Body mass index, triglyceride-glucose index, and prostate cancer death: a mediation analysis in eight European cohorts

BACKGROUND

Insulin resistance is a hypothesised biological mechanism linking obesity with prostate cancer (PCa) death. Data in support of this hypothesis is limited.

METHODS

We included 259,884 men from eight European cohorts, with 11,760 incident PCa's and 1784 PCa deaths during follow-up. We used the triglyceride-glucose (TyG) index as indicator of insulin resistance. We analysed PCa cases with follow-up from PCa diagnosis, and the full cohort with follow-up from the baseline cancer-free state, thus incorporating both PCa incidence and death. We calculated hazard ratios (HR) and the proportion of the total effect of body mass index (BMI) on PCa death mediated through TyG index.

RESULTS

In the PCa-case-only analysis, baseline TyG index was positively associated with PCa death (HR per 1-standard deviation: 1.11, 95% confidence interval (CI); 1.01-1.22), and mediated a substantial proportion of the baseline BMI effect on PCa death (HRtotal effect per 5-kg/m2 BMI: 1.24; 1.14-1.35, of which 28%; 4%-52%, mediated). In contrast, in the full cohort, the TyG index was not associated with PCa death (HR: 1.03; 0.94-1.13), hence did not substantially mediate the effect of BMI on PCa death.

CONCLUSIONS

Insulin resistance could be an important pathway through which obesity accelerates PCa progression to death.

Associations of intakes of total protein, protein from dairy sources, and dietary calcium with risks of colorectal, breast, and prostate cancer: a prospective analysis in UK Biobank

BACKGROUND

Evidence concerning intakes of protein or sources of dairy protein and risks of colorectal, breast, and prostate cancers is inconclusive.

METHODS

Using a subsample of UK Biobank participants who completed ≥2 (maximum of 5) 24-h dietary assessments, we estimated intakes of total protein, protein from total dairy products, milk, and cheese, and dietary calcium in 114,217 participants. Hazard ratios (HRs) and 95% confidence intervals (CI) were estimated using multivariable-adjusted Cox regression.

RESULTS

After a median of 9.4 years of follow-up, 1193 colorectal, 2024 female breast, and 2422 prostate cancer cases were identified. There were inverse associations of total dairy protein, protein from milk, and dietary calcium intakes with colorectal cancer incidence (HRQ4 vs Q1:0.80, 95% CI: 0.67-0.94; 0.79, 0.67-0.94; 0.71, 0.58-0.86, respectively). We also observed positive associations of milk protein and dietary calcium with prostate cancer risk (HRQ4 vs Q1:1.12, 1.00-1.26 and 1.16, 1.01-1.33, respectively). No significant associations were observed between intake of dairy protein and breast cancer risk. When insulin-like growth factor-I concentrations measured at recruitment were added to the multivariable-adjusted models, associations remained largely unchanged. Analyses were also similar when looking at total grams of dairy products, milk, and cheese.

CONCLUSION

Further research is needed to understand the mechanisms underlying the relationships of dairy products with cancer risk and the potential roles of dietary protein and calcium.

Longitudinal body mass index and cancer risk: a cohort study of 2.6 million Catalan adults

Single body mass index (BMI) measurements have been associated with increased risk of 13 cancers. Whether life course adiposity-related exposures are more relevant cancer risk factors than baseline BMI (ie, at start of follow-up for disease outcome) remains unclear. We conducted a cohort study from 2009 until 2018 with population-based electronic health records in Catalonia, Spain. We included 2,645,885 individuals aged ≥40 years and free of cancer in 2009. After 9 years of follow-up, 225,396 participants were diagnosed with cancer. This study shows that longer duration, greater degree, and younger age of onset of overweight and obesity during early adulthood are positively associated with risk of 18 cancers, including leukemia, non-Hodgkin lymphoma, and among never-smokers, head and neck, and bladder cancers which are not yet considered as obesity-related cancers in the literature. Our findings support public health strategies for cancer prevention focussing on preventing and reducing early overweight and obesity.

Separating the effects of early and later life adiposity on colorectal cancer risk: a Mendelian randomization study

BACKGROUND

Observational studies have linked childhood obesity with elevated risk of colorectal cancer; however, it is unclear if this association is causal or independent from the effects of obesity in adulthood on colorectal cancer risk.

METHODS

We conducted Mendelian randomization (MR) analyses to investigate potential causal relationships between self-perceived body size (thinner, plumper, or about average) in early life (age 10) and measured body mass index in adulthood (mean age 56.5) with risk of colorectal cancer. The total and independent effects of body size exposures were estimated using univariable and multivariable MR, respectively. Summary data were obtained from a genome-wide association study of 453,169 participants in UK Biobank for body size and from a genome-wide association study meta-analysis of three colorectal cancer consortia of 125,478 participants.

RESULTS

Genetically predicted early life body size was estimated to increase odds of colorectal cancer (odds ratio [OR] per category change: 1.12, 95% confidence interval [CI]: 0.98-1.27), with stronger results for colon cancer (OR: 1.16, 95% CI: 1.00-1.35), and distal colon cancer (OR: 1.25, 95% CI: 1.04-1.51). After accounting for adult body size using multivariable MR, effect estimates for early life body size were attenuated towards the null for colorectal cancer (OR: 0.97, 95% CI: 0.77-1.22) and colon cancer (OR: 0.97, 95% CI: 0.76-1.25), while the estimate for distal colon cancer was of similar magnitude but more imprecise (OR: 1.27, 95% CI: 0.90-1.77). Genetically predicted adult life body size was estimated to increase odds of colorectal (OR: 1.27, 95% CI: 1.03, 1.57), colon (OR: 1.32, 95% CI: 1.05, 1.67), and proximal colon (OR: 1.57, 95% CI: 1.21, 2.05).

CONCLUSIONS

Our findings suggest that the positive association between early life body size and colorectal cancer risk is likely due to large body size retainment into adulthood.

Long-term use of antihypertensive medications, hypertension and colorectal cancer risk and mortality: a prospective cohort study

BACKGROUND

Hypertension and the use of antihypertensive medications have been intensively investigated in relation to colorectal cancer (CRC). Prior epidemiologic studies have not been able to examine this topic with adequate confounding control and follow-up time, or disentangle the effects of antihypertensive agents and hypertension.

METHODS

Eligible participants in the Nurses' Health Study and Health Professionals Follow-up Study were followed for up to 28 years, with repeat assessments of exposures. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals.

RESULTS

In fully adjusted analyses based on both new-user and prevalent-user designs, there was no association between the use of beta-blockers, calcium-channel blockers, thiazide diuretics, angiotensin-converting enzyme inhibitors, furosemide, other antihypertensive drugs and CRC risk and mortality reached the statistically significant threshold after Bonferroni correction. The results remained similar in sensitivity analyses among participants with hypertension. Before Bonferroni correction, suggestive associations between beta-blocker use and CRC risk and between furosemide use and CRC-specific mortality were observed specifically in analyses using a new-user design. Hypertension was not associated with CRC risk in analyses based on both new-user and prevalent-user designs.

CONCLUSIONS

Hypertension and long-term use of major classes of antihypertensive medications are unlikely to be associated with CRC risk and mortality.

A very-hot food and beverage thermal exposure index and esophageal cancer risk in Malawi and Tanzania: findings from the ESCCAPE case-control studies

BACKGROUND

Consumption of very-hot beverages/food is a probable carcinogen. In East Africa, we investigated esophageal squamous cell carcinoma (ESCC) risk in relation to four thermal exposure metrics separately and in a combined score.

METHODS

From the ESCCAPE case-control studies in Blantyre, Malawi (2017-20) and Kilimanjaro, Tanzania (2015-19), we used logistic regression models adjusted for country, age, sex, alcohol and tobacco, to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for self-reported thermal exposures whilst consuming tea, coffee and/or porridge.

RESULTS

The study included 849 cases and 906 controls. All metrics were positively associated with ESCC: temperature of drink/food (OR 1.92 (95% CI: 1.50, 2.46) for 'very hot' vs 'hot'), waiting time before drinking/eating (1.76 (1.37, 2.26) for <2 vs 2-5 minutes), consumption speed (2.23 (1.78, 2.79) for 'normal' vs 'slow') and mouth burning (1.90 (1.19, 3.01) for ≥6 burns per month vs none). Amongst consumers, the composite score ranged from 1 to 12, and ESCC risk increased with higher scores, reaching an OR of 4.6 (2.1, 10.0) for scores of ≥9 vs 3.

CONCLUSIONS

Thermal exposure metrics were strongly associated with ESCC risk. Avoidance of very-hot food/beverage consumption may contribute to the prevention of ESCC in East Africa.

Ultra-processed foods and cancer risk: from global food systems to individual exposures and mechanisms

Ultra-processed foods (UPFs) have become increasingly dominant globally, contributing to as much as 60% of total daily energy intake in some settings. Epidemiological evidence suggests this worldwide shift in food processing may partly be responsible for the global obesity epidemic and chronic disease burden. However, prospective studies examining the association between UPF consumption and cancer outcomes are limited. Available evidence suggests that UPFs may increase cancer risk via their obesogenic properties as well as through exposure to potentially carcinogenic compounds such as certain food additives and neoformed processing contaminants. We identify priority areas for future research and policy implications, including improved understanding of the potential dual harms of UPFs on the environment and cancer risk. The prevention of cancers related to the consumption of UPFs could be tackled using different strategies, including behaviour change interventions among consumers as well as bolder public health policies needed to improve food environments.

Prevalent diabetes and risk of total, colorectal, prostate and breast cancers in an ageing population: meta-analysis of individual participant data from cohorts of the CHANCES consortium

BACKGROUND

We investigated whether associations between prevalent diabetes and cancer risk are pertinent to older adults and whether associations differ across subgroups of age, body weight status or levels of physical activity.

METHODS

We harmonised data from seven prospective cohort studies of older individuals in Europe and the United States participating in the CHANCES consortium. Cox proportional hazard regression was used to estimate the associations of prevalent diabetes with cancer risk (all cancers combined, and for colorectum, prostate and breast). We calculated summary risk estimates across cohorts using pooled analysis and random-effects meta-analysis.

RESULTS

A total of 667,916 individuals were included with an overall median (P25-P75) age at recruitment of 62.3 (57-67) years. During a median follow-up time of 10.5 years, 114,404 total cancer cases were ascertained. Diabetes was not associated with the risk of all cancers combined (hazard ratio (HR) = 0.94; 95% confidence interval (CI): 0.86-1.04; I2 = 63.3%). Diabetes was positively associated with colorectal cancer risk in men (HR = 1.17; 95% CI: 1.08-1.26; I2 = 0%) and a similar HR in women (1.13; 95% CI: 0.82-1.56; I2 = 46%), but with a confidence interval including the null. Diabetes was inversely associated with prostate cancer risk (HR = 0.81; 95% CI: 0.77-0.85; I2 = 0%), but not with postmenopausal breast cancer (HR = 0.96; 95% CI: 0.89-1.03; I2 = 0%). In exploratory subgroup analyses, diabetes was inversely associated with prostate cancer risk only in men with overweight or obesity.

CONCLUSIONS

Prevalent diabetes was positively associated with colorectal cancer risk and inversely associated with prostate cancer risk in older Europeans and Americans.

Plant foods, dietary fibre and risk of ischaemic heart disease in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort

BACKGROUND

Epidemiological evidence indicates that diets rich in plant foods are associated with a lower risk of ischaemic heart disease (IHD), but there is sparse information on fruit and vegetable subtypes and sources of dietary fibre. This study examined the associations of major plant foods, their subtypes and dietary fibre with risk of IHD in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

We conducted a prospective analysis of 490 311 men and women without a history of myocardial infarction or stroke at recruitment (12.6 years of follow-up, n cases = 8504), in 10 European countries. Dietary intake was assessed using validated questionnaires, calibrated with 24-h recalls. Multivariable Cox regressions were used to estimate hazard ratios (HR) of IHD.

RESULTS

There was a lower risk of IHD with a higher intake of fruit and vegetables combined [HR per 200 g/day higher intake 0.94, 95% confidence interval (CI): 0.90-0.99, P-trend = 0.009], and with total fruits (per 100 g/day 0.97, 0.95-1.00, P-trend = 0.021). There was no evidence for a reduced risk for fruit subtypes, except for bananas. Risk was lower with higher intakes of nuts and seeds (per 10 g/day 0.90, 0.82-0.98, P-trend = 0.020), total fibre (per 10 g/day 0.91, 0.85-0.98, P-trend = 0.015), fruit and vegetable fibre (per 4 g/day 0.95, 0.91-0.99, P-trend = 0.022) and fruit fibre (per 2 g/day 0.97, 0.95-1.00, P-trend = 0.045). No associations were observed between vegetables, vegetables subtypes, legumes, cereals and IHD risk.

CONCLUSIONS

In this large prospective study, we found some small inverse associations between plant foods and IHD risk, with fruit and vegetables combined being the most strongly inversely associated with risk. Whether these small associations are causal remains unclear.

Exploring the role of genetic confounding in the association between maternal and offspring body mass index: evidence from three birth cohorts

BACKGROUND

Maternal pre-pregnancy body mass index (BMI) is positively associated with offspring birth weight (BW) and BMI in childhood and adulthood. Each of these associations could be due to causal intrauterine effects, or confounding (genetic or environmental), or some combination of these. Here we estimate the extent to which the association between maternal BMI and offspring body size is explained by offspring genotype, as a first step towards establishing the importance of genetic confounding.

METHODS

We examined the associations of maternal pre-pregnancy BMI with offspring BW and BMI at 1, 5, 10 and 15 years, in three European birth cohorts (n ≤11 498). Bivariate Genomic-relatedness-based Restricted Maximum Likelihood implemented in the GCTA software (GCTA-GREML) was used to estimate the extent to which phenotypic covariance was explained by offspring genotype as captured by common imputed single nucleotide polymorphisms (SNPs). We merged individual participant data from all cohorts, enabling calculation of pooled estimates.

RESULTS

Phenotypic covariance (equivalent here to Pearson's correlation coefficient) between maternal BMI and offspring phenotype was 0.15 [95% confidence interval (CI): 0.13, 0.17] for offspring BW, increasing to 0.29 (95% CI: 0.26, 0.31) for offspring 15 year BMI. Covariance explained by offspring genotype was negligible for BW [-0.04 (95% CI: -0.09, 0.01)], but increased to 0.12 (95% CI: 0.04, 0.21) at 15 years, which is equivalent to 43% (95% CI: 15%, 72%) of the phenotypic covariance. Sensitivity analyses using weight, BMI and ponderal index as the offspring phenotype at all ages showed similar results.

CONCLUSIONS

Offspring genotype explains a substantial fraction of the covariance between maternal BMI and offspring adolescent BMI. This is consistent with a potentially important role for genetic confounding as a driver of the maternal BMI-offspring BMI association.

Signalling involving MET and FAK supports cell division independent of the activity of the cell cycle-regulating CDK4/6 kinases

Deregulation of cyclin-dependent kinases 4 and 6 (CDK4/6) is highly prevalent in cancer; yet, inhibitors against these kinases are currently used only in restricted tumour contexts. The extent to which cancers depend on CDK4/6 and the mechanisms that may undermine such dependency are poorly understood. Here, we report that signalling engaging the MET proto-oncogene receptor tyrosine kinase/focal adhesion kinase (FAK) axis leads to CDK4/6-independent CDK2 activation, involving as critical mechanistic events loss of the CDKI p21CIP1 and gain of its regulator, the ubiquitin ligase subunit SKP2. Combined inhibition of MET/FAK and CDK4/6 eliminates the proliferation capacity of cancer cells in culture, and enhances tumour growth inhibition in vivo. Activation of the MET/FAK axis is known to arise through cancer extrinsic and intrinsic cues. Our work predicts that such cues support cell division independent of the activity of the cell cycle-regulating CDK4/6 kinases and identifies MET/FAK as a tractable route to broaden the utility of CDK4/6 inhibitor-based therapies in the clinic.