Three Unexpected Risk Factors for Pneumonia Identified

A new large-scale genetic study, published in The Lancet, has shown that the risk of developing pneumonia is influenced not only by lifestyle habits such as smoking and obesity, but also by specific genes, highlighting a combination of hereditary and behavioral factors that significantly increase an individual’s vulnerability to this serious infection.

Researchers at the University of Oulu (Finland) analyzed genetic and medical data from over 600,000 people in Finland and Estonia to determine which factors increase the likelihood of pneumonia—a lung inflammation that remains a leading cause of hospitalizations and mortality worldwide.

The team identified 12 regions in the genome associated with increased pneumonia risk, eight of which were discovered for the first time. Many of these genes are involved in regulating inflammatory processes, a key mechanism the body uses to fight infections.

In addition to genetic predisposition, the researchers confirmed that smoking and a high body mass index (obesity) independently increase pneumonia risk. Importantly, the study provides evidence that these associations may be causal—meaning that smoking and obesity directly contribute to higher susceptibility, rather than merely correlating with it.

For patients with recurrent pneumonia and for older adults, genes related to nicotine dependence were particularly significant, underscoring how strongly smoking can disrupt the protective mechanisms of the respiratory system.

Pneumonia can be caused by bacteria, viruses, or fungi, and its severity ranges from mild to life-threatening. In Finland, approximately 50,000 people develop pneumonia each year, about half of whom require hospitalization.

The authors note that understanding hereditary risk factors could not only help explain why some people fall ill more frequently but also inform the development of future prevention and treatment strategies targeting specific genetic mechanisms.

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