~-.~JiVIi~ s«M .

6 SF3fLTtaN OF WNmDIS-
-3%-
Lry order to pmvide a mme :isoa qrwP. each case ias
irdiv/doally aerrhd to a PW+lacian aatrol
. The aa+rce for soch
coarzols ws fne State DeAarw'X of !btQ uMicles fiies . This
source was cmidered apPopriate sinR it Pon"ided ~e of the
rdoCnetion neoesary to perfara the aeecltLxl . Additiarully. thi s
eethed .es re9asdad as :ess txw-comsumting and lore ecormirwl than
otl+es Possible aeNni+ for the selecting of mncxols
. such as random
di~,t dialvq. For each aue. six potan:ial cosrsols .ere selected w
c1e hasis ct age, an
. and castty of rasidrsoa. Upoa a teled"
lnterview, the tixst Pocartial control V .» was to+md also to mtc.h the
case an tlr. bnsis of ssokvsl status - and Mn . in edtitiom, agreei
to psit.icipate fully -was included in the study . In su,nery, the
eligibility criteria for cartzols w as follous .
11 The control had to be of the ssn+ aga l . - S yearsl as
the cortesEa .vdin4 case .
71 The control had to be of tJn ssm ses as the case .
11 'Ihe control had to te a residmt of Me saae
nmty as the mntrcl .
Ii T.r . control dad to have the sare aaoking l+is :ory as the
©se. That is, both had to oe eitle.r never smkers or
ex-wo4ers for it lnast 1o yiars .
http://legacy.library.ucsf.edu/tid/dsk94c00/pdf
-38-
An ad3itioeal artdiing variable was aaaidemf at the tiae of
caducung the int.eview. it mcerns the aetter of +.hether t2e
questiomaire was reslanded to by the case hiseelf/Msself or, on the
other had by a*nrmgete fesPudent . The awtrlhing on type of
vu:emer is better explaLal in the sectim of oRA CCLl2fia : etiieh
apOSVs next on in this Qupcer.
On the aa .rage, two Pctercial oo'xzols had to be ulled until me
aetd+ed the mse an mddnq history and was rilling to partitipate in
the stUAV .
7 pNfq WyIffi'1W .
Qae the eleqidility of eases and controls was determird . the
Field sr .aff artanged a face to face intesvier vhleh took ap~tely
one hoor to wnduct in the patiaR's hrnr . All rfaaatirn Was
collected using a pre-oeded Gucstiosvaira, The queationnsire was Pre-
tested for a 3 amth-period using patients diagnosed Pnnr to the
study lariod . The sectiov of the qoestiornsire that coarutn the
iteas used for analysis in the prerGit study are found in 11pPeMis A,
AS wuld be siraecced, aoet of that questioro are orncerned with the
measu,eer.nt of exeosore to pusive arcikinq ; but iKorsPtian an social .
,Avo4rePhic and medical variables 'es also souqht . Both cases and
mntrols were iirervie .ed exactly in the saae fsshiui, and eu.ept for
cne ite :n in the questiuwlue reterring to the _ inical asoeets of