Question $12$

You recelve a data request from a concerned citizen regarding a suspected cancer cluster in the Conrad, lowa area, which is in Grundy County. During the period $1973$ through $1991,$ the concerned citizen claims there has been a significant increase in cancer, particularly colorectal cancer, in the Conrad area where she formerly lived.

You decide to approach this investigation via a proportionate incidence ratio $($PIR$)$ analysis. You contact the lowa Cancer Registry and request a frequency distribution of malignant $($invasive$)$ cancers from $1973$ through $1991$ by gender and site. You identify the target area for these cancer cases by any address that includes Conrad, Iowa. You also request an analogous

EPID: $4400$

Epidemiology $1$: Principles

Problem Set $10($Section $15-17)$

distribution for the remaining $98$ counties in the state to serve as a comparison group. Results of this type of analysis for cancer patients identified from Conrad addresses versus the state minus Grundy County are provided in Table $1$ for males and in Table $2$ for females.

Calculate the missing PIRs in the tables. Select the PIR that matches the table field.

Table $1$

Proportional Incidence Ratios $($PIRs$)$ and $95\%$ Confidence Intervals for Addresses involving

$\backslash$table$[[$Cancer Site,Observed Number of Cancer Cases,PIR,$95\%$ Confidence Interval$],[$Conrad$,$State minus Grundy County$],[$Lip$,3,1611,,0\mathrm{.}96-8\mathrm{.}84],[$Colon$,5,11913,0\mathrm{.}66,0\mathrm{.}28-1\mathrm{.}53],[$Rectum$,2,5425,0\mathrm{.}58,0\mathrm{.}15-2\mathrm{.}27],[$Pancreas$,3,3048,1\mathrm{.}54,0\mathrm{.}51-4\mathrm{.}67],[$Lung & bronchus,$11,23268,0\mathrm{.}74,0\mathrm{.}43-1\mathrm{.}28],[$Breast$,2,190,,4\mathrm{.}20-64\mathrm{.}7*],[$Prostate gland,$20,24720,1\mathrm{.}27,0\mathrm{.}87-1\mathrm{.}84],[$Bladder$,11,8440,,1\mathrm{.}18-3\mathrm{.}52*],[$Brain$,2,1856,1\mathrm{.}69,0\mathrm{.}43-6\mathrm{.}62],[$Non$-$Hodgkin's lymphoma,$4,4013,1\mathrm{.}56,0\mathrm{.}60-4\mathrm{.}05],[$Other sites,$11,29934,0\mathrm{.}58,0\mathrm{.}30-1\mathrm{.}01],[$All sites,$74,115904,$reference,$]]$

$P<mn>0</mn><mn>.</mn><mn>0</mn><mn>5</mn>$; interval does not include $1\mathrm{.}00.$

Table $1$: Lip

Table $1$: Breast

$$ Possible answers: $16\mathrm{.}5,2\mathrm{.}92,2\mathrm{.}04$

Table $1$: Bladder