Study supports ’obesity paradox’

Medical researchers at the University of Alberta studied the records of nearly 1,000 patients admitted to hospital with pneumonia and found that those who were obese had a higher likelihood of surviving than who were of normal weight.

For their 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 underweight, 36 were of normal weight, 21 were overweight and 10 were obese. Compared with those of normal weight, obese patients had lower in-hospital mortality rates due to pneumonia. 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 study was led by Faculty of Medicine & Dentistry researcher Sharry Kahlon, who works in the Department of Medicine and is a resident in internal medicine.

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, infections like pneumonia, and death.

“The thinking usually is that obesity equals bad, but 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 only a handful of studies to demonstrate the link with acute medical conditions. She notes that obese patients in the study 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 said. “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.

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