A groundbreaking study involving over half a million individuals reveals that obesity is linked to a 70% higher risk of hospitalization or death from severe infections. Researchers found that one in ten infection-related deaths globally occurred in people with obesity, a connection that persists regardless of metabolic health, socioeconomic status, or physical activity levels.
Experts suggest that excess body fat can impair the immune system by affecting lymphatic function, reducing lung capacity, and increasing chronic low-grade inflammation. This increased susceptibility was notably highlighted during the COVID-19 pandemic, prompting further investigation into the broad impact of obesity on infection outcomes. The research, published in The Lancet, analyzed data from large UK and Finnish cohorts, using BMI and waist circumference measurements to define obesity.
The study found a dose-response relationship: the greater the degree of obesity, the higher the risk. Individuals with a BMI of 30-34.9 faced a 50% increased risk, while those with a BMI of 40 or above experienced a threefold increase in risk. Weight changes also correlated with shifts in infection risk.
While the study did not prove direct causation, evidence indicates that fat tissue and the immune system are closely intertwined. Some research suggests that certain pathogens may also contribute to the development of obesity. Experts emphasize that obesity is a chronic disease, not a matter of willpower, and its impact on immune function can affect vaccination response. Future research aims to pinpoint the exact mechanisms by which obesity increases infection risk and to identify effective reduction strategies.