In a study that followed more than 10,000 Californians for almost 30 years, researchers found that the fatter people were, the greater their risk for Alzheimer's disease or other forms of dementia. The results were published online Friday by the British Medical Journal.
"This adds another major reason for concern about the obesity problem and it now unfolds yet another area where ... we have to say, 'for God's sake, we better get cracking,"' said Philip James, an obesity expert who was not connected with the research and who heads the International Obesity Task Force.
The study data showed that roughly 7 out of 100 normal-weight people developed dementia. Among overweight people, the risk was almost 8 out of 100; and for obese people, it was 9 out of 100.
This latest research comes amid questioning and confusion in the United States over the dangers of being overweight. Last week, the U.S. Centers for Disease Control said a new analysis showed that being too fat caused far fewer deaths than previous government estimates. The announcement led to attacks by critics and restaurant-funded groups who say the threat of fat has been hyped by the U.S. officials.
Funded by the U.S. National Institutes of Health, the California study was conducted by the Kaiser Permanente Medical Foundation. The project followed 10,276 people, in their early to mid-40s, for an average of 27 years. They had detailed health checkups from the mid-1960s to early 1970s.
Between 1994 and 2003, dementia was diagnosed in 713, or about 7 percent, of the study volunteers. The scientists examined links between dementia and obesity using two different measurements - body-mass index and the thickness of skin folds under the shoulder blades and under the arm.
Adjusting for conditions such as diabetes, heart disease and other factors, the study found a higher risk of dementia for heavy people. Using the body-mass index, which measures height and weight to classify how fat people are, obese people were 74 percent more likely to develop mind-robbing dementia than normal weight people. Overweight people were 35 percent more likely to develop it.