The Epidemiological Study On Chronic Obstructive Pulmonary Diseases In Nanjing, China

Chronic Obstructive Pulmonary Disease(COPD)is defined as a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases.Specifically,COPD refers to chronic bronchitis and/or emphysema.COPD has the twelfth highest incidence and is the fourth leading cause of death in the world.It has been estimated that COPD will become the third most frequent cause of death and the fifth most common cause of disability by the year 2020.In China,COPD is currently the forth leading cause of death,however,most previous studies on burden caused by COPD were cross-sectionally designed,and there was no continuously trend analysis on COPD mortality in a long term.World Health Organization(WHO)reported that the average prevalence of COPD was approxiamately 0.8%,while some academic reports stated that the figure would be 4.0-6.0%.In China,up to the year of 2004,due to lack of evidence-based results from representative data,WHO estimated that the COPD prevalence among adult Chinese population was 2.5%according to expert opinions based on the situation in similar countries or regions.The risk factors for COPD mainly included phenotypic susceptibility (sex,bronchial hyper-responsiveness and atopy),cigarette smoking,air pollution,occupation,nutrition,socioeconomic status and potential genetic determinants.Of all those possible factors,cigarette smoking, especially active smoking,was identified as the most important influence factor.Among smokers,10%-15%would develop COPD.There were few domestic studies available on the risk fators,especially on genetic factors,and the conclusions were also inconsistent among those studies.C-reactive protein(CRP)is a non-specific indicator of acute infection,and respiratory tracts infection is the main cause of exacerbation for COPD patients.So,it is reasonably to assume that the serum concentration of CRP will increase when COPD patients are at acute stage.Meanwhile,COPD patients usually experience heart hurt due to insufficient oxygen supply,thus,concentration of serum creatine kinase isoenzyme(CK-MB),a sensitive predictor of heart hurt,will inrease when COPD patients change to be at acute stage and with insufficient oxygen supply.There is no academic report on the relationship between CRP and CK-MB among COPD patients at acute and stable stage.This project was aimed:(1)to evaluate the time trend of COPD mortality within 10 years using continuous data from city vital surveillance system,(2)to estimate the COPD prevalence by age and urban-rural area through a population-based cross-sectional study,(3)to investigate the relationship between cigarette smoking,indoor air pollution and the risk of developing COPD via a well-matched case-control study,and(4)to explore the links between CRP and CK-MB among COPD patients at acute and stable stage with a case-control designed project by serological epidemiology methods.It is assumed that the research results will be of great help of addressing the burden caused by COPD,epidemiological distribution of COPD,influence factors of COPD,and clinical assessment of treatment for COPD patients,and will be of a lot implications for screening residents at high risk,initiating strategies against COPD at both population and individual-level. PART 1Mortality and YPLL of Chronic Obstructive Pulmonary Diseases among Nanjing Residents from 1997 to 2005ObjectivesUsing mortality and Years of Potential Life Lost(YPLL),to estimate the disease burden caused by COPD from 1999 to 2005 in urban area of Nanjing city,and to investigate the time trend of this burden.MethodsCOPD was consistently categorized by ICD-9 and ICD-10 in this study. The information of each dead COPD case was collected via city vital surveillance system.If a person died before 70 years old,then he or she would be defined to have the premature death according to local life expectancy.The data on local general population was from the Municipal Department of Statistics.Also,the national census information in 2000 was used as the standard data to adjust the yearly mortality.ResultsThe average death rate of COPD during 1999-2005 was 56.75/10⁵,while mortality of COPD was 1.08-1.18 times among men more than that among women,and COPD was the third leading cause of death in each year of the period.The death rate of COPD increased with age and reached the highest level in age group of 75+.The average YPLL was 2.14 person-year during this period.ConclusionsCOPD was a major leading cause of death and caused its heavy burden in Nanjing.The prevention of COPD shall be one of the priorities of public health. PART 2Prevalence of Physician-Diagnosed Chronic Obstructive Pulmonary Disease and its Association with Smoking among Urban and Rural Residents in Nanjing,ChinaObjectivesTo investigate the prevalence of physician-diagnosed chronic obstructive pulmonary disease(COPD)and explore the relationship between total amounts of cigarettes smoked(TACS)and COPD among urban and rural adults in Nanjing,China.Designs and settingsPopulation-based cross sectional study,conducted between October 2000 and March 2001.Administrative villages(n=45)randomly selected from three urban districts and two rural counties of Nanjing municipality, Jiangsu province,China,with an overall population of 5.6 million.ParticipantsAll regular local residents aged 35 years or older(n=29,319),67.7%from urban areas and 32.3%from rural areas;49.7%males and 50.3%females.ResultsThe response rate of potential participants was 90.1%.The overall prevalence of diagnosed COPD was 5.9%.The prevalence of COPD was significantly higher among men than in women(7.2%vs.4.7%;P＜0.01), while the difference between urban and rural participants was also statistically significant(6.7%vs.4.4%;P<0.01).The prevalence of COPD was significantly higher among smokers than non-smokers,and after adjusting for age,gender,area of residence,fuels,heating in winter, ventilation in kitchen,passive smoking,education,occupation,average family income,alcohol drinking,cooking oil,body mass index,and physical activity,a dose-response relationship between COPD and total amount of cigarettes smoked(TACS)was evident in this population(OR =1.60,95%CI=1.34,1.92;OR=1.39,95%CI=1.13,1.70;OR=1.24, 95%CI=1.01,1.52 for smokers within upper,middle and lower TACS levels compared with non-smokers,respectively).ConclusionsThe overall prevalence of diagnosed COPD(5.9%)among Chinese adults was higher than that(2.5%)estimated by WHO experts,and there was a significant gradient increase in COPD prevalence from the stratum of non-smokers to the stratum of upper TACS. PART 3Better Understanding the Influence of Cigarette Smoking on COPD:A Case-control Study in Mainland ChinaObjectivesAlthough the association between COPD and smoking status (non-smoking,ex-smoking and current-smoking)and indoor air pollution in Chinese populations is well established,the link between COPD and the amount of cigarettes smoked has not been examined.This study investigated the relationships of total amount of cigarettes smoked (TACS)and indoor air pollution,with risk of COPD among urban and rural Chinese adults.MethodsCase-control study conducted between October 2000 and March 2001 in Nanjing,China.Diagnosed COPD(n=1,743)patients,and sex-,age- and residence- matched controls,were recruited from local residents aged 35 years or older(N=29,319).All participants,76.3%from urban areas and 23.7%from rural areas,60.0%males and 40.0%females,were categorized into non-smokers,ex-smokers and smokers according to smoking behavior,while they were also classified into non-smokers, smokers with lower-TACS,smokers with middle-TACS,and smokers with upper-TACS according to their total amount of cigarettes smoked. ResultsThe COPD proportion among smokers was significantly higher than that among non-smokers.After controlling for possible confounders, compared with non-smokers,the adjusted odds ratios for COPD increased across TACS tertiles:from lower(OR=1.40,95%CI=1.09,1.79);to middle(OR=1.55,95%CI=1.21,1.99);and to upper(OR=1.77,95%CI= 1.37,2.29).Among smokers,women were significantly more likely to develop COPD than men(OR=1.20,95%CI=1.02,1.41).However,no significant associations were found between COPD and domestic fuels used kitchen ventilation,or passive smoking.Heating in winter with coal was weakly but positively linked with COPD among non-smokers overall, among women non-smokers,and specifically for women living in urban areas.ConclusionsA clear dose-response relationship exists between cigarette smoking and COPD;and,compared to men,women smokers are more susceptible to COPD.However,passive smoking,indoor air pollution were not significantly associated with COPD. PART 4Relationship between CRP and CK-MB among Acute and Stable COPD Patients:A Case-Control StudyObjectivesTo investigate the relationship between CRP and CK-MB among acute and stable COPD patients in Nanjing city.MethodsUsing case-control design,81 COPD patients(Mean of age=61.9±6.1) and 73 controls(Mean of age=54.9±2.4)were selected with matching of gender,residence,nationality,smoking,history of tuberculosis and diabetes.For COPD patients,both fasting venous and arterial blood samples were collected at acute and stable stage separately,while fasting venous blood samples were collected at medical examination day for controls.All blood samples were used to test the concentration of CRP, CK-MB or PaO₂.ResultsThe concentration of CRP and CK-MB were significantly higher among stable COPD patients(7.18±5.62,10.92±5.33;respectively)than those among controls(3.00±0.91,3.11±1.46;respectively),while acute patients(51.22±24.53,30.06±16.68;respectively)got much higher concentration of CRP and CK-MB relative to stable patients.However, PaO₂ was significantly higher among stable COPD patients than that among acute patients(93.74±32.99 vs.44.83±14.61).Among acute COPD patients,CK-MB positively correlated with CRP,while PaO₂ negatively correlated with CRP and CK-MB separately.ConclusionsCRP and CK-MB were non-specific predictors of COPD status transition from stable to acute stage of COPD,and both negatively correlated with PaO₂ among these sample COPD patients.