BackgroundOlder adults with hearing impairments are vulnerable to cognitive impairment. Although previous reports suggest a correlation between widowhood and cognitive impairment, further investigation is needed to elucidate the effect of widowhood on cognitive function and the moderating effects of social support and participation on widowhood-related cognitive impairment in this vulnerable demographic.MethodsThe study’s data were sourced from the nationally representative Chinese Longitudinal Healthy Longevity Survey (CLHLS) for the years 2011, 2014, and 2018. Multiple linear regression was used to analyze the association between widowhood and cognitive function among older adults. Multivariate logistic regression examined the effect of widowhood on the likelihood of experiencing various levels of cognitive impairment in older adults with hearing impairments. A moderating effect model explored the roles of social support and participation in mitigating widowhood-related cognitive impairment.ResultsThe cognitive function of older adults with hearing impairment was found to be lower than that of those without hearing impairment. Widowhood was significantly negatively correlated with Mini-Mental State Examination (MMSE) scores in older adults, both with (Coef. = -0.898) and without (Coef.: = -0.680) hearing impairments. A stronger association was observed between widowhood and declining cognitive function among older adults with hearing impairment. Specifically, widowhood may be more likely to significantly increase the likelihood of moderate and severe cognitive impairment (RRR = 1.326, 1.538) among older adults with hearing impairments. Social support and social participation significantly moderated the cognitive impairment associated with widowhood among hearing-impaired older adults. These forms of support and engagement are buffers against the risk of widowhood-related cognitive impairment among this demographic.ConclusionsOur findings indicate that widowhood is significantly associated with cognitive impairment in older adults with hearing impairment. Social support and participation help mitigate this risk. Strategies should prioritize early screening, specialized cognitive rehabilitation, comprehensive care, and enhancing social support and participation to maintain cognitive health in this vulnerable population following widowhood.