OBJECTIVES: To investigate the extent of the association of adverse childhood experiences (ACEs) with co-occurring poor self-reported oral health (SROH) and multimorbidity in middle-aged and older adults, and whether these associations differ by age and sex. METHODS: This cross-sectional study used data from 27 765 adults aged 45-85 years from the first follow-up wave (2015-2018) of the Canadian Longitudinal Study on Aging (CLSA). Four categories were generated to assess co-occurring SROH and multimorbidity: (i) good SROH, no multimorbidity
(ii) poor SROH, no multimorbidity
(iii) good SROH, multimorbidity and (iv) poor SROH and multimorbidity. Age-and sex-stratified multinomial logistic regressions were used to examine associations of ACEs (e.g. childhood maltreatment, neglect, parental death, serious illness or separation) with co-occurring poor SROH and multimorbidity, adjusted for the confounders race/ethnicity, income, level of education, smoking status and alcohol consumption. RESULTS: Over a third of participants reported having multimorbidity (35.3%), 10.4% reported poor SROH, and almost 30% of participants had experienced at least one ACE. There was a gradient in the association between higher ACEs and each of the health outcome categories, with the greater odds being for the co-occurrence of poor SROH and multimorbidity (OR = 1.37, 95% CI: 1.30, 1.44). The associations between ACEs and adverse health outcomes in later life were significant across age groups and sexes, with middle-aged females demonstrating the strongest associations. CONCLUSIONS: ACEs are linked to an increased non-communicable chronic disease burden and poor oral health among middle-aged and older Canadians, highlighting the importance of prevention in early life and the focus on psychosocial factors over the life course for healthy aging.