Lifetime physical activity and cancer incidence--a cohort study of male former elite athletes in Finland.
OBJECTIVE
Physical activity has been shown to decrease the risk of certain cancers. Objective of this study was to assess the effect of physical activity on cancer incidence in former male athletes in older age.


METHODS
A cohort of 2448 elite male athletes and 1712 referents was followed-up for cancer incidence during 1986-2010 through the Finnish Cancer Registry.


METHODS
Standardised incidence ratios were calculated with the general male population as the reference. Self-reported questionnaire-based data on covariates were used in Cox regression analyses comparing the risk of cancer in athletes and referents.


RESULTS
The overall cancer incidence was lower in athletes than in the general population, standardised incidence ratio 0.89 (95% confidence interval 0.81-0.97). It was lowest among middle-distance runners (standardised incidence ratio 0.51, 95% confidence interval 0.22-1.01), long-distance runners (standardised incidence ratio 0.57, 95% confidence interval 0.35-0.88) and jumpers (standardised incidence ratio 0.60, 95% confidence interval 0.37-0.92). The standardised incidence ratio of lung cancer among athletes was 0.40 (95% confidence interval 0.27-0.55) and that of kidney cancer 0.23 (95% confidence interval 0.06-0.57). The hazard ratio for lung cancer between athletes and referents increased from the unadjusted ratio of 0.29 (95% confidence interval: 0.18-0.48) to 0.61 (95% confidence interval: 0.30-1.26) after adjustment for smoking status and pack-years of smoking.


CONCLUSIONS
Former male elite athletes evidently have less cancer than men on the average. The lesser risk can be attributed to lifestyle factors, notably less frequent smoking among the athletes.
University of Tampere, School of Health Sciences, Finland. Electronic address: Jorma.Sormunen@fimnet.fi.
Jorma
J
Sormunen
University of Helsinki, Department of Public Health, Finland; City of Vantaa, Health and Social Welfare Department, Finland.
Heli M
HM
Bäckmand
University of Helsinki, Department of Public Health, Finland.
Seppo
S
Sarna
University of Jyväskylä, Department of Health Sciences, Finland.
Urho M
UM
Kujala
University of Helsinki, Department of Public Health, Finland; University of Helsinki, Institute for Molecular Medicine FIMM, Finland; National Institute for Health and Welfare (THL), Finland.
Jaakko
J
Kaprio
Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Finland.
Tadeusz
T
Dyba
University of Tampere, School of Health Sciences, Finland; Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Finland.
Eero
E
Pukkala
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008019:Life Style; D008175:Lung Neoplasms / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009369:Neoplasms / Q000453:epidemiology*; D012907:Smoking / Q000009:adverse effects; D013177:Sports / Q000706:statistics & numerical data*
Ageing; Endurance; Epidemiology; Exercise; Statistical review