Consumption of Fish and ω-3 Fatty Acids and Cancer Risk: An Umbrella Review of Meta-Analyses of Observational Studies.

Multiple studies have suggested that ω-3 fatty acid intake may have a protective effect on cancer risk; however, its true association with cancer risk remains controversial. We performed an umbrella review of meta-analyses to summarize and evaluate the evidence for the association between ω-3 fatty acid intake and cancer outcomes. We searched PubMed, Embase, and the Cochrane Database of Systematic Reviews from inception to December 1, 2018. We included meta-analyses of observational studies that examined associations between intake of fish or ω-3 fatty acid and cancer risk (gastrointestinal, liver, breast, gynecologic, prostate, brain, lung, and skin) and determined the level of evidence of associations. In addition, we appraised the quality of the evidence of significant meta-analyses by using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We initially screened 598 articles, and 15 articles, including 57 meta-analyses, were eligible. Among 57 meta-analyses, 15 reported statistically significant results. We found that 12 meta-analyses showed weak evidence of an association between ω-3 fatty acid intake and risk of the following types of cancer: liver cancer (n = 4 of 6), breast cancer (n = 3 of 14), prostate cancer (n = 3 of 11), and brain tumor (n = 2 of 2). In the other 3 meta-analyses, studies of endometrial cancer and skin cancer, there were no assessable data for determining the evidence levels. No meta-analysis showed convincing, highly suggestive, or suggestive evidence of an association. In the sensitivity analysis of meta-analyses by study design, we found weak associations between ω-3 fatty acid intake and breast cancer risk in cohort studies, but no statistically significant association in case-control studies. However, the opposite results were found in case of brain tumor risk. Although ω-3 fatty acids have been studied in several meta-analyses with regard to a wide range of cancer outcomes, only weak associations were identified in some cancer types, with several limitations. Considering the nonsignificant or weak evidence level, clinicians and researchers should cautiously interpret reported associations between ω-3 fatty acid consumption and cancer risks.

Association of Hot Tea Consumption with Regional Adiposity Measured by Dual-Energy X-Ray Absorptiometry in NHANES 2003-2006.

OBJECTIVE: This study aimed to investigate the potential antiobesity benefits of hot tea consumption at the population level. METHODS: Using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006, the association between hot tea consumption and dual-energy x-ray-measured body fat was examined in a large representative sample of US adults (n = 5,681, 51.9% women). RESULTS: Compared with non-tea drinkers, men who consumed 0.25 to 1 cup per day of hot tea had 1.5% (95% CI: 0.4% to 2.6%) and 1.7% (95% CI: 0.4% to 3.0%) less total and trunk body fat, respectively. The associations were stronger among men 45 to 69 years old compared with younger men (20-44 years). For men who consumed 1 or more cups per day of hot tea, lower total (-1.2%, 95% CI: -2.3% to -0.2%) and trunk body fat (-1.3%, 95% CI: -2.6 to -0.1%) was observed among men 45 to 69 years old only. In women, those who drank 1 or more cups per day had 1.5% lower (95% CI: -2.7% to -0.3%) trunk body fat compared with non-tea drinkers. CONCLUSIONS: Consumption of hot tea might be considered as part of a healthy diet in order to support parameters associated with metabolic health and may be particularly important in older male age groups in supporting reduced central adiposity.

Moderators of real-world effectiveness of smoking cessation aids: a population study.

BACKGROUND AND AIMS: Understanding whether and how far smokers' characteristics influence the effectiveness of treatment may be important for tailoring recommendations on cessation aids to those most likely to help the user achieve abstinence. This study aimed to estimate the effectiveness of commonly used smoking cessation aids and test whether their effectiveness differs according to cigarette addiction, socio-economic status, age or sex. DESIGN: Correlational design using cross-sectional survey data collected monthly between 2006 and 2018. SETTING: England. PARTICIPANTS: A total of 18 929 adults (aged ≥ 16 years, 52.0% female) who had smoked within the previous 12 months and had made at least one quit attempt during that period. MEASUREMENTS: The outcome was self-reported abstinence from quit date to survey. Independent variables were self-reported use during the most recent quit attempt of: prescription nicotine replacement therapy (NRT), NRT over-the-counter, varenicline, bupropion, e-cigarettes, face-to-face behavioural support, telephone support, written self-help materials, websites and hypnotherapy. Moderators were cigarette addiction, social grade, age and sex. FINDINGS: After adjustment for covariates and use of other cessation aids, users of e-cigarettes [odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.69-2.24] and varenicline (OR = 1.82, 95% CI = 1.51-2.21) had significantly higher odds of reporting abstinence than those who did not report use of these cessation aids. Use of prescription NRT was associated with increased abstinence in older (≥ 45 years) (OR = 1.58, 95% CI = 1.25-2.00) but not younger (< 45 years) smokers (OR = 1.09, 95% CI = 0.85-1.42). Use of websites was associated with increased abstinence in smokers from lower (OR = 2.20, 95% CI = 1.22-3.98) but not higher social grades (OR = 0.74, 95% CI = 0.40-1.38). There was little evidence of benefits of using other cessation aids. CONCLUSIONS: Use of e-cigarettes and varenicline are associated with higher abstinence rates following a quit attempt in England. Use of prescription of nicotine replacement therapy is also associated with higher abstinence rates, but only in older smokers, and use of websites only in smokers from lower socio-economic status.