title: Parental family history of dementia in relation to subclinical brain disease and dementia risk.
abstract: OBJECTIVE
  To determine the association of parental family history with risk of dementia by age at onset and sex of affected parent in a population-based cohort.
  
  
  METHODS
  From 2000 to 2002, we assessed parental history of dementia in participants without dementia of the Rotterdam Study. We investigated associations of parental history with risk of dementia until 2015, adjusting for demographics, cardiovascular risk factors, and known genetic risk variants. Furthermore, we determined the association between parental history and markers of neurodegeneration and vascular disease on MRI.
  
  
  RESULTS
  Of 2,087 participants (mean age 64 years, 55% female), 407 (19.6%) reported a history of dementia in either parent (mean age at diagnosis 79 years). During a mean follow-up of 12.2 years, 142 participants developed dementia. Parental history was associated with risk of dementia independently of known genetic risk factors (hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.12-2.48), in particular when parents were diagnosed at younger age (<80 years: HR 2.58, 95% CI 1.61-4.15; ≥80 years: HR 1.01, 95% CI 0.58-1.77). Accordingly, age at diagnosis in probands was highly correlated with age at diagnosis in their parents <80 years (r= 0.57,p= 0.001) but not thereafter (r= 0.17,p= 0.55). Among 1,161 participants without dementia with brain MRI, parental history was related to lower cerebral perfusion and higher burden of white matter lesions and microbleeds. Dementia risk and MRI markers were similar for paternal and maternal history.
  
  
  CONCLUSIONS
  Parental history of dementia increases risk of dementia, primarily when age at parental diagnosis is <80 years. Unexplained heredity may be attributed in part to cerebral hypoperfusion and small vessel disease. We found no evidence of preferential maternal compared to paternal transmission.
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Wolters
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Sven J
authors.initials: SJ
authors.lastname: van der Lee
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Koudstaal
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: van Duijn
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: M Kamran
authors.initials: MK
authors.lastname: Ikram
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Meike W
authors.initials: MW
authors.lastname: Vernooij
authors.affiliation: Departments of Epidemiology (F.J.W., S.J.v.d.L., C.M.v.D., A.H., M.K.I., M.W.V., M.A.I.), Neurology (F.J.W., P.J.K., M.K.I., M.A.I.), and Radiology and Nuclear Medicine (M.W.V., M.A.I.), Erasmus Medical Centre, Rotterdam, the Netherlands; and Department of Epidemiology (F.J.W., A.H.), Harvard T.H. Chan School of Public Health, Boston, MA. m.a.ikram@erasmusmc.nl.
authors.forename: M Arfan
authors.initials: MA
authors.lastname: Ikram
mesh_terms: D017668:Age of Onset; D000368:Aged; D001057:Apolipoproteins E / Q000235:genetics; D001921:Brain / Q000000981:diagnostic imaging; D002318:Cardiovascular Diseases / Q000453:epidemiology; D015331:Cohort Studies; D003704:Dementia / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000235:genetics; D005144:F Factor; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D060005:Genotyping Techniques; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010290:Parents; D012307:Risk Factors
chemical_list: D001057:Apolipoproteins E