We appreciate Dr Grant's comments on our research findings that link being overweight with AD. While dietary fat intake, as well as total energy intake, is related to overweight and obesity in adults and perhaps to AD as Dr Grant mentions, we cannot make conclusions from our data about the role of these or other dietary factors in AD, since dietary data are not available in this cohort. However, irrespective of dietary habits, the independent effect of excess adipose tissue, as inferred by a high body mass index (BMI), on age-related dementia processes in the brain has high physiological relevance. Excess adipose tissue is a central feature in the metabolic syndrome, which is characterized by insulin resistance, high blood pressure, elevated blood glucose levels, dyslipidemia, and upper body fat distribution.1 While some have evaluated the role of the metabolic syndrome in relationship to AD,2 our analyses show that with consideration of all components of the metabolic syndrome (except for upper body fat distribution, which we have not measured), BMI is strongly and independently related to AD. In addition, adipose tissue secretes a variety of steroid hormones3 and proinflammatory cytokines4 that may be involved in the etiology of AD.
Gustafson D, Skoog I. Obesity and Alzheimer Disease: Roles of Diet and Genetics—Reply. Arch Intern Med. 2004;164(1):109-110. doi:10.1001/archinte.164.1.110