Results

The study included 100 non-stroke adults from the general Egyptian population (median age 64 years, IQR 62–68; 58% male). Baseline characteristics of the overall study population are presented in Table 1. Based on MoCA screening, 61 participants (61%) were classified as possible MCI (MoCA ≤ 25), while 39 (39%) had normal cognitive screening (MoCA 26–30) (Table 2). Higher education (> 9 years) was more frequent in cognitively normal participants (69.2% vs. 29.5%, p < 0.001). Increased CCA IMT (≥ 1 mm) was present in 65 participants (65%), and carotid plaques were detected in 53 (53%). Significant ICA stenosis (≥ 50%) was observed in two participants (2%), both on the right side, one of them received carotid artery stenting. Plaques were most frequently located at the carotid bifurcation (32% right, 30% left), followed by the ICA, CCA, and ECA. Participants with possible MCI had a higher total plaque score than cognitively normal participants (median 1.0 [IQR 0.0–2.0] vs. 0.0 [IQR 0.0–1.5], p = 0.04; Fig. 1). Participantswith possible MCI had a higher median ICA RI (0.63 [IQR 0.57–0.71]) compared with cognitively normal participants (0.59 [IQR 0.53–0.62], p = 0.01). Age correlated positively with plaque score (Spearman ρ = 0.220, p = 0.03). Participants with plaques were older than those without plaques (median 66.0 vs. 64.0 years, p = 0.04). Age correlated inversely with global MoCA score (ρ=−0.297, p = 0.003) and with visuospatial, attention, recall, and orientation domains (Table 3). Plaque score correlated inversely with visuospatial (ρ=−0.26, p = 0.009) and language performance [Sentence repetition and verbal fluency] (ρ=−0.30, p = 0.003), but not with global MoCA score (ρ=−0.127, p = 0.210; Fig. 2). The association between carotid plaque presence and possible MCI did not reach statistical significance (χ²=3.68, p = 0.055; OR 2.22, 95% CI 0.98–5.03).Educational attainment showed strong associations with cognition. Median global MoCA scores increased across education levels (24, 25, and 26 for low, intermediate, and high education, respectively; p < 0.001). Lower education was associated with poorer visuospatial and attention performance (both p < 0.001) and lower abstraction scores (p = 0.046). Univariate logistic regression was performed including age, sex, hypertension, diabetes mellitus, educational attainment, plaque score, and ICA RI . Three variables were significantly associated with possible MCI. Low educational attainment showed the strongest association, with 5.4-fold higher odds of possible MCI compared to high education (OR = 5.38, 95% CI 2.24–12.89, p < 0.001). Carotid plaque score was also significantly associated, with each unit increase associated with 32.4% increased odds of possible MCI (OR = 1.32, 95% CI 1.02–1.72, p = 0.04). ICA RI also demonstrated a univariate significant association, with each 0.1-unit increase associated with 86.3% increased odds of possible MCI (OR = 1.863, 95% CI 1.11–3.14, p = 0.02). Sex, age, hypertension, and diabetes were not significant.Two multivariable logistic regression models were constructed. Variables with p < 0.10 in univariate analysis were considered for inclusion, while age and sex were retained in both models because of their clinical relevance. Plaque score and ICA RI were modeled separately because they represent related structural and hemodynamic carotid measures. In model 1 (Table 4), plaque score (OR 1.41, 95% CI 1.06–1.86, p = 0.02) and lower educational attainment (OR 6.26, 95% CI 2.30–17.02, p < 0.001) remained independently associated with possible MCI (Fig. 3). In Model 2, ICA RI (OR 1.87, 95% CI 1.01–3.46, p = 0.046) and lower educational attainment (OR 5.54, 95% CI 2.08–14.81, p = 0.001) remained significant.

Baseline characteristics
Male sex n (%) | 58 (58%)
Education n (%)
Low | 55 (55%)
Intermediate | 14 (14%)
High | 31(31%)
Age (years)
Min. – Max. | 60.0–78.0
Median (IQR) | 64.0 (62.0–68.0)
Obesity n (%) | 37 (37%)
BMI (kg/m2) n (%)
Normal weight (< 25) | 32 (32%)
Overweight (25–29) | 31 (31%)
Obese (≥ 30) | 37 (37%)
Median (IQR) | 27.0 (24.0–31.0)
Hypertension n (%) | 52 (52%)
Diabetes mellitus n (%) | 26 (26%)
Ischemic heart disease n (%) | 29 (29%)
Smoking n (%)
Non smoker | 73 (73%)
Ex-smoker | 13 (13%)
Smoker | 14 (14%)
Plaque score [median (IQR)] | 0.50 (0.0–2.0)
Increased CCA IMT n (%) | 65 (65.0%)
Atherosclerotic plaque presence n (%) | 53 (53.0%)
MOCA [Median (IQR)] | 25.0 (23.0–26.0)
Possible MCI group n (%) | 61 (61.0%)

Baseline characteristics | No Possible MCI (n = 39) | Possible MCI (n = 61) | p
Male sex n (%) | 25 (64.1%) | 33 (54.1%) | 0.323
Education n (%)
Low | 12 (30.8%) | 43 (70.5%) | < 0.001*
Intermediate | 3 (7.7%) | 11 (18.0%)
High | 24 (61.5%) | 7 (11.5%)
Age (years)
Min.–Max. | 60.0–78.0 | 60.0–75.0 | 0.070
Median (IQR) | 63.0 (61.0–65.5) | 65.0 (62.0–70.0)
BMI (kg/m2)
Median (IQR) | 27.0 (24.0–31.0) | 27.0 (24.0–31.0) | 0.611
Hypertension n (%) | 17 (43.6%) | 35 (57.4%) | 0.178
Diabetes mellitus n (%) | 8 (20.5%) | 18 (29.5%) | 0.317
Smoking n (%)
Non-smoker | 30 (76.9%) | 43 (70.5%) | 0.753
Ex-smoker | 4 (10.3%) | 9 (14.8%)
Smoker | 5 (12.8%) | 9 (14.8%)
Plaque score [median (IQR)] | 0.0 (0.0–1.50) | 1.0 (0.0–2.0) | 0.035*
ICA resistive index [median (IQR)] | 0.59 (0.53–0.62) | 0.63 (0.57–0.71) | 0.011*

Fig. 1: Relation between possible mild cognitive impairment (MoCA ≤ 25) (MCI) with Carotid Plaque Score (n = 100).

 | Age (years)
r s | p
Plaque score | 0.220* | 0.028*
MOCA | − 0.297* | 0.003*
Visuospatial | − 0.248* | 0.013*
Attention | − 0.223* | 0.026*
Language | − 0.188 | 0.062
Abstraction | 0.037 | 0.716
Recall | − 0.270* | 0.007*
Orientation | − 0.268* | 0.007*

Fig. 2: Correlation between Carotid Plaque Score with MOCA (n = 100).

 | Model #1 | Model #2
P | OR (LL – UL 95% C.I) | p | OR (LL – UL 95% C.I)
Sex [male] | 0.91 | 0.94 (0.35–2.57) | 0.79 | 1.15 (0.42–3.14)
Education [low (≤ 9 years)] | < 0.001 * | 6.26 (2.30–17.02) | 0.001 * | 5.54 (2.08–14.81)
Age (years) | 0.70 | 1.02 (0.92–1.14) | 0.86 | 1.01 (0.90–1.13)
Plaque score | 0.02 * | 1.41 (1.06–1.86) |  | 
ICA resistive index |  |  | 0.046 * | 1.87 (1.01–3.46)
Hosmer and Lemeshow test | χ2 = 7.49, p = 0.49 | χ2 = 4.17, p = 0.84

Fig. 3: Model 1#Multivariate logistic regression analysis for baseline characteristics affecting possible mild cognitive impairment (MoCA ≤ 25) CI (no. of CI = 61 vs. no. of No CI = 39).