Critical appraisal of a large population-based case–control study

Author(s):  
Mark Elwood

This chapter shows a large population-based case-control study, to address the quantitative relationship between alcohol consumption and breast cancer. It shows the logistic and design issues, and the assessment of dose-response, consistency and specificity. The critical assessment follows the scheme set out in chapter 10: describing the study, assessing the non-causal explanations of observation bias, confounding, and chance variation; assessing time relationships, strength, dose-response, consistency and specificity, and applying the results to the eligible, source, and target populations; and then comparing the results with evidence from other studies, considering consistency and specificity, biological mechanisms, and coherence with the distribution of exposures and outcomes. The chapter gives a summary and table of the critical assessment and its conclusions; and comments on the impact of the study and research carried out since.

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 45-46
Author(s):  
A. Pascual-Dapena ◽  
A. Prats-Uribe ◽  
D. Prieto-Alhambra

Background:Recent studies show possible mechanisms of microbiota alterations that lead to the development of Ankylosing spondylitis (AS). These disturbances in the microbiota can be caused by long-term and high dose intake of antibioticsObjectives:To analyze the association between antibiotic/s use and the risk of developing AS.Methods:Population based case-control study using electronic medical records data from SIDIAP, covering >80% of the population in Catalonia, Spain. AS diagnoses with 2+ years data available were matched to up to 5:1 controls of same age, sex, and GP practice, and similar follow-up. Tracking of antibiotic use in the previous two years was done through pharmacy dispensation data standardized with ATC codes, and categorized in terms of recency of use and quartiles of cumulative dose. Adjusted odds ratios were estimated using conditional logistic regression analyzing antibiotic use (yes/no), recency of intake (current, recent, past, no use) and cumulative dose (quartiles of daily defined doses in the previous two years). All analyses were adjusted for age, body mass index, smoking, co-morbidity, socio-economic deprivation and number of GP visits as a proxy for healthcare resource use.Results:The study included 4,493 cases diagnosed with AS and 22,016 controls. 46.3% of cases and 28.2% of controls had taken antibiotics. An association between taking beta-lactams (OR 1.18 [95% CI: 1.09-1.28]) and taking macrolides (OR 1.34 [95% CI: 1.18-1.52]) and getting diagnosed with AS was found. This association was stronger with current/recent use (Figure 1), but no dose-response pattern was seen (Figure 2).Figure 1.Recency of use and AS diagnosis.Figure 2.Cumulative use and AS diagnosisConclusion:There is an association between use of certain types of antibiotics and the diagnosis of AS, but no dose-response gradient. These data do not support a causal effect of cumulative antibiotic use on the development of AS. More research is needed on the impact of microbiome disturbance on the risk of developing AS.Acknowledgments:Partial support received from the Oxford NIHR Biomedical Research Centre (BRC)Disclosure of Interests:Ana Pascual-Dapena: None declared, Albert Prats-Uribe: None declared, Daniel Prieto-Alhambra Grant/research support from: Professor Prieto-Alhambra has received research Grants from AMGEN, UCB Biopharma and Les Laboratoires Servier, Consultant of: DPA’s department has received fees for consultancy services from UCB Biopharma, Speakers bureau: DPA’s department has received fees for speaker and advisory board membership services from Amgen


Author(s):  
Mark Elwood

This chapter presents a matched case-control study, of historical importance as the first report of an important aetiological relationship which was subsequently confirmed. It shows the methods for a small matched study, and the complexities of separating the effects of a treatment from the effects of indications for the treatment. The critical assessment follows the scheme set out in chapter 10: describing the study, assessing the non-causal explanations of observation bias, confounding, and chance variation; assessing time relationships, strength, dose-response, consistency and specificity, and applying the results to the eligible, source, and target populations; and then comparing the results with evidence from other studies, considering consistency and specificity, biological mechanisms, and coherence with the distribution of exposures and outcomes. The chapter gives a summary and table of the critical assessment and its conclusions; and comments on the impact of the study and research carried out since.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
C. Airoldi ◽  
C. Magnani ◽  
F. Lazzarato ◽  
D. Mirabelli ◽  
S. Tunesi ◽  
...  

Abstract Background Neighborhood exposure to asbestos increases the risk of developing malignant mesothelioma (MM) in residents who live near asbestos mines and asbestos product plants. The area of Casale Monferrato (Northwest Italy) was impacted by several sources of asbestos environmental pollution, due to the presence of the largest Italian asbestos cement (AC) plant. In the present study, we examined the spatial variation of MM risk in an area with high levels of asbestos pollution and secondly, and we explored the pattern of clustering. Methods A population-based case–control study conducted between 2001 and 2006 included 200 cases and 348 controls. Demographic and occupational data along with residential information were recorded. Bivariate Kernel density estimation was used to map spatial variation in disease risk while an adjusted logistic model was applied to estimate the impact of residential distance from the AC plant. Kulldorf test and Cuzick Edward test were then performed. Results One hundred ninety-six cases and 322 controls were included in the analyses. The contour plot of the cases to controls ratio showed a well-defined peak of MM incidence near the AC factory, and the risk decreased monotonically in all directions when large bandwidths were used. However, considering narrower smoothing parameters, several peaks of increased risk were reported. A constant trend of decreasing OR with increasing distance was observed, with estimates of 10.9 (95% CI 5.32–22.38) and 10.48 (95%CI 4.54–24.2) for 0–5 km and 5–10 km, respectively (reference > 15 km). Finally, a significant (p < 0.0001) excess of cases near the pollution source was identified and cases are spatially clustered relative to the controls until 13 nearest neighbors. Conclusions In this study, we found an increasing pattern of mesothelioma risk in the area around a big AC factory and we detected secondary clusters of cases due to local exposure points, possibly associated to the use of asbestos materials.


2020 ◽  
Vol 39 (11) ◽  
pp. 3402-3407 ◽  
Author(s):  
Ibrahim Abdollahpour ◽  
Dejan Jakimovski ◽  
Nitin Shivappa ◽  
James R. Hébert ◽  
Farhad Vahid ◽  
...  

2005 ◽  
Vol 36 (2) ◽  
pp. 106-107 ◽  
Author(s):  
Jennie Borg ◽  
Deborah Christie ◽  
Pietro Coen ◽  
Robert Booy ◽  
Russell Viner

2008 ◽  
Vol 15 (6) ◽  
pp. 372-382 ◽  
Author(s):  
Sarah Polack ◽  
Hannah Kuper ◽  
Cristina Eusebio ◽  
Wanjiku Mathenge ◽  
Zakia Wadud ◽  
...  

2012 ◽  
Vol 23 (7) ◽  
pp. 1149-1162 ◽  
Author(s):  
Veronika Fedirko ◽  
Gabriela Torres-Mejía ◽  
Carolina Ortega-Olvera ◽  
Carine Biessy ◽  
Angelica Angeles-Llerenas ◽  
...  

2012 ◽  
Vol 107 ◽  
pp. S15-S16 ◽  
Author(s):  
Prasad Iyer ◽  
Herbert Heien ◽  
Bijan Borah ◽  
Gregory Cooper ◽  
Ananya Das ◽  
...  

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