Objective  To investigate the association between marital/partner relationship quality and the accumulation rate of multiple chronic conditions in middle-aged and older adults.

Methods  This study was based on the data from waves 4 to 11 of the English Longitudinal Study of Ageing (ELSA). Multiple imputation by chained equations was used to handle missing covariates. Linear mixed-effects models were fitted to examine the association between marital/partner relationship quality types and the accumulation rate of multiple chronic conditions. Effect heterogeneity was further explored through stratified analyses by sex and age.

Results A total of 7943 participants were included. Compared with individuals in supportive marital/partner relationships (with high support and low strain), all other relationship types and having no partner were associated with faster rates of accumulation of chronic diseases. Individuals with no partners showed the fastest accumulation rate (β = 0.042, 95% CI: 0.033-0.051), followed by those in indifferent relationships (with low support and low strain) and aversive relationships (with low support and high strain) (β = 0.029, 95% CI: 0.007-0.051; β = 0.027, 95% CI: 0.013-0.041). Those in ambivalent relationships (with high support and high strain) showed a relatively weaker effect (β = 0.018, 95% CI: 0.009-0.026). Women were more sensitive to this effect.

Conclusion Adverse marital/partner relationships (including ambivalent, indifferent, and aversive) and the absence of a partner are associated with an accelerated accumulation rate of multiple chronic diseases in middle-aged and older adults, and priority attention should be given to the female population.