Hypothyroidism and risk of mild cognitive impairment in elderly persons a population-based study

IMPORTANCE: An association of clinical and subclinical hypothyroidism with mild cognitive impairment (MCI) has not been established. OBJECTIVE: To evaluate the association of clinical and subclinical hypothyroidism with MCI in a large population-based cohort. DESIGN, SETTING, AND PARTICIPANTS: A randomized, cross-sectional, population-based cohort study was conducted in Olmsted County, Minnesota. Participants were aged 70 to 89 years on October 1, 2004, and were without documented prevalent dementia. A total of 2050 participants were evaluated and underwent in-person interview, neurologic evaluation, and neuropsychological testing to assess performance in memory, attention/executive function, and visuospatial and language domains. Participants were categorized by consensus as being cognitively normal, having MCI, or having dementia according to published criteria. Clinical and subclinical hypothyroidism were ascertained from a medical records linkage system. MAINOUTCOMESAND MEASURES: Association of clinical and subclinical hypothyroidism with MCI. RESULTS: Among 1904 eligible participants, the frequency of MCI was 16% in 1450 individuals with normal thyroid function, 17% in 313 persons with clinical hypothyroidism, and 18% in 141 individuals with subclinical hypothyroidism. After adjusting for covariates (age, educational level, sex, apolipoprotein E e4, depression, diabetes mellitus, hypertension, stroke, body mass index, and coronary artery disease) we found no significant association between clinical or subclinical hypothyroidism and MCI (odds ratio [OR], 0.99 [95% CI, 0.66-1.48] and 0.88 [0.38-2.03], respectively). No effect of sex interaction was seen on these effects. In stratified analysis, the odds of MCI with clinical and subclinical hypothyroidism among men was 1.02 (95% CI, 0.57-1.82) and 1.29 (0.68-2.44) and, among women, was 1.04 (0.66-1.66) and 0.86 (0.37-2.02), respectively. CONCLUSIONS AND RELEVANCE: In this population-based cohort of elderly people, neither clinical nor subclinical hypothyroidism was associated with MCI. Our findings need to be validated in a separate setting using the published criteria for MCI and confirmed in a longitudinal study. © Copyright 2014 American Medical Association. All rights reserved

Chronic obstructive pulmonary disease and association with mild cognitive impairment: The Mayo Clinic Study of Aging

Objective: To investigate the association of chronic obstructive pulmonary disease (COPD) with mild cognitive impairment (MCI) and MCI subtype: amnestic MCI and nonamnestic MCI, in a populationbased study of elderly patients. Patients and Methods: Participants included 1927 individuals aged 70 to 89 years enrolled in the population-based Mayo Clinic Study of Aging. Participants were evaluated by using a nurse assessment, neurological evaluation, and neuropsychological testing, and the diagnosis of MCI was made by a consensus panel according to the standardized criteria. Chronic obstructive pulmonary disease was identified by the review of medical records. The study was conducted from October 1, 2004, through July 31, 2007. The associations of COPD and disease duration with MCI and its subtypes were evaluated by using logistic regression models adjusted for potential covariates. Results: Of 1927 participants, 288 had COPD (men vs women: 18% vs 12%; P\u3c.001). As compared with patients without COPD, patients with COPD had a higher prevalence of MCI (27% vs 15%; P\u3c.001). The odds ratio (OR) for MCI was almost 2 times higher in patients with COPD than in those without (OR, 1.87; 95% CI, 1.34-2.61), with a similar effect in men and women. The OR for MCI increased from 1.60 (95% CI, 0.97-2.57) in patients with a COPD duration of 5 years or less to 2.10 (95% CI, 1.38-3.14) in patients with a COPD duration of more than 5 years. Conclusion: This population-based study suggests that COPD is associated with increased odds of having MCI and its subtypes. There was a dose-response relationship with the duration of COPD after controlling for the potential covariates. © 2013 Mayo Foundation for Medical Education and Research

A prospective study of chronic obstructive pulmonary disease and the risk for mild cognitive impairment

IMPORTANCE Previous studies suggest cross-sectional associations between a diagnosis of chronic obstructive pulmonary disease (COPD) and mild cognitive impairment (MCI). However, few studies have assessed whether COPD, a potentially modifiable factor, is associated with an increased risk for MCI and whether the relation is specific to the type of MCI. OBJECTIVE To investigate whether a diagnosis of COPD and duration of COPD are associated with an increased risk for incident MCI and MCI subtypes (amnestic MCI [A-MCI] and nonamnestic MCI [NA-MCI]). DESIGN, SETTING, AND PARTICIPANTS A prospective population-based cohort from the Mayo Clinic Study on Aging.We included 1425 cognitively normal individuals aged 70 to 89 years who were randomly selected from Olmsted County, Minnesota, on October 1, 2004, using the medical records linkage system. At baseline and every 15 months thereafter, participants underwent assessment with a nurse interview, neurologic examination, and neuropsychological testing. A diagnosis of COPD was confirmed via medical record review. A baseline diagnosis of COPD and duration of COPD were examined as risk factors for MCI and MCI subtypes using Cox proportional hazards models and adjusting for demographic variables and medical comorbidities, with age as the time scale. EXPOSURE A baseline diagnosis of COPD and duration of COPD. MAIN OUTCOMES AND MEASURES Incident MCI, A-MCI, and NA-MCI. RESULTS Of the 1425 participants with normal cognition at baseline, 370 developed incident MCI. The median duration of follow-up was 5.1 years (interquartile range, 3.8-5.4 years). A diagnosis of COPD significantly increased the risk for NA-MCI by 83%(hazard ratio, 1.83 [95% CI, 1.04-3.23]), but not of any MCI or A-MCI in multivariate analyses.We found a dose-response relationship such that individuals with COPD duration of longer than 5 years at baseline had the greatest risk for any MCI (hazard ratio, 1.58 [95%CI, 1.04-2.40]) and NA-MCI (2.58 [1.32-5.06]). CONCLUSIONS AND RELEVANCE A diagnosis of COPD is associated with an increased risk for MCI, particularly NA-MCI.We have found a dose-response relationship between COPD duration and risk for MCI. These findings highlight the importance of COPD as a risk factor for MCI and may provide a substrate for early intervention to prevent or delay the onset and progression of MCI, particularly NA-MCI. © 2014 American Medical Association. All rights reserved