Understanding the role of vegetarian diet, adiposity and grip strength in cancer risk

Cancer is a leading cause of death with rising incidence every year. Lifestyle factors play crucial roles in the risk of this disease. However, more evidence is needed to understand the association between diet, adiposity and physical activity with different cancer site, because most of the evidence still being inconclusive. Therefore, this thesis aims to determine the associations of type of diet, adiposity, grip strength with cancer risk. The thesis includes four research papers that were conducted in order to achieve its general aim. These studies were conducted utilising data from the UK Biobank. Across these manuscripts, the associations between the different exposures (diet, adiposity and grip strength) and cancer outcomes were studied. The cancer risks of four types of diet (meat eaters, poultry eaters, pescatarians, and vegetarians) were investigated in the first paper. The study found that vegetarians had a lower risk of all cancer than meat eaters. The study also found that vegetarians had a lower risk of 7 out of the 19 cancer sites studied, including stomach, bladder, and blood cancers. Pescatarians also had a lower risk of colorectal cancer than meat-eaters. The meta-analysis, which included 15 studies with 1,180,523 participants, supported the findings of the UK Biobank study, with vegetarians having a lower risk of all cancer and fish-eaters having a lower risk of gastric cancer than to meat-eaters. The second study found that higher levels of all six adiposity-related markers were associated with a higher risk of developing and dying from cancer. BMI, waist circumference, hip circumference, and waist-to-hip ratio were positively associated with the incidence and mortality from several cancer types, including liver, lung, and pancreas cancers. The third study identified that both general obesity (defined as BMI ≥30 kg/m²) and central obesity (defined as waist circumference >90 cm for men and >84 cm for women) were independently associated with a higher risk of developing and dying from cancer. The combined presence of general and central obesity was associated with a higher risk of developing and dying from several colorectal, liver, and pancreatic cancers. Finally, the fourth study found that both absolute and relative grip strength were inversely associated with the risk of cancer. The association between grip strength and cancer risk was consistent across different cancer types and subgroups of participants. In conclusion, these four papers provide important insights into the roles of lifestyle factors on cancer risk and highlight the importance of maintaining a healthy diet, maintaining muscle strength, and maintaining a healthy body weight for cancer prevention. All of the studies included in the thesis were observational. Therefore, they cannot establish that a particular diet, adiposity, or grip strength caused cancer. However, they are in line with the current research on cancer prevention

Does insulin-like growth factor moderate the association between height and risk of cancer at 24 sites?

Background: Whether the association of height with cancers differs by insulin-like growth factors has not been fully elucidated. Therefore, this study aimed to investigate the sex-specific associations between height and 24 site-specific cancers and to assess whether the association differed by IGF-1. Methods: In total, 414,923 participants from the UK Biobank prospective cohort study were included. The association of height (per 5-cm increment) with incidence and mortality from 24 cancer sites was investigated by using Cox proportional hazard models. Results: The median follow-up was 6.0 years. In men, height was positively associated with incidence risk of all-cause cancer and at five sites (lung, lymphatic, leukaemia, non-Hodgkin lymphoma and melanoma). In women, it was associated with breast, melanoma, lymphatic, non-Hodgkin lymphoma and all-cause cancer. The association was stronger in women than men for all-cause cancer incidence. The strength of the association did not differ by IGF-1 concentration. Conclusions: Adult height was associated with risk of several cancer sites. However, some of these associations were sex-specific. There was no strong evidence to support IGF-1 moderating the association between height and cancer

Association between visceral adiposity index and cancer risk in the UK Biobank cohort

Background: The visceral adiposity index (VAI) is a marker of visceral fat accumulation and metabolic dysfunction, but there is limited evidence of its association with cancer. The objective of this study was to investigate associations between the VAI and both incident cancer at 23 sites and all-cause cancer. Methods: In total, 385,477 participants (53.3% women; mean age, 56.3 years) from the UK Biobank prospective cohort were included in this study. The median follow-up was 8.2 years (interquartile range, 7.3–8.9 years). The VAI was calculated using formula the published by Amato et al. and was categorized into sex-specific tertiles. Twenty-four incident cancers were the outcomes. Cox proportional hazard models were adjusted for sociodemographics, lifestyle factors, and multimorbidity counts. Results: Over the follow-up period, 47,882 individuals developed cancer. In the fully adjusted models, the VAI was associated with a higher risk of six cancer sites. Individuals in the highest tertile, compared with those in the lowest tertile, had higher risks of uterine (hazard ratio [HR], 2.09; 95% confidence interval [CI], 1.76–2.49), gallbladder (HR, 1.83; 95% CI, 1.26–2.66), kidney (HR, 1.39; 95% CI, 1.18–1.64), liver (HR, 1.25; 95% CI, 1.00–1.56), colorectal (HR, 1.14; 95% CI, 1.05–1.24), and breast (HR, 1.11; 95% CI, 1.03–1.19) cancers and of all-cause cancer (HR, 1.05). There was no evidence of a nonlinear association between the VAI and cancer risk. Conclusions: The VAI was associated with six cancer sites and with all-cause cancer. The prognostic and etiologic roles of visceral fat accumulation and dysfunction in cancer warrant further research

Adherence to the 2018 World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) Cancer Prevention Recommendations and cancer risk: A systematic review and meta‐analysis

Background: The World Cancer Research Fund/American Institute for Cancer Research Cancer Prevention Recommendations are lifestyle‐based guidelines that aim to reduce cancer risk. A systematic review and meta‐analysis of studies investigating associations between a score for adherence to the 2018 Cancer Prevention Recommendations and cancer risk was conducted. Methods: MEDLINE, Embase, Web of Science, and Scopus were searched for studies published to November 28, 2022. In meta‐analysis, the estimated risk ratios and 95% CIs for adherence score as a continuous (per 1‐point increment) and categorical (highest vs. lowest score category) variable using random‐effects models were estimated. Results: Eighteen studies (11 cohort; seven case‐control) were included investigating incidence of breast (n = 7), colorectal (n = 5), prostate (n = 2), lung (n = 2), pancreatic (n = 1), endometrial (n = 1), unknown primary cancer (n = 1), chronic lymphocytic leukemia (n = 1), and overall (any) cancer (n = 1). The summary risk ratio per 1‐point increment in adherence score was 0.89 (95% CI, 0.85–0.93; I2 = 76.5%; n = 7) for breast cancer, 0.88 (95% CI, 0.84–0.91; I2 = 26.2%; n = 4) for colorectal cancer, and 0.92 (95% CI, 0.86–0.98, I2 = 66.0%; n = 2) for lung cancer. There were no significant associations with prostate or other cancers. Meta‐analysis results using categorical adherence score variables were consistent with these findings. Conclusions: Greater adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research Cancer Prevention Recommendations was associated with lower risk of breast, colorectal, and lung cancers. Future studies investigating associations with risk of other forms of cancer are warranted. PROSPERO registration number: CRD42022313327

Changes over 15 years in the contribution of adiposity and smoking to deaths in England and Scotland

Background: For many years smoking has been the major threat to public health in developed countries. However, smoking prevalence has declined over a period when adiposity has increased. The aim of this study was to determine whether adiposity now accounts for more deaths than smoking in the general population as a whole or sub-groups of it. Methods: This is a comparative risk assessment study using Health Surveys for England and Scottish Health Surveys from 2003 to 2017. Annual prevalence of overweight, obesity, current and former smoking were obtained and combined using population-based weights. Sex-specific risk ratios for all-cause mortality were obtained from the most recently published meta-analyses. Population attributable fractions across yeas were then estimated. Findings: Overall, deaths attributable to current/former smoking declined from 23.1% (95% CI 20.6–25.8%) in 2003 to 19.4% (95% CI 17.3–21.6%) in 2017, whilst those attributable to adiposity (overweight or obesity) increased from 17.9% (95% CI 17.3–18.4%) in 2003 to 23.1% (95% CI 22.3–23.8%) in 2017 with cross-over occurring in 2013. Cross-over occurred earlier in men (2011) than women (2014). It occurred in 2006 for those aged over 65 years of age and in 2012 for those aged 45–64 years. Below 45 years, smoking remained the larger contributor to mortality. Interpretation: Adiposity now accounts for more deaths in England and Scotland than smoking among people in middle- and old-age. National strategies to address adiposity should be a public health priority

A healthy eating score is inversely associated with depression in older adults: results from the Chilean National Health Survey 2016-2017

Abstract Objective: To investigate the relationship of a healthy eating score with depression in Chilean older adults. Design: Cross-sectional study. Setting: Older adults from the Chilean National Health Survey 2016-2017. Associations were analysed using complex samples multivariable logistic regressions adjusted for age, sex, socio-demographic, lifestyles (physical activity, smoking, alcohol consumption and sleep duration), BMI and clinical conditions (hypertension, diabetes, hypercholesterolaemia and cardiovascular diseases). Participants: The number of participants was 2031 (≥ 60 years). The Composite International Diagnostic Interview-Short Form was applied to establish the diagnosis of major depressive episode. Six healthy eating habits were considered to produce the healthy eating score (range: 0-12): consumption of seafood, whole grain, dairy, fruits, vegetables and legumes. Participants were categorised according to their final scores as healthy (≥ 9), average (5-8) and unhealthy (≤ 4). Results: Participants with a healthy score had a higher educational level, physical activity and regular sleep hours than participants with an average and unhealthiest healthy eating score. Participants classified in the healthiest healthy eating score had an inverse association with depression (OR: 0·28, (95 % CI 0·10, 0·74)). Food items that contributed the most to this association were legumes (15·2 %) and seafood (12·7 %). Conclusion: Older adults classified in the healthiest healthy eating score, characterised by a high consumption of legumes and seafood, showed a lower risk for depression in a representative sample of Chilean population

Physical fitness, screen time and sleep habits according to obesity levels in schoolchildren: findings from the health survey of the extreme south of Chile

Obesity is a worry because it is associated with a greater burden of disease, and it has been shown to be related to the health habits and physical condition of children and adolescents. Objective: To associate physical fitness, screen time, and sleep habits with the different categories of obesity in schoolchildren from the extreme south of Chile. Methods: 583 schoolchildren were included in this cross-sectional analysis. The screen time and sleep habits were measured with the Sleep Self-Report questionnaire, while the physical fitness was assessed with the Alpha Fitness test battery. The Body Mass Index/age (BMI/age) and the Waist-to-Height ratio (WtHr) were used to define adiposity using the following categories: healthy weight/low-risk waist-to-height ratio (H/LR), healthy weight/high-risk waist-to-height ratio (H/HR), overweight/low-risk waist to height ratio (O/LR), and overweight/high-risk waist to height ratio (O/HR). Results: A considerable number of schoolchildren (23.2%) presented sleep problems, while the mean screen time was 9.3 (95% CI: 8.4; 10.1) hours/day. Schoolchildren classified as H/HR showed better physical fitness than the O/HR group but worse physical fitness than the H/LR group. Conclusions: Significant differences were evidenced in the physical fitness between the adiposity categories, which could open future lines of research concerning the characterization of the healthy weight-obese adiposity categories in children

Adherence to dietary recommendations by socioeconomic status in the United Kingdom biobank cohort study

IntroductionUnderstanding how socioeconomic markers interact could inform future policies aimed at increasing adherence to a healthy diet.MethodsThis cross-sectional study included 437,860 participants from the UK Biobank. Dietary intake was self-reported. Were used as measures socioeconomic education level, income and Townsend deprivation index. A healthy diet score was defined using current dietary recommendations for nine food items and one point was assigned for meeting the recommendation for each. Good adherence to a healthy diet was defined as the top 75th percentile, while poor adherence was defined as the lowest 25th percentile. Poisson regression was used to investigate adherence to dietary recommendations.ResultsThere were significant trends whereby diet scores tended to be less healthy as deprivation markers increased. The diet score trends were greater for education compared to area deprivation and income. Compared to participants with the highest level of education, those with the lowest education were found to be 48% less likely to adhere to a healthy diet (95% Confidence Interval [CI]: 0.60–0.64). Additionally, participants with the lowest income level were 33% less likely to maintain a healthy diet (95% CI: 0.73–0.81), and those in the most deprived areas were 13% less likely (95% CI: 0.84–0.91).Discussion/conclussionAmong the three measured proxies of socioeconomic status – education, income, and area deprivation – low education emerged as the strongest factor associated with lower adherence to a healthy diet

Exploring the underlying mechanisms linking adiposity and cardiovascular disease: a prospective cohort study of 404,332 UK Biobank participants

Background and Aims Obesity is causally associated with multiple cardiovascular outcomes but effective population measure to control obesity is limited. This study aims to decipher to which extent excess atherosclerotic cardiovascular diseases (ASCVD) and heart failure (HF) risk due to obesity can be explained by conventional risk factors. Methods This is a prospective cohort study of 404,332 White UK Biobank participants. Participants with prior CVDs or other chronic diseases at baseline, or body mass index (BMI) <18·5 kg/m2 were excluded. Data were collected at the baseline assessment between 2006 and 2010. Linkage to death registrations and hospital admission records was used to ascertain ASCVD and HF outcomes up to late 2021. Obesity was defined as BMI ≥30 kg/m2. Candidate mediators included lipids, blood pressure, glycated haemoglobin (HbA1c), and liver and kidney function markers, which were chosen based on clinical trials and Mendelian randomisation studies. Cox proportional hazard models were used to estimate hazard ratios (HR) and their 95% confidence intervals (CIs). Mediation analysis based on g-formula was used to separately estimate the relative importance of mediators for ASCVD and HF. Results Compared with people without obesity, obese people had an increased risk of ASCVD (HR 1.30, 95% CI 1.26–1.35) and HF (HR 2.04, 95% CI 1.96–2.13) after adjusting for sociodemographic and lifestyle factors and medications for cholesterol, blood pressure and insulin. The strongest mediators for ASCVD were renal function (eGFR: mediation proportion: 44.6%), blood pressure (SBP: 24.4%; DBP: 31.1%), triglycerides (19.6%), and hyperglycaemia (HbA1c 18.9%). These mediators collectively explained more excess risk of ASCVD than that of HF. Conclusions Interventions that help obese individuals to maintain healthy lipid concentrations, blood pressure, glycaemic control and kidney function could potentially alleviate a sizable proportion of the ASCVD burden. However, HF burden could not be meaningfully reduced without weight management

Diet-related inflammation is associated with worse COVID-19 outcomes in the UK biobank cohort

Diet, the most important modulator of inflammatory and immune responses, may affect COVID-19 incidence and disease severity. Data from 196,154 members of the UK biobank had at least one 24 h dietary recall. COVID-19 outcomes were based on PCR testing, hospital admissions, and death certificates. Adjusted Poisson regression analyses were performed to estimate the risk ratios (RR) and their 95% confidence intervals (CI) for dietary inflammatory index (DII)/energy-adjusted DII (E-DII) scores. Models were adjusted for sociodemographic factors, comorbidities, smoking status, physical activity, and sleep duration. Between January 2020 and March 2021, there were 11,288 incident COVID-19 cases, 1270 COVID-19-related hospitalizations, and 315 COVID-19-related deaths. The fully adjusted model showed that participants in the highest (vs. lowest) DII/E-DII quintile were at 10–17% increased risk of COVID-19 (DII: RR Q5 vs. Q1 = 1.10, 95% CI 1.04–1.17, Ptrend < 0.001; E-DII: RR Q5 vs. Q1 = 1.17, 95% CI 1.10–1.24, Ptrend < 0.001) and ≈40% higher risk was observed for disease severity (DII: RR Q5 vs. Q1 = 1.40, 95% CI 1.18–1.67, Ptrend < 0.001; E-DII: RR Q5 vs. Q1 = 1.39, 95% CI 1.16–1.66, Ptrend < 0.001). There was a 43% increased risk of COVID-19-related death in the highest DII quintile (RR Q5 vs. Q1 = 1.43, 95% CI 1.01–2.01, Ptrend = 0.04). About one-quarter of the observed positive associations between DII and COVID-19-related outcomes were mediated by body mass index (25.8% for incidence, 21.6% for severity, and 19.8% for death). Diet-associated inflammation increased the risk of COVID-19 infection, severe disease, and death