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.

Hyperprogressive Disease during Anti-PD-1 (PDCD1) / PD-L1 (CD274) Therapy: A Systematic Review and Meta-Analysis.

Hyperprogressive disease (HPD) is a recently acknowledged pattern of rapid tumor progression after the initiation of immune checkpoint inhibitors. HPD has been observed across various types of tumors and has been associated with poor survival. We performed a meta-analysis to identify baseline (i.e., prior to programmed cell death 1 [PD-1, PDCD1] / programmed cell death 1 ligand 1 [PD-L1, CD274] inhibitor therapy) patient factors associated with risks of developing HPD during PD-1/PD-L1 inhibitor therapy. We searched eight databases until 6 June 2019. We calculated the summary odds ratio (OR) and its 95% confidence interval (CI) using the random-effects model and explored between-study heterogeneity and small-study effects. A total of nine articles was eligible (217 HPD cases, 1519 cancer patients) for meta-analysis. There was no standard definition of HPD, and the incidence of HPD ranged from 1 to 30%. We identified twenty-three baseline patient factors, of which five factors were statistically significantly associated with HPD. These were serum lactate dehydrogenase (LDH) above the upper normal limit (OR = 1.89, 95% CI = 1.02-3.49, p = 0.043), more than two metastatic sites (OR = 1.86, 1.34-2.57, p < 0.001), liver metastases (OR = 3.33, 2.07-5.34, p < 0.001), Royal Marsden Hospital prognostic score of 2 or above (OR = 3.33, 1.96-5.66, p < 0.001), and positive PD-L1 expression status that was inversely correlated with HPD (OR = 0.60, 0.36-0.99, p = 0.044). Between-study heterogeneity was low. Evidence of small-study effect was found in one association (PD-L1 expression). Subset analyses of patients with non-small cell lung cancer showed similar results. Future studies are warranted to identify underlying molecular mechanisms and to test their roles as predictive biomarkers of HPD.

Association of type and intensity of physical activity with plasma biomarkers of inflammation and insulin response.

Several biological mechanisms linking physical activity with cancer have been proposed. However, the influence of specific components of physical activity (volume, type and intensity), and their interaction with adiposity and diet, on cancer-related biomarkers remain unclear. We used cross-sectional data on 7,219 men in the Health Professionals Follow-up Study (1992-1994) with C-reactive protein (CRP), interleukin-6 (IL6), tumor necrosis factor alpha receptor 2 (TNFαR2), adiponectin, C-peptide and triglycerides/high-density lipoprotein cholesterol ratio (TG/HDL). Details on physical activity, diet and adiposity were assessed by questionnaires. We used multivariable-adjusted linear regression analyses to estimate relative concentrations of biomarkers by physical activity. Total physical activity was favorably associated with all biomarkers in a fairly linear manner. Comparing the highest (63+ metabolic equivalent (MET)-hr/week) to the lowest (0-8.9 MET-hr/week) physical activity groups, the percent relative difference in concentration of biomarkers was -31% for CRP, -22% for IL6, -8% for TNFαR2, +9% for adiponectin, -22% for C-peptide, and -20% for TG/HDL. These differences were modestly attenuated after adjustment for adiposity. For the same total MET-hours of physical activity, the association was stronger for men engaging in both aerobic and resistance exercises compared to those engaging in aerobic only. However, no difference was found between those engaging in vigorous activities (≥20% of total MET-hours) compared to those who did smaller amount of vigorous activities. Physical activity showed similar associations for these biomarkers regardless of adiposity and dietary pattern. In conclusion, high physical activity, preferably aerobic plus resistance training, was associated with favorable cancer-related biomarkers.

Reporting bias in the literature on the associations of health-related behaviors and statins with cardiovascular disease and all-cause mortality.

Reporting bias in the literature occurs when there is selective revealing or suppression of results, influenced by the direction of findings. We assessed the risk of reporting bias in the epidemiological literature on health-related behavior (tobacco, alcohol, diet, physical activity, and sedentary behavior) and cardiovascular disease mortality and all-cause mortality and provided a comparative assessment of reporting bias between health-related behavior and statin (in primary prevention) meta-analyses. We searched Medline, Embase, Cochrane Methodology Register Database, and Web of Science for systematic reviews synthesizing the associations of health-related behavior and statins with cardiovascular disease mortality and all-cause mortality published between 2010 and 2016. Risk of bias in systematic reviews was assessed using the ROBIS tool. Reporting bias in the literature was evaluated via small-study effect and excess significance tests. We included 49 systematic reviews in our study. The majority of these reviews exhibited a high overall risk of bias, with a higher extent in health-related behavior reviews, relative to statins. We reperformed 111 meta-analyses conducted across these reviews, of which 65% had statistically significant results (P < 0.05). Around 22% of health-related behavior meta-analyses showed small-study effect, as compared to none of statin meta-analyses. Physical activity and the smoking research areas had more than 40% of meta-analyses with small-study effect. We found evidence of excess significance in 26% of health-related behavior meta-analyses, as compared to none of statin meta-analyses. Half of the meta-analyses from physical activity, 26% from diet, 18% from sedentary behavior, 14% for smoking, and 12% from alcohol showed evidence of excess significance bias. These biases may be distorting the body of evidence available by providing inaccurate estimates of preventive effects on cardiovascular and all-cause mortality.

Lifestyle among former cancer patients in Brazil in 2013.

People who have been diagnosed with cancer tend to adopt healthier lifestyles. This study analyzes the prevalence of smoking, eating fruits and vegetables, exercise and the use of alcoholic beverages among individuals who reported to have been diagnosed with cancer in the PNS (Pesquisa Nacional de Saúde or National Health Survey). The prevalence and corresponding 95% confidence intervals were calculated for consuming fruits and vegetables, sedentary lifestyle (no exercise), use of alcoholic beverages, being overweight and tobacco use. The associa-tion between having received a diagnosis of cancer and the risk and protection factors was analyzed using a Poisson regression, adjusted by sociodemographic variables and other chronic comorbidities. The analyses were stratified by time since the diagnosis and the type of cancer related to the factors analyzed. The types of cancer most often reported were breast and cervix in women, and prostate and stomach in men. Among those who had cancer diagnoses, there was a higher consumption of fruits and vegetables, higher proportion of ex-smokers, however, increased use of alcohol. There was no difference in the frequency of exercise or incidence of being overweight between the two groups. Measures to promote health and prevent chronic diseases should be implemented in the follow-up of people who have had cancer, in an effort to ensure integrated healthcare.

Effect of physical inactivity on major noncommunicable diseases and life expectancy in Brazil.

BACKGROUND: In Brazil, one-fifth of the population reports not doing any physical activity. This study aimed to assess the impact of physical inactivity on major noncommunicable diseases (NCDs), all-cause mortality and life expectancy in Brazil, by region and sociodemographic profile. METHODS: We estimated the population attributable fraction (PAF) for physical inactivity associated with coronary heart disease, type 2 diabetes, breast cancer, colon cancer, and all-cause mortality. To calculate the PAF, we used the physical inactivity prevalence from the 2008 Brazilian Household Survey and relative risk data in the literature. RESULTS: In Brazil, physical inactivity is attributable to 3% to 5% of all major NCDs and 5.31% of all-cause mortality, ranging from 5.82% in the southeastern region to 2.83% in the southern region. Eliminating physical inactivity would increase the life expectancy by an average of 0.31 years. This reduction would affect mainly individuals with ≥ 15 years of schooling, male, Asian, elderly, residing in an urban area and earning ≥ 2 times the national minimum wage. CONCLUSIONS: In Brazil, physical inactivity has a major impact on NCDs and mortality, principally in the southeastern and central-west regions. Public policies and interventions promoting physical activity will significantly improve the health of the population.

Sedentary behavior and health outcomes: an overview of systematic reviews.

OBJECTIVE: 1) To synthesize the current observational evidence for the association between sedentary behavior and health outcomes using information from systematic reviews. 2) To assess the methodological quality of the systematic reviews found. METHODOLOGY/PRINCIPAL FINDINGS: Medline; Excerpta Medica (Embase); PsycINFO; and Web of Science were searched for reviews published up to September 2013. Additional publications were provided by Sedentary Behaviour Research Network members. The methodological quality of the systematic reviews was evaluated using recommended standard criteria from AMSTAR. For each review, improper use of causal language in the description of their main results/conclusion was evaluated. Altogether, 1,044 review titles were identified, 144 were read in their entirety, and 27 were included. Based on the systematic reviews with the best methodological quality, we found in children and adolescents, strong evidence of a relationship between time spent in sedentary behavior and obesity. Moreover, moderate evidence was observed for blood pressure and total cholesterol, self-esteem, social behavior problems, physical fitness and academic achievement. In adults, we found strong evidence of a relationship between sedentary behavior and all-cause mortality, fatal and non-fatal cardiovascular disease, type 2 diabetes and metabolic syndrome. In addition, there is moderate evidence for incidence rates of ovarian, colon and endometrial cancers. CONCLUSIONS: This overview based on the best available systematics reviews, shows that sedentary behavior may be an important determinant of health, independently of physical activity. However, the relationship is complex because it depends on the type of sedentary behavior and the age group studied. The relationship between sedentary behavior and many health outcomes remains uncertain; thus, further studies are warranted.

Sedentary behavior and health outcomes among older adults: a systematic review.

BACKGROUND: In the last decade, sedentary behavior has emerged as a new risk factor for health. The elderly spend most of their awake time in sedentary activities. Despite this high exposure, the impact of this sedentary behavior on the health of this population has not yet been reviewed. We systematically reviewed evidence for associations between sedentary behavior and multiple health outcomes in adults over 60 years of age. METHODS: We searched the Medline, Embase, Web of Science, SPORTDiscus, PsycINFO, CINAHL, LILLACS, and Sedentary Research Database for observational studies published up to May 2013. Additionally, we contacted members of the Sedentary Behaviour Research Network to identify articles that were potentially eligible. After inclusion, the methodological quality of the evidence was assessed in each study. RESULTS: We included 24 eligible articles in our systematic review, of which only 2 (8%) provided high-quality evidence. Greater sedentary time was related to an increased risk of all-cause mortality in the older adults. Some studies with a moderate quality of evidence indicated a relationship between sedentary behavior and metabolic syndrome, waist circumference, and overweightness/obesity. The findings for other outcomes such as mental health, renal cancer cells, and falls remain insufficient to draw conclusions. CONCLUSION: This systematic review supports the relationship between sedentary behavior and mortality in older adults. Additional studies with high methodological quality are still needed to develop informed guidelines for addressing sedentary behavior in older adults.