Interaction between exposure to environmental smoke and the family history of chronic bronchitis (CB) on the risk of CB in rural females in Liuyang city, Hunan province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the relationships and interaction among the exposure to environmental smoke, family history of chronic bronchitis (CB) and CB, in rural women.</p><p><b>METHODS</b>A population-based case-control study chi(2) was used to analyze the relationship between environmental smoke exposure, CB family history and CB. Additive effects model was used to analyze the interaction.</p><p><b>RESULTS</b>In the first stage, 157 CB patients were screened from 24 268 women residents (prevalence rate is 6.47 per thousand), then 92 patients (case group) and 114 healthy women (control group) were investigated in the second stage. Results showed that: coal/firewood for heating (OR = 36.21) and CB family history (OR = 6.41) might serve as the risk factors of CB in rural women (P < 0.05). Factors as frequent cooking and using coal/firewood for heating had a positive interaction with family history of CB in rural women, CB with S as 5.39 and 9.02, attributable proportions of interaction (API) as 72% and 88%, relative excess risk of interaction (RERI) as 6.50 and 225.99, respectively.</p><p><b>CONCLUSION</b>Using coal/firewood for heating and CB family history might be the risk factors of CB for rural women. A positive interaction between cooking frequently, heating model and CB family history was also seen.</p>

Study on risk factors and predictive model for lumbar intervertebral disc herniation in the rural population / 中华流行病学杂志

Objective To explore the risk factors on the symptoms of lumbar intervertebral disc herniation so as to develop a predictive model for the disease. Methods With a populationbased case-control study, 303 of 50 123 residents were diagnosed as having lumbar intervertebral disc herniation symptoms. 152 cases and 167 healthy controls, matched by gender and age, were randomly chosen as case and control groups. Questionnaires were used to collect information on the exposure to risk factors and logistic predictive model was then established. Results Through non-conditional logistic regression analysis, data showed that the positive family history of lumbar vertebra disorder, lumbar treatment or surgery, mental stress, acute low back injury, permanent work pose, and body mass index ≥23.0 kg/m2 were the risk factors among residents from the countryside. The area under the receiver operator characteristic curve of logistic predictive model was 0.809. When 0.4 was set as the classification cutoff, the total predictive correct rate, sensitivity, and specificity were 74.0%, 73.7%, and 74.3% respectively. Conclusion The occurrence of lumbar disk herniationcan in countryside population was affected by multi-variables including genetic and environmental, and could be predicted with the logistic regression model established by our group.The positive predictive results could be used to alarm the patients and doctors for prevention and treatment of the disease.