Case-Control Studies: Uterine Cancer and BMI

Task

Unmatched and Matched Case-Control Analyses

Exposure: BMI

Outcome: Uterine Cancer

1. What are the crude and adjusted associations between your putative exposure and uterine cancer in the unmatched case-control study? (One table with crude ORs and adjusted ORs [add additional rows as needed], and summary of results, <300 words)

Table 5. Multivariable analysis among 147 cases and 147 controls for uterine cancer, National Health Interview Study (NHIS), United States, 2015

	Crude OR (95% CI)	Full model Adjusted/Pooled OR (95% CI)
Body Max Index
Underweight or healthy weight	ref	ref
Overweight	1.37 (0.77 – 2.44)	1.01 (0.50 – 2.02)
Obese	1.74 (1.01 – 3.02 )	1.39 ( 0.73 – 2.66)
Age (yrs)
<50	ref	ref
50-64	2.35 (1.28 – 4.30)	2.23 (1.06 – 4.66)
65+	5.77 (3.15 – 10.56)	10.61 (4.34 - 25.94)
Ever travel outside USA since 1995 (Excluding (excluding Europe, Japan, Australia, New Zealand, and Canada)
Yes	0.83 (0.49 – 1.41)	0.85 (0.45 – 1.61)
No	ref	ref
Ever used an indoor tanning device
Yes	0.79 (0.437 – 1.44)	0.95 (0.45 – 2.00)
No	ref	ref
Menstruation before age 12
Yes	2.38 (1.27 – 4.49)	2.42 (1.16 – 5.06)
No	ref	ref
Ever gave birth to live born infant
Yes	1.93 (1.19 – 3.15)	1.09 (0.58 – 2.06)
No	ref	ref
Ever taken hormone replacement therapy
Yes	2.88 (1.41 – 5.88)	1.99 (0.86 – 4.57)
No	ref	ref
Biological father ever have cancer
Yes	1.45 (0.79 – 2.66)	0.94 (0.46 – 1.91)
No	ref	ref
Biological mother ever have cancer
Yes	1.73 (1.01 – 2.97)	1.20 (0.60 – 2.38)
No	ref	ref
Mother had uterine cancer
Yes	5.86 (1.27 – 26.93)	5.96 (1.04 – 34.05)
No	ref	ref
Hispanic
Yes	0.67 (0.34 – 1.30)	1.09 (0.48 – 2.49)
No	ref	ref
Marital status
Never Married	ref	ref
Married or Cohabitating	1.35 (0.70 – 2.60)	1.02 (0.44 – 2.33)
Widowed	2.13 (1.00 – 4.53)	0.51 (0.17 – 1.50)
Separated	2.35 (1.11 – 5.00)	1.18 (0.44 – 3.14)
Possible occupational exposure to chemicals or radiation
Yes	0.62 (0.31 – 1.23)	0.41 (0.18 – 0.94)
No	ref	ref
Current smoking status
Never	ref	ref
Current	1.85 (0.96 – 3.53)	3.23 (1.47 – 7.12)
Former	2.18 (1.27 – 3.74)	1.88 (0.98 – 3.58)

OR = Odds ratio

CI = Confidence interval

Answer draft (<300 words..)

A Multivariable logistic regression analysis among 147 cases and 147 controls from the National Health Interview Study is shown above. For the full model with an adjusted odds ratio, the odds of uterine cancer were 1.39 times higher among individuals who were obese compared with those who were underweight/healthy weight, 95% CI [0.73 – 2.66]. As for the ones who were obese, the odds of uterine cancer were 1.01 times higher when compared with the underweight ones, 95% CI [0.50 – 2.02]. The odds of uterine cancer were 2.23 times more likely among the 50-64 age group, 95%CI [1.06- 4.66] and 10.61 times higher for the 65+ age group, 95% CI [4.34 - 25.94]. The likelihood of having uterine cancer is 15% lower if travel outside the USA since 1993, 95%CI [0.45 -1.61]. If the individual has ever used an indoor tanning device, the likelihood of uterine cancer is 5% lower, 95%CI [0.45 – 2.00].The odds of uterine cancer is 2.42 times higher if menstruated before age 12, 95%CI 1.16 – 5.06]. The odds of uterine cancer

To assess confounding I compared each stratified OR to the crude OR for the main association. X, y, and z are possible confounders because the stratified ORs are more than 10% different from the crude OR. To assess effect modification, I compared ORs across the strata. X, y, and z are possible effect modifiers because the stratified ORs are more than 10% different from each other. ….Interaction…because…

2. What are the crude and adjusted associations between your putative exposure and uterine cancer in the 1:1 age-matched case-control study? (One table with crude/matched ORs and adjusted/pooled ORs [add additional rows as needed], and summary of results, <300 words)

5. Multivariable analysis among 147 cases and 147 controls for uterine cancer matched by age, National Health Interview Study (NHIS), United States, 2015

	Crude/Matched OR (95% CI)	Full model Adjusted/Pooled OR (95% CI)
Body Max Index
Underweight or healthy weight	ref	ref
Overweight	1.47 (0.77 - 2.79)	1.56 (0.72 – 3.37)
Obese	2.07 (1.11 - 3.88)	2.22 (1.02 – 4.85)
Ever travel outside USA since 1995 (Excluding (excluding Europe, Japan, Australia, New Zealand, and Canada)
Yes	0.79 (0.46 – 1.37)	0.44 (0.19 – 1.00)
No	ref	ref
Ever used an indoor tanning device
Yes	0.96 (0.51 - 1.81)	0.85 (0.36 – 1.97)
No	ref	ref
Menstruation before age 12
Yes	1.85 (1.01 – 3.38)	1.84 (0.84 – 4.02)
No	ref	ref
Ever gave birth to live born infant
Yes	0.69 (0.36 – 1.39)	0.32 (0.11 – 0.89)
No	ref	ref
Ever taken hormone replacement therapy
Yes	1.07 (0.58 - 1.97)	0.90 (0.41 – 1.99)
No	ref	ref
Biological father ever have cancer
Yes	0.79 (0.44 - 1.41)	0.52 (0.24 – 1.10)
No	ref	ref
Biological mother ever have cancer
Yes	1.12 (0.65 - 1.92)	1.07 (0.54 – 2.13)
No	ref	ref
Hispanic
Yes	1.15 (0.57 - 2.57)	2.74 (0.85 – 8.84)
No	ref	ref
Possible occupational exposure to chemicals or radiation
Yes	0.48 (0.21 - 1.09)	0.22 (0.06 – 0.70)
No	ref	ref
Current smoking status
Never	ref	ref
Current	1.89 (0.92 – 3.87)	1.99 (0.75 – 5.27)
Former	2.12 (1.19 – 3.79)	1.88 (0.79 – 4.48)

OR = Odds ratio

CI = Confidence interval

3. What are the crude and adjusted associations between your putative exposure and uterine cancer in the 1:1 age- and region matched case-control study? (One table with crude/matched ORs and adjusted/pooled ORs, and summary of results [add additional rows as needed], <300 words)

5. Multivariable analysis among 147 cases and 147 controls for uterine cancer matched by age and region, National Health Interview Study (NHIS), United States, 2015

	Crude/Matched OR (95% CI)	Full model Adjusted/Pooled OR (95% CI)
Body Max Index
Underweight or healthy weight	ref	ref
Overweight	1.44 (0.77 – 2.79)	1.33 (0.663 – 2.68)
Obese	2.21 (1.11 – 3.88)	2.62 (1.32– 5.19)
Ever travel outside USA since 1995 (Excluding (excluding Europe, Japan, Australia, New Zealand, and Canada)
Yes	0.79 (0.46 – 1.37)	0.67 (0.38 – 1.18)
No	ref	ref
Ever used an indoor tanning device
Yes	0.99 (0.52 – 1.88)	1.01 (0.52 – 1.94)
No	ref	ref
Menstruation before age 12
Yes	1.44 (0.79 – 2.63)	1.22 (0.64 – 2.30)
No	ref	ref
Ever gave birth to live born infant
Yes	0.70 (0.36 – 1.29)	0.66 (0.11 – 0.89)
No	ref	ref
Ever taken hormone replacement therapy
Yes	1.27 (0.68 – 2.36)	1.16 (0.62 – 2.22)
No	ref	ref
Biological father ever have cancer
Yes	1.18 (0.65 – 2.11)	1 (0.55 – 1.84)
No	ref	ref
Biological mother ever have cancer
Yes	1.18 (0.65 – 2.04)	1.13 (0.63 – 2.01)
No	ref	ref
Hispanic
Yes	0.77 (0.38 – 1.56)	0.86 (0.33 – 2.23)
No	ref	ref
Possible occupational exposure to chemicals or radiation
Yes	0.66 (0.32 – 1.38)	0.72 (0.34 – 1.54)
No	ref	ref
Current smoking status
Never	ref	ref
Current	2.14 (1.07 – 4.27)	2.22 (1.09 – 4.52)
Former	2.40 (1.34 – 4.44)	2.34 (1.26 – 4.31)

OR = Odds ratio

CI = Confidence interval

4. What are the crude and adjusted associations between your putative exposure and uterine cancer in the 1:5 age-matched case-control study? (One table with crude/matched ORs and adjusted/pooled ORs [add additional rows as needed], and summary of results, <300 words)

Table 5. Multivariable analysis among 147 cases and 147 controls for uterine cancer 1:5 matched by age, National Health Interview Study (NHIS), United States, 2015

	Crude/Matched OR (95% CI)	Full model Adjusted/Pooled OR (95% CI)
Body Max Index
Underweight or healthy weight	ref	ref
Overweight	1.41 (0.89 – 2.23)	1.46 (0.90 – 2.36)
Obese	1.75 (1.14 – 2.69)	1.82 (1.16 – 2.85 )
Ever travel outside USA since 1995 (Excluding (excluding Europe, Japan, Australia, New Zealand, and Canada)
Yes	0.87 (0.58 – 1.32)	0.87 (0.56 -1.34)
No	ref	ref
Ever used an indoor tanning device
Yes	1.02 (0.63 – 1.64)	0.97 (0.58 – 1.64)
No	ref	ref
Menstruation before age 12
Yes	1.97 ( 1.27 – 3.03)	1.89 (1.19 – 2.98)
No	ref	ref
Ever gave birth to live born infant
Yes	0.78 (0.51 – 1.17)	0.66 (0.43 – 1.02)
No	ref	ref
Ever taken hormone replacement therapy
Yes	1.33 (0.84 – 2.10)	1.08 (0.67 – 1.76)
No	ref	ref
Biological father ever have cancer
Yes	0.86 (0.55 – 1.32)	0.75 (0.48 – 1.18)
No	ref	ref
Biological mother ever have cancer
Yes	1.28 (0.87 – 1.89)	1.26 (0.84 – 1.89)
No	ref	ref
Hispanic
Yes	0.84 (0.48 – 1.47)	1.01 ( 0.56 - 1.84)
No	ref	ref
Possible occupational exposure to chemicals or radiation
Yes	0.65 ( 0.37 – 1.14)	0.61 (0.35 – 1.09)
No	ref	ref
Current smoking status
Never	ref	ref
Current	2.20 (1.32 – 3.68)	2.40 (1.39 – 4.12)
Former	1.85 (1.24 – 2.76)	1.93 (1.27 – 2.95)

OR = Odds ratio

CI = Confidence interval

5. Compare and contrast the findings from the unmatched and 1:1 age-matched case-control study. How did matching on age influence the results? Do you think matching on age was necessary? (Narrative, <300 words)

6. Compare and contrast the findings from the unmatched, 1:1 age-matched, and 1:1 age- and region-matched case-control study. How did matching on age, as well as age and region, influence the results? Do you think matching on age or age/region was necessary? (Narrative, <300 words)

7. Compare and contrast the findings from the unmatched and 1:5 age-matched case-control study. How did matching on age influence the results? Do you think matching on age was necessary? (Narrative, <300 words)

8. Compare and contrast the findings from the 1:1 and 1:5 age-matched case-control studies. What did we gain by matching cases to 5 controls? (Narrative, <300 words)

9. What are the limitations of case-control studies generally and in these analyses specifically? How would the limitations affect the odds ratios for your chosen covariate and uterine cancer? (Narrative, <300 words)

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