Study: Obesity may prolong life in oldest old

Despite being one of the leading preventable causes of death worldwide, obesity may actually decrease mortality in a specific age group: seniors 85 and up.

According to researchers at Tel Aviv University, excess fat seems to have a "protective" effect on the oldest old, reducing the risk of death when compared to those who are considered a normal body weight. The research was recently published in the Journal of Aging Research.

Researchers argue that some of the factors that typically affect mortality in younger people may no longer be significant in obese elders. Heavier people have lower rates of osteoporosis, which could decrease incidences of falls and subsequent injury, researchers argued. Obesity could also provide excess energy storage in times of trauma or stress, or prolong the period of weight loss caused by a decrease in appetite.

The study was based on data collected as part of the Cross Sectional and Longitudinal Aging Study, which included 1,349 people between the ages of 75-94. Participants were asked basic questions about their height and weight, age, gender, family, education, socioeconomic status and smoking history.

Two decades after the data was first collected, the researchers completed a mortality analysis on the original sample. During the course of these 20 years, 95 percent of the participants had died, leaving 59 subjects still living.

Obesity continued to be a predictor of death for those aged 75-84, researchers said. But past the age of 85, participants who were in the obese category were not only at lower risk of death than their underweight peers, but also appeared to be less at risk than those who had a normal weight as well.

Researchers pointed out that while obesity may decrease the risk of mortality, quality of life is another matter.

"Though obese people over the age of 85 may be less at risk of death, they may suffer more from obesity-related illnesses. There are other factors to consider, such as pain, multiple ailments and mobility," researchers said.