Akbaraly TN, et al. - In this prospective cohort study involving 8,225 participants without dementia, researchers ascertained if midlife (mean age: 50 years) diet is correlated with subsequent dementia risk. According to findings, the quality of the diet evaluated during midlife was not significantly related to subsequent dementia risk.

Methods

• This was a population-based cohort study established in 1985-1988 in which researchers assessed dietary intake in 1991-1993, 1997-1999, and 2002-2004, and followed-up for incident dementia until March 31, 2017.
• Diet quality during midlife was assessed using the Alternate Healthy Eating Index (AHEI; diet quality score (score range, 0-110), with higher scores indicating a healthier diet.
• The main outcome assessed was incident dementia, which was determined by electronic health records linkage.

Results

• A total of 344 reports of incident dementia were recorded during a median follow-up of 24.8 years.
• During 1991-1993, 1997-1999 (median follow-up, 19.1 years), and 2002-2004 (median follow-up, 13.5 years), no significant difference in the incidence rate for dementia was observed in tertiles of AHEI exposure.
• Compared with a dementia incidence rate of 1.76 (95% CI: 1.47 to 2.12) per 1,000 person-years in the worst tertile of AHEI (lowest tertile of diet quality) in 1991-1993, the absolute rate difference for the intermediate tertile was 0.03 (95% CI: −0.43 to 0.49) per 1,000 person-years and 0.04 (95% CI: −0.42 to 0.51) per 1,000 person-years for the best tertile.
• Compared with the worst AHEI tertile in 1997-1999 (incidence rate for dementia, 2.06 [95% CI: 1.62 to 2.61] per 1,000 person-years), the absolute rate difference for the intermediate AHEI tertile was 0.14 (95% CI: −0.58 to 0.86) per 1,000 person-years and 0.14 (95% CI: −0.58 to 0.85) per 1,000 person-years for the best AHEI tertile.
• Compared with the worst AHEI tertile in 2002-2004 (incidence rate for dementia, 3.12 [95% CI: 2.49 to 3.92] per 1,000 person-years), the absolute rate difference for the intermediate AHEI tertile was −0.61 (95% CI: −1.56 to 0.33) per 1,000 person-years and −0.73 (95% CI: −1.67 to 0.22) per 1,000 person-years for the best AHEI tertile.
• The adjusted hazard ratios (HRs) for dementia per 1-SD (10-point) increase in AHEI were not significant in the multivariable analysis as assessed in 1991-1993 (adjusted HR: 0.97 [95% CI: 0.87 to 1.08]), 1997-1999 (adjusted HR: 0.97 [95% CI: 0.83 to 1.12]), or 2002-2004 (adjusted HR: 0.87 [95% CI: 0.75 to 1.00]), respectively.