Association Of Lung Function Reduction And Chronic Respiratory Diseases With Quality Of Life In Middle-aged And Elder People

Quality of life(QOL)was reported to reflect overall life and individual physiological function,psychological function,social function,living environment and other aspects,mainly referring to individual subjective assessment.In recent years,QOL has caught more and more attention and became a hot topic because QOL is used not only to assess the impact of physical condition,but also to evaluate possible effects of various factors such as medical service systems,living habits and social welfare on daily life.Nowadays chronic respiratory diseases(CRDs)are common diseases and a lot of patients suffer from them.As an index of CRDs,decreased lung function is associated with reduced ventilation and oxygen intake and reported to affect body functions.The effects of lung function reduction and CRDs,which are common conditions among middle-aged and elderly people,on QOL are still unclear.We developed this study using baseline data of retired workers to estimate the impacts of lung function reduction and CRDs on QOL.Objective: To investigate the prevalence of lung function reduction and CRDs,and to analyze the influencing factors;to analyze the association between lung function and CRDs with quality of life and its facets.Methods: A total of 10893 retired workers from Dongfeng-Tongji Cohort Study were included in this cross-section study.General demographic data,disease history,and lifestyle were collected by face-to-face questionnaires conducted by trained investigators.Lung function was measured using an electronic spirometer by trained investigators.The electronic spirometer device was calibrated before each test.Each subject completed three tests,of which the highest result was used in the analysis.We used forced vital capacity(FVC),forced expiratory volume in one second(FEV1)and FEV1/FVC to assess lung function.The poor lung function group included individuals with FVC%<80% and FEV1/FVC?70% or FEV1/FVC<70%.Others were divided into normal lung function group.CRDs include chronic bronchitis,chronic obstructive pulmonary disease(COPD)and asthma,etc.QOL was evaluated through a questionnaire designed according to the World Health Organization Quality of Life-100(WHOQOL-100)and the World Health Organization Quality of Life-BREF(WHOQOL-BREF).The questionnaire includes four domains(physical health,psychological state,social relationships and environment)and 15 facets.The scores of all fields and aspects are positive,which means the higher the score,the better the quality of life.Quantitative variables were expressed as mean ± SD,and categorical variables were expressed as number and percentages.Lung function indexes were normally distributed.Student's t-test and Kruskal-Wallis test were used to analyze differences in the normal distribution variables and abnormal distribution variables between two or three groups,respectively.Chi-square test was used to analyze categorical variables in two or three groups.Logistic model was used to analyze the effects of lung function reduction and CRDs.A general linear model was used to evaluate the association between QOL scores and lung function or CRDs.All analyses were performed using SAS version 9.4(SAS Institute,Cary,North Carolina).P<0.05 was considered statistically significant.Results:(1)The study included 10893 individuals with a mean age of 64.46±7.97(4919 men = 45.16%).The mean of FVC and FEV1 were 2.40±0.63 L and 2.07±0.54 L,respectively.The prevalence of lung function reduction and CRDs in retired workers was about 40%(4356 people)and 15%(1646 people),respectively.The prevalence of lung function reduction and CRDs increased with the increasing age of the participants.The rate of lung function decline and CRDs in males were higher than in females.Smoking,drinking,comorbiditis could also increase the rate of lung function decline and CRDs.Age,gender,marriage status,education level,physical activity,smoking and comorbiditis could be potential risk factors of lung function decline.And age,gender,physical activity,smoking and comorbiditis could be potential risk factors of CRDs.The risk of lung function decline was increased with age,and the OR were 1.38(1.24,1.54)When compared with males,females had a lower risk of lung function decline and CRDs,and the OR were 0.63(0.57,0.70)and 0.75(0.65,0.85),respectively.(2)The scores of the total QOL,physical health domain,psychological state domain,social relationships domain and environment domain were 74.51±10.78,73.05±17.97,73.07±13.25,74.12±12.82,and 77.80±12.43,respectively.No significant difference was found between the QOL scores in male(74.53±10.55)and female(74.50±10.97).Age,body mass index(BMI),marriage status,education level,physical activity,drinking and comorbiditis all influenced the QOL scores(P<0.05).In the analysis by the general linear model,lung function was associated with the QOL scores.After adjusting for all confounders,each unit increase in FVC was associated only with a 0.66(0.29,1.03)and 1.90(1.30,2.50)score increase in the total QOL and physical health domain scores,respectively(P<0.05).Each unit increase in FEV1 was associated with a 0.68(0.25,1.11)and 1.53(0.83,2.24)score increase in the total QOL and physical health domain scores,respectively(P<0.05).In the categorical analysis,there was a linear trend between FVC and FEV1 with the total QOL and physical health scores after adjusting for all confounders.Further analysis suggested that elevated lung function could improve the scores of pain and discomfort facet and independence facet of physical health domain.In the stratified analysis,it was found that marriage status,smoking and physical activity had modifying effects on the relationship between lung function and QOL scores(P<0.05).But the positive association between lung function and quality of life remained after stratified.(3)No relationship was found between COPD and the QOL scores,while asthma and chronic bronchitis had an impact on the total QOL score and its domain scores,which were significantly associated with a 2.45(1.36,3.54)and 0.97(0.35,1.59)unit reduction in total QOL score,respectively.Decreased lung function and CRDs are associated with reduced ventilation and oxygen intake,which result in limited activity and decreased independence.At the same time,severe diseases and their corresponding symptoms lead to physical discomfort and pain,and the scores of QOL,especially the physical health domain scores,decrease.Conclusions: The prevalence of lung function reduction and CRDs in middle-aged and elder people was high.The lung function was significantly positively associated with QOL,especially physical health domain and its facets.Asthma and chronic bronchitis were associated with the reduction of QOL scores among middle-aged and elderly people.