Xin Xu

A plant-based diet index and all-cause and cause-specific mortality: a prospective study

Dose–response analysis for the relationship between a plant-based diet index (PDI) and all-cause (A), cardiovascular disease (B), and cancer (C) mortality in a Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening study.

Dietary fiber intake and the risk of bladder cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) cohort

Abstract Dietary fiber intake has been implicated as a protective factor for several human cancers in multiple epidemiologic studies. However, little is known about the effect of fiber intake on bladder cancer. This study examines the association between dietary fiber intake and bladder cancer risk among participants in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. A total of 101 721 participants were included in this study as they completed both the baseline questionnaire and the diet history questionnaire (cancer free before completion of the diet history questionnaire). Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were estimated using the Cox proportional hazards regression model. After a median of 12.5 years of follow-up, 776 new cases of bladder cancer were identified. Higher intake of total fiber, insoluble fiber and soluble fiber were not significantly associated with a reduced risk of bladder cancer. The multi-adjusted HRs (95 CIs) of highest versus lowest tertile of intake were 0.83 (0.66–1.04) for total fiber (P for trend = 0.098), 0.83 (95% CI: 0.67–1.03) for insoluble fiber (P for trend = 0.092) and 0.86 (95% CI: 0.68–1.08) for soluble fiber (P for trend = 0.168), respectively. There was no significant interaction of potential confounders, including education, body mass index and smoking status, with total fiber intake on bladder cancer risk. In summary, the findings of this prospective study show that there is no obvious evidence for a link between dietary fiber consumption and bladder cancer risk. Further large cohort studies are warranted to confirm these findings.

Associations between dietary fiber intake and mortality from all causes, cardiovascular disease and cancer: a prospective study

Abstract Objective Several studies suggest that dietary fiber intake may reduce mortality risk, but this might depend on the fiber types and the evidence regarding the role of soluble fiber or insoluble fiber on death risk remain limited and inconsistent. Therefore, this study aimed to comprehensively evaluate multiple types of dietary fiber intake on mortality from all causes, cardiovascular disease and cancer in the large-scale Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening Trial. Methods A multivariate Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results This study finally included 86,642 participants with 17,536 all-cause deaths, 4842 cardiovascular deaths and 5760 cancer deaths identified after a total of 1,444,068 follow-up years. After adjusting for potential confounders, dietary total fiber intake was statistically significantly inversely associated with all-cause death (Q5 vs Q1: HR 0.71, 95% CI 0.66–0.75; P for trend < 0.001), cardiovascular death (Q5 vs Q1: HR 0.73, 95% CI 0.65–0.83; P for trend < 0.001) and cancer mortality (Q5 vs Q1: HR 0.77, 95% CI 0.69–0.86; P for trend < 0.001). Similar results were observed for both insoluble and soluble fiber intake. Restricted cubic spline model analysis suggested that there was a nonlinear association of dietary fiber intake with mortality risk (all P for nonlinearity < 0.05). Conclusions In this large nationally representative sample of US adult population, intakes of total fiber, soluble fiber, and insoluble fiber were associated with lower risks of all-cause, cardiovascular and cancer mortality.