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AlzRisk Paper Detail
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Reference: Olsson, 2015
Cohort: Uppsala Longitudinal Study of Adult Men
Risk Factor: Dietary Pattern


Exposure Detail
Dietary intake was recorded using a seven day food diary. A computerized program was used to calculate daily energy intake, nutrient intake, and food groups. Three different diet scores were used: the Healthy Diet Indicator (HDI), the modified Mediterranean Diet Score (mMDS), and the Low-Carbohydrate High-Protein Score (LCHP).

"Dietary variables were adjusted for energy intake either by the residual method [26] or as nutrient density (divided by energy intake), depending on the nature of components included in each diet score. Variables in g/day are adjusted by the residual method and those in energy percent or g/MJ are nutrient densities."

The HDI was based on dietary guidelines from the World Health Organization which were then modified according to the Swedish Nutrition Recommendations as described by Sjogren et al. The HDI comprises nine categories of food items and macronutrients, with 1 point assigned to a participant if intake for that category falls within a pre-defined desirable range. Zero points are assigned for the category if the intake does not fall within the desired range, except for sucrose, where a -1 is assigned. Therefore, the total score ranges from 0 to 8, with higher scores representing a healthier dietary pattern.

The mMDS was a version of the traditional Mediterranean diet modified to accommodate food items commonly consumed in Sweden. The score consists of nine categories: eight for food items and one category for the ratio of polyunsaturated to saturated fatty acid intake. For food categories considered to be beneficial, participants were assigned 1 point if intake was above the population median. For food categories considered harmful, 1 point was assigned if intake was below the median intake for the population. For alcohol intake, 1 point was assigned for optimal intake defined as 10-50 grams per day, and an aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio below 2, in order to exclude heavy drinkers. The total score ranges from 0 to 8, with higher scores representing stronger adherence to the modified Mediterranean diet.

For the LCHP score, participants' carbohydrate and protein intake was first classified into deciles. Decreases in carbohydrate intake corresponded to lower scores, with intake in the lowest decile representing 10 points and intake in the highest decile representing 1 point. Likewise, increases in protein intake corresponded to higher scores, resulting in a total range between 2 and 20, with higher scores representing stronger adherence to the LCHP diet.

Ethnicity Detail
No information on race/ethinicty is provided. All participants were residents in the municipality of Uppsala, Sweden.

Screening and Diagnosis Detail
AD Diagnosis:
DSM IV Diagnostic and Statistical Manual IV
NINCDS ADRDA National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association Criteria (McKhann 1984)

Total dementia definition: Dementia via DSM-IV.

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

AD Covariates:
Eeducation
APOE4APOE e4 genotype
Kcalcaloric intake
LSLiving situation
PAphysical activity
SMsmoking status

TD Covariates:
Eeducation
APOE4APOE e4 genotype
Kcalcaloric intake
LSLiving situation
PAphysical activity
SMsmoking status