener et al.1,12,16 confirmed the link between cigarette smoking and hearing ability deprivation among hypertension and stroke patients, aligning with this study’s findings.
This study also identified a strong correlation between obesity, comorbidities, and diminished hearing in cigarette as well waterpipe smokers, which is consistent with previous findings8,12-16,20-21. The results of this study align with previous research concerning stroke, hypertension, and tinnitus2-4,8,9,12-13. Latest literature findings have indicated that hearing deterioration is rather prevalent among hypertension and diabetes patients in contrast to the healthy population1-14-16,20.
The current survey indicated a notable positive association between hearing disease and obesity, which is in line with previously reported studies1,8,12,22. The popularity of MP3 players for listening to music, as noted in this study, is consistent with another research24.
A recent study5 reported significant variations in the burden of tracheal, bronchus, and lung (TBL) cancer across 204 countries and territories. While global age-standardized incidence, death, and disability-adjusted life years (DALY) rates are declining, some countries still show increasing trends in these rates.
Research by Dawes et al.11, Bener et al.1,16,19, and Bigman20 suggested that increasing vitamin D levels can reduce hearing problems. Additionally, vitamin D deficiency has been linked to both low and high-frequency hearing loss in adults and the elderly18-20. These findings align with the present study. Vitamin D performs a key role in the human auditory system, and its deficiency negatively affects the ears, particularly the inner ear18-20. Overall, this study found that hypertension, vitamin D deficiency, and sleepiness were potential risk factors for hearing loss among smokers, suggesting the need for immediate prevention strategies through media campaigns. Some studies have also observed a relationship between sleep disorders, hearing loss, and tinnitus26.
Limitations
The study has some limitations. First, the cross-sectional design does not allow for determining causal relationships. Second, some patients were excluded due to the time required for audiometric assessments. Third, the smoking information was self-reported, which may introduce bias. Fourth, the sleepiness data obtained from the Epworth scale is subjective and may not be entirely accurate.
CONCLUSIONS
This study puts forward that smoking cigarette along with factors like hypertension, obesity, vitamin D deficiency, and sleepiness, serve as notable risks for loosing hearing ability among stroke patients. There is increasing evidence linking cigarette tobacco smoking to lung cancer and various adverse health effects.
