Table 1

Characteristics of included studies

Study (first author and year of publication)Study designCountryNumber of participantsMean year of birthMean age at marital status evaluation (years)Baseline marital status of participants (%)Mean/range of follow-up (years)Method of dementia case ascertainmentQuality rating
 MarriedWidowedDivorcedLifelong single
Amieva 201027 CohortFrance208919147460.732.52.74.25–15Clinical assessment5
Arai 200428 CohortJapan8531929697129 (unmarried)5Clinical assessment3
Bae 201417 CohortS Korea35919367270.229.8003.5Clinical assessment3
Bickel 199418 CohortGermany33119187442.447.53.86.47–8Clinical assessment5
Fratiglioni 200019 CohortSweden136819058227.845.45.920.93Clinical assessment6
Håkansson 200929 CohortSweden200019265180.17.84.47.820.9Clinical assessment8
Hatch 201330 CohortUSA509219207565.929.94.1N/A12Clinical assessment8
Sundström 201431 CohortSweden167719197557.614.25.732.68.6Clinical assessment7
Sundström 201632 CohortSweden7 50 12919286964.98.416.010.86Clinical register/death register9
Beard 199215 Case-controlUSA48218978028.848.05.417.8N/ASecondary care clinical register3
Seidler 200314 Case-controlGermany42419247778.511.13.86.6N/AGeneral practice clinical register2
Correa Ribeiro 201333 Cross-sectionalBrazil68319317841.640.87.510.1N/AClinical assessment3
Fan 201534 Cross-sectionalTaiwan10 43219367664.231.04.8 (Div/single)N/AClinical assessment4
Guaita 201535 Cross-sectionalItaly132119397267.124.62.26.1N/AClinical assessment4
Zhang 200636 Cross-sectionalChina34 80719296877.420.81.6 (Div/single)N/AClinical assessment4
  • N/A,Not applicable