Dataset Information

Association of parathyroid hormone with 20-year cognitive decline: The ARIC study.

ABSTRACT:

Objective

We hypothesized that elevated parathyroid hormone (PTH) levels will be independently associated with 20-year cognitive decline in a large population-based cohort.

Methods

We studied 12,964 middle-aged white and black ARIC participants without a history of prior stroke who, in 1990-1992 (baseline), had serum PTH levels measured and cognitive function testing, with repeat cognitive testing performed at up to 2 follow-up visits. Cognitive testing included the Delayed Word Recall, the Digit Symbol Substitution, and the Word Fluency tests, which were summed as a global Z score. Using mixed-effects models, we compared the relative decline in individual and global cognitive scores between each of the top 3 quartiles of PTH levels to the reference bottom quartile. We adjusted for demographic variables, education, vascular risk factors, and levels of calcium, phosphate, and vitamin D. We imputed missing covariate and follow-up cognitive data to account for attrition.

Results

The mean (SD) age of our cohort was 57 (6) years, 57% were women, and 24% were black. There was no cross-sectional association of elevated PTH with cognitive global Z score at baseline (p > 0.05). Over a median of 20.7 years, participants in each PTH quartile showed a decline in cognitive function. However, there was no significant difference in cognitive decline between each of the top 3 quartiles and the lowest reference quartile (p > 0.05). In a subset, there was also no association of higher mid-life PTH levels with late-life prevalent adjudicated dementia (p > 0.05).

Conclusions

Our work does not support an independent influence of PTH on cognitive decline in this population-based cohort study.

SUBMITTER: Kim SM

PROVIDER: S-EPMC5577963 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background:Smaller (<3-mm) infarctions are associated with stroke and stroke mortality, but relationships with cognitive decline are unknown. Objective:To characterize the relationships of smaller, larger, and both smaller and larger infarctions in middle age with 20-year cognitive decline. Design:Longitudinal cohort study. Setting:Two ARIC (Atherosclerosis Risk in Communities) study sites with magnetic resonance imaging data (1993 to 1995) and up to 5 cognitive assessments over 20 years. Participants:Stroke-free participants aged 50 years or older. Measurements:Infarctions were categorized as none, smaller only, larger only (3 to 20 mm), or both smaller and larger. Global cognitive Z scores were derived from 3 cognitive tests administered up to 5 times. Mixed-effects models estimated adjusted associations between infarctions and cognitive decline. Results are the average difference in standardized cognitive decline associated with infarctions versus no infarctions. Results:Among 1884 participants (mean age, 62 years; 60% women; 50% black), 1611 (86%) had no infarctions, 50 (3%) had smaller infarctions only, 185 (10%) had larger infarctions only, and 35 (2%) had both. Participants with both smaller and larger infarctions had steeper cognitive decline by more than half an SD (difference, -0.57 SD [95% CI, -0.89 to -0.26 SD]) compared with those who had no infarctions. Amounts of cognitive decline associated with only smaller infarctions and only larger infarctions were similar and were not statistically different from that associated with no infarctions. Limitation:Few participants had only smaller infarctions or both smaller and larger infarctions, and the data lacked counts of smaller infarctions and volumes of white matter hyperintensities. Conclusion:The substantial cognitive decline from middle age associated with having both smaller and larger infarctions, but not larger infarctions alone, suggests that the combination of smaller and larger infarctions may escalate risk for cognitive decline later in life in stroke-free persons. Primary Funding Source:National Institutes of Health.