P4‐017: Dietary fat intake and rate of cognitive decline in diabetic women

Individuals with type 2 diabetes have a particularly increased risk of developing cognitive impairment, yet little is known about factors that may modify this risk. Insulin resistance and vascular complications (e.g. dyslipidemia) are common in diabetics, and elevate the risk of cognitive decline; thus, we explored whether differences in dietary fat, which modulates glucose and lipid metabolism, might affect rates of cognitive decline in older adults. Beginning in 1995 and again two years later, we assessed cognitive function in 1,486 Nurses' Health Study participants, aged 70+ years, with type 2 diabetes. Fat intake was assessed regularly beginning in 1980, and cumulatively averaged from 1980 through initial cognitive interview. We used multivariate-adjusted, linear regression models to obtain mean differences in cognitive decline over two years across tertiles of fat intake. Higher intakes of saturated and trans fat, and a lower polyunsaturated to saturated fat ratio, were each highly associated with worse rates of cognitive decline. For example, on a global score combining results of all six cognitive tests, mean decline among women in the highest trans fat tertile was 0.15 standard units worse compared to those in the lowest tertile (95 percent confidence interval, -0.24, -0.06, p=0.002); this mean difference was comparable to the difference we find in women seven years apart in age. These findings suggest that lower intake of saturated and trans fat and higher intake of polyunsaturated relative to saturated fat may reduce rates of cognitive decline in those with type 2 diabetes.