ABSTRACT
BACKGROUND: Several liver diseases have been associated with oxidative stress. Accordingly, antioxidants have been suggested as potential therapeutics for various liver diseases. The evidence supporting these suggestions is equivocal. AIM: To assess the benefits and harms of antioxidant supplements for patients with liver diseases. METHODS: We identified trials through electronic and manual searches until August 2009. We included randomized trials comparing antioxidant supplements (beta-carotene, vitamin A, C, E and selenium) vs. placebo or no intervention for autoimmune liver diseases, viral hepatitis, alcoholic liver disease and cirrhosis (any aetiology). Random-effects and fixed-effect meta-analyses were conducted. Results were presented as relative risks (RR), or mean difference (MD), both with 95% confidence intervals (CI). RESULTS: Twenty randomized trials with 1225 participants were included. The trials assessed beta-carotene (3 trials), vitamin A (2 trials), vitamin C (9 trials), vitamin E (15 trials) and selenium (8 trials). The majority of the trials had high risk of bias and showed heterogeneity. Overall, the assessed antioxidant supplements had no significant effect on all-cause mortality [relative risk (RR) 0.84, 95% confidence interval (CI) 0.60-1.19, I(2) = 0%] or liver-related mortality (RR 0.89, 95% CI 0.39-2.05, I(2) = 37%). Stratification according to the type of liver disease assessed did not affect the conclusions. Antioxidant supplements significantly increased the activity of gamma glutamyl transpeptidase (MD 24.21 IU/L, 95% CI 6.67-41.75, I(2) = 0%). CONCLUSIONS: We found no evidence to support or refute antioxidant supplements in patients with liver disease. Antioxidant supplements may increase liver enzymes.
Subject(s)
Antioxidants/administration & dosage , Liver Diseases/drug therapy , Adult , Ascorbic Acid/administration & dosage , Bias , Female , Humans , Male , Middle Aged , Selenium/administration & dosage , Vitamin A/administration & dosage , Vitamin E/administration & dosage , beta Carotene/administration & dosageABSTRACT
PURPOSE: To examine possible associations between dietary factors and gastric cancer risk among residents in the area of Nis, Serbia. METHODS: This hospital based case-control study was conducted at the Clinical Centre Nis between 2005 and 2006. Cases (n=102) with histologically confirmed gastric cancer and matched non-cancer patients (controls, n=204) were interviewed. Diet was assessed using a food frequency questionnaire and odds ratios (OR), 95% confidence interval (95% CI), and p-trends were calculated across tertiles of intake. RESULTS: High intake of salt, salty meals and hot food were associated with higher risk of gastric cancer. After searching for potential confounders, multivariate logistic regression analysis showed elevated risk for the highest vs. the lowest tertile of intake for smoked and barbecue meat (OR 4.21; 95% CI 1.43-12.37), processed meat (OR 9.17; 95% CI 2.78-15.23), desert (OR 2.85; 95% CI 1.28-6.38), potatoes (OR 4.79; 95% CI 1.44-5.94), pickled vegetables (OR 2.02; 95% CI 1.21-3.0) and milk (OR 5.08; 95% CI 1.59-10.16) intake but reduced for citrus fruits (OR= 0.13, 95% CI 0.03- 0.53), other fruits (OR 0.05; 95% CI 0.02-0.18), allium vegetables (e.g. onion, garlic, leek) (OR 0.11; 95% CI 0.02-0.60) and cooked meat intake (OR 0.07; 95% CI 0.02-0.27). Intake of bread, dairy, fish, legumes and raw and cooked vegetables was not significantly related with gastric cancer risk. CONCLUSION: A low risk diet for gastric cancer in the area of Nis should include increased fruits and alliums vegetables consumption and limited processed meat, salt, preserved food, deserts, potatoes and milk intake.
Subject(s)
Adenocarcinoma/etiology , Diet/adverse effects , Feeding Behavior , Hospitals, University , Life Style , Stomach Neoplasms/etiology , Adenocarcinoma/epidemiology , Aged , Aged, 80 and over , Case-Control Studies , Diet/statistics & numerical data , Female , Hospitals, University/statistics & numerical data , Humans , Logistic Models , Male , Middle Aged , Odds Ratio , Risk Assessment , Risk Factors , Serbia/epidemiology , Stomach Neoplasms/epidemiology , Surveys and QuestionnairesABSTRACT
BACKGROUND: Colorectal cancer may be prevented by reducing the development of adenomatous polyps. AIM: To assess the benefits and harms of antioxidant supplements in preventing colorectal adenoma. METHODS: Using the Cochrane Collaboration methodology we reviewed all randomized clinical trials comparing antioxidant supplements with placebo or no intervention. We searched electronic databases and the reference lists until October 2005. Outcome measures were development of colorectal adenoma adverse events. We analysed dichotomous outcomes with fixed- and random-effects model meta-analyses and calculated the relative risk with 95% confidence interval. RESULTS: We identified eight randomized trials (17 620 participants). Neither fixed-effect (relative risk: 0.93, 95% CI: 0.81-1.1) nor random-effect model meta-analyses (0.82, 0.60-1.1) showed statistically significant effects of supplementation with beta-carotene, vitamins A, C, E and selenium alone or in combination. Antioxidant supplements seemed to increase the development of colorectal adenoma in three low-bias risk trials (1.2, 0.99-1.4) and significantly decrease its development in five high-bias risk trials (0.59, 0.47-0.74). The estimates difference is significant (P < 0.0001). There was no significant difference between the intervention groups regarding adverse events, including mortality (0.82, 0.47-1.4). CONCLUSION: We found no convincing evidence that antioxidant supplements have significant beneficial effect on primary or secondary prevention of colorectal adenoma.
