Hospital visitors as controls in case-control studies

Mendonça, Gulnar Azevedo Silva; Eluf-Neto, José

doi:10.1590/s0034-89102001000500005

Cited by 7 publications

(7 citation statements)

References 12 publications

(14 reference statements)

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“…As we expected, cigarette smoking was very close to each other between two series of controls while alcohol drinking was less reported by neighborhood controls (18% vs. 12%, respectively), however, the underreporting was not statistically significant [23]. The other study on organochloride compounds and risk of breast cancer was also used visitor as the control group but no other type of control recruited for comparison [28].…”

Section: Discussionmentioning

confidence: 60%

Opium Use Reporting Error in Case-Control Studies: Neighborhood Controls vs. Hospital Visitor Controls

Mohebbi

Rashidian

Tahami

et al. 2019

Preprint

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Background There are relatively scant data to determine whether hospital visitors could serve as a proper source of controls in substance abuse case-control studies. The aim of this study was to evaluate using neighborhood versus hospital visitor controls in reporting opium use.Methods We conducted two independent case-control studies of cancer in Iran. In the first study, we selected controls from neighborhoods of the patients. For the second one, we selected controls among hospital visitors. In the latter study, hospital visitors could be companions of the patients or others visiting the hospital for any reasons except disease treatment from non-oncology wards of referral hospitals. Opium use and cigarette smoking information were self-reported in both studies.Results A total of 616 of neighborhood controls and 414 of hospital visitor controls were analyzed. Regular opium use among men was significantly higher in hospital visitors than neighborhood controls (43.3% vs. 32.2%, P=0.03) while the prevalence of regular cigarette smokers was very similar in both control groups (46.3 vs. 47.2, P=0.87). After adjusting for potential confounders using logistic regression, the differences of opium use between the two control groups became more pronounced (Adjusted OR=0.26, 95% CI: 0.10-0.69).Conclusions Because of the similarity of reporting cigarette smoking among neighborhood controls but substantially lower reporting of opium use among them, we concluded that neighborhood controls underreported opium use-a sensitive question- and that their use biases the findings in case-control studies. Hospital visitor controls may be more appropriate than neighborhood controls for studies of banned substances.

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Section: Discussionmentioning

confidence: 60%

Opium Use Reporting Error in Case-Control Studies: Neighborhood Controls vs. Hospital Visitor Controls

Mohebbi

Rashidian

Tahami

et al. 2019

Preprint

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“…The literature search led to 23 studies. After reading the studies, nine were excluded: five because they were repeat publications 10,11,12,13,14 ; two were international multi-center studies originating from the same database and which failed to present the data from the Brazilian sample separately 15,16 ; one failed to present the distribution of risk factors in the comparison groups 17 ; and one because the sample consisted only of confirmed breast cancer cases 18 . The review of references in the articles identified above failed to identify new contributions.…”

Section: Resultsmentioning

confidence: 99%

Risk factors for breast cancer: a systematic review of studies with female samples among the general population in Brazil

Pinho

Coutinho

2005

Cad. Saúde Pública

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A systematic review of studies was conducted to determine the characteristics of epidemiological research on risk factors for breast cancer in female samples from the general population in Brazil. Of the 23 articles identified, only 14 were selected for review. Most of the studies were from Southeast Brazil. Three were cross-sectional, conducted in specific populations, and 11 used case-control designs. The sample sizes varied from 40 to 164,269 women. Twenty-nine risk factors were researched, and among these, 11 were investigated in four or more studies. Nulliparity was the most frequent factor, found in 12 of the studies. Prevalence of the factors varied widely among the samples, and since the samples were heterogeneous and the studies presented several methodological limitations, a summary mean was not calculated.

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“…Noncancer hospital‐based controls were not feasible because we would have had to enlist the cooperation of nearby general hospitals, thereby greatly increasing the complexity of the study. Therefore, we chose to select controls from those visiting certain types of other cancer patients at our study hospitals, as has been done in other studies . To do this, we evaluated at each study hospital (1) the number of inpatient surgical and medical oncology wards, the number of rooms in each ward, and the number of beds in each room; (2) whether there were separate inpatient wards for free‐of‐charge patients, those with insurance, or those paying out of pocket; (3) whether there were inpatient wards for patients coming from a distance; (4) visiting days and hours; (5) whether there was a charge for visiting; (6) methods for ascertaining the diagnosis for the patients in each hospital bed; and (7) availability of study staff to complete study procedures, including interviews, during visiting hours.…”

Section: Methodsmentioning

confidence: 99%

Considerations in setting up and conducting epidemiologic studies of cancer in middle‐ and low‐income countries: the experience of a case–control study of inflammatory breast cancer in North Africa in the past 10 years

Soliman

Schairer

2012

Cancer Medicine

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This article illustrates some issues we faced during our experience in conducting an epidemiologic case–control study of inflammatory breast cancer in North Africa. We expect that some of the questions we had to ask in order to address these issues might be helpful to others in setting up epidemiologic studies in developing regions. We describe our experience from different angles including the use of multiple sites to achieve adequate sample size, standardizing diagnosis of disease, identifying cancer cases at the time of diagnosis, control selection procedures, logistics of study implementation, questionnaire development and interviewing, biologic specimens, and procedures for protection of human subjects. We have developed a brief checklist to summarize important issues for conducting future epidemiologic studies in these or similar low- or middle-income countries.

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Hospital visitors as controls in case-control studies

Cited by 7 publications

References 12 publications

Opium Use Reporting Error in Case-Control Studies: Neighborhood Controls vs. Hospital Visitor Controls

Opium Use Reporting Error in Case-Control Studies: Neighborhood Controls vs. Hospital Visitor Controls

Risk factors for breast cancer: a systematic review of studies with female samples among the general population in Brazil

Considerations in setting up and conducting epidemiologic studies of cancer in middle‐ and low‐income countries: the experience of a case–control study of inflammatory breast cancer in North Africa in the past 10 years

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