Association Between Age at Diagnosis of Hyperlipidemia and Subsequent Risk of Dementia.

OBJECTIVES: The relationship between age at diagnosis of hyperlipidemia and dementia remains unclear. We examined whether younger age at diagnosis of hyperlipidemia is associated with higher risk of subsequent dementia.

DESIGN: A longitudinal population-based study with a median follow-up of 12.8 years.

SETTING AND PARTICIPANTS: We analyzed data on a sample of 489,642 participants in the United Kingdom.

METHODS: This study was based on the UK Biobank. Information on hyperlipidemia and dementia diagnoses was collected at baseline (2006-2010) and follow-up (median = 12.8 years, interquartile range [IQR]: 12.1-13.6 years). Propensity score matching method and Cox proportional hazards models were used to assess the association between age at diagnosis of hyperlipidemia and dementia.

RESULTS: Among 489,642 participants (mean age: 56.9 ± 8.1 years; female: 54.7%), 114,112 (23.3%) were diagnosed with hyperlipidemia. Younger age at diagnosis of hyperlipidemia (per 10-year decrease) was significantly associated with higher risks of all-cause dementia (hazard ratio [HR], 1.12; 95% CI, 1.07-1.18; P < .001), Alzheimer's disease (AD) (HR, 1.22; 95% CI, 1.14-1.31; P < .001), and vascular dementia (VD) (HR, 1.16; 95% CI, 1.05-1.27; P < .001). After propensity score matching, hyperlipidemia patients diagnosed before 50 years had the highest HR for all-cause dementia (HR, 1.46; 95% CI, 1.15-1.86; P = .002), followed by patients diagnosed between 50 and 69 years (HR, 1.21; 95% CI, 1.12-1.31; P < .001) and then patients diagnosed at 70 years and older (HR, 0.94; 95% CI, 0.84-1.06; P = .302). Similar results were observed for AD and VD.

CONCLUSIONS AND IMPLICATIONS: A dose-response relationship between age at hyperlipidemia diagnosis and risk of dementia was found in the longitudinal cohort study, with younger age at diagnosis of hyperlipidemia being associated with higher subsequent risk.