Mumbai: Winter is the deadliest season for lung disease in urban India, accounting for nearly a third of all respiratory hospitalisations and deaths nationwide, according to a recent study published in the journal Lung India.The Seasonal Waves of Respiratory Disorders (SWORD) survey was conducted across 245 medical centres in different parts of the country, including about 17 in Mumbai, MMR and Navi Mumbai. The data include patient trends through four seasonal weeks in 2017-2018.The study, led by the department of pulmonary medicine at Rajasthan Hospital in Jaipur, tracked nearly 2,900 hospitalisations across summer, monsoon and winter, and analysed 394 deaths.The lead author of the study, Sheetu Singh, said, “While we were looking at urban centres, some of the patients at these hospitals also came from rural parts of the country. For now, we have established a trend, but to conclude the causes, we would need large-scale studies.”The findings identify chronic obstructive pulmonary disease (COPD) as the primary killer, accounting for the highest proportion of mortality, closely followed by respiratory tract infections (RTIs). Researchers have identified key risk factors: biomass fuel exposure, smoking, mould exposure and even exposure to pets or birds at home in cases of interstitial lung disease (ILD).Common comorbidities that increase mortality risk included smoking, diabetes mellitus, GERD, hypertension, coronary artery disease and anaemia, the researchers said. Men made up 64.3% of all hospitalised patients, compared to 35.7% women, and accounted for 69% of all respiratory deaths.Dr Sundeep Salvi, a pulmonologist at the Pune-based Pulmocare Research and Education Foundation and one of the study’s authors, said, “The summer season is now considered to be safe for lung patients. While pollution has a direct correlation with high mortality in the winter, during the monsoon, it is viral infections.”Interestingly, more lung cancer cases were reported in the monsoon season. Still, researchers said the data “warrants further validation in larger, prospective datasets to determine whether this represents a true seasonal pattern or a chance finding”.Dr Pralhad Prabhudesai, a city-based pulmonologist who contributed case studies to the paper, said doctors have long known that serious cases increase with changes in weather patterns. For instance, respiratory tract infections show seasonal shifts; routine clinic visits for minor infections peak during the monsoon, affecting younger people, but snowball into emergencies in winter for the elderly. Winter accounts for nearly 45% of all RTI-related deaths, the study said.“Age is a contributing factor, but that is not always true. We have seen young lung patients lose their lives due to worsening symptoms in winter,” Dr Prabhudesai said.“Age is a contributing factor, but that is not always true. We have seen young lung patients lose their lives due to worsening of symptoms in winter,” Dr Prabhudesai said.
