Citrus fruit intake and bladder cancer risk: a meta-analysis of observational studies

Epidemiological studies have investigated the association between citrus fruit and bladder cancer risk; however, the results are inconsistent. To assess these issues, we conducted a meta-analysis of currently available studies. We identified relevant articles by searching the MEDLINE and EMBASE databases. We calculated the summary relative risk (RR) with 95% confidence interval (95% CI) using a random effect model. We included eight case–control studies and six cohort studies in the meta-analysis. There was a significant inverse association between citrus fruit intake and bladder cancer risk in all pooled studies (RR: 0.85; 95% CI, 0.76–0.94) and case–control studies (RR: 0.77; 95% CI, 0.64–0.92), but not in the cohort studies (RR: 0.96; 95% CI, 0.87–1.07). Our results suggest that citrus fruit intake is related to decreased bladder cancer risk. Subsequent well-designed, large prospective studies are needed to obtain better understanding of this relationship.     

Association between fruit and vegetable intake and risk for glioma: A meta-analysis

ObjectiveEpidemiologic studies evaluating the association between the intake of vegetables and fruit and the risk for glioma have produced inconsistent results. Therefore, the aim of this study was to test the hypothesis that higher vegetable and fruit intake may have a protective effect on risk for glioma.MethodsPertinent studies were identified by a search in PubMed, Web of Knowledge, and Wan Fang Med Online up to January 2014. Random-effect model was used to combine study-specific results. Publication bias was estimated using Begg's funnel plot and Egger's regression asymmetry test.ResultsFifteen studies involving 5562 cases focusing on vegetable intake and 17 studies involving 3994 cases of fruit intake compared with the risk for glioma were included in this meta-analysis. The combined relative risk (RR) of glioma associated with vegetable intake was 0.775 (95% confidence interval [CI], 0.688–0.872) overall, and the association for subgroup analysis by study design, sources of control, ethnicity, and number of cases was consistent with overall data. For fruit intake and glioma risk, significant protective associations were found in an Asian population (RR, 0.573; 95% CI, 0.346–0.947), but not in a white population. No publication bias was found.ConclusionsThis analysis indicated that intake of vegetables might have a protective effect on glioma. The intake of fruit might have a protective effect on glioma in the Asian population; however, the results need to be confirmed.     

Primary school interventions to promote fruit and vegetable consumption: a systematic review and meta-analysis

ObjectiveThe consumption of fruits and vegetables (FV) may contribute to the prevention of many diseases. However, children at school age do not eat an enough amount of those foods. We have systematically reviewed the literature to assess the effectiveness of school interventions for promoting the consumption of FV.MethodsWe performed a search in MEDLINE, EMBASE, CINAHL and CENTRAL. We pooled results and stratified the analysis according to type of intervention and study design.ResultsNineteen cluster studies were included. Most studies did not describe randomization method and did not take the cluster's effect into account. Pooled results of two randomized controlled trials (RCTs) of computer-based interventions showed effectiveness in improving consumption of FV [Standardized Mean Difference (SMD) 0.33 (95% CI 0.16, 0.50)]. No significant differences were found in pooled analysis of seven RCTs of multicomponent interventions or pooling results of two RCTs evaluating free/subsidized FV interventions.ConclusionsMeta-analysis shows that computer-based interventions were effective in increasing FV consumption. Multicomponent interventions and free/subsidized FV interventions were not effective. Improvements in methodology are needed in future cluster studies. Although these results are preliminary, computer-based interventions could be considered in schools, given that they are effective and cheaper than other alternatives.     

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.     

Association between the Mediterranean diet and cancer risk: a review of observational studies

The aim of this article was to summarize the evidence concerning the association between Mediterranean dietary pattern and cancer risk in observational epidemiological studies. All the studies that met the following criteria were reviewed: human cohort and case-control studies that examined the effect of the Mediterranean diet as an entire food pattern (the combined effect of individual components of the Mediterranean diet) and whose results were published in English. Out of the 12 reviewed studies (7 cohort and 5 case-control), 10 studies (6 cohort and 4 case-control) provided some evidence that the Mediterranean diet was associated with a reduced risk of cancer incidence or mortality. Although the reviewed studies varied according to certain study characteristics, such as being set in different populations and studying different cancer outcomes, the existing evidence from observational studies collectively suggests that there is a "probable" protective role of the Mediterranean diet toward cancer in general. Specific results for several outcomes such as different cancer sites deserve additional evidence. This favorable effect of the Mediterranean diet on cancer reduction is of public health relevance, given the tendency of modern societies to shift toward a more U.S. and Northern European dietary pattern.     

Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies

Observational studies on tea consumption and prostate cancer (PCa) risk are still inconsistent. The authors conducted a meta-analysis to investigate the association between green tea and black tea consumption with PCa risk. Thirteen studies providing data on green tea or black tea consumption were identified by searching PubMed and ISI Web of Science databases and secondary referencing qualified for inclusion. A random-effects model was used to calculate the summary odds ratios (OR) and their corresponding 95% confidence intervals (CIs). For green tea, the summary OR of PCa indicated a borderline significant association in Asian populations for highest green tea consumption vs. non/lowest (OR = 0.62; 95% CI: 0.38-1.01); and the pooled estimate reached statistically significant level for case-control studies (OR = 0.43; 95% CI: 0.25-0.73), but not for prospective cohort studies (OR = 1.00; 95% CI: 0.66-1.53). For black tea, no statistically significant association was observed for the highest vs. non/lowest black tea consumption (OR = 0.99; 95% CI: 0.82-1.20). In conclusion, this meta-analysis supported that green tea but not black tea may have a protective effect on PCa, especially in Asian populations. Further research regarding green tea consumption across different regions apart from Asia is needed.     

Fruit and vegetable consumption and health outcomes: an umbrella review of observational studies

The aim of this study was to provide a comprehensive evaluation of current evidence on fruit and vegetable consumption and health outcomes. A systematic search for quantitative syntheses was performed. Several criteria, including study design, dose–response relationship, heterogeneity and agreement of results over time, and identification of potential confounding factors, were used to assess the level of evidence. The strongest (probable) evidence was found for cardiovascular disease protection; possible evidence for decreased risk of colon cancer, depression and pancreatic diseases was found for fruit intake; and colon and rectal cancer, hip fracture, stroke, depression and pancreatic diseases was found for vegetable intake. Suggestive and rather limited associations with other outcomes have been found. Evidence of potential confounding by sex and geographical localisation has been reported. Despite findings are consistent enough for hypothesising causation (at least for cardiovascular-related outcomes), further studies are needed to clarify the role of potential confounding factors.     

Association between parenting styles and own fruit and vegetable consumption among Portuguese mothers of school children

The aim of the present study was to evaluate the association between parenting styles and own fruit and vegetable consumption among Portuguese mothers of school children. A cross-sectional study was performed in Portugal as part of the Pro Children cross-sectional European survey. Portuguese mothers (n 1601) of 11-13-year-old school children were included in the present study. A self-administered questionnaire was developed to assess fruit and vegetable consumption as well as the parenting styles. Fruit and vegetable consumption was assessed by a validated FFQ. Parenting styles based on two dimensions - strictness and involvement - were classified into authoritative, authoritarian, indulgent and neglectful. The higher mean intakes of fruit, vegetables and total fruit and vegetables were observed for mothers classified as indulgent, whereas the lower mean intakes were observed for mothers classified as neglectful. Differences in intake among parenting styles were significant for fruit, vegetables and total fruit and vegetables. When partial correlations were calculated between the two dimensions, strictness and involvement (controlled one for the other), and intakes, only involvement was positively associated with fruit, vegetables and total fruit and vegetable intake. Findings from the present study show that fruit and vegetable consumption of Portuguese mothers of school children seems to be related to their own parenting styles, especially with the dimension involvement. Future interventions to promote fruit and vegetable intake should take into account these variables.     

Intake of vegetables and fruit and risk of esophageal adenocarcinoma: a meta-analysis of observational studies

Objectives

To study the association between the intake of fruit and vegetables and risk of esophageal adenocarcinoma (EAC), we summarized the evidence from observational studies in categorical and linear dose–response meta-analyses.

Methods

Eligible studies published up to June 2013 were retrieved via computerized searches of MEDLINE and EMBASE. Random-effects models were used to calculate summary relative risks (SRRs) and the corresponding 95 % confidence intervals (CIs). Between-study heterogeneity was assessed using the Cochran’s Q and I ² statistics.

Results

A total of 12 studies involving 1,572 cases of EAC were included in this meta-analysis. Based on the highest versus lowest analysis, inverse associations were observed between intakes of vegetable (SRRs = 0.76, 95 % CIs 0.59–0.96; P _{heterogeneity} = 0.098, I ² 40.4 %; n = 9 studies), intakes of fruit (SRRs = 0.73, 95 % CIs, 0.55–0.98; P _{heterogeneity} = 0.03, I ² = 52.9 %; n = 9 studies), and intakes of total vegetables and fruit combined (SRRs = 0.68, 95 % CI 0.49–0.93; P _{heterogeneity} = 0.162, I ² = 38.9 %; n = 5 studies). Similar results were also observed in a linear dose–response analysis.

Conclusion

These data support the hypothesis that intakes of vegetables and fruit may significantly reduce the risk of EAC. Further investigation with prospective designs, validated questionnaires, and good control of important confounders is warranted.     

Quantity and variety of fruit and vegetable consumption and cancer risk

The recommendation for fruit and vegetable intake includes eating a certain quantity as well as a variety. The evidence for eating a variety is limited. We examined the association with cancer in a prospective cohort study among 730 Dutch men aged 65-84 yr followed for 10 years, resulting in 138 cancer cases. The quantity of fruits and vegetables was assessed using a dietary history and the variety in intake was based on a food frequency questionnaire. Adherence to the recommended amounts of fruit and vegetables was inversely associated with total cancer risk: The adjusted relative risk (RR) was 0.56 [95% confidence interval (CI) = 0.31-1.00]. Eating the recommended daily 200 g of vegetables was not related to cancer incidence, whereas eating the recommended 200 g of fruit was associated with a 38% lower risk. Variety in vegetable intake was inversely associated with total cancer and non-lung epithelial cancer: The RRs (95% CI) for the highest and lowest tertiles were 0.64 (0.43-0.95) and 0.51 (0.27-0.97), respectively. Only after excluding the first two years of follow-up, variety in fruit intake was associated with reduced cancer risk. In conclusion, adherence to the guidelines for fruit and vegetable intake was associated with lower cancer risk. Besides quantity, variety in intake is also of importance.     

Association between fruit and vegetable consumption in mothers and children in low-income, urban neighborhoods.

To understand factors influencing fruit and vegetable (F&V) consumption in children, the authors studied the association between F&V consumption in mothers and children in a sample of 1,106 boys and girls in Grades 4-6 in 24 elementary schools in low-income, multiethnic neighborhoods in Montreal, Canada. Approximately 10% of girls and 19% of boys reported not having eaten any vegetables in the week prior to questionnaire administration; 53% of girls and 63% of boys did not consume whole fruits daily. Each unit increase in F&V consumption in mothers was associated with a 10% to 20% increase in F&V consumption in children. Interventions to improve F&V consumption should aim to improve awareness among parents of the importance of fruits and vegetables and of the impact of their own behavior on their children's F&V consumption.     

Fruit and vegetable consumption and risk of coronary heart disease: a meta-analysis of cohort studies

The consumption of fruit and vegetables is associated with a reduced rate of coronary heart disease (CHD) in observational cohorts. The purpose of this study was to assess the strength of this association in a meta-analysis. Cohort studies were selected if they reported relative risks (RRs) and 95% CI for coronary heart disease or mortality and if they presented a quantitative assessment of fruit and vegetable intake. The pooled RRs were calculated for each additional portion of fruit and/or vegetables consumed per day, and the linearity of the associations were examined. Nine studies were eligible for inclusion in the meta-analysis that consisted of 91,379 men, 129,701 women, and 5,007 CHD events. The risk of CHD was decreased by 4% [RR (95% CI): 0.96 (0.93-0.99), P = 0.0027] for each additional portion per day of fruit and vegetable intake and by 7% [0.93 (0.89-0.96), P < 0.0001] for fruit intake. The association between vegetable intake and CHD risk was heterogeneous (P = 0.0043), more marked for cardiovascular mortality [0.74 (0.75-0.84), P < 0.0001] than for fatal and nonfatal myocardial infarction [0.95 (0.92-0.99), P = 0.0058]. Visual inspection of the funnel plot suggested a publication bias, although not statistically significant. Therefore, the reported RRs are probably overestimated. This meta-analysis of cohort studies shows that fruit and vegetable consumption is inversely associated with the risk of CHD. The causal mechanism of this association, however, remains to be demonstrated.     

Association between physical activity and mortality in breast cancer: a meta-analysis of cohort studies

Previous studies concerning the association between physical activity (PA) and mortality in breast cancer yielded mixed results. We investigated the association by performing a meta-analysis of all available studies. Relevant studies were identified by searching PubMed and EMBASE to January 2014. We calculated the summary relative risk (RR) and 95 % confidence intervals (CIs) using random-effects models. The dose–response relationship was assessed by restricted cubic spline model and multivariate random-effect meta-regression. Sixteen cohort studies involving 42,602 patients of breast cancer were selected for meta-analysis. The analyses showed that patients who participated in any amount of PA before diagnosis had a RR of 0.82 (95 % CI 0.74–0.91) for breast cancer-specific mortality (vs. low PA). Those who participated in high PA and moderate PA before diagnosis had a RR of breast cancer-specific mortality of 0.81 (95 % CI 0.72–0.90) and 0.83 (95 % CI 0.73–0.94), respectively. Similar inverse associations of prediagnosis PA were found for all-cause mortality. Postdiagnosis PA on breast cancer-specific and all-cause mortality also showed the same results. Stratifying by body mass index (<25 vs. ≥25) or menopausal status, all the subgroups experienced benefits with PA, with a stronger mortality reduction among overweight women than normal weight women and among postmenopausal women than premenopausal women. A linear and significant dose–response association was only found for breast cancer-specific or all-cause mortality and prediagnosis PA (P for nonlinearity = 0.07 and 0.10, respectively). In conclusion, both prediagnosis and postdiagnosis PA were associated with reduced breast cancer-specific mortality and all-cause mortality.     

What epidemiologic studies tell us about the relationship between fruit and vegetable consumption and body weight

Clinical evidence shows that combining advice to increase fruit and vegetable consumption with caloric restriction is an effective strategy for weight management. The purpose of this review is to evaluate epidemiologic evidence to determine whether it supports an association between fruit and/or vegetable consumption and body weight. Few studies have been designed to specifically address this issue, and those that are available vary in methodology and offer inconsistent results. We make recommendations on how to strengthen future studies so that the influence of fruit and vegetable consumption on body weight in free-living individuals is better understood.     

The association between fruit and vegetable consumption and peripheral arterial disease

BACKGROUND: High fruit and vegetable consumption has been associated with a lower risk of cardiovascular diseases, but few studies have focused on peripheral arterial disease. In this study, we evaluated the association of consumption of fruits and vegetables with peripheral arterial disease. METHODS: In a cohort of 44,059 men initially free of cardiovascular disease and diabetes, we documented 295 cases of peripheral arterial disease during a 12-year follow-up. Fruit and vegetable consumption was assessed by food frequency questionnaire. RESULTS: In the age-adjusted model, men in the highest quintile had a relative risk of 0.55 (95% confidence interval = 0.38-0.80) for overall fruit and vegetable intake, 0.52 (0.36-0.77) for fruit intake, and 0.54 (0.36-0.81) for vegetable intake, compared with those in the lowest quintile of intake. However, the associations were greatly weakened after adjustment for smoking and other traditional cardiovascular disease risk factors. Comparing men in the highest quintile versus the lowest quintile, relative risks and 95% confidence intervals were 0.95 (0.62-1.44) for overall fruit and vegetable intake, 0.97 (0.64-1.48) for fruit intake, and 0.76 (0.50-1.17) for vegetable intake. CONCLUSIONS: We did not find evidence that fruit and vegetable consumption protects against peripheral arterial disease, although a modest benefit cannot be excluded.     

Association between dietary fiber and endometrial cancer: a meta-analysis

Abstract

To explore a potential relationship between dietary fiber consumption and risk of endometrial cancer (EC), eligible studies published up to 30 June 2018 were retrieved via computer searches and manual review of references. Random-effects models were used to calculate summary relative risk (RR) estimates based on contrasting high- and low-fiber intake values. Sensitivity analysis was conducted, and heterogeneity among study results was explored through stratified analyses by study design, geographic region, Newcastle-Ottawa Scale (NOS) score, impact factor, and adjustment for several confounders (age, body mass index, smoking, energy intake, and education). We extracted data from 16 studies (involving 6,563 cases). There was a significant association between dietary fiber intake and EC (RR?=?0.86, 95% confidence interval [CI]: 0.78, 0.93). In stratified analysis, this trend was more pronounced in the case–control studies, and in studies conducted in the Americas and Asia. The relationship was further confirmed after adjusting for education level (RR?=?0.74; 95% CI: 0.60, 0.88) and age (RR?=?0.70; 95% CI: 0.57, 0.83), and NOS scores of 6 (RR?=?0.81; 95% CI: 0.67, 0.95) and 7 (RR?=?0.75; 95% CI: 0.62, 0.88). In conclusion, our meta-analysis revealed an inverse association between dietary fiber consumption and EC risk. Further efforts should be made to confirm these findings.