Doctors studying the 2009 H1N1 flu pandemic have come up with a new concern for people who are overweight. Statistics show that extreme obesity was a key factor in dying as a result of the H1N1 flu virus. In a study to be published in the February 1, 2011 issue of Clinical Infectious Diseases, researchers reported that people who were extremely obese had a three-times greater chance of dying from the 2009 flu. They also report that half of all adults over the age of 20 who had to be hospitalized because of the 2009 H1N1 flu were obese.
Doctors determine obesity based on the body mass index (BMI). BMI is calculated using a person’s weight and height. The number provides an indicator of fatness for adults and is used as a screening tool when considering health conditions that are affected by weight. The general categories for BMI are:
• Below 18.5 - Underweight
• 18.5 – 24.9 – Normal
• 25.0-29.9 – Overweight
• 30.0 and higher – Obese
For purposes of the H1N1 study, people with a BMI of 40.0 or higher were considered to be extremely obese. The study looked at data collected between April 20 and August 11, 2009. During that time, 50 percent (one-half) of all influenza cases in patients over age 20 were caused by the H1N1 virus. Patients under 20 and women who were pregnant were not included in the study.
The researchers concluded that extremely obese people with a BMI of 40 or higher are at much greater risk if they catch the H1N1 flu virus. They recommend that all extremely obese people get a flu shot every year. They also recommend that those who are extremely obese should see a health care provider promptly if flu symptoms develop so they can be treated as quickly as possible. This is particularly important if the flu is known to be active in the area.
The National Heart Lung and Blood Institute has a simple BMI calculator available online. Just enter your height and weight to find out your Body Mass Index.