PLANNING THE SIZE OF A MATCHED CASE-CONTROL STUDY FOR ESTIMATION OF THE ODDS RATIO

Campylobacter infection has one of the highest rates of all the notifiable diseases in Australia, with a peak in children aged 0–35 months. A matched case-control study was conducted to investigate risk factors for campylobacter infection for children in this age group. Eighty-one cases and 144 controls were enrolled in the study that was conducted between 24 January 1996 and 21 January 1997. The following risk factors were found to be independently associated with illness: ownership of pet puppies (adjusted odds ratio [OR] 16·58, 95% confidence interval [CI] 3·73–73·65) and pet chickens (OR 11·80, CI 1·37–101·75), and consumption of mayonnaise (OR 4·13, CI 1·61–10·59). We propose that children aged less than 3 years are at risk of campylobacter infection if residing in a household which has puppies or chickens as pets.

Download Full-text

Outbreak ofSalmonellaStrathcona caused by datterino tomatoes, Denmark, 2011

Epidemiology and Infection ◽

10.1017/s0950268816000121 ◽

2016 ◽

Vol 144 (13) ◽

pp. 2802-2811 ◽

Cited By ~ 12

Author(s):

L. MÜLLER ◽

C. KJELSØ ◽

C. FRANK ◽

T. JENSEN ◽

M. TORPDAHL ◽

...

Keyword(s):

Public Health ◽

Odds Ratio ◽

Case Control Study ◽

Disease Onset ◽

Case Control ◽

The European Union ◽

Population Register ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

SUMMARYIn September 2011, a patient cluster with a rareSalmonellaserotype – Strathcona – was identified in Denmark. An outbreak investigation was initiated to reveal the source in order to stop the outbreak. In addition to hypothesis-generating interviews, comparable analyses of patients’ household shopping receipts were conducted. A matched case-control study with 25 cases and 56 population register controls was conducted to test the findings of the hypothesis-generating investigation. In total, 43 cases ofSalmonellaStrathcona were reported in Denmark. Additionally, 28 cases were reported from Germany, Italy, Austria and Belgium. The results of the investigation in Denmark showed that 8/10 cases had bought datterino tomatoes prior to disease onset. Illness was associated with a specific supermarket chain [matched odds ratio (mOR) 16·9, 95% confidence interval (CI) 2·2–130], and having consumed elongated small tomatoes (OR 28·1, 95% CI 2·6–302). Traceback investigation showed that the tomatoes came from an Italian producer. This outbreak, linked to tomatoes, underpins the growing recognition of the broad source range ofSalmonellaand the ability of fresh produce to cause multi-country outbreaks. It is important to strengthen the international cooperation between public-health and food-safety authorities in the European Union to investigate future multi-country outbreaks in order to prevent illness from ready-to-eat produce.

Download Full-text

Are lower preoperative serum sodium levels associated with postoperative surgical site infection? Results from a propensity matched case-control study

Journal of Medical Laboratory Science & Technology of South Africa ◽

10.36303/jmlstsa.2020.2.2.63 ◽

2020 ◽

pp. 100-104

Author(s):

N Naidoo ◽

TE Madiba ◽

Y Moodley

Keyword(s):

Serum Sodium ◽

Odds Ratio ◽

Case Control Study ◽

Case Control ◽

Surgical Patients ◽

Site Infection ◽

Preoperative Serum ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

Background: We previously reported a statistical trend toward a harmful association between lower preoperative serum sodium levels and surgical site infection (SSI) in South African (SA) laparotomy patients. Serum sodium tests are widely available and could serve as a cost-effective method for preoperatively identifying patients at risk for SSI who might benefit from additional preventative strategies. We sought to investigate the possible association between lower serum sodium levels and SSI further, in a larger sample of SA patients undergoing various surgical procedures. Objective: To determine if lower preoperative serum sodium levels are associated with SSI in SA surgical patients. Method: This was a propensity matched case-control study involving data from 729 surgical patients who attended a quaternary SA hospital between 01 January 2012 and 31 July 2016. Cases were defined as patients who developed SSI. Controls were defined as patients who did not develop SSI. Multivariate logistic regression was used to investigate the association between preoperative serum sodium levels (in mmol/L) and SSI. Results: Lower preoperative serum sodium levels were associated with a higher risk of SSI (odds ratio per 1.0 mmol/L decrease in serum sodium: 1.051, 95% confidence interval: 1.007–1.097; p = 0.026). Conclusion: Although we report a statistically significant association between lower preoperative serum sodium levels and a higher risk of SSI, the magnitude of this effect size (odds ratio) is minimal and clinically insignificant. Preoperative serum sodium levels are unlikely to be useful for SSI risk stratification in our setting.

Download Full-text

Risk factors for methicillin-resistant Staphylococcus aureus bacteremia: A multicenter matched case-control study

Biomédica ◽

10.7705/biomedica.v36i4.3193 ◽

2016 ◽

Vol 36 (4) ◽

pp. 612 ◽

Cited By ~ 3

Author(s):

Paola Mariana Arias-Ortiz ◽

Libia Del Pilar Calderón ◽

Juan Sebastián Castillo ◽

José Moreno ◽

Aura Lucía Leal ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Odds Ratio ◽

Methicillin Resistant Staphylococcus Aureus ◽

Case Control Study ◽

Case Control ◽

Staphylococcus Aureus Bacteremia ◽

Factores De Riesgo ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

Introducción. Staphylococcus aureus resistente a la meticilina es uno de los agentes patógenos más frecuentes en las unidades de cuidados intensivos. Su presencia prolonga las hospitalizaciones y aumenta el riesgo de mortalidad en los pacientes con bacteriemia. Sin embargo, la etiología de este marcador de resistencia no ha sido completamente estudiada.Objetivo. Determinar los factores asociados con la aparición de S. aureus resistente a la meticilina causante de bacteriemia en pacientes atendidos en unidades de cuidados intensivos en Bogotá.Materiales y métodos. Se hizo un estudio retrospectivo de casos y controles emparejados, anidado en una cohorte de pacientes con diagnóstico de bacteriemia por S. aureus atendidos en unidades de cuidados intensivos de Bogotá entre 2006 y 2008. Los casos fueron pacientes con hemocultivo positivo para resistencia a la meticilina, emparejados 1 a 1 con controles con hemocultivos sensibles a la meticilina de la misma institución y año de hospitalización. Se analizaron mediante regresión logística condicional los factores de riesgo asociados con la presencia de resistencia, con énfasis en el tratamiento previo con antibióticos.Resultados. Se incluyeron 372 pacientes con bacteriemia por S. aureus. Factores como el uso de dispositivos previos a la hospitalización: vasculares (Odds ratio, OR=1,986; IC95% 1,038-3,801) y urinarios (OR=2,559; IC95% 1,170-5,596), así como el número de antibióticos administrado previamente, se asociaron con la aparición de resistencia. Se registró un efecto de gradiente con el número de antibióticos usados previamente, especialmente carbapenémicos.Conclusiones. El uso racional de antibióticos y la vigilancia de la exposición a procedimientos quirúrgicos o al uso de dispositivos invasivos, son intervenciones que podrían disminuir la aparición de S. aureus resistente a meticilina causante de bacteriemia.

Download Full-text

Cryptosporidiosis in Wisconsin: A case-control study of post-outbreak transmission

Epidemiology and Infection ◽

10.1017/s0950268800001473 ◽

1996 ◽

Vol 117 (2) ◽

pp. 297-304 ◽

Cited By ~ 21

Author(s):

P. Osewe ◽

D. G. Addiss ◽

K. A. Blair ◽

A. Hightower ◽

M. L. Kamb ◽

...

Keyword(s):

Risk Factors ◽

Odds Ratio ◽

Case Control Study ◽

Case Control ◽

Watery Diarrhoea ◽

Waterborne Outbreak ◽

Water Plant ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

SummaryDuring March–April 1993, an estimated 403000 residents of the 5-county greater Milwaukee, Wisconsin area developed cryptosporidiosis after drinking contaminated municipal water. Although the number of cases dropped precipitously after the implicated water plant closed on 9 April, cases continued to occur. To investigate risk factors for post-outbreak cryptosporidiosis, 33 Milwaukee-area residents who had laboratory-confirmed Cryptosporidium infection with onset of diarrhoea between 1 May and 27 June 1993 were interviewed by telephone. Of these, 28(85%) had onset of diarrhoea during May, 12(36%) had watery diarrhoea during the outbreak, and 5 (15%) were HIV-infected. In a neighbourhood-matched case-control study, immunosuppression (matched odds ratio (MOR) not calculable, 95 % confidence interval (CI) 3·0, infinity) and having a child less than 5 years old in the household (MOR = 17·0, CI 2·0, 395·0) were independently associated with infection. When persons who had diarrhoea during the outbreak were excluded, immunosuppression remained significantly associated with illness (MOR not calculable, CI 1·6, infinity). Cryptosporidium transmission continued after this massive waterborne outbreak but decreased rapidly within 2 months.

Download Full-text

Risk factors forClostridium difficileinfection in the community: a case-control study in patients in general practice, Denmark, 2009–2011

Epidemiology and Infection ◽

10.1017/s0950268813002380 ◽

2013 ◽

Vol 142 (7) ◽

pp. 1437-1448 ◽

Cited By ~ 21

Author(s):

L. M. SØES ◽

H. M. HOLT ◽

B. BÖTTIGER ◽

H. V. NIELSEN ◽

V. ANDREASEN ◽

...

Keyword(s):

Risk Factors ◽

General Practice ◽

Odds Ratio ◽

Case Control Study ◽

Conditional Logistic Regression ◽

Gastrointestinal Symptoms ◽

Case Control ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

SUMMARYTo identify risk factors forClostridium difficileinfection (CDI) in Danish patients consulting general practice with gastrointestinal symptoms, a prospective matched case-control study was performed; cases (N = 259) had positive cultures for toxigenicC. difficileand controls (N = 455) negative cultures. Data were analysed by conditional logistic regression. In patients aged ⩾2 years (138 cases), hospitalization [odds ratio (OR) 8·4, 95% confidence interval (CI) 3·1–23], consumption of beef (OR 5·5, 95% CI 2·0–15), phenoxymethylpenicillin (OR 15, 95% CI 2·7–82), dicloxacillin (OR 27, 95% CI 3·6–211), and extended spectrum penicillins (OR 9·2, 95% CI 1·9–45) were associated with CDI. In patients aged <2 years none of these were associated with CDI, but in a subgroup analysis contact with animals was associated with CDI (OR 8·1, 95% CI 1·0–64). This study emphasizes narrow-spectrum penicillins, and suggests beef consumption, as risk factors for CDI in adults, and indicates a different epidemiology of CDI in infants.

Download Full-text

Relationship Between Sexual Abuse in Childhood and the Occurrence of Mental Illness in Adulthood: A Matched Case–Control Study in Nigeria

Sexual Abuse ◽

10.1177/1079063216672172 ◽

2016 ◽

Vol 30 (4) ◽

pp. 438-453

Author(s):

C. U. Okeafor ◽

I. N. Okeafor ◽

C. I. Tobin-West

Keyword(s):

Mental Illness ◽

Sexual Abuse ◽

Odds Ratio ◽

Case Control Study ◽

Case Control ◽

Non Governmental Organizations ◽

Matched Case ◽

The Government ◽

Matched Case Control Study ◽

Control Study

This study aimed to examine the relationship between exposure to childhood sexual abuse (CSA) and the occurrence of mental illness in adulthood in Nigeria. An age- and gender-matched case–control study was conducted in the University of Port Harcourt Teaching Hospital, Nigeria, from January to March 2014. Cases were defined as individuals aged 18 to 60 years diagnosed with mental illness while controls were aged 18 to 60 years who did not have mental illness. The study had 304 subjects comprised of 152 case–control pairs. This case–control study showed a statistically significant association between exposure to CSA and occurrence of mental illness in adulthood (pair-matched odds ratio = 3.25, 95% CI = [1.70, 6.21]). The association between CSA and mental illness was still significant (adjusted odds ratio = 3.11, 95% CI = [1.67, 5.82]) after controlling for family functionality. A robust CSA prevention and treatment strategy that considers the victim and the perpetrator in Nigeria is hereby advocated. This could be achieved by the collaborative efforts of the government of Nigeria and non-governmental organizations.

Download Full-text

Toxoplasma gondii exposure and epilepsy: A matched case-control study in a public hospital in northern Mexico

SAGE Open Medicine ◽

10.1177/2050312118767767 ◽

2018 ◽

Vol 6 ◽

pp. 205031211876776 ◽

Cited By ~ 3

Author(s):

Cosme Alvarado-Esquivel ◽

Yazmin del Rosario Rico-Almochantaf ◽

Jesús Hernández-Tinoco ◽

Gerardo Quiñones-Canales ◽

Luis Francisco Sánchez-Anguiano ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Confidence Interval ◽

Odds Ratio ◽

Public Hospital ◽

Case Control Study ◽

Case Control ◽

Igg Antibodies ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

Objectives: This study aimed to determine the association between infection with Toxoplasma gondii and epilepsy in patients attended to in a public hospital in the northern Mexican city of Durango. Methods: We performed an age- and gender-matched case-control study of 99 patients suffering from epilepsy and 99 without epilepsy. Sera of participants were analyzed for anti- T. gondii IgG and IgM antibodies using commercially available enzyme-linked immunoassays. Seropositive samples to T. gondii were further analyzed for detection of T. gondii DNA by polymerase chain reaction. Results: Anti- T. gondii IgG antibodies were found in 10 (10.1%) of the 99 cases and in 6 (6.1%) of the 99 controls (odds ratio = 1.74; 95% confidence interval: 0.60–4.99; p = 0.43). High (> 150 IU/mL) levels of anti- T. gondii IgG antibodies were found in 6 of the 99 cases and in 4 of the 99 controls (odds ratio = 1.53; 95% confidence interval: 0.41–5.60; p = 0.74). Anti- T. gondii IgM antibodies were found in 2 of the 10 IgG seropositive cases, and in 2 of the 6 IgG seropositive controls (odds ratio = 0.50; 95% confidence interval: 0.05–4.97; p = 0.60). T. gondii DNA was not found in any of the 10 anti- T. gondii IgG positive patients. Bivariate analysis of IgG seropositivity to T. gondii and International Statistical Classification of Diseases and related Health Problems, 10th Edition codes of epilepsy showed an association between seropositivity and G40.1 code (odds ratio = 22.0; 95% confidence interval: 2.59–186.5; p = 0.008). Logistic regression analysis showed an association between T. gondii infection and consumption of goat meat (odds ratio = 6.5; 95% confidence interval: 1.22–34.64; p = 0.02), unwashed raw vegetables (odds ratio = 26.3; 95% confidence interval: 2.61–265.23; p = 0.006), and tobacco use (odds ratio = 6.2; 95% confidence interval: 1.06–36.66; p = 0.04). Conclusions: Results suggest that T. gondii infection does not increase the risk of epilepsy in our setting; however, infection might be linked to specific types of epilepsy. Factors associated with T. gondii infection found in this study may aid in the design of preventive measures against toxoplasmosis.

Download Full-text