THE ASSOCIATION OF HABITUAL MILK INTAKE WITH THE RATE OF COGNITIVE DECLINE, AND RISK OF MILD COGNITIVE IMPAIRMENT AND DEMENTIA. Public Deposited

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  • March 20, 2019
Creator
  • Petruski-Ivleva, Natalia
    • Affiliation: Gillings School of Global Public Health, Department of Epidemiology
Abstract
  • Greater than average rates of cognitive decline in the elderly are likely to result in earlier onset of mild cognitive impairment and dementia. D-galactose, a derivative of lactose, is used in animal studies to mimic naturally occurring aging and neurodegeneration through increased oxidative stress. Milk is the primary source of lactose in the diet and its effects on oxidative stress levels or the rate of cognitive decline have not been fully evaluated. Thus, the objective of this work was to study the association of milk intake with cognitive change over a 20-year period. We further examined the association of milk intake with oxidative stress, defined as levels of mitochondrial DNA copy number. Analyses accounted for participants’ genetic predisposition to lactose intolerance, or lactase non-persistence, which determines the metabolic pathways through which lactose is metabolized. We used data from a large biracial cohort of men and women, who completed dietary assessment at midlife and had multiple assessments of cognitive function in three cognitive domains: processing speed, executive function, and language. Our results suggest that milk intake at midlife in amounts greater than 1 glass/day may result in faster rate of cognitive decline over the subsequent 20-year period than that observed for participants reporting “Almost never” consuming milk. In our study population, that difference in decline was equivalent to a 10% additional decline. No effect modification of this association was observed by race. A significant association with a mitochondrial DNA copy number was observed among Black participants, but not among Whites. Milk intake was inversely proportional to mitochondrial DNA copy number, suggesting higher levels of oxidative stress among milk drinkers. Due to the small number of participants classified as lactase non-persistent we were not able to capture difference in the effect of milk on cognitive change or oxidative stress by lactase persistence genotype. Given that billions of people around the world consume milk daily, further studies are needed to evaluate the association of milk intake with oxidative stress and health outcomes in diverse populations and patterns of milk intake. Genetic variation in lactose metabolism should be considered to avoid potential confounding.
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  • In Copyright
Advisor
  • Heiss, Gerardo
  • Kucharska-Newton, Anna
  • Graff, Misa
  • Couper, David
  • Meyer, Katie
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2017
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