Metabolic syndrome and risk of colorectal cancer: A Mendelian randomization study.

Background: Observational studies have previously demonstrated a significant relationship among both metabolic syndrome (Mets) and colorectal cancer (CRC). Whether there is a causal link remains controversial. Objective: To clarify whether Mets and their components have a causal effect on colorectal cancer, we have carried out a bidirectional Mendelian randomization analysis (MR). Methods: This study started from genome-wide association data for Mets and its 5 components (hypertension, waist circumference, fasting blood glucose, serum triglycerides, and serum high-density lipoprotein cholesterol) and colorectal cancer. Mendelian randomization (MR) techniques were used in the study to examine their associations. Results: After Benjamini-Hochberg multiple corrections, genetically predicted significant causal link exists between WC (waist circumference) and CRC. The OR was 1.35 (95 % CI: 1.08-1.69; p = 0.0096). Other Mets components (HBP, FBG, TG, HDL), on the other hand, found no evidence of a genetic link between CRC and Mets. In addition, MR results showed that CRC was not causally related to either Mets or the components. We get the same result in the validated dataset. Conclusion: According to the bidirectional MR investigation shows a significant causal relationship among obesity and CRC in the Mets component but no causal relationship in the opposite direction.

Association of environmental tobacco smoke exposure with chronic constipation: a nationwide survey (NHANES 2005-2010).

Environmental tobacco smoke (ETS) exposure has been proven to induce digestive diseases such as hepatic steatosis, cirrhosis, and gastrointestinal cancer, yet little is known about the link between ETS exposure and constipation. This study aimed to investigate the impact of ETS exposure on the risk of chronic constipation in adults aged 20 years or older. This is a cross-sectional study based on population. A total number of 7705 participants from the National Health and Nutrition Examination Survey (NHANES) 2005-2010 were included. Cotinine, an alkaloid found in tobacco, serves as a reliable and precise biomarker for measuring exposure to ETS. Hence, the categorization of exposure to ETS was conducted based on serum cotinine levels, resulting in four distinct categories. The association between ETS exposure and the risk of constipation was assessed using multivariable restricted cubic spline and logistic regression with odds ratio (OR) and 95% confidence interval (CI). The weighted prevalence of constipation in this study was estimated to be 7.51% based on stool consistency, or 3.11% based on stool frequency. The fully adjusted models indicated a positive correlation between exposure to ETS and constipation as measured by stool frequency, among adults with poor dietary quality (OR (95% CI): moderate exposure: 2.49 (1.05, 5.94); high exposure: 2.36(1.13, 4.95), P for trend = 0.03), while no significant difference was observed in the subgroup with a higher healthy eating index. Furthermore, the log10-transformed serum cotinine level exhibited a non-linear inverted U-shaped association with constipation in individuals with poor dietary quality (P overall = 0.0207, P non-linear = 0.0427). Conversely, a J-shaped non-linear relationship was observed in the subgroup with a higher healthy eating index (P overall = 0.0028, P non-linear = 0.0036). Our results show that ETS exposure appears to be positively associated with stool frequency-related chronic constipation in adults with poor dietary quality.

Association between dietary carotenoids intake and chronic constipation in American men and women adults: a cross-sectional study.

BACKGROUND: Dietary carotenoids have been proven to improve intestinal disorders like inflammatory bowel disease and colon cancer, yet little is known about the link between dietary carotenoids and constipation. This study aims to examine the relationship between dietary carotenoids intake and constipation, using data from the National Health and Nutrition Examination Survey (NHANES) 2005-2010. METHODS: A total of 11,722 participants were enrolled. Chronic constipation was defined as type 1 (separate hard lumps, like nuts) and type 2 (sausage-like, but lumpy) in the Bristol stool form scale (BSFS). Carotenoids intake was obtained from the average of two 24-hour dietary recall questionnaires (if only one 24-hour was available, we used it) and divided into quartiles (Q). The prevalence of constipation was calculated across men and women individuals. The relationship between dietary carotenoids intake and constipation in men and women was assessed with weighted logistic regression and smoothed curve fitting after adjusting confounders, with results displayed as weighted odds ratio (OR) with 95% confidence intervals (95% CI). The model was further stratified by age, race, and HEI 2015 scores (with median as cutoff) among men and women. RESULTS: The total weighted prevalence of chronic constipation in this study was 8.08%, 11.11% in women and 5.18% in men. After multivariable adjustment, compared with the lowest intake, participants with the highest dietary lycopene intake (ORQ4 vs. Q1= 0.55, 95% CI: 0.36-0.84, p for trend = 0.01) and total lycopene intake (ORQ4 vs. Q1 = 0.52, 95% CI: 0.34-0.80, p for trend = 0.01) were negatively associated with the risk of chronic constipation in men, whereas increased dietary α-carotene intake reduced the risk of chronic constipation in women (ORQ4 vs. Q1 = 0.69, 95% CI: 0.48-0.98, p for trend = 0.04). Smoothing curve fitting further supported these results and provided evidence of dose-response effects. No association was found between other types of carotenoids and chronic constipation in men and women. CONCLUSIONS: Increasing lycopene intake may improve bowel function in men while increased α-carotene intake may reduce the risk of chronic constipation in women. Further studies are essential to explore the role that the intake of carotenoids plays in chronic constipation.