Impact of Shift Work on the Morbidity Profile and Respiratory Health Among Pig Iron Industry Workers: A Cross Sectional Study

Introduction: Shift work adversely affects worker productivity, performance, health and quality of life and puts others at risk due to workplace or driving accidents. Shift work, including night work, is known to impact workers’ health due to disrupted circadian rhythms and lifestyle modifications such as irregular and reduced quality of food intake along with impairment of social life. This study examines the differences in morbidity profiles, metabolic health and respiratory function among shift and regular workers in the pig iron industry where pig iron is produced by smelting of iron ore in blast furnaces.

Methods: This cross-sectional study was conducted between August 2024 to January 2025 among 641 workers in the pig iron industry in Goa, India. Following written informed consent, the workers were conveniently sampled. A semi-structured interview schedule was administered to collect data on socio-demography, morbidity profile and work-related characteristics. Anthropometric measures, laboratory parameters and spirometry data (to evaluate respiratory function) were obtained from records of annual medical screening. Data was entered in Microsoft Excel and analyzed using SPSS V.21. Descriptive statistics were represented as frequencies and percentages. Chi square test was used to study association and between group differences. Binomial logistic regression analysis was performed with illness as the dependent variable and gender, shift work, body mass index (BMI) and spirometry readings as covariates. A p value of <0.05 was considered to be statistically significant.

Results: Of the 641 workers, 277 (43.2%) were engaged in shift work. The mean age of the participants was 40.85 ± 10.08 years and 89.7% were male. Majority of workers were between 36–45 years (34.9%), followed by 46–55 years (28.2%). The prevalence of hypertension was significantly higher among shift workers (20.1%) compared with regular workers (10.4%) (p < 0.040). Diabetes was slightly more common among shift workers (10.8%) than regular workers (6.6%) (p < 0.04). Obesity (BMI >30) was more prevalent among shift workers (18.3%) than regular workers (12.5%). Almost 8.1% of the workers had high total cholesterol levels with significant differences between night shift workers and regular shift workers (10.8% vs 6.0%, p = 0.020). Spirometry findings showed a higher prevalence of mild restriction among shift workers (17.7%) compared with regular workers (10.4%). Binomial logistic regression showed that shift workers were at1.5 times higher risk of developing chronic illness (p < 0.001).

Conclusion: The findings suggest that shift work is associated with a higher prevalence of hypertension, obesity and mild lung restriction compared with regular work schedules and this may predispose them to ill health conditions such as cardiovascular diseases and accidents at workplace. These results emphasize the need for targeted occupational health interventions such as risk assessment and periodic medical surveillance to mitigate the adverse health effects of shift work in the pig iron industry.