Associations of pre-diagnostic body mass index with overall and cancer-specific mortality in a large Austrian cohort.
OBJECTIVE
Although obesity is a well-known risk factor for several cancers, its role on cancer survival is poorly understood.


METHODS
Within the VHM&PP cohort, 8,673 cancer patients (42.2% women) were followed over a median time of 11.9 years. Cox proportional hazard models were used to estimate the association of pre-diagnostic overweight (BMI 25.0-29.9 kg/m(2)) and obesity (BMI ≥ 30.0 kg/m(2)) with all-cause and cancer-specific mortality. Cubic restricted splines were additionally modeled.


RESULTS
During 71,126 person-years, 4,571 deaths were observed. Compared to normal weight, overweight was associated with statistically significantly decreased all-cause mortality (HR 0.93; 95% CI 0.87-0.997) and cancer-specific mortality (HR 0.91; 95% CI 0.84-0.99). Underweight was statistically significantly associated with 28% increased overall mortality, in particular in men [HR 2.02 (95% CI 1.43-2.83) vs. HR 0.96 (95% CI 0.71-1.30) in women]. J-shaped associations were found between BMI and mortality with the nadir around a BMI of 25 kg/m(2). Analysis by cancer site showed though not statistically significantly that overweight was associated with reduced mortality, while obesity was associated with increased cancer-specific mortality except cancers of the upper digestive tract. In patients with local stage colorectal cancers, obesity was associated with increased all-cause (vs. normal weight HR 1.90; 95% CI 1.03-3.52) and cancer-specific mortality (HR 3.17; 95% CI 1.29-7.81).


CONCLUSIONS
Overweight patients have a better overall prognosis, while for obesity no association and for underweight worse prognosis were found. Our results on common cancers indicate that there are tumor- and stage-specific differences.
Institute of Epidemiology and Medical Biometry, Ulm University, Helmholtzstr. 22, 89081, Ulm, Germany.|Agency for Preventive and Social Medicine, Rheinstraße 61, 6900, Bregenz, Austria.
Katharina
K
Reichle
Institute of Epidemiology and Medical Biometry, Ulm University, Helmholtzstr. 22, 89081, Ulm, Germany.
Raphael S
RS
Peter
Agency for Preventive and Social Medicine, Rheinstraße 61, 6900, Bregenz, Austria.
Hans
H
Concin
Institute of Epidemiology and Medical Biometry, Ulm University, Helmholtzstr. 22, 89081, Ulm, Germany. gabriele.nagel@uni-ulm.de.|Agency for Preventive and Social Medicine, Rheinstraße 61, 6900, Bregenz, Austria. gabriele.nagel@uni-ulm.de.
Gabriele
G
Nagel
D000368:Aged; D001317:Austria / Q000453:epidemiology; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009369:Neoplasms / Q000150:complications / Q000401:mortality* / Q000473:pathology; D050177:Overweight / Q000150:complications*; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D013851:Thinness / Q000150:complications*
Body mass index; Cancer; Epidemiology; Mortality; Prognosis; Survival; VHM&PP; Weight