Population aging in China is deepening, and the widowed rate of the elderly is also on the rise. Widower is one of the most stressful events in the human life course, and its impact also affects the mental health and economic level of widower. In many studies on the impact of widower on the mental health of the elderly at home and abroad, the proxy variables used are traditional indicators, such as subjective well-being, loneliness, depression level, and some studies do not consider the endogeneity between widowhood and health status.

To evaluate the impact of widowhood on the mental health of older adults in China, and provide a basis and reference for formulating the mental health intervention program for older adults in China.

Using the 2018 China Health and Retirement Longitudinal Study (CHARLS) as the data source, 4 694 older adults aged 60 years and above were selected as study subjects and divided into the widowed group (n=644) and non-widowed group (n=4 050) . The mental frailty index was used as a perspective for evaluating the mental health status of older adults. Using propensity score matching (PSM) model, the propensity score was calculated by using Logit regression analysis, the robustness was tested by using standard deviation variation, common support bar graph and nuclear density distribution, the impact of widowhood on the physical and mental health of older adults was analyzed by using K-nearest neighbor matching, radius matching and kernel matching, and the heterogeneity was tested based on gender, household type and age.

Compared to the non-widowed group, the mental health of older adults in the widowed group was impaired (P<0.05) . Logit regression model results showed that female (OR=2.274, 95%CI=1.917-2.698) , age (OR=0.975, 95%CI=0.972-0.978) , secondary education level (OR=0.618, 95%CI=0.505-0.756) and monthly family consumption (OR=1.000, 95%CI=1.000-1.000) were correlated with widowhood (P<0.05) . The robustness test results after matching were better. The results of PSM showed that widowhood significantly increased the mental frailty index level (ATT ranged from 0.054 to 0.055, P<0.05) . The results of heterogeneity test showed that there were significant differences between urban and rural areas and among different age groups in the impact of widowhood on the mental frailty index of older adults, but there was no significant difference between male and female in the impact of widowhood on the mental frailty index of older adults. Among them, the impact of widowhood on the older adults in rural areas was more significant (ATT ranged from 0.072 to 0.075, P<0.05) , but the impact on older adults in urban areas was not significant; the impact on older adults in the low age group and high age group was more significant (ATT ranged from 0.061 to 0.081, P<0.05; 0.067-0.078, P<0.05) , but the impact on older adults in the middle age group was not significant.

Widowhood has a negative impact on the mental health of the older adults. The impact varies among different older adults. The widowed older adults in rural areas, just entering old age and in their later years need attention and psychosocial support.