Association between marital status and age dynamics of cognitive functions in ageing in a Russian population sample

Abstract

Introduction. The identification of risk factors for cognitive decline during ageing is of great importance for prevention of dementia. Being married or cohabited is considered a protective factor for health. The impact of marital status on age-related decrease of cognitive functions (CF) is understudied.The aim of the study was to investigate the relationship between the indicators of CF and marital status in a cross-sectional analysis and in 2 serial measurements over 9 years in a population sample of middle to older age in Russia.Materials and methods. The study was based on a random population sample of men and women aged 45–69 years old examined at baseline in 2003–2005 in Novosibirsk (n = 9360, HAPIEE project). Present analysis included a subsample of persons with repeated serial measurements – 3153 people. The average follow-up period was 9.2 (SD = 0.7) years. CF was assessed using standard validated methods, including immediate and delayed recall of 10 words, semantic verbal fluency and letter cancellation test. Marital status was determined by standardized questionnaires, groups of single and married/cohabiting participants were identified.Results. In studied population sample (n = 3153, 62% of women), the mean age of participants at baseline examination was 60.3 ± 6.8 years old, and at follow-up examination – 69.5 ± 6.9 years old. During the 9-year follow-up, a significant negative dynamics of the studied cognitive domains (p < 0.001) was revealed in single for both sexes. In multivariable-adjusted models, the rate of CF regress per year did not differ by marital status in both sexes, except for increased rate of decline in semantic verbal fluency in women, partly it was explained by high baseline level. Married or cohabiting women had faster rate of decline in this indicator (p = 0.007) compared with single, regardless of age and other risk factors.Conclusion. The findings obtained in this population sample in Novosibirsk support a potential protective effect of marriage or cohabitation on CF preservation during ageing.