Abstract: Objective To investigate the interaction effect of hypertension and advanced age (≥80 years old) on the risk of cognitive impairment in the elderly. Methods Based on the Chinese Longitudinal Healthy Longevity Survey (2018), according to the Mini-Mental State Examination (MMSE), the elderly aged ≥65 years were divided into cognitive impaired group and cognitive intact group. The logistic regression model was utilized to analyze the influence of hypertension and advanced age on cognitive impairment. The multiplicative and additive models were applied to analyze the interaction effect of hypertension and advanced age. Results A total of 11 508 elderly people were included, and 2 101 cases of cognitive impairment were identified, with a prevalence rate of 18.3%. The prevalence of hypertension was 53.7% (6 183 cases). After adjusting for confounding factors by multivariate logistic regression, the results still showed that the hypertensive population (OR=1.787, 95% CI: 1.262-2.530) and the advanced age population (OR=5.472, 95% CI: 2.986-9.865) had a higher risk of cognitive impairment, and there was a multiplicative interaction between hypertension and advanced age (OR=1.520, 95% CI: 1.056-2.188)(all P<0.05). The risk of cognitive impairment in hypertensive and advanced age individuals was 4.617 times that of the non-hypertensive and non- advanced age (95% CI: 3.606-5.913), the relative excess risk of interaction (RERI) was 8.363 (95% CI: 6.438-10.288), the attributable proportion of interaction (API) was 0.667 (95% CI: 0.623-0.711), and the synergy index (SI) was 3.631 (95% CI: 2.983-4.421)(all P<0.05). Conclusion The effects of hypertension and advanced age on cognitive impairment are multiplicative and additive.

Key words: Hypertension, Advanced age, Cognitive impairment, Interaction effect