Sugar-sweetened soft drink consumption and risk of pancreatic cancer in two prospective cohorts

Background: A history of diabetes mellitus and a diet high in glycemic load are both potential risk factors for pancreatic cancer. Sugar-sweetened soft drinks are a prevalent source of readily absorbable sugars and have been associated with an increased risk of obesity and diabetes. We investigated whether higher consumption of sugar-sweetened soft drinks increases the risk of pancreatic cancer. Methods: We examined the relation between consumption of sugar-sweetened soft drinks and the development of pancreatic cancer in the Nurses' Health Study and the Health Professionals Follow-up Study. Among 88,794 women and 49,364 men without cancer at baseline, we documented 379 cases of pancreatic cancer during up to 20 years of follow-up. Soft drink consumption was first assessed at baseline (1980 for the women, 1986 for the men) and updated periodically thereafter. Results: Compared with participants who largely abstained from sugar-sweetened soft drinks, those who consumed more than three sugar-sweetened soft drinks weekly experienced overall a multivariate relative risk (RR) of pancreatic cancer of 1.13 [95% confidence interval (95% CI), 0.81-1.58; P for trend = 0.47]. Women in the highest category of sugar-sweetened soft drink intake did experience a significant increase in risk (RR, 1.57; 95% CI, 1.02-2.41; P for trend = 0.05), whereas there was no association between sweetened soft drink intake and pancreatic cancer among men. Among women, the risk associated with higher sugar-sweetened soft drink was limited to those with elevated body mass index (>25 kg/m²; RR, 1.89; 95% CI, 0.96-3.72) or with low physical activity (RR, 2.02; 95% CI, 1.06-3.85). In contrast, consumption of diet soft drinks was not associated with an elevated pancreatic cancer risk in either cohort. Conclusion: Although soft drink consumption did not influence pancreatic cancer risk among men, consumption of sugar-sweetened soft drinks may be associated with a modest but significant increase in risk among women who have an underlying degree of insulin resistance.