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.

Objectives were to provide an overview and understand the strength of evidence and extent of potential biases and validity of claimed associations between body mass index (BMI) and risk of developing cancer. We carried out an umbrella review and comprehensively re-analyzed the data of dose–response meta-analyses on associations between BMI and risk of 20 specific cancers (bladder, brain, breast, colonic, rectal, endometrial, gallbladder, gastric, leukemia, liver, lung, melanoma, multiple myeloma, non-Hodgkins lymphoma, esophagus, ovarian, pancreatic, prostate, renal, thyroid) by adding big data or missed individual studies. Convincing evidence for an association was defined as a strong statistical significance in fixed-effects and random-effects meta-analyses at P < 0.001, 95% prediction interval (PI) excluded null, there was no large between-study heterogeneity and no small study effects. Suggestive evidence was defined as meeting the significance threshold for the random summary effects of P < 0.05, but 95% PI included the null. Weak evidence was defined as meeting the significance threshold for the random summary effects at a P < 0.05, but 95% PI included the null and there was large between-study heterogeneity or there were small study effects. Convincing evidence for an association with BMI was detectable for six cancers (leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma). Suggestive evidence was detectable for malignant melanoma, non-Hodgkins lymphoma, and esophageal adenocarcinoma. Weak evidence was detectable for brain and central nervous system tumors, breast, colon, gall bladder, lung, liver, ovarian, and thyroid cancer. No evidence was detectable for bladder, gastric, and prostate cancer. The association of increased BMI and cancer is heterogeneous across cancer types. Leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma are convincingly associated with an increased BMI by dose–response meta-analyses.

Study design: Experimental, prospective study. Objectives: Fecal incontinence and constipation affect the quality of life (QOL) of children with spina bifida and their caregivers. We evaluated the clinical efficacy of a stepwise bowel management program on QOL for children with spina bifida and their caregivers. Setting: Republic of Korea. Methods: Between December 2010 and April 2011, 53 children with constipation, fecal incontinence or both underwent a stepwise bowel management program at our spina bifida clinic. The children and their caregivers were evaluated before and after this program using a self-administered questionnaire. Results: Among the children, 11.3% received only oral laxatives and controlled well, 88.7% received transanal irrigation. After this program, the mean number of episodes of fecal incontinence per week, number of diaper changes and total time for bowel care decreased from 6.9 to 0.5 (P=0.004), from 1.6 to 0.2 (P=0.001) and from 27 to 15.9 min (P=0.003), respectively. Caregivers and children were able to leave their houses more often (P=0.006), and caregivers’ bothersomeness, anxiety and depression due to bowel care decreased (P<0.001). Factors related to family relationships (P=0.265) and financial impact (P=0.071) improved, but not significantly. Conclusions: We observed significant improvement in defecation symptoms and QOL scores of spina bifida patients who underwent this program. We recommend that this simple therapeutic method be considered as a safe and valid choice for the treatment of chronic constipation and fecal incontinence.

Bowel management is a concern in patients with spina bifida. We evaluated the status of bowel management in children with spina bifida (SB) and the effects on quality of life (QoL) of children and their caregivers. Data were collected from 173 children with SB between January and June 2011, whose bowel management status and QoL were assessed using a self-administered questionnaire. Of the 173 children, 38 (22.0%) reported normal defecation, 73 (42.2%) reported constipation only, and 62 (35.8%) reported fecal incontinence with/without constipation. For defecation, 59 children (34.1%) used digital stimulation or manual extraction, 28 (16.2%) used suppositories or enemas, 35 (20.3%) used laxatives, 4 (2.3%) used an antegrade continence enema, and 3 (1.7%) used transanal irrigation. There were significant differences in QoL, depending on defecation symptoms. Children with fecal incontinence and their caregivers had difficulties in travel and socialization (p < .0001), caregivers' emotions (p < .0001), family relationships (p < .0001), and finances (p < .0001). Constipation and fecal incontinence affect QoL of children with SB and their caregivers. Therefore, more attention should be paid to bowel problems and help should be provided to children and their caregivers to improve QoL.