TY - JOUR
T1 - Long-term systemic inflammation and cognitive impairment in a population-based cohort
AU - Wichmann, Margarete A.
AU - Cruickshanks, Karen J.
AU - Carlsson, Cynthia M.
AU - Chappell, Rick
AU - Fischer, Mary E.
AU - Klein, Barbara E.K.
AU - Klein, Ronald
AU - Tsai, Michael Y.
AU - Schubert, Carla R.
N1 - Publisher Copyright:
© 2014, The American Geriatrics Society.
PY - 2014/9/1
Y1 - 2014/9/1
N2 - Objectives Evidence suggests inflammation is associated with cognitive impairment, but previous epidemiological studies have reported conflicting results. Design Prospective population-based cohort. Setting Epidemiology of Hearing Loss Study participants. Participants Individuals without cognitive impairment in 1998-2000 (N = 2,422; 1,947 with necessary data). Measurements Cognitive impairment (Mini-Mental State Examination score <24 or diagnosis of dementia) was ascertained in 1998-2000, 2003-2005, and 2009-2010. Serum C-reactive protein (CRP) and interleukin-6 (IL-6) were measured in 1988-1990, 1998-2000, and 2009-2010; tumor necrosis factor-alpha was measured from 1998-2000. Results Participants with high CRP in 1988-1990 and 1998-2000 had lower risk of cognitive impairment than those with low CRP at both time points (hazard ratio (HR) = 0.46, 95% confidence interval (CI) = 0.26-0.80). Risk did not differ according to 10-year IL-6 profile or baseline inflammation category in the whole cohort. In sensitivity analyses restricted to statin nonusers, those with high IL-6 at both times had greater risk of cognitive impairment than those with low IL-6 at both times (HR = 3.35, 95% CI = 1.09-10.30). In secondary analyses, each doubling of IL-6 change over 20 years was associated with greater odds of cognitive impairment in 2009-2010 in the whole cohort (odds ratio (OR) = 1.40, 95% CI = 1.04-1.89), whereas a doubling of CRP change over 20 years was associated with cognitive impairment only in statin nonusers (OR = 1.32, 95% CI = 1.06-1.65). Conclusion With data collected over 20 years, this study demonstrated greater likelihood of cognitive impairment in individuals with repeated high or increasing IL-6. The inconsistent CRP findings may reflect effects of statin medications, survival effects, or adverse effects associated with chronically low CRP. Further studies of long-term inflammation and cognitive impairment are needed.
AB - Objectives Evidence suggests inflammation is associated with cognitive impairment, but previous epidemiological studies have reported conflicting results. Design Prospective population-based cohort. Setting Epidemiology of Hearing Loss Study participants. Participants Individuals without cognitive impairment in 1998-2000 (N = 2,422; 1,947 with necessary data). Measurements Cognitive impairment (Mini-Mental State Examination score <24 or diagnosis of dementia) was ascertained in 1998-2000, 2003-2005, and 2009-2010. Serum C-reactive protein (CRP) and interleukin-6 (IL-6) were measured in 1988-1990, 1998-2000, and 2009-2010; tumor necrosis factor-alpha was measured from 1998-2000. Results Participants with high CRP in 1988-1990 and 1998-2000 had lower risk of cognitive impairment than those with low CRP at both time points (hazard ratio (HR) = 0.46, 95% confidence interval (CI) = 0.26-0.80). Risk did not differ according to 10-year IL-6 profile or baseline inflammation category in the whole cohort. In sensitivity analyses restricted to statin nonusers, those with high IL-6 at both times had greater risk of cognitive impairment than those with low IL-6 at both times (HR = 3.35, 95% CI = 1.09-10.30). In secondary analyses, each doubling of IL-6 change over 20 years was associated with greater odds of cognitive impairment in 2009-2010 in the whole cohort (odds ratio (OR) = 1.40, 95% CI = 1.04-1.89), whereas a doubling of CRP change over 20 years was associated with cognitive impairment only in statin nonusers (OR = 1.32, 95% CI = 1.06-1.65). Conclusion With data collected over 20 years, this study demonstrated greater likelihood of cognitive impairment in individuals with repeated high or increasing IL-6. The inconsistent CRP findings may reflect effects of statin medications, survival effects, or adverse effects associated with chronically low CRP. Further studies of long-term inflammation and cognitive impairment are needed.
KW - cognition
KW - dementia
KW - epidemiology
KW - inflammation
KW - population-based
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U2 - 10.1111/jgs.12994
DO - 10.1111/jgs.12994
M3 - Article
C2 - 25123210
AN - SCOPUS:84921681131
SN - 0002-8614
VL - 62
SP - 1683
EP - 1691
JO - Journal of the American Geriatrics Society
JF - Journal of the American Geriatrics Society
IS - 9
ER -