Descriptive-longitudinal Study

Descriptive-longitudinal Descriptive-longitudinal StudyStudy

Colleen SoColleen So Aaron Bryks Aaron Bryks

Maile Capistrano Maile Capistrano Crystal FongCrystal Fong

Physical Activity and Lung Physical Activity and Lung Cancer Risk in Male SmokersCancer Risk in Male Smokers

Authors & AffiliationsAuthors & Affiliations Center for Cancer Research, National Cancer Center for Cancer Research, National Cancer

Institute, Bethesda, MD, USAInstitute, Bethesda, MD, USA Lisa H. Colbert, Joseph A. Tangrea, Philip R. TaylorLisa H. Colbert, Joseph A. Tangrea, Philip R. Taylor

Department of Nutrition, Pennsylvania State Department of Nutrition, Pennsylvania State University, University Park, PA, USAUniversity, University Park, PA, USA Terryl J. HartmanTerryl J. Hartman

Department of Epidemiology and Health Department of Epidemiology and Health Promotion, National Public Health Institute, Promotion, National Public Health Institute, Helsinki, FinlandHelsinki, Finland Pirjo Pietinen, Jarmo VirtamoPirjo Pietinen, Jarmo Virtamo

Division of Cancer Epidemiology and Genetics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USANational Cancer Institute, Bethesda, MD, USA Demetrius AlbanesDemetrius Albanes

Grant SponsorGrant Sponsor

National Cancer Institute, USANational Cancer Institute, USA

PurposePurpose

Was to examine the association between Was to examine the association between physical activity (occupational and leisure-physical activity (occupational and leisure-time) and lung cancer risk in a large group time) and lung cancer risk in a large group (27,087) of Finnish white male smokers, (27,087) of Finnish white male smokers, ages 50-69 over a period of 10 years.ages 50-69 over a period of 10 years.

Type of ResearchType of Research

Prospective studyProspective studyextrapolates to unknown outcomesextrapolates to unknown outcomesslow processslow process

LongitudinalLongitudinalassesses changes in behavior in one group of assesses changes in behavior in one group of

subjects at more than one point in time subjects at more than one point in time e.g. over 10 year periode.g. over 10 year periodsubjects act as their own controlssubjects act as their own controls

intra-individual variability is minimizedintra-individual variability is minimized

Type of ResearchType of Research

DescriptiveDescriptivereveals current patterns associated with a reveals current patterns associated with a

phenomenon (e.g. lung cancer) and how they phenomenon (e.g. lung cancer) and how they relate to other factorsrelate to other factors

gives researchers something to build on for gives researchers something to build on for future researchfuture research

does not include treatment or control groupdoes not include treatment or control groupdoes not attempt to determine causal relationshipsdoes not attempt to determine causal relationships

Research MethodsResearch Methods

Study populationStudy population: white male smokers : white male smokers enrolled in the Alpha-Tocopherol Beta-enrolled in the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) studyCarotene Cancer Prevention (ATBC) studyliving in the southwestern Finland arealiving in the southwestern Finland areaall subjects volunteered all subjects volunteered smoked 5 or more cigarettes per daysmoked 5 or more cigarettes per daybetween ages 50-69between ages 50-69subjects recruited from 1985-1988subjects recruited from 1985-1988


Cases of lung cancer were identified Cases of lung cancer were identified through the Finnish Cancer registrythrough the Finnish Cancer registry

Examined the associations between Examined the associations between occupational and leisure time physical occupational and leisure time physical activities and lung cancer activities and lung cancer age age smoking characteristics: years of smoking, smoking characteristics: years of smoking,

number of cigarettes smoked dailynumber of cigarettes smoked daily


Collected baseline dataCollected baseline data general medical history questionnairegeneral medical history questionnaireblood sampleblood sample

Other question included in the Other question included in the questionnaire:questionnaire:working environmentworking environment

-risk factor to lung cancer-risk factor to lung cancer

Research MethodsResearch Methods Crudely classified them as occupationally Crudely classified them as occupationally

exposed:exposed:asbestosasbestosother causes of lung cancer (e.g. mining and other causes of lung cancer (e.g. mining and

quarrying)quarrying) Completed a self-administered food-use Completed a self-administered food-use

questionnairequestionnairereport usual frequency of consumption and report usual frequency of consumption and

portion size of more than 276 food items, mixed portion size of more than 276 food items, mixed dishes and beverages during previous 12 dishes and beverages during previous 12 monthsmonths


Two questions to Two questions to assess usual assess usual occupational and occupational and leisure-time leisure-time physical activityphysical activity11stst Question Question: :

Describe your activity Describe your activity during work in the during work in the past year aspast year as::

(i) not working(i) not working

(ii) mainly sitting(ii) mainly sitting

e.g. office workere.g. office worker

(iii) walking quite a lot but (iii) walking quite a lot but not lifting or carryingnot lifting or carrying

e.g. foreman, shop assistante.g. foreman, shop assistant

(iv) walking and lifting(iv) walking and lifting

e.g. carpentere.g. carpenter

(v) heavy physical work(v) heavy physical work

ee.g. forestry work/ heavy .g. forestry work/ heavy farm workfarm work


22ndnd Question Question: :

Describe your usual Describe your usual

leisure-time activity inleisure-time activity in

the past year as:the past year as:

(i) sedentary (i) sedentary

e.g. reading, watching TVe.g. reading, watching TV

(ii) moderate(ii) moderate

e.g. walking, gardeninge.g. walking, gardening

(iii) heavy (iii) heavy

e.g. running, skiing, swimming e.g. running, skiing, swimming fairly regularlyfairly regularly

Research MethodResearch Method

Sedentary men used as the reference Sedentary men used as the reference groupgroup

Non-workers kept as a separate Non-workers kept as a separate occupational activity categoryoccupational activity categoryincludes retireesincludes retirees

Regular and heavy leisure-time physical Regular and heavy leisure-time physical activity combined to create an “active” activity combined to create an “active” leisure groupleisure group


Cox proportional hazards models were Cox proportional hazards models were used to estimate the relative risk (RR) and used to estimate the relative risk (RR) and 95% confidence intervals (CI) of lung 95% confidence intervals (CI) of lung cancer associated with level of physical cancer associated with level of physical activityactivity

All models were run excluding the first 2 All models were run excluding the first 2 years of follow-upyears of follow-upno significant changes in any of the estimatesno significant changes in any of the estimates


Validity of the proportional hazards Validity of the proportional hazards assumption was checked by examining assumption was checked by examining the cross-product terms of follow-up time the cross-product terms of follow-up time and the covariates of interestand the covariates of interestno departures from this assumption for any no departures from this assumption for any

covariate in the final modelscovariate in the final models

Main FindingsMain Findings

No inverse association between No inverse association between occupational and/ or leisure-time physical occupational and/ or leisure-time physical activity and risk of lung cancer in long-term activity and risk of lung cancer in long-term cigarette smokerscigarette smokersmay be due to length of time smokingmay be due to length of time smokingany beneficial effect of occupational activity any beneficial effect of occupational activity

may be outweighed by the related increase in may be outweighed by the related increase in risk due to exposure to asbestos and other risk due to exposure to asbestos and other high-risk exposureshigh-risk exposures


Only age appeared to modify the Only age appeared to modify the relationship between leisure-time activity relationship between leisure-time activity and lung cancerand lung canceramong younger men, approximately 20-25% of among younger men, approximately 20-25% of

active men at lower riskactive men at lower riskmay be a protective relationship for leisure physical may be a protective relationship for leisure physical

activity among younger smokersactivity among younger smokersno risk reduction among older menno risk reduction among older men

may be due to the accumulation of more may be due to the accumulation of more carcinogenic insultscarcinogenic insults

slight increase of physical activity may go unnoticedslight increase of physical activity may go unnoticed


Neither age nor amount of smoking Neither age nor amount of smoking modified the occupational physical activity modified the occupational physical activity associationassociation

Main FindingsMain Findings Non-workers appear to be at increased risk Non-workers appear to be at increased risk

of lung cancerof lung cancer Non-workers tend to be: Non-workers tend to be:

olderoldersmoked longersmoked longerless educatedless educatedeat fewer vegetableseat fewer vegetablesexposed to higher levels of carcinogens exposed to higher levels of carcinogens

(asbestos) (asbestos)


Men in moderate and heavy occupational Men in moderate and heavy occupational activity categories, like non-working men, activity categories, like non-working men, at increased risk to lung cancerat increased risk to lung cancerless education, higher exposure to less education, higher exposure to

carcinogens (e.g. asbestos)carcinogens (e.g. asbestos)perhaps non-working category may largely perhaps non-working category may largely

consist of men retired from occupations consist of men retired from occupations requiring moderate to heavy physical activityrequiring moderate to heavy physical activity


Men who participated in physical activity Men who participated in physical activity during their leisure time:during their leisure time:smoke fewer cigarettes/daysmoke fewer cigarettes/dayinhale smoke less often inhale smoke less often consume foods of greater dietary energy consume foods of greater dietary energy

sources and vegetablessources and vegetables

Weaknesses of Research Weaknesses of Research StudyStudy

Sample is not generalizable to the entire Sample is not generalizable to the entire populationpopulation reliabilityreliability

if we were to conduct a similar study in the future, if we were to conduct a similar study in the future, would we end up with the same resultswould we end up with the same results??

Homogeneous population (target sample)Homogeneous population (target sample)not representative of entire populationnot representative of entire populationpopulation differences are controlledpopulation differences are controlled

amount of tobacco exposureamount of tobacco exposurewhite males between ages of 50-69 from white males between ages of 50-69 from

southwestern Finlandsouthwestern Finland


Subjects derived from a previous studySubjects derived from a previous studyno link between study objectivesno link between study objectivessubjects volunteered (convenience sampling)subjects volunteered (convenience sampling)

selection biasselection bias


Threats to internal validity:Threats to internal validity:possible history threatpossible history threat

an uncontrolled event that influences the an uncontrolled event that influences the participant’s testing outcomes over the extended participant’s testing outcomes over the extended period of timeperiod of time

selection biasselection biasvolunteers (convenience sampling)volunteers (convenience sampling)

whoever was available from the ATBC studywhoever was available from the ATBC study

mortalitymortalitypotential for high drop-out ratespotential for high drop-out rates

changing the characteristics and qualities of the changing the characteristics and qualities of the original sampleoriginal sample


Threats to internal validity (cont.):Threats to internal validity (cont.):instrumentationinstrumentation

studied white, long-term male smokersstudied white, long-term male smokersused only one question each to measure usual used only one question each to measure usual

occupational and leisure-time physical activity occupational and leisure-time physical activity in the past year in the past year questions are insufficientquestions are insufficientmany things can happen over a yearmany things can happen over a yearlimited assessment (not specific enough)limited assessment (not specific enough)


Threats to external validity:Threats to external validity: reactive arrangementreactive arrangement

social desirabilitysocial desirabilityquestionnaire: participants answer how they think questionnaire: participants answer how they think

you want them to answeryou want them to answer

Does not evaluate long-term effects of Does not evaluate long-term effects of asbestos exposureasbestos exposurenon-working category (I.e. retirees)non-working category (I.e. retirees)

Does not specify how often testing occurs Does not specify how often testing occurs over 10 year periodover 10 year period

Strengths of Research StudyStrengths of Research Study

Attempted to control for the influences of Attempted to control for the influences of education, food consumption (in particular education, food consumption (in particular vegetables), and asbestos and other high-vegetables), and asbestos and other high-risk carcinogensrisk carcinogensmay still be residual confounding effects from may still be residual confounding effects from

these and/or other factors in our risk these and/or other factors in our risk estimatesestimates

Controlled the type of people who were at Controlled the type of people who were at the extremes of the populationthe extremes of the population

Strengths of Research StudyStrengths of Research Study

Prospective natureProspective nature

Considerations for Future Considerations for Future ResearchResearch

Use a more diverse populationUse a more diverse population careful considerations of smoking statuscareful considerations of smoking status

smokers and/or non-smokerssmokers and/or non-smokerswider range of ageswider range of agesdifferent ethnicities and genderdifferent ethnicities and gender

Question more extensively to determine the Question more extensively to determine the level of physical activity at different ages level of physical activity at different ages associated with lung cancerassociated with lung cancerfrequency, duration, type, and intensity of frequency, duration, type, and intensity of

exerciseexercise

Research QuestionsResearch Questions

Prospective research addresses changes Prospective research addresses changes that occur over timethat occur over timee.g. e.g. "violence in "violence in childrenchildren and television" and television"

Descriptive research (e.g. studying a Descriptive research (e.g. studying a different culture) does not have any different culture) does not have any treatmentstreatments observationalobservational no manipulation no manipulation observes natural progression that occurs within an observes natural progression that occurs within an

environmentenvironment

ReferenceReference

Colbert, L.H., Hartman, T.J., Tangrea, J.A., Colbert, L.H., Hartman, T.J., Tangrea, J.A.,

Pietinen, P., Virtamo, J., Taylor P.R., &Pietinen, P., Virtamo, J., Taylor P.R., &

Albanes, D., (2002). Physical Activity andAlbanes, D., (2002). Physical Activity and

Lung Cancer Risk in Male Smokers. Lung Cancer Risk in Male Smokers.

Int. J. Cancer, 98,Int. J. Cancer, 98, 770-773. 770-773.

Questions?Questions?

Descriptive-longitudinal Study

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