A case-control study of the impact of improved sanitation on diarrhoea morbidity in Lesotho

A health impact evaluation of the Rural Sanitation Pilot Project in Mohale's Hoek district, Lesotho, was conducted from October 1987 to September 1988. A clinic-based case-control design was used to investigate the impact of improved sanitation on diarrhoea morbidity in young children. The results indicate that under-5-year-olds from households with a latrine may experience 24% fewer episodes of diarrhoea than such children from households without a latrine (odds ratio = 0.76; 95% confidence interval, 0.58-1.01). The impact of latrines on diarrhoea was greater in those households that used more water, practised better personal hygiene, and where the mothers had a higher level of education or worked outside the home. In common with studies conducted in Malawi, Philippines, and Sri Lanka, little evidence was found that the relationship between latrine ownership and diarrhoea was confounded by socioeconomic status or environmental variables. For a sample of cases and controls, data on exposure status (presence or absence of a latrine) that were collected by interview at the clinics agreed closely with those obtained by observation during a home visit.     

Case-control studies of the effect of environmental sanitation on diarrhoea morbidity: methodological implications of field studies in Africa and Asia

The problems and prospects in the use of case-control studies to assess the effects of improvements in environmental sanitation on diarrhoea morbidity are discussed on the basis of two field studies. It is concluded that an adequate design is available for assessing the effects of a single improvement on diarrhoeal disease. The estimates of effect appear to be valid and sufficiently precise. For addressing more complex questions of interactions, sample sizes would have to be increased substantially. The experience with two field studies suggests that there is hope that a simpler protocol may be feasible, in which only limited information is collected, in which few home visits are made, and in which analytical techniques are simple. Until more field studies have been conducted definitive conclusions cannot be reached on the applicability of such a simple, rapid and inexpensive approach.     

An investigation of district spatial variations of childhood diarrhoea and fever morbidity in Malawi

Although diarrhoea and malaria are among the leading causes of child mortality and morbidity in Sub-Saharan Africa, few detailed studies have examined the patterns and determinants of these ailments in the most affected communities. In this paper, we investigate the spatial distribution of observed diarrhoea and fever prevalence in Malawi using individual data for 10,185 children from the 2000 Malawi Demographic and Health survey. We highlight inequalities in child health by mapping the residual district spatial effects using a geo-additive probit model that simultaneously controls for spatial dependence in the data and potential nonlinear effects of covariates. The residual spatial effects were modelled via a Bayesian approach. For both ailments, we were able to identify a distinct district pattern of childhood morbidity. In particular, the results suggest that children living in the capital city are less affected by fever, although this is not true for diarrhoea, where some urban agglomerations are associated with a higher childhood morbidity risk. The spatial patterns emphasize the role of remoteness as well as climatic, environmental, and geographic factors on morbidity. The fixed effects show that for diarrhoea, the risk of child morbidity appears to be lower among infants who are exclusively breastfed than among those who are mixed-fed. However, exclusive breastfeeding was not found to have a protective effect on fever. An important socio-economic factor for both diarrhoea and fever morbidity was parental education, especially maternal educational attainment. Diarrhoea and fever were both observed to show an interesting association with child's age. We were able to discern the continuous worsening of the child morbidity up to 8-12 months of age. This deterioration set in right after birth and continues, more or less linearly until 8-12 months, before beginning to decline thereafter. Independent of other factors, a separate spatial process produces district inequalities in child's health.     

Evidence for recent diarrhoeal morbidity as a risk factor for persistent diarrhoea: a case-control study

The association between persistent diarrhoea and 'recent morbidity' defined as that occurring within the two-month period immediately preceding the onset of persistent diarrhoea was investigated in a population-based case-control study in rural North India. In two separate matched case-control analyses children with persistent diarrhoea (cases) were compared to population controls (five controls matched to each case) and acute diarrhoeal controls (three controls matched to each case). After correcting for possible confounding variables, comparing children with persistent diarrhoea and matched population controls, presence of a recent diarrhoeal illness was significantly associated with persistent diarrhoea with an odds ratio (OR) 2.6 (95%) confidence interval (CI): 1.1-7.1; p less than 0.05); during infancy this OR was 5.2 (95% CI: 1.0-31.9; p less than 0.01). Comparing children with persistent diarrhoea to matched acute diarrhoeal controls, presence of recent diarrhoeal illness was associated with an OR of 5.1 (95% CI: 1.3-20.3) in favour of the episode becoming persistent; in infants this OR was 10.4 (95% CI: 1.1-132.4; p less than 0.001).     

Rotavirus diarrhoea in Apache children: a case-control study

A case-control study of rotavirus diarrhoea in Apache children up to two years old was conducted at the White Mountain Apache reservation from 1 May through 15 December 1985 to identify risk factors for rotavirus diarrhoea. The mothers of fifty cases, forty-five hospital controls and twenty-five neighbourhood controls participated in this study. Exposure to other children with diarrhoea stood out as the single most important factor for acquiring rotavirus diarrhoea (Odds ratio = 14.0). Other significant risk factors were living in homes with septic tanks and in homes with 'poor environmental sanitation.'. Minimizing contacts of children with diarrhoea therefore would be the most effective measure in preventing the spread of this disease in the community.     

Risk factors of acute diarrhoea in summer--a nation-wide French case-control study

The aim of this study was to identify risk factors for acute diarrhoea (AD) during the summer in France. A matched case-control study was conducted at a national level among patients of 500 general practitioners (GPs). From July to September 1996, 468 case-control pairs were included. Cases were more likely than controls (i) to live away from their main residence (OR 3.0; 95% CI 1.6-5.7), (ii) to have returned from a country at high risk of AD (OR 4.6; CI 0.9-23.1), and (iii) to have been in contact with a case of AD (OR 2.0; CI 1.3-3.1). A significantly decreased risk of AD was found for consumption of well-cooked chicken (OR 0.5; CI 0.3-0.8) and raw or undercooked home-made egg-containing products (OR 0.6; CI 0.4-0.8). These findings suggest that travel to high-risk areas, or travel within France, and being in contact with a case of AD, are risk factors for the occurrence of AD in summer in France.     

Modelling the effect of malaria endemicity on spatial variations in childhood fever,diarrhoea and pneumonia in Malawi

Background  

Co-morbidity with conditions such as fever, diarrhoea and pneumonia is a common phenomenon in tropical Africa. However, little is known about geographical overlaps in these illnesses. Spatial modelling may improve our understanding of the epidemiology of the diseases for efficient and cost-effective control.     

Risk factors for the transmission of diarrhoea in children: a case-control study in rural Malaysia.

In response to a recorded increasing incidence of diarrhoea in Tumpat District, Malaysia, a case-control study was performed to identify modifiable risk factors for the transmission of diarrhoea, in children aged 4-59 months. Ninety-eight pairs of children, matched on age and sex, were recruited prospectively from health centres. Exposure status was determined during a home visit. Interviewers were 'blinded' as to the disease status of each child. Odds ratios were measured through matched pair analysis and conditional logistic regression. Risk factors for diarrhoea identified were: reported--drinking of unboiled water, storage of cooked food before consumption and bottle feeding; and observations--animals inside the house and absence of washing water in latrines. Water quality, source of drinking water, reported hand washing behaviour, indiscriminate defecation by children, cup use and the absence of a functional latrine were not associated with diarrhoea. Nonsignificant associations were found for: accessibility of washing water source, type of water storage container and use of fly covers for food.     

Childhood psychologic environmental exposure in women with diagnosed somatoform disorders. A case-control study

Fifty-three female patients with diagnosed somatoform disorders (having pronounced somatic symptoms without objective somatic signs) were studied regarding childhood exposure to death, divorce, serious somatic illness and prolonged pain in members of their core family. Similar registrations were made in a control group of 53 healthy women. The two groups were compared using the case-control method. The results revealed a more frequent exposure in the somatoform disorder patients regarding all four items, and for serious somatic illness and prolonged pains the difference was statistically significant. Further elaboration of the data suggested that exposure to pain in the family was the most important of the studied factors. The findings are thought to demonstrate the environmental etiologic impact on somatoform disorders occasioned by such psychologic exposure as those registered. The possibility of a genetic etiologic implication of the findings is also discussed.     

Risk factors for human cysticercosis morbidity: a population-based case-control study.

A population-based case-control study to determine social and behavioural risk factors for Taenia solium cysticercosis in humans was carried out in a rural area. Shandong province, China. Forty-eight cases with cysticercosis were ascertained through a prevalence survey conducted among 7281 persons in 1993. For each case, four controls residing in the same village and matched for age and sex were randomly selected. Information regarding demographic, social and behavioural factors was collected during house visits through interviews and direct observation. Risk factors strongly associated with human cysticercosis included poor personal hygiene, being unable to recognize cysticerci-containing meat, poor pig-raising practices and a history of passing tapeworm proglottides. The results indicate that health education in combination with chemotherapy for taeniasis is required for the control of cysticercosis in humans.     

An industrial hygiene methodology developed in support of a retrospective morbidity case-control study.

An industrial hygiene methodology that was developed in support of an epidemiologic case-control study is described. This study was conducted to investigate a potentially increased incidence of colorectal cancer among employees who worked at a unit that manufactured polypropylene by a heavy diluent process. Retrospective epidemiologic case-control studies typically have exposure assessment problems because industrial hygiene monitoring data are often not available. Misleading job titles are another problem that can provide a poor framework for estimating exposures. In addition, a job title-based exposure assessment assumes individual work patterns are not important in assessing worker exposures, although this is contradictory to industrial hygiene experience. The design of the case-control study provided an innovative industrial hygiene approach to circumvent these typical exposure estimating problems. The industrial hygiene methodology of the case-control study included assessing historical exposures, developing an exposure estimating matrix, selecting candidate etiologic agents based on a joint toxicologic and industrial hygiene review, administering a work activity questionnaire, calculating exposure scores, and conducting a statistical analysis. The study design also provided an additional exposure measurement independent of the toxicologic and industrial hygiene review. This provided an opportunity to compare the likelihood of exposure misclassification and, as expected, showed that a more detailed exposure estimate resulted in less misclassification.     

浙江省狂犬病免疫效果病例-对照研究

目的 评价狂犬病疫苗免疫预防措施效果,并分析免疫失败的原因. 方法 对2005-2006年浙江省132例狂犬病病例和与其有同源暴露的狂犬病暴露者73名采用统一调查表进行入户个案面对面调查,采用病例-对照研究方法和非条件logistic回归分析研究探讨免疫预防措施效果和造成免疫预防失败的因素. 结果 14.4%(19/132)的病例和93.2%(68/73)的对照在狂犬病暴露后去医疗机构注射过狂犬病疫苗,对应的OR值(95%CI)为0.012(0.004～0.035);72.2%(13/18)的病例和7.7%(5/65)的对照末完成狂犬病疫苗注射,相对规范且完成全程注射者的OR值(95% CI)为15.60(3.85～63.26).暴露前免疫史与暴露后疫苗免疫对狂犬病暴露者均有一定的保护作用,以暴露后疫苗免疫保护作用为佳,两者的OR值(95%CI)分别为0.065(0.032～0.132)和0.012(0.004～0.035).分层分析表明暴露后疫苗免疫对狂犬病暴露者有保护作用,校正后的OR值(95% CI)为0.010(0.002～0.047).经济条件差、不知道狂犬病的危害等是未接种狂犬病疫苗的原因. 结论 狂犬病暴露后的疫苗免疫对狂犬病暴露者有很好的保护作用,未完成狂犬病疫苗注射是导致免疫失败的主要原因.

Abstract：

Objective This research was to evaluate the effect of pre-and post-exposure prophylaxis for rabies and to analyze the reasons of invalidation. Methods A case-control study was conducted in 132rabies patients and 73 subjects exposed to homologous rabies in Zhejiang province.All the subjects were investigated face to face by using the same questionnaires at home.Non-conditional logistic regression was used to analyze the effect of measures and the reasons of invalidation. Results 14.4%(19/132) of cases and 93.2%(68/73) of controls had post-exposure,which resulted in an OR (95% CI) of 0.012 (0.004-0.035).However,72.2%(13/18) of cases and 7.7%(5/65)of controls had not finished their postexposure,and thus had an OR (95% CI) of 15.60 (3.85-63.26).Stratified analysis stated that postexposure prophylaxis was a protective factor,with an OR(95% CI) of 0.01 (0.002-0.047).Poor financial condition and poor knowledge of rabies were the causes of nonvaccination. Conclusion Post-exposure prophylaxis could protect the people exposed to rabies well and unfinished post-exposure prophylaxis was the main reason for its invalidation.     

唐山市女性乳腺癌环境危险因素病例对照研究

目的探讨乳腺癌发病的环境危险因素，为乳腺癌的病因研究及其一级预防提供理论依据。方法采用1：1配比的病例对照研究，调查2004年4月-2005年7月在唐山市各大医院就诊的新发女性乳腺癌患者和非乳腺癌对照各175例。采用面对面访谈式进行调查，应用配对X^2检验进行单因素分析，用条件Logistic回归进行多因素分析。结果单因素分析表明，室内杀虫剂使用年限长、有机溶剂暴露年限长、农药暴露年限长、居住区环境污染、被动吸烟年限长、放射线检查次数多为乳腺癌的危险因素；多因素条件Logistic回归分析显示，室内杀虫剂使用年限长、有机溶剂暴露年限长与女性乳腺癌的发生有关，即接触年限越长，患乳腺癌的危险性越高。豆类食品摄入、蔬菜摄入对女性乳腺癌的发生有保护作用，即摄入频率越高，患乳腺癌的危险性降低。结论室内杀虫剂使用年限长、有机溶剂等化学物接触年限长为乳腺癌的危险因素；蔬菜、豆类食品摄入量高为保护因素。     

A reassessment of the cost-effectiveness of water and sanitation interventions in programmes for controlling childhood diarrhoea

Cost-effectiveness analysis indicates that some water supply and sanitation (WSS) interventions are highly cost-effective for the control of diarrhoea among under-5-year-olds, on a par with oral rehydration therapy. These are relatively inexpensive "software-related" interventions such as hygiene education, social marketing of good hygiene practices, regulation of drinking-water, and monitoring of water quality. Such interventions are needed to ensure that the potentially positive health impacts of WSS infrastructure are fully realized in practice. The perception that WSS programmes are not a cost-effective use of health sector resources has arisen from three factors: an assumption that all WSS interventions involve construction of physical infrastructure, a misperception of the health sector's role in WSS programmes, and a misunderstanding of the scope of cost-effectiveness analysis. WSS infrastructure ("hardware") is generally built and operated by public works agencies and financed by construction grants, operational subsidies, user fees and property taxes. Health sector agencies should provide "software" such as project design, hygiene education, and water quality regulation. Cost-effectiveness analysis should measure the incremental health impacts attributable to health sector investments, using the actual call on health sector resources as the measure of cost. The cost-effectiveness of a set of hardware and software combinations is estimated, using US$ per case averted, US$ per death averted, and US$ per disability-adjusted life year (DALY) saved.     

Endometriosis in Lebanon. A case-control study

To explore some of the risk factors for endometriosis, the authors compared 170 cases with 170 age-matched controls similarly undergoing laparoscopy at the American University of Beirut Medical Center between 1979 and 1981. The findings include a positive association with first-class admissions (odds ratio = 2.77) and a negative association with parity and gravidity. Both associations are consistent with the findings of other studies. There was no association with occupational status, nationality, religion, marital status, or past medical history.     

环境和遗传因素与广东前列腺癌关系的病例对照研究

Objective To explore the etiologic relationship of prostate cancer and environmental and genetic polymorphism in southern China. Methods A hospital-based and 1 : 1 matched case-control study was conducted. A total of 142 matched pains of subjects were investigated in this study. The blood samples were collected from 85 cases of prostate cancer and 82 controls of other diseases after informing consent. The CYPIAI ,CYPI7 and AR genes were analyzed by using the method of PCR, PCR-RFLP. The data were analyzed with conditional logistic regression model. Results An increased risk of prostate cancer development was observed with the early first spermatorrbea (age<18) (OR=2. 90,95% CI: 1.76-4. 80), early first sexual intercourse (age≤ 24) (OR=2. 38,95% CI: 1.14 -4. 96), frequent sexual intercourse before 35 year old (OR=1.80,95% CI: 1.19 -2. 70), family history of cancer (OR=2. 70,95% CI: 1.31 -5.58), more intake of pork (OR=2. 27,95% CI: 1.38 -3.70). Factors in lowing the risks were the fruit intake and drinking of green tea by OR value at 0. 25 (95% CI: 0. 08 -0. 75) and 0. 52 (95% CI:0. 28 -0. 96) respectively. CYP17 A1/A2 and CYP17 A2/A2 genotypes were related with a high risk of prostate cancer and OR values of 1.78 (95% CI: 0. 70 -4. 53) and 2. 57 (95% CI: 0. 91 -7. 25) respectively. Study also showed that there was an interaction between CYP17 polymorphisms and early first spermatorrbea and family cancer history related to the risk of prostate cancer with OR value at 13.35 (95%CI: 1.58 -113.00) and 4.01 (95% CI: 1.22 -13.17) respectively. Conclusion Sexual intercourse, dietary intake and family cancer history should be related to prostate cancer occurrence. CYP17 polymorphism might be associated with a high risk of prostate cancer. It suggests that there are multiple environmental and genetic factors to the prostate cancer.     

环境和遗传因素与广东前列腺癌关系的病例对照研究

Objective To explore the etiologic relationship of prostate cancer and environmental and genetic polymorphism in southern China. Methods A hospital-based and 1 : 1 matched case-control study was conducted. A total of 142 matched pains of subjects were investigated in this study. The blood samples were collected from 85 cases of prostate cancer and 82 controls of other diseases after informing consent. The CYPIAI ,CYPI7 and AR genes were analyzed by using the method of PCR, PCR-RFLP. The data were analyzed with conditional logistic regression model. Results An increased risk of prostate cancer development was observed with the early first spermatorrbea (age<18) (OR=2. 90,95% CI: 1.76-4. 80), early first sexual intercourse (age≤ 24) (OR=2. 38,95% CI: 1.14 -4. 96), frequent sexual intercourse before 35 year old (OR=1.80,95% CI: 1.19 -2. 70), family history of cancer (OR=2. 70,95% CI: 1.31 -5.58), more intake of pork (OR=2. 27,95% CI: 1.38 -3.70). Factors in lowing the risks were the fruit intake and drinking of green tea by OR value at 0. 25 (95% CI: 0. 08 -0. 75) and 0. 52 (95% CI:0. 28 -0. 96) respectively. CYP17 A1/A2 and CYP17 A2/A2 genotypes were related with a high risk of prostate cancer and OR values of 1.78 (95% CI: 0. 70 -4. 53) and 2. 57 (95% CI: 0. 91 -7. 25) respectively. Study also showed that there was an interaction between CYP17 polymorphisms and early first spermatorrbea and family cancer history related to the risk of prostate cancer with OR value at 13.35 (95%CI: 1.58 -113.00) and 4.01 (95% CI: 1.22 -13.17) respectively. Conclusion Sexual intercourse, dietary intake and family cancer history should be related to prostate cancer occurrence. CYP17 polymorphism might be associated with a high risk of prostate cancer. It suggests that there are multiple environmental and genetic factors to the prostate cancer.     

环境和遗传因素与广东前列腺癌关系的病例对照研究

Objective To explore the etiologic relationship of prostate cancer and environmental and genetic polymorphism in southern China. Methods A hospital-based and 1 : 1 matched case-control study was conducted. A total of 142 matched pains of subjects were investigated in this study. The blood samples were collected from 85 cases of prostate cancer and 82 controls of other diseases after informing consent. The CYPIAI ,CYPI7 and AR genes were analyzed by using the method of PCR, PCR-RFLP. The data were analyzed with conditional logistic regression model. Results An increased risk of prostate cancer development was observed with the early first spermatorrbea (age<18) (OR=2. 90,95% CI: 1.76-4. 80), early first sexual intercourse (age≤ 24) (OR=2. 38,95% CI: 1.14 -4. 96), frequent sexual intercourse before 35 year old (OR=1.80,95% CI: 1.19 -2. 70), family history of cancer (OR=2. 70,95% CI: 1.31 -5.58), more intake of pork (OR=2. 27,95% CI: 1.38 -3.70). Factors in lowing the risks were the fruit intake and drinking of green tea by OR value at 0. 25 (95% CI: 0. 08 -0. 75) and 0. 52 (95% CI:0. 28 -0. 96) respectively. CYP17 A1/A2 and CYP17 A2/A2 genotypes were related with a high risk of prostate cancer and OR values of 1.78 (95% CI: 0. 70 -4. 53) and 2. 57 (95% CI: 0. 91 -7. 25) respectively. Study also showed that there was an interaction between CYP17 polymorphisms and early first spermatorrbea and family cancer history related to the risk of prostate cancer with OR value at 13.35 (95%CI: 1.58 -113.00) and 4.01 (95% CI: 1.22 -13.17) respectively. Conclusion Sexual intercourse, dietary intake and family cancer history should be related to prostate cancer occurrence. CYP17 polymorphism might be associated with a high risk of prostate cancer. It suggests that there are multiple environmental and genetic factors to the prostate cancer.