1.
Sedentary behavior and cancer-an umbrella review and meta-analysis.
Hermelink, R, Leitzmann, MF, Markozannes, G, Tsilidis, K, Pukrop, T, Berger, F, Baurecht, H, Jochem, C
European journal of epidemiology. 2022;37(5):447-460
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Globally, cancer is one of the leading causes of death. In modern day-to-day life, sedentary behaviour is prevalent, with adults spending an average of 8.2 hours without any physical activity. It is believed that sedentary behaviour plays a significant role in the increase in all-cause mortality, obesity, chronic diseases, and cancer risk. The purpose of this review and meta-analysis was to examine previous studies that reported associations between sedentary behaviour and cancer incidence and all-cancer mortality. A total of 14 meta-analyses were included in the study, and the strength of the evidence for each association was rated. A significant association was found between sedentary behaviour and cancer incidence across various cancer sites, including ovarian, endometrial, colon, breast, rectal, and prostate cancers. All-cancer mortality also showed positively significant associations with sedentary behaviour. There is a need for further research to evaluate the mechanisms associated with sedentary behaviour and the development of cancer at various sites. However, the results of this study can be used by healthcare professionals to better understand the importance of recommending physical activity and other therapeutic strategies.
Abstract
Several systematic reviews and meta-analyses have summarized the association between sedentary behavior (SB) and cancer. However, the level of evidence and the potential for risk of bias remains unclear. This umbrella review summarized the current data on SB in relation to cancer incidence and mortality, with a particular emphasis on assessing the risk of bias. We searched PubMed, Web of Science and Cochrane Database for systematic reviews and meta-analyses on the association between SB and cancer incidence and mortality. We also searched for recent observational studies not yet included in existing meta-analyses. We re-calculated summary risk estimates for cancer incidence and mortality using random effects models. We included 14 meta-analyses covering 17 different cancer sites from 77 original studies. We found that high SB levels increase the risk for developing ovarian, endometrial, colon, breast, prostate, and rectal cancers, with relative risks of 1.29 (95% confidence interval (CI) = 1.08-1.56), 1.29 (95% CI = 1.16-1.45), 1.25 (95% CI = 1.16-1.33), 1.08 (95% CI = 1.04-1.11), 1.08 (95% CI = 1.00-1.17), and 1.07 (95% CI = 1.01-1.12), respectively. Also, we found an increased risk of cancer mortality of 1.18 (95% CI = 1.09-1.26). Most associations between SB and specific cancer sites were supported by a "suggestive" level of evidence. High levels of SB are associated with increased risk of several types of cancer and increased cancer mortality risk.
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Effect of Ramadan Fasting on Weight and Body Composition in Healthy Non-Athlete Adults: A Systematic Review and Meta-Analysis.
Fernando, HA, Zibellini, J, Harris, RA, Seimon, RV, Sainsbury, A
Nutrients. 2019;11(2)
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Ramadan is the Islamic tradition of fasting for one month from sunrise to sunset. Generally, Ramadan is known to impact weight. This systematic review and meta-analysis specifically evaluated the effects of Ramadan on both weight and body mass (fat mass and fat-free mass), pre and post fasting, and in the context of there being no attempt to influence physical activity or diet. The meta-analysis was conducted on 70 publications, 90 comparison groups and 2947 participants. Data was also extracted for diverse sub-groups such as overweight/obese, gender and geographical location. The results showed that Ramadan promoted a significant reduction in weight pre and post fasting across all participants, and that the greater the BMI prior to Ramadan fasting, the greater the weight loss. No significant differences were noted between genders. Weight loss was significant in the Middle East + North Africa, South Asia and South East Asia, but not in Westernized countries. Ramadan fasting promoted a transient reduction in fat mass as a percentage of weight, and absolute fat mass, but quickly returned to pre-fasting levels at follow-up 2-5 weeks later. A significant reduction in fat-free mass was also noted but 30% less than total fat mass. There was insufficient data to analysis the possible impact of physical activity. The authors conclude that Ramadan represents an opportunity for promoting weight and fat loss for people with overweight or obesity but requires strategies for long-term maintenance
Abstract
BACKGROUND Ramadan involves one month of fasting from sunrise to sunset. In this meta-analysis, we aimed to determine the effect of Ramadan fasting on weight and body composition. METHODS In May 2018, we searched six databases for publications that measured weight and body composition before and after Ramadan, and that did not attempt to influence physical activity or diet. RESULTS Data were collected from 70 publications (90 comparison groups, 2947 participants). There was a significant positive correlation between starting body mass index and weight lost during the fasting period. Consistently, there was a significant reduction in fat percentage between pre-Ramadan and post-Ramadan in people with overweight or obesity (-1.46 (95% confidence interval: -2.57 to -0.35) %, p = 0.010), but not in those of normal weight (-0.41 (-1.45 to 0.63) %, p = 0.436). Loss of fat-free mass was also significant between pre-Ramadan and post-Ramadan, but was about 30% less than loss of absolute fat mass. At 2⁻5 weeks after the end of Ramadan, there was a return towards, or to, pre-Ramadan measurements in weight and body composition. CONCLUSIONS Even with no advice on lifestyle changes, there are consistent-albeit transient-reductions in weight and fat mass with the Ramadan fast, especially in people with overweight or obesity.
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Prevention of Type 2 Diabetes by Lifestyle Changes: A Systematic Review and Meta-Analysis.
Uusitupa, M, Khan, TA, Viguiliouk, E, Kahleova, H, Rivellese, AA, Hermansen, K, Pfeiffer, A, Thanopoulou, A, Salas-Salvadó, J, Schwab, U, et al
Nutrients. 2019;11(11)
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With Type 2 Diabetes growing globally this paper analyses whether T2D is preventable with lifestyle measures including diet. Seven RCTs were included for review with a total of 4090 participants, and 2466 incidents of T2D, and were chosen on the basis that the lifestyle interventions included both physical exercise and diet (typically Mediterranean Diet). They found that diet and lifestyle intervention reduced the risk of T2D by 47%. Sustained risk reduction was also found in follow-up studies up to 10 years later with participants maintaining improved blood glucose control. Lifestyle interventions may also reduce risk factors for cardiovascular disease. Weight reduction was considered a cornerstone of preventing T2D and adherence to lifestyle changes a key element in long term prevention. Dietary foods reviewed include processed meats, white rice and sugars which correlated highly with T2D whilst leafy greens, berries, wholegrains, legumes, dietary fibre and yoghurt correlate with a lower risk of T2D. Dietary patterns of skipping breakfast and snacking correlate higher with T2D. Different criteria for evaluating physical activity estimate that it reduces risk factors by 50%. In conclusion there is high evidence that lifestyle factors which optimise diet, increase physical activity and promote weight reduction are preventative factors for T2D and can be sustained long term.
Abstract
Prevention of type 2 diabetes (T2D) is a great challenge worldwide. The aim of this evidence synthesis was to summarize the available evidence in order to update the European Association for the Study of Diabetes (EASD) clinical practice guidelines for nutrition therapy. We conducted a systematic review and, where appropriate, meta-analyses of randomized controlled trials (RCTs) carried out in people with impaired glucose tolerance (IGT) (six studies) or dysmetabolism (one study) to answer the following questions: What is the evidence that T2D is preventable by lifestyle changes? What is the optimal diet (with a particular focus on diet quality) for prevention, and does the prevention of T2D result in a lower risk of late complications of T2D? The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was applied to assess the certainty of the trial evidence. Altogether seven RCTs (N = 4090) fulfilled the eligibility criteria and were included in the meta-analysis. The diagnosis of incident diabetes was based on an oral glucose tolerance test (OGTT). The overall risk reduction of T2D by the lifestyle interventions was 0.53 (95% CI 0.41; 0.67). Most of the trials aimed to reduce weight, increase physical activity, and apply a diet relatively low in saturated fat and high in fiber. The PREDIMED trial that did not meet eligibility criteria for inclusion in the meta-analysis was used in the final assessment of diet quality. We conclude that T2D is preventable by changing lifestyle and the risk reduction is sustained for many years after the active intervention (high certainty of evidence). Healthy dietary changes based on the current recommendations and the Mediterranean dietary pattern can be recommended for the long-term prevention of diabetes. There is limited or insufficient data to show that prevention of T2D by lifestyle changes results in a lower risk of cardiovascular and microvascular complications.