Investigating the causal effect of cognition on the self-reported loss of functional dentition using marginal structural models: The Panel on Health and Ageing of Singaporean Elderly study.

Abstract

To assess the effect of cognition on the loss of functional dentition. We used data from the three waves of the Panel on Health and Ageing of Singaporean Elderly study (n=4990 at baseline, 774 complete cases analysed) over 6 years (2009-2015). The outcome was the loss of functional dentition (<21 teeth). The exposure was cognitive impairment, while baseline confounders included age, sex, education, and ethnicity. Time-varying confounders included income, living arrangements, smoking, diabetes, depressive symptoms, cardiovascular disease, and body mass index. We used marginal structural mean models with inverse probability treatment weighted. The mean age of the participants was 70.2 years at baseline. The proportion of participants with loss of functional dentition increased from 74.6% to 89.9% over 6 years. Women, ethnic Chinese, less educated, smokers, people with diabetes, and individuals with depression had a higher proportion of loss of functional dentition than their counterparts. Loss of functional dentition was 1.8 times higher (odds ratio 1.80; 95% confidence interval 0.88-3.69) among those with cognitive impairment after taking well-known confounders into account. After accounting for the time-varying exposure and confounding evidence, the association between cognition and functional dentition among the elderly in Singapore remains uncertain.