Thirty-one-year-old Sunil (name changed), a dental equipment dealer from Mumbai, weighed 186 kg when he was hospitalised twice last year—in August and December—for severe respiratory infections. Each episode involved worsening breathlessness and critically low oxygen levels, requiring intensive care.
Despite his young age and absence of major chronic illnesses, doctors placed him on oxygen therapy and non-invasive ventilatory support (BiPAP) during both admissions. Although he recovered each time, the recurrence of severe infections raised concerns about an often-overlooked risk factor: obesity.
How Obesity Compromised Lung Function
Sunil’s condition stemmed from class III obesity, the most severe category. This level of obesity significantly increases the risk of multiple comorbidities, including type 2 diabetes, hypertension, stroke, heart disease, osteoarthritis, and impaired breathing.
According to Dr Aparna Govil Bhasker, laparoscopic and bariatric surgeon, obesity compromised Sunil’s lung function and reduced his respiratory reserve, or extra breathing capacity. While treatment led to recovery, repeated hospitalisations highlighted the under-recognised role of obesity in worsening infectious disease outcomes.
Obesity Weakens Immunity and Increases Infection Severity
Excess body fat impairs immune responses, promotes chronic inflammation, and restricts lung expansion. As a result, infections become more frequent, more severe, and slower to resolve, Dr Bhasker explained.
These clinical observations align with findings from a large new study showing that people with obesity face a 70% higher risk of hospitalisation or death from infectious diseases. Those with severe obesity carry nearly three times the risk.
Study Links Obesity to Global Infection Deaths
As reported by The Indian Express, the study, which analysed data from 5.4 lakh individuals, found that obesity increased the risk of severe outcomes from flu, Covid-19, pneumonia, gastroenteritis, urinary tract infections, and respiratory tract infections.
When extrapolated globally, the findings suggest obesity contributed to approximately 0.6 million of the 5.4 million infectious disease deaths recorded worldwide in 2023—about 10.8%.
India Faces a Dual Disease Burden
In India, obesity was linked to one in 26 infectious disease deaths in 2023, according to estimates from the Global Burden of Diseases (GBD). In comparison, the figure was one in four in the US and one in 11 in China, as reported in The Lancet.
Study authors caution that global estimates should be interpreted carefully. However, they warn that rising obesity rates could sharply increase the burden of serious infections in the coming decades.
Importance of Weight Management and Prevention
Prof Mika Kivimaki of University College London, the study’s lead author, emphasised the importance of weight management in reducing health risks. He also advised individuals with obesity to seek prompt treatment for infections and stay up to date with vaccinations.
Obesity as a Major Risk Factor in India
Dr Bhasker stressed that obesity acts as a risk factor for both communicable and non-communicable diseases. In a country already burdened by infectious diseases, rising obesity adds a significant and often underestimated strain on the healthcare system.
She also noted that impaired immune responses and vitamin D deficiency may increase susceptibility to infections in people with obesity.
Broad-Based Study Design and Findings
The study analysed data from 67,000 adults in Finland and more than 4.7 lakh participants from the UK Biobank. Researchers assessed body mass index (BMI) at enrolment and followed participants for an average of 13–14 years.
Individuals with obesity (BMI >30 kg/m²) had a 70% higher risk of hospitalisation or death from infectious diseases compared to those with a healthy BMI. However, researchers acknowledged that the observational nature of the data prevents confirmation of direct causality.