Sustainable diets and risk of overweight and obesity: A systematic review and meta-analysis

Sustainable diets are gaining interest as a possible approach to tackle climate change and the global extent of obesity. Yet, the association between sustainable diets and adiposity remains unclear. We performed a systematic review and meta-analysis, calculating summary relative risks and 95% confidence intervals (CI). We pooled maximally adjusted risk estimates, assessed heterogeneity and publication bias, calculated the E-value, and evaluated the risk of bias across the included studies. A total of eight studies were eligible for analysis. Comparing the highest versus the lowest levels of adherence to sustainable diets, the pooled effect estimate was 0.69 (95% CI = 0.62-0.76) for overweight and 0.61 (95% CI = 0.47-0.78) for obesity. These results suggest that sustainable diets may decrease the risk of overweight/obesity and therefore could serve as enablers for improving both public and planetary health. An agreed-upon clear definition of sustainable diets would enhance the comparability of future studies in this area.

Tissue-specific genetic variation suggests distinct molecular pathways between body shape phenotypes and colorectal cancer

It remains unknown whether adiposity subtypes are differentially associated with colorectal cancer (CRC). To move beyond single-trait anthropometric indicators, we derived four multi-trait body shape phenotypes reflecting adiposity subtypes from principal components analysis on body mass index, height, weight, waist-to-hip ratio, and waist and hip circumference. A generally obese (PC1) and a tall, centrally obese (PC3) body shape were both positively associated with CRC risk in observational analyses in 329,828 UK Biobank participants (3728 cases). In genome-wide association studies in 460,198 UK Biobank participants, we identified 3414 genetic variants across four body shapes and Mendelian randomization analyses confirmed positive associations of PC1 and PC3 with CRC risk (52,775 cases/45,940 controls from GECCO/CORECT/CCFR). Brain tissue-specific genetic instruments, mapped to PC1 through enrichment analysis, were responsible for the relationship between PC1 and CRC, while the relationship between PC3 and CRC was predominantly driven by adipose tissue-specific genetic instruments. This study suggests distinct putative causal pathways between adiposity subtypes and CRC.

Multi-Trait Body Shape Phenotypes and Breast Cancer Risk in Postmenopausal Women: A Causal Mediation Analysis in the UK Biobank Cohort

Body shape phenotypes combining multiple anthropometric traits have been linked to postmenopausal breast cancer (BC). However, underlying biological pathways remain poorly understood. This study investigated to what extent the associations of body shapes with postmenopausal BC risk is mediated by biochemical markers. The study included 176,686 postmenopausal women from UK Biobank. Four body shape phenotypes were derived from principal component (PC) analysis of height, weight, body mass index, waist and hip circumferences, and waist-to-hip ratio (WHR). The four-way decomposition of the total effect was used to estimate mediation and interaction effects simultaneously as well as the mediated proportions. After 10.9 years median follow-up, 6,396 incident postmenopausal BC were diagnosed. There was strong evidence of positive associations between PC1 (general obesity) and PC2 (tall, low WHR), and BC risk. The association of PC1 with BC risk was positively mediated by testosterone and negatively by insulin-like growth factor-1 (IGF-1), with the overall proportion mediated (sum of the mediated interaction and pure indirect effect (PIE)) accounting for 11.4% (95% confidence intervals: 5.1 to 17.8%) and -12.2% (-20.5% to -4.0%) of the total effect, respectively. Small proportions of the association between PC2 and BC were mediated by IGF-1 (PIE: 2.8% (0.6 to 4.9%)), and sex hormone-binding globulin (SHBG) (PIE: -6.1% (-10.9% to -1.3%)). Our findings are consistent with differential pathways linking different body shapes with BC risk, with a suggestive mediation through testosterone and IGF-1 in the relationship of a generally obese body shape and BC risk, while IGF-1 and SHBG may mediate a tall/lean body shape-BC risk association.

Differences in Anthropometric Measures Based on Sex, Age, and Health Status: Findings From the German National Cohort (NAKO)

BACKGROUND

Obesity is a worldwide health problem. We conducted detailed analyses of anthropometric measures in a comprehensive, population-based, current cohort in Germany.

METHODS

In the German National Cohort (NAKO), we analyzed cross-sectional data on body-mass index (BMI), waist and hip circumference, subcutaneous (SAT) and visceral adipose tissue (VAT) as measured by ultrasound, and body fat percentage. The data were stratified by sex, age, and self-reported physicians' diagnoses of cardiovascular diseases (CVD), metabolic diseases (MetD), cardiometabolic diseases (CMD), and cancer.

RESULTS

Data were available from 204 751 participants (age, 49.9 ± 12.8 years; 50.5% women). Body size measures generally increased with age. Men had a higher BMI, larger waist circumference, and more VAT than women, while women had a larger hip circumference, more SAT, and a higher body fat percentage than men. For example, the mean BMI of participants over age 60 was 28.3 kg/m2 in men and 27.6 kg/m2 in women. CVD, MetD, and CMD were associated with higher anthropometric values, while cancer was not. For example, the mean BMI was 25.3 kg/m2 in healthy women, 29.4 kg/m2 in women with CMD, and 25.4 kg/m2 in women with cancer.

CONCLUSION

Obesity is widespread in Germany, with notable differences between the sexes in anthropometric values. Obesity was more common in older participants and those with chronic diseases other than cancer. Elevated values were especially common in multimorbid individuals.

Large-scale assessment of physical activity in a population using high-resolution hip-worn accelerometry: the German National Cohort (NAKO)

Large population-based cohort studies utilizing device-based measures of physical activity are crucial to close important research gaps regarding the potential protective effects of physical activity on chronic diseases. The present study details the quality control processes and the derivation of physical activity metrics from 100 Hz accelerometer data collected in the German National Cohort (NAKO). During the 2014 to 2019 baseline assessment, a subsample of NAKO participants wore a triaxial ActiGraph accelerometer on their right hip for seven consecutive days. Auto-calibration, signal feature calculations including Euclidean Norm Minus One (ENMO) and Mean Amplitude Deviation (MAD), identification of non-wear time, and imputation, were conducted using the R package GGIR version 2.10-3. A total of 73,334 participants contributed data for accelerometry analysis, of whom 63,236 provided valid data. The average ENMO was 11.7 ± 3.7 mg (milli gravitational acceleration) and the average MAD was 19.9 ± 6.1 mg. Notably, acceleration summary metrics were higher in men than women and diminished with increasing age. Work generated in the present study will facilitate harmonized analysis, reproducibility, and utilization of NAKO accelerometry data. The NAKO accelerometry dataset represents a valuable asset for physical activity research and will be accessible through a specified application process.

Association between circadian physical activity patterns and mortality in the UK Biobank

BACKGROUND

The benefit of physical activity (PA) for increasing longevity is well-established, however, the impact of diurnal timing of PA on mortality remains poorly understood. We aimed to derive circadian PA patterns and investigate their associations with all-cause mortality.

METHODS

We used 24 h PA time series from 96,351 UK Biobank participants aged between 42 and 79 years at accelerometry in 2013-2015. Functional principal component analysis (fPCA) was applied to obtain circadian PA patterns. Using multivariable Cox proportional hazard models, we related the loading scores of these fPCs to estimate risk of mortality.

RESULTS

During 6.9 years of follow-up, 2,850 deaths occurred. Four distinct fPCs accounted for 96% of the variation of the accelerometry data. Using a loading score of zero (i.e., average overall PA during the day) as the reference, a fPC1 score of + 2 (high overall PA) was inversely associated with mortality (Hazard ratio, HR = 0.91; 95% CI: 0.84-0.99), whereas a score of -2 (low overall PA) was associated with higher mortality (1.69; 95% CI: 1.57-1.81; p for non-linearity < 0.001). Significant inverse linear associations with mortality were observed for engaging in midday PA instead of early and late PA (fPC3) (HR for a 1-unit increase 0.88; 95% CI: 0.83-0.93). In contrast, midday and nocturnal PA instead of early and evening PA (fPC4) were positively associated with mortality (HR for a 1-unit increase 1.16; 95% CI: 1.08-1.25).

CONCLUSION

Our results suggest that it is less important during which daytime hours one is active but rather, to engage in some level of elevated PA for longevity.

Association of epidemiological and clinical features with PCR cycle threshold values of SARS-CoV-2 infection: a cross-sectional study

The cycle threshold (Ct) in quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) is inversely correlated to the amount of viral nucleic acid or viral load and can be regarded as an indicator of infectivity. We examined the association of socio-demographic and clinical characteristics of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) polymerase chain reaction (PCR) positive cases with PCR cycle threshold (Ct) values at the time of diagnosis. SARS-CoV-2 cases reported between 12 October 2020 and 24 January 2021 in Regensburg were analyzed employing bivariate and multivariable methods. We included 3,029 SARS-CoV-2 cases (31% asymptomatic at diagnosis) and analyzed the association of case characteristics with Ct values in 2,606 cases. Among symptomatic patients, cough (38.0%), rhinitis (32.4%), headache (32.0), and fever/chills (29.9%) were the most frequent complaints. Ct values ≤20 were more frequent in symptomatic cases (20.9% vs. 11.3%), whereas Ct values >30 were more common in asymptomatic cases (32.6% vs. 18.0%). Ct values >20 and ≤30 were most common in symptomatic and asymptomatic cases (48.0% vs 40.7%). We observed lower median Ct values of E and N gene in symptomatic cases. In a random forest model, the total number of symptoms, respiratory symptoms, and age were most strongly associated with low Ct values. In conclusion, certain symptoms and age were associated with lower Ct values. Ct values can be used as a pragmatic approach in estimating infectivity at the first notification of a case and, thus, in guiding containment measures.

Health-Promoting and Sustainable Behavior in University Students in Germany: A Cross-Sectional Study

Health-promoting and sustainable behaviors, such as active transportation and sustainable diets, are associated with positive effects on human health and the environment. In order to unlock the potential of university students as key actors and multipliers, it is of interest to investigate their level of knowledge about the health effects of climate change and their willingness toward and implementation of health-promoting and sustainable behaviors. In November 2021, an online survey was conducted among students at the University of Regensburg, Germany. A total of 3756 participants (response rate 18%; mean age 23 years; 69% women) provided valid data. A large proportion of medical students (48%) considered themselves well-informed about the health-related effects of climate change, while only a small proportion (22%) of students within economic/computer/data sciences and law felt informed. Most participants knew about the impact of climate change on malnutrition (78%), but considerably fewer were aware of its impact on cardiovascular diseases (52%). Participants who considered themselves informed were consistently more willing to engage in climate-friendly behavior, and this willingness was also reflected in their actions, as they simultaneously promoted a healthy lifestyle. Across all academic disciplines, there is a strong need for knowledge transfer regarding topics that combine health and sustainable development.

Body Shape Phenotypes and Breast Cancer Risk: A Mendelian Randomization Analysis

Observational and genetic studies have linked different anthropometric traits to breast cancer (BC) risk, with inconsistent results. We aimed to investigate the association between body shape defined by a principal component (PC) analysis of anthropometric traits (body mass index [BMI], height, weight, waist-to-hip ratio [WHR], and waist and hip circumference) and overall BC risk and by tumor sub-type (luminal A, luminal B, HER2+, triple negative, and luminal B/HER2 negative). We performed two-sample Mendelian randomization analyses to assess the association between 188 genetic variants robustly linked to the first three PCs and BC (133,384 cases/113,789 controls from the Breast Cancer Association Consortium (BCAC)). PC1 (general adiposity) was inversely associated with overall BC risk (0.89 per 1 SD [95% CI: 0.81-0.98]; p-value = 0.016). PC2 (tall women with low WHR) was weakly positively associated with overall BC risk (1.05 [95% CI: 0.98-1.12]; p-value = 0.135), but with a confidence interval including the null. PC3 (tall women with large WHR) was not associated with overall BC risk. Some of these associations differed by BC sub-types. For instance, PC2 was positively associated with a risk of luminal A BC sub-type (1.09 [95% CI: 1.01-1.18]; p-value = 0.02). To clarify the inverse association of PC1 with breast cancer risk, future studies should examine independent risk associations of this body shape during childhood/adolescence and adulthood.

Body shape phenotypes of multiple anthropometric traits and cancer risk: a multi-national cohort study

BACKGROUND

Classical anthropometric traits may fail to fully represent the relationship of weight, adiposity, and height with cancer risk. We investigated the associations of body shape phenotypes with the risk of overall and site-specific cancers.

METHODS

We derived four distinct body shape phenotypes from principal component (PC) analysis on height, weight, body mass index (BMI), waist (WC) and hip circumferences (HC), and waist-to-hip ratio (WHR). The study included 340,152 men and women from 9 European countries, aged mostly 35-65 years at recruitment (1990-2000) in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 15.3 years, 47,110 incident cancer cases were recorded. PC1 (overall adiposity) was positively associated with the risk of overall cancer, with a HR per 1 standard deviation (SD) increment equal to 1.07 (95% confidence interval 1.05 to 1.08). Positive associations were observed with 10 cancer types, with HRs (per 1 SD) ranging from 1.36 (1.30-1.42) for endometrial cancer to 1.08 (1.03-1.13) for rectal cancer. PC2 (tall stature with low WHR) was positively associated with the risk of overall cancer (1.03; 1.02-1.04) and five cancer types which were not associated with PC1. PC3 (tall stature with high WHR) was positively associated with the risk of overall cancer (1.04; 1.03-1.05) and 12 cancer types. PC4 (high BMI and weight with low WC and HC) was not associated with overall risk of cancer (1.00; 0.99-1.01).

CONCLUSIONS

In this multi-national study, distinct body shape phenotypes were positively associated with the incidence of 17 different cancers and overall cancer.

Bilirubin as an indicator of cardiometabolic health: a cross-sectional analysis in the UK Biobank

BACKGROUND

Mildly elevated bilirubin, a by-product of hemoglobin breakdown, might mitigate cardiometabolic risk factors including adiposity, dyslipidemia, and high blood pressure (BP). We investigated the cross-sectional relationship between (total) bilirubin and baseline cardiometabolic risk factors in 467,519 UK Biobank study participants.

METHODS

We used multivariable-adjusted linear regression to estimate associations between bilirubin levels and risk factors of cardiometabolic diseases including body mass index (BMI), waist and hip circumferences (WC, HC), waist-to-hip ratio (WHR), fat mass (FM), and trunk FM, and the blood lipids: apolipoprotein A-I (apoA-I), apolipoprotein B (apoB), apoB/apoA-I, lipoprotein (a), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), LDL/HDL, TC/HDL, triglycerides (TG). Log-transformed bilirubin was modelled with restricted cubic splines and predicted mean values with 99% confidence intervals (CI) for each risk marker were estimated, separately. Second, we applied principal component analysis (PCA) for dimension reduction to in turn six anthropometric traits (height, weight, BMI, WC, HC, and WHR) and all above lipids. Last, we estimated associations (99%CI) between bilirubin and three components of the metabolic syndrome, i.e. WC, TG, and BP using logistic regression.

RESULTS

After multivariable adjustments, higher levels of bilirubin were inversely associated with indicators of general adiposity (BMI and FM) and of body fat distribution (WC, HC, WHR, and trunk FM) in both men and women. For example, women with mildly elevated bilirubin (95th percentile equal to 15.0 µmol/L), compared to women with low bilirubin (5th percentile equal to 4.5 µmol/L), had on average a 2.0 kg/m2 (99% CI 1.9-2.1) lower BMI. Inverse associations were also observed with dyslipidemia among men and women. For example, mildly elevated bilirubin among men (95th percentile equal to 19.4 µmol/L) compared to low levels of bilirubin (5th percentile equal to 5.5 µmol/L) were associated with approx. 0.55 mmol/L (99% CI 0.53-0.56) lower TG levels, with similar inverse associations among women. Multiple-trait analyses using PCA confirmed single-trait analyses. Men and women with mildly elevated bilirubin levels ≥ 17.1 µmol/L, compared to low-normal bilirubin < 10 µmol/L had 13% (99% CI 8%-18%) and 11% (99% CI 4%-17%) lower odds of exceeding systolic BP levels of ≥ 130 mm Hg, respectively.

CONCLUSIONS

Higher levels of bilirubin were inversely associated with cardiometabolic risk factors including adiposity, dyslipidemia, and hypertension.

Relation of body fat mass and fat-free mass to total mortality: results from 7 prospective cohort studies

BACKGROUND

Fat mass and fat-free mass may play independent roles in mortality risk but available studies on body composition have yielded inconsistent results.

OBJECTIVE

The aim was to determine the relations of body fat mass and fat-free mass to risk of mortality.

METHODS

In pooled data from 7 prospective cohorts encompassing 16,155 individuals aged 20 to 93 y (median, 44 y), we used Cox regression and restricted cubic splines to estimate HRs and 95% CIs for the relation of body composition, measured by bioelectrical impedance analysis, to total mortality. We adjusted for age, study, sex, ethnicity, history of diabetes mellitus, education, smoking, physical activity, and alcohol consumption.

RESULTS

During a median follow-up period of 14 y (range, 3-21 y), 1347 deaths were identified. After mutual adjustment for fat mass and fat-free mass, fat mass showed a J-shaped association with mortality (overall P value < 0.001; P for nonlinearity = 0.003). Using a fat mass index of 7.3 kg/m2 as the reference, a high fat mass index of 13.0 kg/m2 was associated with an HR of 1.56 (95% CI: 1.30, 1.87). In contrast, fat-free mass showed an inverse association with mortality (overall P value < 0.001; P for nonlinearity = 0.001). Compared with a low fat-free mass index of 16.1 kg/m2, a high fat-free mass of 21.9 kg/m2 was associated with an HR of 0.70 (95% CI: 0.56, 0.87).

CONCLUSIONS

Fat mass and fat-free mass show opposing associations with mortality. Excess fat mass is related to increased mortality risk, whereas fat-free mass protects against risk of mortality. These findings suggest that body composition provides important prognostic information on an individual's mortality risk not provided by traditional proxies of adiposity such as BMI.

Sedentary behaviour in relation to ovarian cancer risk: a systematic review and meta-analysis

Sedentary behaviour is an emerging risk factor for several site-specific cancers. Ovarian cancers are often detected at late disease stages and the role of sedentary behaviour as a modifiable risk factor potentially contributing to ovarian cancer risk has not been extensively examined. We systematically searched relevant databases from inception to February 2020 for eligible publications dealing with sedentary behaviour in relation to ovarian cancer risk. We conducted a systematic review and meta-analysis, calculating summary relative risks (RR) and 95% confidence intervals (CI) using a random-effects model. We calculated the E-Value, a sensitivity analysis for unmeasured confounding. We tested for publication bias and heterogeneity. Seven studies (three prospective cohort studies and four case–control studies) including 2060 ovarian cancer cases were analysed. Comparing highest versus lowest levels of sedentary behaviour, the data indicated a statistically significant increase in the risk of ovarian cancer in relation to prolonged sitting time (RR = 1.29, 95% CI = 1.07–1.57). Sub-analyses of prospective cohort studies (RR = 1.33, 95% CI = 0.92–1.93) and case–control studies (RR = 1.28, 95% CI = 0.98–1.68) showed statistically non-significant results. Sensitivity analysis showed that an unmeasured confounder would need to be related to sedentary behaviour and ovarian cancer with a RR of 1.90 to fully explain away the observed RR of 1.29. Our analyses showed a statistically significant positive association between sedentary behaviour and ovarian cancer risk.

[Anthropometric measures in the German National Cohort-more than weight and height]

High levels of adiposity in the population have a major impact on various diseases, but previous epidemiologic studies have largely been restricted to simple anthropometric measures such as the body mass index (BMI), an imperfect predictor of disease risk. There is a critical need for the use of improved measures of relative weight and body composition in large-scale, population-based research.The current article presents initial descriptive results of body composition and fat distribution based on the midterm baseline dataset of the German National Cohort, which included 101,817 participants who were examined in 18 study centers in Germany between March 2014 and March 2017. The anthropometric measures encompassed body weight, height, waist and hip circumference, bioelectrical impedance analysis (BIA), sonography of abdominal adipose tissue, 3D-body scanning, and magnetic resonance imaging.BMI analyses showed that 46.2% of men and 29.7% of women were overweight and 23.5% of men and 21.2% of women were obese. On average, women in almost all age groups demonstrated more subcutaneous adipose tissue layer thickness than men. The mean values of visceral adipose tissue layer thickness, on the other hand, were higher among men than among women in all age groups and increased continuously across age groups in both sexes.The comprehensive assessment of body composition and fat distribution provides novel future opportunities for detailed epidemiologic analyses of overweight and adiposity in relation to the development of chronic diseases.

Association between cardiorespiratory fitness and colorectal cancer in the UK Biobank

Increased cardiorespiratory fitness is related to decreased risk of major chronic illnesses, including cardiovascular disease, type 2 diabetes, and cancer, but its association with colorectal cancer specifically has received very little attention. We examined the relation of cardiorespiratory fitness to colorectal cancer in 59,191 UK Biobank participants aged 39-70 years without prevalent cancer at baseline, followed from 2009 to 2014. Submaximal bicycle ergometry was conducted at study entry, and cardiorespiratory fitness was defined as physical work capacity at 75% of the maximum heart rate, standardised to body mass (PWC_75%). Multivariable Cox proportional hazards regression was performed to obtain hazard ratios (HR) and corresponding 95% confidence intervals (CI). During a mean follow-up of 4.6 years, 232 participants developed colorectal cancer (151 colon cancers; 79 rectal cancers). When comparing the 75th to the 25th percentiles of PWC_75%, the multivariable-adjusted HR of colorectal cancer was 0.78 (95% CI 0.62-0.97). That relation was largely driven by an inverse association with colon cancer (HR 0.74, 95% CI 0.56-0.97) and less so with rectal cancer (HR 0.88, 95% CI 0.62-1.26; p value for difference by colorectal cancer endpoint = 0.056). The inverse relation of cardiorespiratory fitness with colorectal cancer was more evident in men (HR 0.72, 95% CI 0.55-0.94) than women (HR 0.99, 95% CI 0.71-1.38), although the gender difference was not statistically significant (p value for interaction = 0.192). Increased cardiorespiratory fitness is associated with decreased risk of colorectal cancer. Potential heterogeneity by colorectal cancer anatomic subsite and gender requires further study.

Sedentary Behavior and Prostate Cancer: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

Prostate cancer is the second most common cancer in men worldwide, and sedentary behavior is widespread, yet reviews and meta-analyses summarizing the role of sedentary behavior as a potential risk factor for prostate cancer are scarce. We searched PubMed, Web of Science, and Cochrane databases for relevant articles up to January 2019. We pooled maximally adjusted risk estimates in a random effects model and performed meta-regression meta-analysis, assessed heterogeneity and publication bias using I², funnel plots, and Egger and Begg tests, and conducted sensitivity analyses and influence diagnostics. Data from 12 prospective cohort studies including a total of 30,810 prostate cancer cases were analyzed. We found no statistically significant association between high versus low sedentary behavior and prostate cancer incidence [RR = 1.07; 95% confidence interval (CI), 0.99-1.16; P = 0.10]. We noted that adjustment for body mass index (BMI) modified the relation of sedentary behavior to prostate cancer, particularly aggressive cancer. Sedentary behavior was related to a statistically significant increased risk of aggressive prostate cancer in analyses not adjusted for BMI (RR = 1.21; 95% CI, 1.03-1.43), whereas no association was apparent in BMI-adjusted analyses (RR = 0.98; 95% CI, 0.90-1.07), and the difference between those summary risk estimates was statistically significant (P _difference = 0.02). Sedentary behavior is not independently associated with prostate cancer. However, prolonged sedentary behavior may be related to increased risk of aggressive prostate cancer through a mechanism involving obesity. This finding represents a potentially important step toward considering sedentary behavior as a modifiable behavioral risk factor for aggressive prostate cancer.