The allele of the apolipoprotein E gene (APOE), recently determined to be a risk factor for developing Alzheimer’s disease, may also be a clue to the unexplained weight loss inherent in Alzheimer’s disease, primarily in women.
Study Makes the Connection
Researchers studied an association between APOE allele and weight loss in nearly a thousand patients, of which 46 had Alzheimer’s disease. They looked at weight loss and other health risk factors at baseline and during a follow-up study 3.5 years later.
On average, Alzheimer’s disease patients with the APOE allele lost, whereas those without it gained weight. Clinically significant weight loss, considered more than 5 percent loss of weight, occurred remarkably more often in Alzheimer’s disease patients, and to a lesser extent in control subjects who were carrying the APOE gene. When women and men were analyzed separately, weight loss was observed only in the women with Alzheimer’s and who were carriers of the APOE allele.
Among the controls – those not diagnosed with Alzheimer’s but who carried the APOE allele — a lesser degree of weight loss or change in body mass index (BMI) was found in both women and men.
Conclusions of Study’s Author
Matti Vanhanen, MD, a neuropsychologist with the Kuopio University Hospital in Kuopio, Finland, where the study was conducted, said: “Our study demonstrated that APOE allele is associated with weight loss, especially in women with Alzheimer’s disease. Furthermore, both patients and controls with the allele experienced more often clinically significant weight loss than the non-carriers during the 3.5 year follow-up period.”
Causes of Weight Loss in Alzheimer’s
Weight loss in Alzheimer’s disease could be caused by inadequate energy intake or by abnormally high energy expenditure, or both.
Recently, APOE allele has been associated with impaired sense of smell, which could cause a decrease in appetite, and cause weight loss. The exact reasons for weight loss, however, remain to be proven, said Vanhanen.