Abstract PR-5: A pooled analysis of 14 cohort studies of body mass index and pancreatic cancer risk Free

Overweight and obesity have been hypothesized to promote pancreatic carcinogenesis by increasing insulin and IGF-1 levels. These factors may stimulate cell division, promote tumor development and increase local blood flow. Studies have reported inconsistent results between overweight and obesity and pancreatic cancer risk.

A pooled analysis of the primary data from 14 prospective cohort studies was conducted. The study sample consisted of 786,042 men and women among whom 2,135 pancreatic cases were identified. All studies measured height and weight at baseline; weight in early adulthood was measured in 11 studies. Study-specific multivariate relative risks (MV RR) and 95% confidence intervals (CI) were calculated by Cox proportional hazards models, and then pooled by a random effects model.

Compared to individuals with a BMI between 21-22.9 kg/m², a 16% (95% CI: 1-34%) and 47% (95% CI: 23-75%) higher pancreatic cancer risk was observed among overweight (BMI between 25-29.9 kg/m²) and obese (BMI≥30 kg/m²) individuals, respectively. Results were similar for men and women. A positive association was observed for BMI in early adulthood (pooled MV RR = 1.29, 95% CI= 1.07-1.55) comparing BMI≥25 kg/m² to a BMI between 21-22.9 kg/m². Pancreatic cancer risk was higher among individuals who were overweight in early adulthood (BMI≥25 kg/m²) and not obese at baseline (BMI<30 kg/m²) (pooled MV RR=1.30, 95% CI=1.08-1.57), among those who were not overweight in early adulthood (BMI<25 kg/m²) and obese at baseline (BMI≥30 kg/m²) (pooled MV RR=1.38, 95% CI=1.13-1.67) and among those who were overweight in early adulthood (BMI≥25 kg/m²) and obese at baseline (BMI≥30 kg/m²) (pooled MV RR=1.55, 95% CI=1.24-1.95) compared to individuals with a BMI in early adulthood<25 kg/m² and BMI at baseline<30kg/m². Although the association with BMI at baseline and BMI in early adulthood and pancreatic cancer risk was not significantly modified by smoking status, statistically significant positive associations were observed in never and past smokers, whereas a non-significant and weaker association was observed in current smokers.

Overall, positive associations were observed for overweight and obese individuals and pancreatic cancer risk. As pancreatic tumors are highly fatal, determining preventive factors offers a feasible approach to reducing this disease’s morbidity and mortality. These results are in line with The World Cancer Research Fund recommendation to maintain body weight within the normal range, as overweight and obesity are also linked to other cancers, diabetes and cardiovascular disease.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):PR-5.