A Follow-up Study on the Trajectory and Sex Differences of Different Cognitive Dimensions in the Normal Aging Elderly in Guangzhou

OBJECTIVE: To explore trajectory and sex differences of varied cognitive dimensions over time in the normal aging elderly. METHODS: The cluster sampling method was used to select a representative community (n = 341). Individuals aged 60 years and above with normal cognitive function were identified (n = 281). One-to-one neuropsychological tests were conducted at baseline and repeated 1 and 5 years later. A mixed linear model was developed to analyze the changes and sex discrepancies in different cognitive dimensions of the elderly based on the scores of the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and World Health Organization Battery of Cognitive Assessment Instruments for the elderly (WHO-BCAI). RESULTS: When comparing the 1-year follow-up with baseline data, the scores of auditory vocabulary in both men and women had significantly increased (t = -2.52, t = -4.8, p < 0.05), while the Wechsler mapping in women had significantly increased (t = -2.62, p < 0.05). When comparing the 5-year follow-up with baseline data, MMSE (t = 6.38, t = 6.06, p < 0.05) and MoCA (t = 7.34, t = 7.03, p < 0.05) scores had significantly decreased in both groups, the digit span scores had significantly decreased in men (t = 2.67, p < 0.05), and the scores of auditory vocabulary in women had significantly increased (t = -2.54, p < 0.05). When comparing the 5-year follow-up with the 1-year follow-up data, the digit span scores in women had significantly decreased (t = 2.88, p < 0.05), and the Wechsler mapping scores in both groups had significantly decreased (t = 3.68, t = 3.14, p < 0.05). A sex discrepancy emerged in several tests of specific cognitive domains after adjusting for education. At baseline, women outperformed men in auditory vocabulary, associative learning, and delayed recall while men outperformed women in Wechsler mapping. Importantly, auditory vocabulary and Wechsler mapping were better in women and men, respectively, at all visit times. The superiority of associative learning and delayed recall of women shrunk with advancing age. CONCLUSIONS: Sex differences in cognitive variation indicated a steeper decline for women in verbal episodic memory, associative memory, and short-term memory. Meanwhile, a sharper deterioration in memory, comprehension and recognition of spatial relationships, and visual structure ability was observed in men. The sex differences in different cognitive dimensions diminished over time.