The Mediating Effect Analysis Of Pain And The Association Between Multimorbidity And Physical Function Status Among Community-dwelling Older Adults

Background As the aging of the population and the variation of medical treatments and lifestyles,a growing proportion of older populations are diagnosed with multiple coexisting chronic diseases.As a result,the prevalence of multimorbidity becomes a widespread phenomenon and a rapidly growing health care problem.Physical function is considered as an important indicator to evaluate the health status of the older population.Previous studies have demonstrated that multimorbidity may have synergistic or additional effects on disability,and it is also a strong risk factor for physical disability.However,the pathways related to the association between multimorbidity and physical function disability are briefly mentioned and the mediating factors have not been thoroughly studied.Persistent pain often occurs among older adults with multimorbidity.Body pain is also associated with mobility problems,fall,and high levels of functional disability.However,little is known about the extent to which pain affects the physical function status in elder people with multimorbidity.This study used a cross-sectional study based on community population to investigate the association between multimorbidity and physical function disability among community-dwelling older adults and to further evaluate the mediating effects of physical pain.Objectives1.To investigate the association between multimorbidity and physical function status among community-dwelling older adults.2.To assess the mediating effects of physical pain on the association betweenmultimorbidity and physical function status.Methods Data were collected from the health survey of community residents conducted in Foshan City and Shenzhen City,Guangdong Province.Stratified sampling and cluster sampling were used to investigate 1321 older adults aged 60 years and older.All respondents were asked to complete the questionnaire and physical function assessment.The questionnaire included demographic characteristics,residents' health behaviors,pain levels,and chronic diseases of residents;Physical function was assessed by activities of daily living(ADL),instrumental activities of daily living(IADL),index of mobility scale(NAGI),index of basic physical activities scale(RB),and short physical performance battery(SPPB).Multimorbidity was defined as the simultaneous presence of two or more chronic conditions.The multivariable regression models including logistic regression and linear regression were employed to analyze the association between chronic diseases number or pain and different physical function assessments.Mediation analysis was performed using the KHB(Karlson Holm Breen)method to understand the extent to which pain(potential mediator variable)can explain the association between multimorbidity(independent variable)and physical function disability(dependent variables).Main results1.The prevalence of multimorbidity status was 44.6%.The highest prevalence of chronic diseases was hypertension,and other frequent chronic diseases included bone diseases,chronic pain,and diabetes,etc..Participants with multimorbidity were more likely to be elder,female,single,and having a higher BMI.2.In gender stratification analysis,multimorbidity was significantly associated with ADL disability(OR=2.16,P<0.05),IADL disability(OR=1.97,P<0.001),NAGI disability(OR=2.84,P<0.001),RB disability(OR=2.65)and lower SPPB score(?=-0.83,P<0.001)in women.3.The rate of pain increased with the number of chronic diseases and the multimorbidity patients with higher pain prevalence.Moreover,the presence of painwas also significantly associated with physical function status.Mediation analysis illustrated that pain was accounted for 16.5% to 22.1% of the adverse efects of multimorbidity on physical function disability in women.Conclusions1.Multimorbidity was significantly associated with physical function status,and community-dwelling older adults with multimorbidity were significantly more likely to suffer physical function disability.2.Pain might be a mediating factor of multimorbidity associated with physical function disability in women.Interventions for older women are required to prevent multimorbidity and relieve pain so that it could reduce the risk of functional disability.