#case-control

[symbiosisonlinepublishing]

A stock or some other security speaking to a possession intrigue. On an organization’s accounting report, the measure of the assets contributed by the proprietors (the investors) in addition to the held income (or misfortunes).

[floridaepidemiology-blog]

Hypothetical Scenario, Case-Control, Odds Ratio Example Problem:

A medical facility’s oncology program reported an increased number of cases of liver cancer during a certain month.  In an effort to research the problem, an epidemiologist searched tumor registry records to identify all cases of liver cancer during a ten-year period; cancer patients were matched with patients treated for other diseases during the same ten-year period.  All subjects in the study were questioned about lifestyle factors including alcohol, tea, and soda consumption.  The resulting data are displayed in the table below.  Additional information: there were a total of 150 women cancer patients and a total of 300 women patients with disease other than cancer.

DATA

                                    Cancer Patients           Other Patients

                                    Men     Women            Men     Women

LIFESTYLE              

VARIABLE

Alcohol                       180      119                  265      259

Tea Drinking               135      109                  225      224

Soda Drinking             185      139                  265      239

  NOTES:

Total number of women cancer patients = 150

Total number of women patients (other diseases) = 300

The above data may be “simplified,” by ignoring data for “men,” since the specific question refers only to women patients.  Then combine “tea” and “soda” into non-exposed group.  Then create 2x2 table and calculate Odds Ratio (OR).

  Considering the 2X2 table: A=number of exposed w/ disease; B=number of exposed w/out disease; C=number not exposed but w/ disease; D=number w/out disease or exposure.).

                                             Disease

                                         Yes        No        

Exposure             Yes         A           B       

                            No          C           D        

  In this example “exposed” will refer to exposure to (usage of) alcohol

Here’s how you work it out using the “simplified” data set using a 2x2 table (for women patients only):

                                    Cancer

                                Yes         No        

Alcohol       Yes        119        259       

                   No          C            D        

                   Total      150        300        

  You can calculate “C” (cancer patients without alcohol usage)

C=Total cancer patients – Cancer patients with alcohol usage

C=150-119=31 cancer patients without alcohol usage

  You can calculate “D” (non-cancer patients without alcohol usage)

D=Total non-cancer patients – non-cancer patients with alcohol usage

D=300 – 259 = 41 non-cancer patients without alcohol usage

  Plug “C” and “D” into the 2x2 table and solve for the Odds Ratio (OR).

  The final version of the 2x2 table is therefore:

                                    Cancer

                                Yes         No        

Alcohol       Yes        119        259       

                   No         31           41       

                   Total     150        300        

  OR = AD/BC = [119 x 41] / [31 x 259] = 4,879/8,029 = 0.61

[epidemiologists-blog]

Hypothetical Scenario, Case-Control, Odds Ratio Example Problem:

A medical facility’s oncology program reported an increased number of cases of liver cancer during a certain month.  In an effort to research the problem, an epidemiologist searched tumor registry records to identify all cases of liver cancer during a ten-year period; cancer patients were matched with patients treated for other diseases during the same ten-year period.  All subjects in the study were questioned about lifestyle factors including alcohol, tea, and soda consumption.  The resulting data are displayed in the table below.  Additional information: there were a total of 150 women cancer patients and a total of 300 women patients with disease other than cancer.

DATA

                                    Cancer Patients         Other Patients

                                    Men     Women            Men     Women

LIFESTYLE              

VARIABLE

Alcohol                       180      119                  265      259

Tea Drinking               135      109                  225      224

Soda Drinking             185      139                  265      239

  NOTES:

Total number of women cancer patients = 150

Total number of women patients (other diseases) = 300

The above data may be “simplified,” by ignoring data for “men,” since the specific question refers only to women patients.  Then combine “tea” and “soda” into non-exposed group.  Then create 2x2 table and calculate Odds Ratio (OR).

  Considering the 2X2 table: A=number of exposed w/ disease; B=number of exposed w/out disease; C=number not exposed but w/ disease; D=number w/out disease or exposure.).

                                   Disease

                                Yes        No        

Exposure    Yes         A           B       

                   No          C           D        

  In this example “exposed” will refer to exposure to (usage of) alcohol

Here’s how you work it out using the “simplified” data set using a 2x2 table (for women patients only):

                                    Cancer

                                Yes         No        

Alcohol       Yes        119        259       

                   No         C            D        

                   Total      150        300        

  You can calculate “C” (cancer patients without alcohol usage)

C=Total cancer patients – Cancer patients with alcohol usage

C=150-119=31 cancer patients without alcohol usage

  You can calculate “D” (non-cancer patients without alcohol usage)

D=Total non-cancer patients – non-cancer patients with alcohol usage

D=300 – 259 = 41 non-cancer patients without alcohol usage

  Plug “C” and “D” into the 2x2 table and solve for the Odds Ratio (OR).

  The final version of the 2x2 table is therefore:

                                    Cancer

                                Yes         No        

Alcohol       Yes        119        259       

                   No         31          41       

                   Total      150        300        

OR = AD/BC = [119 x 41] / [31 x 259] = 4,879/8,029 = 0.61

[floridaepidemiology-blog]

Case-control studies

[resci]

"MRSA was detected on fomites in 30 (32%) case households and 5 (5%; p<.001) control households. More case patients, 20 (21%) were nasally colonized with MRSA than were control indexes, 2 (2%; p<.001). In a subgroup analysis, the clinical isolate ... Environmental colonization may contribute to the community spread of epidemic strains such as USA300."