Lower Respiratory Tract Infections (LRTIs), encompassing acute bronchitis, pneumonia, and acute exacerbations of chronic obstructive pulmonary disease (AECOPD), are major contributors to the global burden of disease. While environmental pollution and occupational hazards play a role, cigarette and bidi smoking remains the most significant modifiable risk factor for respiratory pathogenesis.

Smoking induces structural changes in the respiratory tract, including ciliary dysfunction, mucous gland hypertrophy, and impaired macrophage activity. These alterations create an optimal environment for microbial colonization and subsequent infection. In rural and semi-urban Indian demographics, such as the Kalahandi district of Odisha, smoking habits often involve unfiltered tobacco products (bidis), which yield higher concentrations of tar and particulate matter.

This study was undertaken at the Saheed Rendo Majhi Medical College and Hospital (SRM MCH) in Bhawanipatna to evaluate the clinical prevalence and epidemiological characteristics of LRTIs among the local smoking population.

• Study Design: Cross-sectional observational study. • Study Setting: Department of Pulmonary Medicine and General Medicine, SRM MCH, Bhawanipatna, Odisha. • Study Duration: June 2025 to June 2026. • Sample Size: 84 subjects. • Inclusion Criteria: Patients aged 18 years and above with a current or past history of smoking (minimum 1 pack-year) presenting with cough, sputum production, fever, or dyspnea. • Exclusion Criteria: Patients with active pulmonary tuberculosis, established lung malignancies, immunodeficiency disorders (e.g., HIV), or those who refused consent. • Data Collection & Analysis: Clinical diagnoses were confirmed via chest radiography, sputum culture, and routine hematology. Smoking intensity was quantified using pack-years. Data were analyzed using SPSS software. Categorical variables were assessed using the Chi-square test, and a p-value of <0.05 was considered statistically significant.

The study included 84 participants, showing a strong male predominance, which aligns with regional cultural patterns of tobacco use. The majority of the patients fell into the 41-60 years age bracket, a period where the cumulative effects of smoking typically begin manifesting as symptomatic clinical disease.

Table 1: Demographic Distribution of the Study Population

Out of the 84 symptomatic smokers evaluated, 58 individuals (69.04%) had a confirmed Lower Respiratory Tract Infection. The clinical spectrum reveals that acute bronchitis was the most frequent diagnosis, highlighting the chronic inflammatory state of the airways in smokers.

Table 2: Prevalence and Spectrum of LRTIs Among Smokers

*Patients presented with upper respiratory symptoms or non-infectious smoker's cough.

Patients presented with overlapping symptoms, with cough and sputum production being nearly universal. The high prevalence of purulent sputum indicates active bacterial infection requiring antibiotic intervention.

Table 3: Clinical Presentation and Symptomatology

This table illustrates the dose-response relationship between smoking exposure and infection risk. A significantly higher proportion of patients with a smoking history exceeding 20 pack-years developed LRTIs compared to those with fewer pack-years. The association is statistically significant ().

Table 4: Association Between Smoking Intensity (Pack-Years) and LRTI Incidence

Severity was classified based on the need for hospital admission (Moderate) or ICU care (Severe) versus outpatient management (Mild). The presence of systemic comorbidities, particularly Type 2 Diabetes Mellitus and Hypertension, resulted in more severe disease manifestations. This correlation was found to be statistically significant ().

Table 5: Impact of Co-morbidities on the Severity of LRTI

The current study conducted at SRM MCH, Bhawanipatna, demonstrates a high prevalence of LRTIs (69.04%) among symptomatic smokers. This finding corroborates global literature which asserts that the structural and immunological damage inflicted by tobacco smoke severely compromises pulmonary defenses. We observed a distinct male preponderance (85.7%). This is largely reflective of the demographic realities in rural Odisha, where smoking (particularly bidi and loose tobacco) is culturally more prevalent among adult men, whereas women are more frequently exposed to biomass fuel smoke (which was excluded from this specific cohort). The data in Table 4 is of particular clinical importance. It establishes a clear, statistically significant (p=0.012) dose-response relationship between the cumulative exposure to tobacco smoke (measured in pack-years) and the likelihood of developing a clinical LRTI. Patients with over 20 pack-years had an 88.8% LRTI positivity rate upon presentation. This underscores the progressive deterioration of alveolar macrophage function and mucociliary clearance over time. Furthermore, Table 5 highlights the dangerous intersection of chronic metabolic diseases and respiratory infections. Smokers with diabetes or cardiovascular disease were significantly (p=0.024) more likely to require inpatient admission or intensive care, emphasizing the need for aggressive, multidisciplinary management in this subgroup.

LRTIs represent a severe health burden among the smoking population in the Bhawanipatna region. Our findings from the 2025–2026 period at SRM MCH clearly indicate that heavier smoking (higher pack-years) directly translates to a higher risk and greater severity of lower respiratory tract infections. Comorbidities further compound this risk, leading to worse clinical outcomes. Public health initiatives in Odisha must aggressively prioritize accessible smoking cessation clinics and early screening for chronic respiratory decline to reduce regional morbidity.