An estimated 4 in 10 cancers are preventable through modifiable risk factors. This review summarizes the epidemiologic evidence linking physical activity, sedentary behavior, and obesity with cancer ...risk. We explore the possible biologic mechanisms underpinning the associations between these lifestyle factors and cancer incidence, including effects on endogenous sex steroids and metabolic hormones, insulin sensitivity, and chronic inflammation.
An estimated 30–40% of cancers can be prevented through changes in modifiable lifestyle and environmental risk factors known to be associated with cancer incidence. Despite this knowledge, there remains limited awareness that these associations exist. The purpose of this review article was to summarize the epidemiologic evidence concerning the contribution of physical activity, sedentary behavior, and obesity to cancer etiology and to provide an overview of the biologic mechanisms that may be operative between these factors and cancer incidence. Strong and consistent evidence exists that higher levels of physical activity reduce the risk of six different cancer sites (bladder, breast, colon, endometrial, esophageal adenocarcinoma, gastric cardia), whereas moderate evidence inversely associates physical activity with lung, ovarian, pancreatic and renal cancer, and limited evidence inversely correlates physical activity with prostate cancer. Sedentary behavior, independent of physical activity, has been shown to increase the risk of colon, endometrial, and lung cancers. Obesity is an established risk factor for 13 different cancer sites (endometrial, postmenopausal breast, colorectal, esophageal, renal/kidneys, meningioma, pancreatic, gastric cardia, liver, multiple myeloma, ovarian, gallbladder, and thyroid). The main biologic mechanisms whereby physical activity, sedentary behavior, and obesity are related to cancer incidence include an effect on endogenous sex steroids and metabolic hormones, insulin sensitivity, and chronic inflammation. Several emerging pathways related to oxidative stress, DNA methylation, telomere length, immune function, and gut microbiome are presented. Key recommendations for future research in both the epidemiology and biology of the associations between physical activity, sedentary behavior, obesity, and cancer risk are also provided.
The time of arrival of people in Australia is an unresolved question. It is relevant to debates about when modern humans first dispersed out of Africa and when their descendants incorporated genetic ...material from Neanderthals, Denisovans and possibly other hominins. Humans have also been implicated in the extinction of Australia's megafauna. Here we report the results of new excavations conducted at Madjedbebe, a rock shelter in northern Australia. Artefacts in primary depositional context are concentrated in three dense bands, with the stratigraphic integrity of the deposit demonstrated by artefact refits and by optical dating and other analyses of the sediments. Human occupation began around 65,000 years ago, with a distinctive stone tool assemblage including grinding stones, ground ochres, reflective additives and ground-edge hatchet heads. This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans.
Purpose
In this systematic review and meta-analysis, we aimed to estimate cancer-specific mortality and all-cause mortality among cancer survivors associated with both short (typically 5 or ...6 h/night) and long (typically 9 or 10 h/night) sleep duration (versus recommendations), separately by sex, cancer site, and sampling frame.
Methods
We completed a systematic literature search in five databases and captured relevant literature published through December 2018. Two reviewers independently screened 9,823 records and 32 studies were included representing over 73,000 deaths in cancer survivors. Estimates for short and long sleep duration compared to ‘recommended’ were pooled using random-effects models.
Results
Pooled hazards ratios for short and long sleep duration for all-cancer-specific mortality were 1.03 (95% CI 1.00–1.06) and 1.09 (95% CI 1.04–1.13), respectively. In subgroup analyses by cancer site, statistically significant increased risks were found for both short and long sleep durations for lung cancer-specific mortality. These associations were maintained when stratified by sex and sampling frame. There were no statistically significant associations found between either short or long sleep duration and breast, colorectal, ovarian, or prostate cancer-specific mortality. Statistically significant increases in all-cause mortality were observed with long sleep duration in breast cancer survivors (1.38; 95% CI 1.16–1.64) with no significant associations found for colorectal or liver/pancreatic cancers.
Conclusions
We observed that long sleep duration increases cancer-specific mortality for all-cancers and lung cancers, while all-cause mortality is increased for breast cancer survivors. Limitations were found within the existing literature that need to be addressed in future studies in order to improve the understanding regarding the exact magnitude of the effect between sleep duration and site-specific mortality.
Kratom (Mitragyna speciosa) is a plant‐based substance with psychoactive properties similar to opioids but is not currently classified as an opioid. One of its more prevalent uses is to treat opioid ...dependency and withdrawal symptoms. Opioid use disorder is a leading cause of pregnancy‐associated maternal mortality, and pregnant women may be using kratom as a substitute or alternative to opioids. Prevalence of kratom use is increasing rapidly, but scientific evidence specific to therapeutic and adverse effects is lacking overall, and the implications of its use in pregnancy and on the fetus‐newborn are limited to a few case reports. Kratom is a legal substance by federal law, although some states have banned its use. The lack of regulation is concerning. Significant illness and associated deaths have been reported with kratom use. Lack of disclosure by people using kratom and limited laboratory testing options are major challenges for health care providers and public health.
South Africa’s Still Bay technocomplex (77–70 ka) is an early example of a technological system organised around the production of bifacial points. Noting the diversity of raw materials used and the ...frequency of non-local raw materials found among excavated bifacial point assemblages, numerous researchers have argued that Still Bay foragers were highly mobile. This pattern, however, is in contrast to that observed in some open-air surface Still Bay assemblages, where raw material diversity among bifacial points is low and local rocks dominate. We resolve this apparent discrepancy by combining information on raw material distribution, least-cost path analysis, and artefact data from two rock shelters and numerous open-air sites located along the Doring and Olifants Rivers in South Africa. The results demonstrate that raw material selection for bifacial point production was responsive to geological resources within river catchments but that bifacial points were transported regularly between catchments over minimum distances of 30–60 km. Our data appears to support the inference that Still Bay foragers were wide-ranging.
Objective
This study assessed the degree of interindividual responses in energy intake (EI) to an imposed sleep restriction versus habitual sleep duration protocol. It also investigated participant ...(age, sex, ethnicity, and BMI) and study (study site and protocol order) characteristics as potential contributors to the variance in EI responses to sleep restriction between individuals.
Methods
Data from two randomized crossover trials were combined. All participants (n = 43; age: 31 ± 7 years, BMI: 23 ± 2 kg/m2) were free of medical/sleep conditions, were nonsmokers, reported not performing shift work, and had an average sleep duration of 7 to 9 hours per night. Ad libitum, 24‐hour EI was objectively assessed following sleep restriction (3.5‐4 hours in bed per night) and habitual sleep (7‐9 hours in bed per night) conditions.
Results
Large interindividual variations in EI change (ΔEI) between restricted and habitual sleep conditions were noted (−813 to 1437 kcal/d). Only phase order was associated with ΔEI (β = −568 kcal/d, 95% confidence interval for β = −921 to −215 kcal/d; P = 0.002); participants randomized to the habitual sleep condition first had greater increases in EI when sleep was restricted (P = 0.01).
Conclusions
Large interindividual variations in ΔEI following sleep restriction were noted, suggesting that not all participants were negatively impacted by the effects of sleep restriction.
Exercise is one of the most widely used non‐pharmacological strategies to prevent bone resorption during menopause. Given the detrimental consequences of bone demineralization, the purpose of this ...study was to examine the effects of prescribing different exercise volumes on bone mineral density and content in previously inactive, post‐menopausal women during a 12‐month intervention and 1 year after intervention completion. Four hundred post‐menopausal women were randomized to either 150 min/wk (MODERATE dose group) or 300 min/wk (HIGH dose group) of aerobic exercise. Total bone mineral density (g/cm2) and bone mineral content (g) were assessed at baseline, 12 months (end of the intervention) and 24 months (follow‐up) using whole body dual‐energy X‐ray absorptiometry. At 12 months, mean bone mineral density among women in the HIGH dose group was estimated to be 0.006 g/cm2 (95% CI: 0.001‐0.010; P = 0.02) higher than that of women randomized to the MODERATE dose group. At 24 months, the mean difference between groups remained statistically significant, indicating higher mean bone mineral density among women in the HIGH dose group (0.007 g/cm2; 0.001‐0.001; P = 0.04). No significant differences between groups were found at any time point for bone mineral content. In an exploratory analysis, women who completed more min/wk of impact exercises had significantly higher mean levels of bone mineral density at 12 months compared to baseline (0.006 g/cm2, 95% CI: 0.006‐0.012; P = 0.03). These findings suggest that higher volumes of exercise, especially impact exercise, lead to a smaller decline in total bone mineral density, which may remain following intervention completion.
Purpose
The study of energy balance i.e., energy intake (EI) and energy expenditure (EE) is a powerful tool for understanding body weight regulation and may contribute to our understanding of rapid ...weight gain risk in certain cancer survivors post-diagnosis. The purpose of this review was to summarize studies that assessed longitudinal, prospective changes in components of energy balance from diagnosis/start of treatment to any duration of follow-up in cancer survivors with prior evidence of weight gain (breast, prostate, thyroid, gynecologic, testicular, and acute lymphoblastic leukemia)
Results
The available literature suggests that energy balance components may be altered in cancer survivors who have a heightened risk of weight gain post-diagnosis. The evidence for EI was overall inconsistent. Conversely, decreases in resting and physical activity EE during the active phases of treatment (e.g., chemotherapy, hypothyroid state) were commonly noted, which then slowly rebounded towards baseline levels at the end of treatment and during follow-up assessments. Much of this evidence is based on data collected from breast cancer survivors, which highlights a paucity of data currently available on other cancer types.
Conclusions
While there is growing acknowledgement that weight management interventions in cancer survivors are needed, it is important to recognize that changes in both behavioral (EI, physical activity EE) and passive (resting EE, thermic effect of food) components of energy balance may occur post-diagnosis. This information can help to inform weight management interventions which often entail modifications in diet and/or physical activity.
Evidence suggests that fat-free mass and resting metabolic rate (RMR), but not fat mass, are strong predictors of energy intake (EI). However, body composition and RMR do not explain the entire ...variance in EI, suggesting that other factors may contribute to this variance.
We aimed to investigate the associations between body mass index (in kg/m2), fat mass, fat-free mass, and RMR with acute (1 meal) and daily (24-h) EI and between fasting appetite ratings and certain eating behavior traits with daily EI. We also evaluated whether RMR is a predictor of the error variance in acute and daily EI.
Data collected during the control condition of 7 studies conducted in Ottawa, Ontario, Canada, were included in these analyses (n = 191 and 55 for acute and daily EI, respectively). These data include RMR (indirect calorimetry), body composition (dual-energy X-ray absorptiometry), fasting appetite ratings (visual analog scales), eating behavior traits (Three-Factor Eating Questionnaire), and EI (food buffet or menu).
Fat-free mass was the best predictor of acute EI (R2 = 0.46; P < 0.0001). The combination of fasting prospective food consumption ratings and RMR was the best predictor of daily EI (R2 = 0.44; P < 0.0001). RMR was a statistically significant positive predictor of the error variance for acute (R2 = 0.20; P < 0.0001) and daily (R2 = 0.23; P < 0.0001) EI. RMR did, however, remain a statistically significant predictor of acute (R2 = 0.32; P < 0.0001) and daily (R2 = 0.30; P < 0.0001) EI after controlling for this error variance.
Our findings suggest that combined measurements of appetite ratings and RMR could be used to estimate EI in weight-stable individuals. However, greater error variance in acute and daily EI with increasing RMR values was observed. Future studies are needed to identify whether greater fluctuations in daily EI over time occur with increasing RMR values. This trial was registered at clinicaltrials.gov as NCT02653378.
Abstract Objective The objective of this study was to investigate the association between self-reported sleep duration and the incidence of features of the metabolic syndrome in adults. Methods A ...longitudinal analysis from the Quebec Family Study (Canada) was conducted on 293 participants, aged 18 to 65 years, followed for a mean of 6 years (until 2001). Participants were categorized as short (≤ 6 h), adequate (7–8 h) or long (≥ 9 h) sleepers. The metabolic syndrome was defined according to the American Heart Association/National Heart, Lung, and Blood Institute's criteria. The hypertriglyceridemic waist phenotype was defined as high waist circumference (≥ 90 cm in men and ≥ 85 cm in women) combined with high fasting triglyceride level (≥ 2.0 mmol/L in men and ≥ 1.5 mmol/L in women). Results The incidence rates of metabolic syndrome and hypertriglyceridemic waist phenotype were 9.9% and 7.5%, respectively. Short sleepers were significantly more at risk of developing the metabolic syndrome (relative risk (RR): 1.74; 95% confidence interval (CI): 1.05–2.72) and the hypertriglyceridemic waist phenotype (RR: 1.82; 95% CI: 1.16–2.79), compared to those sleeping 7 to 8 h per night after adjusting for covariates. However, long sleep duration was not associated with an increased risk of developing the metabolic syndrome or the hypertriglyceridemic waist phenotype (either unadjusted or adjusted models). Conclusion Short sleep duration is associated with an increased risk of developing features of the metabolic syndrome in adults.
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