Extrinsic Risk Factors for Women Breast Cancer in Gaza Strip, Palestine: Associations and Interactions in a Case-Control Study

Background: Worldwide, breast cancer (BC) is the most frequently diagnosed neoplastic disease in women around menopause that is the leading cause of DALYs, because it causes a significant reduction of these women’s ability to function normally in everyday life. Methods: The present hospital-based case-control study was carried out between January and August 2018 using a structured questionnaire on 105 breast cancer women and 210 controls who are clinically free from breast cancer. Data about the study cases were collected in the oncology day-care clinics of the two main hospitals in Gaza strip “Al-Shifa and European Gaza hospitals”. Univariate logistic regression and multivariate logistic regression analyses were employed to identify the significant factors associated with BC. Results: Multivariate logistic regression analyses with adjustment for all confounders revealed that woman with BMI more than or equal 30 kg/m2 are under risk of getting BC 2.9 times greater than those having BMI less than 29 kg/m2 (AOR = 2.895;95% CI: 1.305 - 6.423). Analysis of risk according to reaching menopause showed that the estimated AOR was greater among those reached menopause (3.137, 95% CI 1.824 - 5.395) than among those that did not reach menopause. The risk of developing BC in the case of a history of incidence of BC in the family was more than two times higher (AOR = 2.632, 95% CI 1.528 - 4.535) than in case of the history of a free family of BC. Conclusion: In this context, the above-mentioned risk factors must be taken into consideration in BC management processes in the Gaza strip.

Environmental and Psycho-social Factors Related to Prostate Cancer Risk in the Chinese Population:a Case-control Study

Objective To study the risk environmental and psycho-social factors associated to prostate cancer （PCa） in Chinese population. Methods 250 PCa patients and 500 controls were enrolled in this case-control study. Information was collected and logistic regression analysis was used to estimate the odds ratios （OR） and 95% confidence intervals （95% CI） for relationship between lifestyle, eating habits and psycho-social factors with PCa risk. Results Green vegetables and green tea were associated with a decreased risk of PCa （0R=0.39, 95% CI： 0.28-0.53; 0R=0.59, 95% Cl： 0.40-0.87, respectively）. Family history of PCa （0R=7.16, 95% CI： 2.01-25.49）, history of prostate diseases （0R=2.28, 95% Cl： 1.53-3.41）, alcohol consumption （0R=1.97, 95% CI： 1.33-2.90）, red meat consumption （0R=1.74, 95% CI： 1.20-2.52）, barbecued （0R=2.29, 95% CI： 1.11-4.73） or fried （0R=2.35, 95% CI： 1.24-4.43） foods were related with increased PCa risk. Negative psycho-social factors including occupational setbacks （0R=1.61, 95% CI： 2.00-2.59）, marital separation （0R=1.94, 95% CI： 1.29-2.91）, self-contained suffering {0R=2.37, 95% CI： 1.58-3.55）, and high sensitivity to the personal comments （0R=1.73, 95% CI： 1.18-2.54） were related to PCa. Conclusion Regular consumption of green vegetables and green tea may suggest protective effects on PCa. Alcohol consumption, red meat consumption and barbecued or fried foods were associated with PCa. Negative psycho-social factors may also play a role in the incidence of PCa in Chinese population.

Multicenter case-control study of the risk factors for ulcerative colitis in China

AIM:To evaluate potential risk factors in the development of ulcerative colitis(UC) in China.METHODS:A total of 1308 patients with UC and 1308 age-matched and sex-matched controls were prospectively studied in China.The UC cases were collected from 17 hospitals in China from April 2007 to April 2010.Uniform questionnaires were designed to investigate risk factors including smoking,appendectomy,stress,socio-economic conditions,nonsteroidal antiinflammatory drugs(NSAIDs),oral contraceptives,diet,breastfeeding,infections and family sanitary conditions.Group comparisons by each factor were done using simple logistic regression analysis.Conditional logistic regression was used for multivariate analysis.RESULTS:By univariate analysis,the variables predictive of UC included feeling stress,light and heavy alcoholic drinking,spicy food,sugar consumption and infectious diarrhea,while heavy tea intake and tap water consumption were protective against UC.On multivariate analysis,the protective factor for UC was tap water consumption [odds ratios(OR) = 0.424,95%CI:0.302-0.594,P < 0.001];while the potential risk factors for UC were heavy sugar consumption(OR = 1.632,95%CI:1.156-2.305,P < 0.001),spicy food(light intake:OR = 3.329,95%CI:2.282-4.857,P < 0.001;heavy intake:OR = 3.979,95%CI:2.700-5.863,P < 0.001),and often feeling stress(OR = 1.981,95%CI:1.447-2.711,P < 0.001).Other factors,such as smoking habit,appendectomy,breastfeeding,a history of measles,rural or urban residence,education,oral contraceptives,and NSAID use have not been found to have a significant association with the development of UC in the present study.CONCLUSION:Our study showed tap water consumption was a protective factor for UC,while spicy food,heavy sugar consumption and often feeling stress were risk factors for UC in this Chinese population.

Risk factors for liver-related mortality in chronic hepatitis C patients:A deceased case-living control study

AIM: To investigate the risk factors for liver-related mortality in chronic hepatitis C (CHC) patients.

Risk factors of intrahepatic cholangiocarcinoma in patients with hepatolithiasis:a case-control study

BACKGROUND:Why 3.3% to 10% of all patients with hepatolithiasis develop intrahepatic cholangiocarcinoma (ICC) remains unknown.We carried out a hospital-based case-control study to identify risk factors for the development of ICC in patients with hepatolithiasis in China.METHODS:Eighty-seven patients with pathologically diagnosed hepatolithiasis associated with ICC and 228 with hepatolithiasis alone matched by sex,age (±2 years),hospital admittance and place of residence were interviewed during the period of 2000-2008.Odds ratios (OR) and 95% confidence intervals (CI) were calculated for each risk factor.RESULTS:Among the patients with hepatolithiasis associated with ICC,the mean age was 57.7 years and 61.0% were female Univariate analysis showed that the significant risk factors for ICC development in hepatolithiasis were smoking,family history of cancer,appendectomy during childhood (under age 20),and duration of symptoms >10 years.In multivariate stepwise logistic regression analysis,smoking (OR=1.931,95% CI:1.000-3.731),family history of cancer (OR=5.175,95% CI:1.216-22.022),and duration of symptoms >10 years (OR=2.348 95% CI:1.394-3.952) were independent factors.CONCLUSION:Smoking,family history of cancer and duration of symptoms >10 years may be risk factors for ICC in patients with hepatolithiasis.

Risk Factors of Low Back Pain among the Chinese Occupational Population:A Case-control Study

Objective To explore the risk factors of low back pain among the Chinese occupational population in several major industries. Methods A total of 7200 subjects （3600 cases and 3600 controls） were randomly sampled from a cross-sectional study, and they were investigated for individual and occupational factors of low back pain. The potential risk factors were first selected by using chi-square tests. Secondly, collinearity diagnosis proceeded by using the Kendall＇s rank correlation. Finally, binary logistic regression model was used for multi-factor analysis. Results Collinearity diagnosis showed that there was a severe collinearity problem among the potential risk factors of low back pain. Logistic regression model included 20 variables with statistical significance. Bending neck forward or holding neck in a forward posturefor long periods （0R=1.408） was the most important risk factor inducing low back pain in this study, followed by bending heavily with the trunk （0R=1.402）, carrying out identical work almost for the whole day （0R=1.340）. Additionally, suHicient normal break was a protective factor of low back pain. Conclusion Low back pain among the Chinese occupational population was associated with body height, occupation, work organization, physical work, working posture, and others. All these risk factors could be regarded as the indicators of low back pain, and some relevant preventive measures should be taken to reduce low back pain risk.

Risk factors for the occurrence of insulinoma: a case-control study

BACKGROUND: The etiology of insulinoma is poorly understood. Few studies investigated the possible roles of environmental factors and lifestyle in the pathogenesis of insulinoma. The aim of this study is to identify risk factors associated with occurrence of insulinoma in the Chinese population. METHODS: This study consisted of 196 patients with insulinoma and 233 controls. Demographic information of the patients and controls and risk factors of the disease were analyzed. Univariate and unconditional multivariable logistic regression analyses were made to estimate odds ratios (ORs) and possible risk factors. RESULTS: Approximately 68.88% (135/196) of the patients were from rural areas in contrast to 10.30% (24/233) of the controls (P【0.0001). This difference was confirmed by the multivariate analysis (OR=4.950; 95% CI: 2.928-8.370). Family history of pancreatic endocrine tumor (OR=16.754; 95% CI: 2.125-132.057) and other cancers (OR=2.360; 95% CI: 1.052-5.291) was also related to a high-risk population of insulinoma. CONCLUSION: Rural residents or people who have a family history of pancreatic endocrine tumor and other cancers are a high-risk population of insulinoma.

Risk Factors for Birth Defects: A Conditional LogisticRegression Analysis of a Case-Control Study in Guang-dong Province of China

Information was obtained from the same questionnaire (23 risk factors listed) of cases and controls. We used a multivariate logistic model, which described variables significantly increased risk of birth defects. The risk factors included maternal educational levels, medicine taken during pregnancy and antenatal care. It was suggested to strengthen antenatal care was the main preventive measure against birth defects.

Among the risk factors of myocardial infarction, anthropometry has no association: A case control study in the central region of Sri Lanka

Background: In the face of rising incidence of cardiovascular disease in the globe, the associated risk factors could be country or area specific. This study aimed to identify the important risk factors of myocardial infarction (MI) prevailing in the Kandydistrict of Sri Lanka. Methods: In a case control design, the cases were recruited from the Coronary Care Unit, General Hospital Kandy, with the diagnosis of myocardial infarction. Matched controls were selected from the Out Patient Department with other ailments, unrelated to cardiovascular diseases. Results: There were 205 cases and 197 controls with the mean age of 56 years (SD ± 8.4 years) and 54 years (SD ± 9.8 years) respectively with male: female ratio of 1:0.2. In analysis, hypertension (OR = 5.09, CI = 2.64 - 9.83), type 11 diabetes (OR = 3.45, CI = 1.90 - 6.10), smoking (OR = 1.95, CI= 1.44 - 2.65) and high LDL cholesterol levels (OR = 1.06, CI = 1.04 - 1.06) were identified as the independent risk factors of myocardial infarction. However, the anthropometric measurements, waist hip ratio (OR = 0.64, CI = 0.33 - 1.34) and body mass index ≥ 25 (OR = 0.75, CI = 0.46 - 1.22) did not show an association with myocardial infarctions. Conclusions: Anthropometric measurements did not qualify as risk factors of myocardial infarction in the local setting even though hypertension, diabetes, smoking and high LDL levels showed a significant association in par with the established data.

THE STUDY ON RISK FACTORS ASSOCIATED WITH BREAST CANCER AMONG WOMEN IN TIANJIN, CHINA AND ADELAIDE, AUSTRALIA

To explore the possible explanation of the marked difference in the incidence of breast cancer between Chinese and Australian women, the authors have compared and analysed the results of two case-control studies completed recently in Tianjin, China and Adelaide, Australia. Of 10 known risk factors for breast cancer 9 were significantly higher in level in Adelaide women than in Tianjin women, i.e., women in Adelaide were much taller, heavier, more obese, earlier at menarche, later at first full-term pregnancy, more nulliparous, less parity, more in history of breast cancer in first degree relatives, more educated. From the 7 risk factors analysed by use of logistic regression model 5 factors, i.e., earlier age at menarche, later age at first full-term pregnancy, less parity, history of benign disease, and history of breast cancer in first degree relatives, were associated significantly with the increased risk for breast cancer in the Tianjin study, but not in Adelaide study. These factors being not associated with breast cancer in Adelaide women were unexpected. The explanation of the indefinite findings in Adelaide study was due to the fact that the level of the risk factor is universally high, relatively uniform and lack of categories. The difference in the risk factor distribution between cases and controle would not be seen in case-control studies, and significance of the risk factor therefore may not be found. According to data on diet survey in these two cities, the calories from fat was significantly higher in Adelaide women than in Tianjin women. The marked difference in incidence in women in the two cities resulted from the summing-up effect of a number of factors. The important role of fat intake in geographical incidence difference and in the development of breast cancer was also discussed.

A case－control study on risk factors of stress fractures in military recruits during basic training

Stress fracture(SF) is an important training injury with a high incidence during recruits' basic training. In order to primarily investigate its risk factors and to provide etiologic threads for a further study,we carried out a case control study on SF. The results of univariate analysis and multivariate logistic regression analysis revealed that attending training on the occasion of injury or fatigue , and a lower length ratio of tibia and pelvic limb were the main risk factors of SF. The authors are of the opinion that compared with the absolute length of tibia , the relative length of tibia(tibia length/pelvic limb length) may be more relevant to the tibia biomechanical characteristics. , The harm of attending training under the circumstances of injury or fatigue is discussed in this paper.

A Case-control Study on High-risk Factors for Newborn Hearing Loss in Seven Cities of Shandong Province

To investigate the high-risk factors for newborn hearing loss and to provide information for preventing the development of hearing loss and delaying its progression, from May 2003 to June 2006, neonates who failed to pass the universal newborn hearing screening （UNHS） were referred to Jinan Newborn Hearing Screening and Rehabilitation Center from 7 newborn hearing screening centers in seven cities of Shandong province. One-to-one pair-matched case-control method was employed for statistical analysis of the basic features of definitely identified cases. High-risk factors relating to the bilateral hearing loss were evaluated by univariate and multivariate Logistic regression analysis. Our results revealed that 721 transferred newborns who didn＇t pass the heating screening received audiological and medical evaluation and 367 were confirmed to have hearing loss. Of them, 177 neonates with hearing loss who met the matching requirements were included in the study as subjects. Univariate analysis showed that high-risk factors related to hearing loss incuded age of father, education backgrounds of parents, parity, birth weight, gestational weeks, craniofacial deformity, history of receiving treatment in neonatal intensive care unit （NICU）, neonatal disease, family history of otopathy and family history of congenital hearing loss. Multivariate Logistic regression analysis revealed that 4 independent risk factors were related to bilateral hearing loss, including parity （OR=16.285, 95% CI 3.379--78,481）, neonatal disease （OR=34;968, 95% CI 2.720 449.534）, family history of congenital hearing loss （OR=69.488, 95% CI 4.417--1093.300） and birth weight （OR=0.241, 95% CI 0.090--0.648）. It is concluded that parity, neonatal disease and family history of heating loss are the promoting factors of bilateral hearing loss in neonates and appropriate intervention measures should be taken to deal with the risk factors.

Clinical and pathological features and risk factors for primary breast cancer patients

BACKGROUND Breast cancer is the most common malignancy in women all around the world.According to the latest statistics in 2018,there were more than 2.08 million new breast cancer cases all around the world and more than 620000 deaths;the proportion of breast cancer deaths in women with cancer is 15%.By studying age,clinicopathological characteristics and molecular classification,age at menarche,age at birth,number of births,number of miscarriages,lactation time,surgical history of benign breast lesions,history of gynecological diseases,and other factors,we retrospectively summarized and compared the disease history of patients with primary breast cancer and patients with benign thyroid tumors admitted to our hospital in the past 10 years to explore the clinicopathological characteristics and risk factors for primary breast cancer.AIM To investigate the clinical and pathological features and risk factors for primary breast cancer treated at our center in order to provide a reference for the prevention and treatment of breast cancer in the Zhuhai-Macao region.METHODS Through a retrospective case-control study,149 patients with primary breast cancer diagnosed and treated at Zhuhai Hospital of Guangdong Provincial Hospital of Traditional Chinese Medicine from January 2013 to March 2020 were included as a case group,and 165 patients with benign breast tumors diagnosed and treated from January 2019 to March 2020 were included as a control group.The data collected included age,age at menarche,age at first birth,number of births,number of miscarriages,lactation time,history of surgery for benign breast lesions,history of familial malignant tumors,history of gynecological diseases,history of thyroid diseases,and the tumor characteristics of the patients in the case group including pathological diagnosis,pathological type,tumor size,lymph node metastasis,distant metastasis,stage,and molecular classification,among others.In the case group,the chi-square test was used to analyze the clinical and pathological features of patients in three age groups(<40,40-59,and≥60 years).A multifactor logistic regression analysis was used to analyze correlations between the two groups.RESULTS Among 149 patients with primary breast cancer,the average age was 48.20±12.06 years,and the proportion of patients at 40-59 years old was the highest,accounting for 61.8%of cases.The molecular type was mainly luminal B type,accounting for 69.2%of cases,and at the time of diagnosis,the tumor stage was mainly stage I/II,accounting for 62.4%of cases.There were no statistically significant differences in the distributions of tumor location,pathological type,tumor size,lymph node metastasis,stage,or molecular classification among the three age groups(<40,40-59,and≥60 years)(P≥0.05).The differences in the distribution of distant metastasis among the three age groups(<40,40-59,and≥60 years)were statistically significant(P<0.01).The differences in lactation time,history of familial malignant tumors,history of gynecological diseases,and history of thyroid diseases between the two groups were not statistically significant(P≥0.05).The differences in age at disease diagnosis,age at menarche,and history of surgery for benign breast lesions were statistically significant(P<0.01).The difference in age at first birth was also statistically significant(P<0.05).CONCLUSION The highest incidence of breast cancer in the Zhuhai-Macao region is present among women aged 40-59 years.There is a larger proportion of stage I/II patients,and the luminal B type is the most common molecular subtype.Distant metastasis occurs mainly in the≥60-year-old group at the first diagnosis;increased age,late age at menarche,and late age at first birth may be risk factors for primary breast cancer,and a history of surgery for benign breast lesions may be a protective factor for primary breast cancer.

Association between Prenatal Environmental Factors and Child Autism: A Case Control Study in Tianjin,China

Objective To investigate the association between autism and prenatal environmental risk factors.Methods A case-control study was conducted among 193 children with autism from the specialeducational schools and 733 typical development controls matched by age and gender by usingquestionnaire in Tianjin from 2007 to 2012. Statistical analysis included quick unbiased efficientstatistical tree （QUEST） and logistic regression in SPSS 20.0.Results There were four predictors by QUEST and the logistic regression analysis, maternal airconditioner use during pregnancy （OR=0.316, 95% CI： 0.215-0.463） was the single first-level node（χ2=50.994, P=0.000）; newborn complications （OR=4.277, 95% CI： 2.314-7.908） and paternalconsumption of freshwater fish （OR=0.383, 95% CI： 0.256-0.573） were second-layer predictors（χ2=45.248, P=0.000; χ2=24.212, P=0.000）; and maternal depression （OR=4.822, 95% CI： 3.047-7.631）was the single third-level predictor （χ2=23.835, P=0.000）. The prediction accuracy of the tree was 89.2%.Conclusion The air conditioner use during pregnancy and paternal freshwater fish diet might bebeneficial for the prevention of autism, while newborn complications and maternal depression might bethe risk factors.

Periodontal disease is associated with increased coronary heart disease risk:A meta-analysis based on 38 case-control studies

AIM: To investigate whether periodontal disease(PD) is associated with increasing coronary heart disease(CHD) risk by performing a meta-analysis.METHODS: Two authors independently searched Pub Med and China National Knowledge Infrastructure up to January 10 th, 2013 for relevant case-control studies that investigated the association between PD and CHD. After quality assessment using Newcastle-Ottawa Scale and data extraction by two independent authors, the overall and subgroup meta-analyses were performed and publication bias were examined using the Comprehensive Meta-Analysis V2 software. Potential publication bias was assessed using visual inspection of the funnel plots, Egger linear regression test, and trims and fill method.RESULTS: Finally 38 relevant case-control studies were identified, involving 4950 CHD patients and 5490 controls. Eleven studies were rated low quality and 27 were high quality. Based on random-effects, a significant association was identified between PD and CHD(OR 3.79, 95%CI: 2.23-6.43, P < 0.001, I2 = 98.59%), and sensitivity analysis showed that this result was robust. Subgroup analyses according to adjusted/unadjusted ORs, source of control, methodological quality, end point, assessment of PD/CHD, and ethnicity also indicated a significant association. Publication bias was detected, and the estimated OR including the "missing" studies did not substantially differ from our estimate with adjustment for missing studies(OR 4.15, 95%CI: 2.62-6.54, P < 0.001).CONCLUSION: Based on the meta-analysis, PD is probably associated with CHD risk independently and significantly.

Risk factors related to female breast cancer in regions of Northeast China： a 1：3 matched case-control population-based study

Background There has been an increase in the incidence of breast cancer in China, but no definite risk and protective factors for breast cancer have been identified in Chinese females. This study was designed to identify the risk factors for female breast cancer in North and East China.

Interaction of methylenetetrahydrofolate reductase C677T,cytochrome P4502E1 polymorphism and environment factors in esophageal cancer in Kazakh population

AIM： To evaluate the association and interaction of genetic polymorphisms in methylenetetrahydrofolate reductase （MTHER） and cytochrome P4502E1 （CY- P4502E1）, environment risk factors with esophageal cancer （EC） in Kazakh, a high EC incidence area of Xinjiang Uygur Autonomous Region, China. METHODS： A 1：2 matched case-control study was conducted with 120 cases of EC and 240 populationor hospital-based controls. The controls were matched for sex, nationality, area of residence and age within a 5-year difference. MTHER and CYP4502E1 genotypes were identified by PCR-based restriction fragment length polymorphism （RFLP）. A conditional logistic regression model was established to identify risk factors. The strata method was adopted in interaction analysis. RESULTS： Low consumption of green vegetables and fresh fruits, alcohol drinking, and unsafe water （shallow well, or river） were found to be the risk factors for EC. Individuals with the MTHFR677 （C/T ＋ T/T） genotype had a 2.62-fold （95% CI： 1.61-4.28） risk of developing EC compared with those who carried the C/C genotype. Individuals with the CYP4502EIC1/C1 genotype had a 3.00-fold （95% CI： 1.82-4.96） risk compared with those who carried the CYP4502E1 （C1/C2 ＋ C2/C2） genotype. Gene-environment interaction analysis showed that MTHFR677 gene polymorphism was correlated with consumption of green vegetables and fresh fruit, while CYP4502E1 C1/C1 was correlated with alcohol drinking and unsafe drinking water. MTHFR and CYP4502E1 analysis of gene-gene interaction showed that individuals with the MTHFR677 （C/T ＋ T/T） and CYP4502EIC1/ C1 genotypes had a 7.41-fold （95% CI： 3.60-15.25） risk of developing EC compared with those who carried the MTHFR677C/C and CYP4502E1 RsaI C1/C2 ＋ C2/C2 genes, and the interaction rate was higher than that of the two factors alone. CONCLUSION： Low consumption of green vegetables and fresh fruits, alcohol drinking, and unsafe water （shallow well, or river） and polymorphisms in MTHFR and CYP4502E1 genes are important risk factors for EC. There is a synergistic interaction among polymorphisms in MTHFR and CYP4502E1 genes and environment factors. MTHFR and CYP4502E1 genes can be used as biomarkers for prevention of EC in Kazakh, Xinjiang Uygur Autonomous Region, China.

A scoring system for predicting the risk of breast cancer-related lymphedema

Objective:We aimed to establish a scoring system to predict the risk of breast cancer-related lymphedema.Methods:From April 2017 to December 2018,533 patients who previously underwent surgery for breast cancer were enrolled in this cross-sectional study.Univariate analysis was performed to explore and define the risk factors.A scoring system was then established on the basis of odds ratio values in the regression analysis.Results:The additive scoring system values ranged from 6 to 22.The receiver operating characteristic(ROC)curve of this scoring system showed a sensitivity and specificity of 83.3%and 57.3%,respectively,to predict the risk of lymphedema at a cut-off of 15.5 points;the area under the curve was 0.736(95%confidence interval:0.662-0.811),with x2=5.134(P=0274)for the Hosmer-Lemeshow test.Conclusions:The predictive efficiency and accuracy of the scoring system were acceptable,and the system could be used to predict and screen groups at high risk for breast cancer-related lymphedema.

How Work Organization Affects the Prevalence of WMSDs: A Case-control Study

Objective In this study, we aimed at exploring the association between work-related musculoskeletal disorders（WMSDs） and work organization based on a case-control study. Methods A total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors. Results A total of 13 variables（P〈0.1） were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance（P〈0.05）. The odds ratios（OR） of ＇work changing with season＇ and ＇sufficient rest time＇ did not reach 1（0.749 and 0.441, respectively）. In addition, ＇sufficient rest time＇ seemed to be the stronger protective factor according to its higher standardized coefficient. And ＇repetitive work every minute＇, ＇constantly repetitive work＇（every day）, ＇shortage of site personnel＇, and ＇often switching shifts with others＇ seemed to be the risk factors. Conclusion Work organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.

Risk factors for Parkinson's disease and interaction analysis in Chinese patients

BACKGROUND： The etiology of Parkinson＇s disease （PD） remains unclear. The majority of studies have focused on the correlation between various factors and PD, with very different conclusions. To date, there has been no study on the interaction between PD family history and other risk factors, and very few studies have reported on hedtability. OBJECTIVE： To explore the risk factors for PD, the interaction between family history and other risk factors, and the impact of genetic factors on PD. DESIGN, TIME AND SETTNG： A paired, retrospective, case-control study was performed at the Department of Neurology, Qilu Hospital of Shandong University from November 2006 to October 2008. PARTICIPANTS： The case group included 157 Chinese PD patients selected from the Department of Neurology, Qilu Hospital of Shandong University in China from 2006 to 2008. An additional 157 patients treated in the same department during the same period were selected as the control group, and they were paired with regard to gender, age, and nationality to the case group. METHODS： Various scored factors were investigated in all participants. The association between various factors and PD was analyzed using univariate and multivariate logistic regression analysis. Interaction analysis between family history and other risk factors was performed using a logistic regression model. Heritability analysis was performed with the Falconer method. MAIN OUTCOME MEASURES： Risk factors for PD, interaction between family history and other risk factors, and heritability. RESULTS： Logistic regression analysis showed that family history, mental work, insecticide exposure, alcohol, and depression positively correlated with PD （odds ratio = 6.75, 2.37, 2.42, 2.03, 5.20, P〈 0.05）, whereas smoking had a negative correlation with PD （odds ratio = 0.49, P 〈 0.001）. The proportions of the effect attributable to interaction of family history and insecticide exposure, alcohol, and depression were 55.2%, 34.0%, and 41.4%, respectively, with a relative excess risk due to interaction of 8.96, 3.31, and 7.85, respectively. PD heritability from first-degree relatives was （36.86 ± 5.76） % and from second-degree relatives was （20.66 ± 6.81） %. CONCLUSION： Family history, mental work, insecticide exposure, alcohol, and depression were determined to be risk factors for PD, whereas smoking was a protective factor. Family history had a positive interaction with coexisting risk factors. Genetic factors had a smaller action on PD than environmental factors.