Medical researchers at the University of Alberta studied the records of nearly 1000 patients who were admitted to hospital with pneumonia and noted those who were obese were more apt to survive compared to those who were of normal weight.

For their research study, the team examined the records of 907 patients with pneumonia who were admitted to six Edmonton hospitals and also had their body mass index recorded. Two-thirds of the patients had severe pneumonia and 79 died in hospital. Of those who died, 12 were under weight, 36 were normal weight, 21 were overweight and 10 were obese. Compared to those who were normal weight, obese patients had lower in-hospital mortality rates due to pneumonia, says the study, which was led by Faculty of Medicine & Dentistry researcher Sharry Kahlon, who works in the Department of Medicine and is a resident in internal medicine. Mortality was 10 per cent for those who were normal weight and 4 per cent for those who were obese. This translates into a 54 per cent reduction in mortality associated with being obese.

The results of the study were recently published in the peer-reviewed journal Clinical Microbiology and Infection.

Kahlon says the research supports the 'obesity paradox' -- that in some circumstances being obese may be better for your health, even though obesity is associated with an increased risk of diabetes, hypertension, death and catching infections like pneumonia.

"The thinking usually is obesity equals bad and this research demonstrated something different. It shows that perhaps we're not looking at obesity in the right way. Is all fat bad? Is all fat equal? For acute illnesses, maybe we're not looking at the right indicators for body mass index and obesity."

Kahlon says previous studies have demonstrated the 'obesity paradox' in relation to chronic diseases, but this is one of a handful of studies to demonstrate the link with acute medical conditions. In the study, she notes obese patients may have had better survival rates because they had more nutritional reserves.

"It might be a misregulation of the inflammatory system that allows these individuals to do better," she says. "These mechanisms still need to be better studied."

She noted physicians may need to adjust prescriptions or care for obese patients hospitalized with pneumonia -- to better meet their medical needs.

Former Faculty of Medicine & Dentistry Dean Tom Marrie was part of the research team and found the patients to take part in the study.

The research was funded by the Canadian Institutes of Health Research, Alberta Innovates -- Health Solutions and Alberta Health Services.