Epidemiologic Investigation Of Risk Factors Of COPD In Peripheral Villages Of Shenyang

PrefaceChronic obstructive pulmonary disease (COPD) is one of the most frequent diseases in clinic with highly morbidity rate and case - fatality rate. Now COPD is a serious public health problem and a heavy burden in society. A study from the northern and middle area of our country shows that the prevalence of COPD accounts 3% in the population above 15 years old. The researches from abroad shows that the prevalence is higher in men than that in women but there is no difference in the rural area of the developing countries. COPD is a complex disease that is influenced by many factors such as hereditary and environmental factors. Because of most of the population in china live in the countryside, so it is important to control the morbidity rate and risk factors of COPD in our country. In our research we investigated the risk factors of COPD in the Peripheral Villages of Shenyang and examined the X ray film and lung function of each patients. Through this we discussed the prevalence and risk factors of COPD in our countryside.Objects and Methods1. ObjectsWe selected 2000 objects above 40 years old using the method of random -cluster sampling in the countryside around Shenyang.2. Methods2.1 The questionnaire: The questionnaire includes the following: the dataof individual and family, living area, custom of living and cooking, history of smoking, family history, symptom of respiratory track and lung function.2.2 Investigating steps: The objects were interviewed and examined lung function by the specialist in the department of respiratory.2.3 The diagnose and classify of COPDAccording to the standard of " the guideline of diagnose and treatment of COPD"2.4 Statistical analysis; We chose t - test and Logistic regression analysis of SPSS for 11.5 to deal with the numerical data and calculated the OR value and confidence interval of 95% . We adopted two - sided test and the standard of test is a =0.05.Results1. Prevalence:2010 cases from 2053 ones were complete. There are 138 patients of COPD and the prevalence of COPD is 6. 87%. The prevalence of COPD is 7. 9% in men, and 5.9% in women. There is no difference between the two groups. The Prevalence of COPD in Heishan is 8.6% and 5.1% in Yuhong. There is significant difference in the two groups ( P < 0. 05 ). The prevalence of COPD of women in the two groups is 7. 6% and 4.3% , there is significant difference (P <0.05).2. Risk Factors2.1 Age: The prevalence of COPD increases along with age. There is a significant difference of the prevalence among each age stage except for some ones.2.2 Smoking: When we evaluate the responses relate to smoking, we found that OR value of the study group is larger compared with control group along with the smoking time. Smdking can raise the risk of suffering COPD.2.3 Living area of family: When we study the relationship between living areas and COPD, we note that more patients live in small houses (5. 3% , 8. 6%, 15.9%) (P<0.05).2.4 Category of fuels: The prevalence of women in Heishan is significantly higher than which in Yuhong(P <0.05). OR value is 1. 81 and 95% CI is 1. 08-3.03.2. 5 Index of corpulence: the IBW% , BMI, abdominal girth of the study group decrease significantly compared with the control group. The patients of COPD are serious with nutrition.2. 6 Heritage: The prevalence of COPD in which has family history of COPD is much higher than that in which has not history (P <0.05).2.7 The influence of multiple risk factors to the prevalence of COPD: The risk factors which were significant were analyzed by Logistic regression and only the heritage, smoking history, category of fuel, living area could increase the risk of suffering from COPD( P <0.05, OR > 1) .3. The diagnosis of COPD;Only 18 of 138 patients were diagnosed by doctors, the diagnosis rate is 13.04%. The diagnosis of classification of severe degree of COPD is higher in Yuhong than in Heishan ( P < 0.05 ).4. The results of lung functionWhen the pulmonary function test results were compared, although the findings were within normal limits in both study and control groups, FEV₁, FEV₁/FVC% ,FEV₁/prediction% were lower in Heishan than in Yuhong ( P < 0.05 ). The value of FVC,FVC/prediction% is opposite (the latter P < 0. 05 ).DiscussionCOPD is a disease which is characterized by airflow restricting. The data recently show that people died from COPD become more and more. The researches of abroad showed that smoking is the major risk factor of COPD. The risk of people suffering from COPD is significantly larger in smokers than in nonsmok-ers. But in our research there is no difference between in men and in women, Although the smoking rate is more prevalent in male than in female. So there are other potentially risk factors in men and in women. Through analyzing, we found that the category of fuel may be a potential risk factor. In rural countryside, theprevalence of COPD and CB in women is higher than that in city due to domestic cooking more so with biomass fuel, Although the smoking rate is higher in latter. We choose women in the two parts as the investigating objects. After adjusting for heritage and current smoking by logistic regression, we found that the risk of suffering from COPD by fuel is higher in Heishan than in Yuhong ( OR = 1.6,95%CI:1.1 ².3,P<0.05). When the particle (with a 50% cut-off diameter of 10) exposure reaches 100ug/m3the risk of COPD becomes more obvious. In rural areas air pollution inside dwelling usually reaches lOOOug/m and during cooking it increases up to 10000 ug/m³. Thus, it is reasonable to conclude that when biomass fuels were used, the risk of suffering from COPD increases 10 -100 times. All of these suggest that the air pollution inside dwellings from the biomass can increase the prevalence of COPD.In our research we found the nutritional index of the COPD patients is lower than normal people. It is maybe related to the factors as follows: (1) energy expenditure increasing, (2) insufficient intake of nutrient substance such as vitamin A and C, (3) metabolism increasing (4) metabolic disorder mediated by cytokine. In 1994 Zhang first positional cloned obese gene from fat mouse and it encoded secreting protein LEP. It's major functions are mediating anorexy and metabolism of material and energy.In our research we discussed the relationship between heritage factor and the prevalence of COPD by the data of epidemiology. The results show that people with family history of COPD are more easily to suffer from COPD, so the heritage factor participates in the development of COPD. But we havent found the specific gene yet. The major difficulty has been the lack of large - scale family and sib - pair studies using the modern technique of genome wide screening. Most researches are accomplished based on the case control study.Because lung function is affected by the air pollution inside dwellings from the biomass. Although the findings were within normal limits in both study and control groups, the FEV₁,FVC/PV% ,FEV/FVC ratio in study group are lower than in the control group and the difference is significant ( P <0.05). The living area of family is related to the development of COPD and the infection of respiratory tract is a major factor of the development and aggravation of COPD.