Research On Hypothetical Interventions Of Cognitive Impairment Among Chinese Older Adults

ObjectivesChina has been experience a rapid aging problem,accompanied with more serious age-related diseases,and the cognitive impairment has become one of the most common diseases in an aging society and has a heavy effect on the quality of order's daily life.Thus,the G-formula hypothetical intervention model was applied to explore the statistics causal effect of social psychological and diet factors on cognitive impairment among older adults in China,aiming to address the issue of the short follow-up,small sample and limited interventions brought by field intervention studies.In order to provide an evidence-based guidance for lower the incidence of cognitive impairment and further could improve the quality of life among older adults.MethodsThe data was drawn from the Chinese Longitudinal Healthy Longevity Survey(CLHLS),we used the 2002?2005?2008 and 2011 follow-up survey,which lasted a 9 years follow-up.The subjects were whose older than 65 years and not suffered from dementia at 2002 baseline survey,leaving 7377 interviewees and totally 22131 observations.The Mini-Mental State Examination(MMSE)was used to measure the cognitive function,and an age and education adjusted scores was applied to assess whether or not suffering from cognitive impairment.The index of social engagement included 5 items:current marital status,whether live alone,if have a close friend,the accessibility of help when required and social participant.The subjective well-being was measured by positive and negative well-being combined.The diet factors included vegetable,fruit,meat and fish,and the intake frequency was grouped as every day,sometimes and rarely or never.The controlled covariates were as follows:age,education,gender,occupation,residence,exercise status,the smoke/drink status,whether or not had hypertension,diabetes,stroke or cerebrovascular disease,the ability of daily life.The positive hypothetical interventions were conducted,like intervene those who had low social engagement to had high social engagement.First of all,the distributive proportions were applied to describe the basic information of baseline population.And the prevalence of cognitive impairment among different age groups,gender,education and residence was calculated at each investigation wave.Finally,the G-formula hypothetical intervention model was conducted to test the statistical causal effect of social engagement,subjective well-being and diet factors on cognitive impairment,further,the gender,education and residence differential of the causal associations was explored.ResultsAt the end of the follow-up in 2011,there were 1014 person developed cognitive impairment among the 9 year follow-up,and the incidence was 13.75%.The mean scores of baseline MMSE was 26.There were more than half populations whose ages were between 65 and 85 years.Those who were female(54%),live in rural(55.3%),literacy(57.2%)and occupied(59.2%)in farming was more than half.There was a slight difference between the low and high social engagement(low vs.high:48.1%vs.51.9%),and the mean scores of subjective well-being was 4.39.As for diet factors,the proportion of those who intake vegetables every day was highest(89.3%),the proportion of intake frequency of fruit and meat between every day and sometime was close.When only intervene one factors,the social engagement could low the incident risk of cognitive impairment(RR=0.72,95%CI:0.65-0.82)to the most extent compared with subjective well-being and diet factors,following was intake fruit(RR=0.9395%CI:0.89-0.95),however intake meat or fish did not have significant association with cognitive impairment.Results of stratified analysis:?gender,only intake vegetables had difference relationship among female and male;?education,subjective well-being and intake vegetables was only significantly associated with literacy;?residence,only intake vegetables was significantly associated with those living in western area.As for the three factors combined hypothetical interventions,when intervene three factor together,the RR was the smallest(RR=0.64,95%CI=0.58-0.73),following by social engagement and diet combined intervention(RR=0.66,95%CI=0.59-0.75).In all,the intake of meat or fish was not significant no matter under what situation.ConclusionsThe incidence of cognitive impairment was 13.75%in the 9 years follow-up,which was consistent with other research.The prevalence at each wave was:young aged<elderly aged,eastern<western,male<female,illiteracy<literacy.Social engagement could lower the risk developing cognitive impairment to the most extent,and increase the frequency of social engagement was especially helpful for those living in rural and female,but had a close effect between different education levels.Under extreme situation,subjective well-being had greatest effect on cognitive impairment,and only lower the risk among literacy population,besides subjective well-being did not have gender and residence differential.However,the influence of diet factors were complex,increase the intake frequency of vegetables and fruits were beneficial and the effect of vegetables were stronger then fruits.Furthermore,the beneficial effect of vegetables were only for female,literacy and those living in western,in contrast,fruits could lower the risk of developing cognitive impairment for whole population.And in our study,the intake of meat and fish did not have a relationship with cognitive impairment.