During 3,521,088 person-years of follow-up (mean: 7.2 years), we identified 1,258 incident cases of pancreatic cancer (808 men and 450 women). For men and women combined, the median intakes for the lowest and highest quintiles of total added sugar intake were 3.0 teaspoons/day (12.6 g/day) and 22.9 teaspoons/day (96.2 g/day). Compared to those with low intake of total added sugar, individuals with high sugar intake were younger, of Black race or ethnic group, less educated, physically inactive, likely to smoke and consume more fat but less alcohol, folate and multivitamins (). Forty-eight percent of men and 36% of women were drinkers of regular soft drink; 42% of men and 49% of women were drinkers of diet soft drink. Individuals with high consumption of regular soft drinks generally had similar characteristics to those with high sugar intake. In contrast, individuals who drank diet soft drinks were more educated, less likely to smoke and consumed more folate and multivitamins than those who never drank diet soft drink.
Baseline characteristics of NIH-AARP participants according to consumption of total added sugar, regular soft drink and diet soft drink1
Among all participants, intake of total added sugar was not associated with pancreatic cancer risk (: for the highest versus lowest quintile, RR=0.85; 95% CI: 0.68, 1.06; P trend= 0.07). Although women with the highest intake of total added sugar had a significantly reduced risk (RR=0.65; 95% CI: 0.44, 0.95; P trend=0.01), the association was attenuated and no longer of statistical significance after excluding the first 2 years of follow-up (RR=0.72; 95% CI: 0.47, 1.10; P trend=0.09). In addition, when examining energy-adjusted added sugar intake as teaspoons per 1000 kcal, no association was observed for men or women or men and women combined (data not shown).
Relative risks and 95% confidence intervals for pancreatic cancer according to consumption of total added sugar, sugar-sweetened beverages and foods
In this population, the main food sources for total added sugar were sweets (25.7%), sugar-sweetened beverages (24.8%; 19.3% from regular soft drinks and 5.5% from regular fruit drink), dairy desserts (9.1%), and sugar added to coffee/tea (8.4%). Correlations between sugar-sweetened foods and beverages were weak, with Spearman correlation coefficients ranging from −0.01 to 0.34 (sweets with dairy desserts).
After adjustment for potential confounders, consumption of sugar-sweetened beverages, sugar added to coffee/tea, sweets, dairy desserts, and other sugar-sweetened foods showed no trends for pancreatic cancer risk (). Neither regular soft drink nor diet soft drink had a significant trend towards greater risk of pancreatic cancer (). Although risks were significantly increased for a few mid-quintiles of soft drink consumption, those increases were not monotonic across quintiles. Separate analyses among men or women showed similar associations (data not shown). The results for sugar-sweetened foods and beverages did not change after excluding the first 2 years of follow-up. Analyzing energy-adjusted intake as grams per 1000 kcal instead of absolute amount of sugar-sweetened foods and beverages had essentially no impact on the risk ratios (data not shown).
Relative risks and 95% confidence intervals for pancreatic cancer according to consumption of regular soft drink and diet soft drink
The above findings remained the same after removing BMI from the multivariate models, excluding those with heart disease, or restricting to those who reported their health status as excellent or very good (data not shown).
There was no statistical interaction between sex and intake of total added sugar or soft drinks (likelihood ratio test p=0.17 for total added sugar, p=0.75 for regular soft drink and p=0.24 for diet soft drink). For men and women combined, the associations between intake of added sugar or soft drinks and the risk of pancreatic cancer did not significantly vary across strata of BMI (<30 versus ≥30 kg/m2), physical activity and smoking history (). Compared to non-obese women, women who were obese appeared to have higher risks of pancreatic cancer for total added sugar and regular soft drink but lower risk for diet soft drink. However, none of the risk estimates were significantly different from null (data not shown). In addition, interactions by BMI among women were not statistically significant (likelihood ratio test p=0.50 for total added sugar and p=0.38 for diet soft drink) or only borderline significant (p=0.05 for regular soft drink). Although p values were significant for interaction between total added sugar and physical activity among women (p=0.03) and interaction between diet soft drink and smoking among men (p=0.03), none of the risk estimates were statistically significantly (data not shown).
Relative risks and 95% confidence intervals for pancreatic cancer according to consumption of total added sugar, regular soft drink and diet soft drink, stratified by BMI, physical activity, and smoking status1
We further explored the associations stratified by BMI ≥35 kg/m2 as the risk for pancreatic cancer is greatest at these BMI levels. For men and women combined, high intake of total added sugar was associated with a nonsignificant increase in pancreatic cancer risk among those with BMI ≥35 kg/m2 (compared to the lower tertile, the middle tertile, RR=1.59, 95% CI: 0.80, 3.17 and the upper tertile, RR=1.83, 95% CI: 0.80, 4.19; P trend=0.20; the cases for lower, middle and upper tertiles were 16, 21 and 20). Similarly, among those with BMI≥35 kg/m2 and physical activity<3 times/week, total added sugar also increased the risk of pancreatic cancer (compared to the lower tertile, the middle tertile, RR=2.70, 95% CI: 1.12, 6.52 and the upper tertile, RR=2.96, 95% CI: 1.05, 8.40; p trend=0.09; the cases for lower, middle and upper tertiles were 8, 17 and 16). Nevertheless, we lacked the statistic power due to small number of cases and sex-specific analyses showed no statistically significant associations (data not shown). Regular soft drink and diet soft drink were not associated with pancreatic cancer risk for those who were extremely obese or those who were both extremely obese and less active among men or women or combined (data not shown).
The risk estimates for subgroup analyses were virtually unchanged and the confidence intervals were wider after excluding the first 2 years of follow-up, excluding those with heart disease, or restricting to those who reported their health status as excellent or very good (data not shown).