Body mass index and risk of over 100 cancer forms and subtypes in 4.1 million individuals in Sweden: the Obesity and Disease Development Sweden (ODDS) pooled cohort study.

Background: Obesity, assessed by body mass index (BMI), is an established risk factor for 13 cancers. We aimed to identify further potential obesity-related cancers and to quantify their association with BMI relative to that of established obesity-related cancers. Methods: Using Cox regression models on 4,142,349 individuals in Sweden (mean age 27.1 years at weight measurement), we calculated hazard ratios (HRs) for the association between BMI and the risk of 122 cancers and cancer subtypes, grouped by topography and morphology. Cancers with a positive association (i.e., HR >1) at an α-level of 0.05 for obesity (BMI ≥30 kg/m2) vs. normal weight (BMI 18.5-24.9 kg/m2) or per 5 kg/m2 higher BMI, for which obesity is not an established risk factor, were considered potentially obesity related. Findings: After 100.2 million person-years of follow-up, 332,501 incident cancer cases were recorded. We identified 15 cancers in men and 16 in women as potentially obesity related. These were cancers of the head and neck, gastrointestinal tract, malignant melanoma, genital organs, endocrine organs, connective tissue, and haematological malignancies. Among these, there was evidence of differential associations with BMI between subtypes of gastric cancer, small intestine cancer, cervical cancer, and lymphoid neoplasms (P values for heterogeneity in HRs <0.05). The HR (95% confidence interval) per 5 kg/m2 higher BMI was 1.17 (1.15-1.20) in men and 1.13 (1.11-1.15) in women for potential obesity-related cancers (51,690 cases), and 1.24 (1.22-1.26) in men and 1.12 (1.11-1.13) in women for established obesity-related cancers (84,384 cases). Interpretation: This study suggests a large number of potential obesity-related cancers could be added to already established ones. Importantly, the magnitudes of the associations were largely comparable to those of the already established obesity-related cancers. We also provide evidence of specific cancer subtypes driving some associations with BMI. Studies accounting for cancer-specific confounders are needed to confirm these findings. Funding: Swedish Research Council, Swedish Cancer Society, Mrs. Berta Kamprad's Cancer Foundation, Crafoord Foundation, Cancer Research Foundation at the Department of Oncology, Malmö University Hospital, and China Scholarship Council.

Food biodiversity and gastrointestinal cancer risk in nine European countries: Analysis within a prospective cohort study.

BACKGROUND: Food biodiversity in human diets has potential co-benefits for both public health and sustainable food systems. However, current evidence on the potential relationship between food biodiversity and cancer risk, and particularly gastrointestinal cancers typically related to diet, remains limited. This study evaluated how dietary species richness (DSR) was associated with gastrointestinal cancer risk in a pan-European population. METHODS: Associations between DSR and subsequent gastrointestinal cancer risk were examined among 450,111 adults enrolled in the European Prospective Investigation into Cancer and Nutrition cohort (EPIC, initiated in 1992), free of cancer at baseline. Usual dietary intakes were assessed at recruitment with country-specific dietary questionnaires. DSR of an individual's yearly diet was calculated based on the absolute number of unique biological species in each food and drink item. Associations between DSR and cancer risk were assessed by multivariable Cox proportional hazards regression models. FINDINGS: During a median follow-up time of 14.1 years (SD=3.9), 10,705 participants were diagnosed with gastrointestinal cancer. Hazard ratios (HRs) and 95 % confidence intervals (CIs) comparing overall gastrointestinal cancer risk in the highest versus lowest quintiles of DSR indicated inverse associations in multivariable-adjusted models [HR (95 % CI): 0.77 (0.69-0.87); P-value < 0·0001] (Table 2). Specifically, inverse associations were observed between DSR and oesophageal squamous cell carcinoma, proximal colon, colorectal, and liver cancer risk (p-trend<0.05 for all cancer types). INTERPRETATION: Greater food biodiversity in the diet may lower the risk of certain gastrointestinal cancers. Further research is needed to replicate these novel findings and to understand potential mechanisms.

Time trends of the association of body mass index with mortality in 3.5 million young Swedish adults.

PURPOSE: We investigated time trends of the obesity-mortality association, accounting for age, sex, and cause-specific deaths. METHODS: We analysed pooled nationwide data in Sweden for 3,472,310 individuals aged 17-39 years at baseline in 1963-2016. Cox regression and flexible parametric survival models investigated BMI-mortality associations in sub-groups of sex and baseline calendar years (men: <1975, 1975-1985, ≥1985 and women: <1985, 1985-1994, ≥1995). RESULTS: Comparing men with obesity vs. normal weight, all-cause and "other-cause" mortality associations decreased over periods; HR (95% CI) 1.92 (1.83-2.01) and 1.70 (1.58-1.82) for all-cause and 1.72 (1.58-1.87) and 1.40 (1.28-1.53) for "other-cause" mortality in <1975 and ≥1985, but increased for CVD mortality; HR 2.71 (2.51-2.94) and 3.91 (3.37-4.53). Higher age at death before 1975 coincided with more obesity-related deaths at higher ages. Furthermore, the all-cause mortality association for different ages in men showed no clear differences between periods (p-interaction=0.09), suggesting no calendar effect after accounting for attained age. Similar, but less pronounced, results were observed in women. Associations with cancer mortality showed no clear trends in men or in women. CONCLUSIONS: Accounting for differences in age and death causes between calendar periods when investigating BMI-mortality time trends may avoid misinterpreting the risks associated with obesity over time.

Early Prostate Cancer Deaths Among Men With Higher vs Lower Genetic Risk.

Importance: Prostate cancer, a leading cause of cancer death among men, urgently requires new prevention strategies, which may involve targeting men with an underlying genetic susceptibility. Objective: To explore differences in risk of early prostate cancer death among men with higher vs lower genetic risk to inform prevention efforts. Design, Setting, and Participants: This cohort study used a combined analysis of genotyped men without prostate cancer at inclusion and with lifestyle data in 2 prospective cohort studies in Sweden and the US, the Malmö Diet and Cancer Study (MDCS) and the Health Professionals Follow-Up Study (HPFS), followed up from 1991 to 2019. Data were analyzed between April 2023 and April 2024. Exposures: Men were categorized according to modifiable lifestyle behaviors and genetic risk. A polygenic risk score above the median or a family history of cancer defined men at higher genetic risk (67% of the study population); the remaining men were categorized as being at lower genetic risk. Main Outcomes and Measures: Prostate cancer death analyzed using time-to-event analysis estimating hazard ratios (HR), absolute risks, and preventable deaths by age. Results: Among the 19 607 men included for analysis, the median (IQR) age at inclusion was 59.0 (53.0-64.7) years (MDCS) and 65.1 (58.0-71.8) years (HPFS). During follow-up, 107 early (by age 75 years) and 337 late (after age 75 years) prostate cancer deaths were observed. Compared with men at lower genetic risk, men at higher genetic risk had increased rates of both early (HR, 3.26; 95% CI, 1.82-5.84) and late (HR, 2.26; 95% CI, 1.70-3.01) prostate cancer death, and higher lifetime risks of prostate cancer death (3.1% vs 1.3% [MDCS] and 2.3% vs 0.6% [HPFS]). Men at higher genetic risk accounted for 94 of 107 early prostate cancer deaths (88%), of which 36% (95% CI, 12%-60%) were estimated to be preventable through adherence to behaviors associated with a healthy lifestyle (not smoking, healthy weight, high physical activity, and a healthy diet). Conclusions and Relevance: In this 20-year follow-up study, men with a genetic predisposition accounted for the vast majority of early prostate cancer deaths, of which one-third were estimated to be preventable. This suggests that men at increased genetic risk should be targeted in prostate cancer prevention strategies.

Cohort profile: The Obesity and Disease Development Sweden (ODDS) study, a pooled cohort.

PURPOSE: The Obesity and Disease Development Sweden (ODDS) study was designed to create a large cohort to study body mass index (BMI), waist circumference (WC) and changes in weight and WC, in relation to morbidity and mortality. PARTICIPANTS: ODDS includes 4 295 859 individuals, 2 165 048 men and 2 130 811 women, in Swedish cohorts and national registers with information on weight assessed once (2 555 098 individuals) or more (1 740 761 individuals), in total constituting 7 733 901 weight assessments at the age of 17-103 years in 1963-2020 (recalled weight as of 1911). Information on WC is available in 152 089 men and 212 658 women, out of whom 108 795 have repeated information on WC (in total 512 273 assessments). Information on morbidity and mortality was retrieved from national registers, with follow-up until the end of 2019-2021, varying between the registers. FINDINGS TO DATE: Among all weight assessments (of which 85% are objectively measured), the median year, age and BMI (IQR) is 1985 (1977-1994) in men and 2001 (1991-2010) in women, age 19 (18-40) years in men and 30 (26-36) years in women and BMI 22.9 (20.9-25.4) kg/m2 in men and 23.2 (21.2-26.1) kg/m2 in women. Normal weight (BMI 18.5-24.9 kg/m2) is present in 67% of assessments in men and 64% in women and obesity (BMI≥30 kg/m2) in 5% of assessments in men and 10% in women. The median (IQR) follow-up time from the first objectively measured or self-reported current weight assessment until emigration, death or end of follow-up is 31.4 (21.8-40.8) years in men and 19.6 (9.3-29.0) years in women. During follow-up, 283 244 men and 123 457 women died. FUTURE PLANS: The large sample size and long follow-up of the ODDS Study will provide robust results on anthropometric measures in relation to risk of common diseases and causes of deaths, and novel findings in subgroups and rarer outcomes.

Lifestyle changes in middle age and risk of cancer: evidence from the European Prospective Investigation into Cancer and Nutrition.

In this study, we aimed to provide novel evidence on the impact of changing lifestyle habits on cancer risk. In the EPIC cohort, 295,865 middle-aged participants returned a lifestyle questionnaire at baseline and during follow-up. At both timepoints, we calculated a healthy lifestyle index (HLI) score based on cigarette smoking, alcohol consumption, body mass index and physical activity. HLI ranged from 0 (most unfavourable) to 16 (most favourable). We estimated the association between HLI change and risk of lifestyle-related cancers-including cancer of the breast, lung, colorectum, stomach, liver, cervix, oesophagus, bladder, and others-using Cox regression models. We reported hazard ratios (HR) with 95% confidence intervals (CI). Median time between the two questionnaires was 5.7 years, median age at follow-up questionnaire was 59 years. After the follow-up questionnaire, we observed 14,933 lifestyle-related cancers over a median follow-up of 7.8 years. Each unit increase in the HLI score was associated with 4% lower risk of lifestyle-related cancers (HR 0.96; 95%CI 0.95-0.97). Among participants in the top HLI third at baseline (HLI > 11), those in the bottom third at follow-up (HLI ≤ 9) had 21% higher risk of lifestyle-related cancers (HR 1.21; 95%CI 1.07-1.37) than those remaining in the top third. Among participants in the bottom HLI third at baseline, those in the top third at follow-up had 25% lower risk of lifestyle-related cancers (HR 0.75; 95%CI 0.65-0.86) than those remaining in the bottom third. These results indicate that lifestyle changes in middle age may have a significant impact on cancer risk.

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.

A body shape index (ABSI) is associated inversely with post-menopausal progesterone-receptor-negative breast cancer risk in a large European cohort.

BACKGROUND: Associations of body shape with breast cancer risk, independent of body size, are unclear because waist and hip circumferences are correlated strongly positively with body mass index (BMI). METHODS: We evaluated body shape with the allometric "a body shape index" (ABSI) and hip index (HI), which compare waist and hip circumferences, correspondingly, among individuals with the same weight and height. We examined associations of ABSI, HI, and BMI (per one standard deviation increment) with breast cancer overall, and according to menopausal status at baseline, age at diagnosis, and oestrogen and progesterone receptor status (ER+/-PR+/-) in multivariable Cox proportional hazards models using data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. RESULTS: During a mean follow-up of 14.0 years, 9011 incident breast cancers were diagnosed among 218,276 women. Although there was little evidence for association of ABSI with breast cancer overall (hazard ratio HR = 0.984; 95% confidence interval: 0.961-1.007), we found borderline inverse associations for post-menopausal women (HR = 0.971; 0.942-1.000; n = 5268 cases) and breast cancers diagnosed at age ≥ 55 years (HR = 0.976; 0.951-1.002; n = 7043) and clear inverse associations for ER + PR- subtypes (HR = 0.894; 0.822-0.971; n = 726) and ER-PR- subtypes (HR = 0.906; 0.835-0.983 n = 759). There were no material associations with HI. BMI was associated strongly positively with breast cancer overall (HR = 1.074; 1.049-1.098), for post-menopausal women (HR = 1.117; 1.085-1.150), for cancers diagnosed at age ≥ 55 years (HR = 1.104; 1.076-1.132), and for ER + PR + subtypes (HR = 1.122; 1.080-1.165; n = 3101), but not for PR- subtypes. CONCLUSIONS: In the EPIC cohort, abdominal obesity evaluated with ABSI was not associated with breast cancer risk overall but was associated inversely with the risk of post-menopausal PR- breast cancer. Our findings require validation in other cohorts and with a larger number of PR- breast cancer cases.

Prediagnostic markers of insulin resistance and prostate cancer risk and death: A pooled study.

BACKGROUND: Insulin resistance has been shown to be related to a higher risk of several cancers, but the association with prostate cancer (PCa) has been inconsistent. METHODS: We investigated prediagnostic markers of insulin resistance in men in four cohorts in Sweden, in relation to PCa risk (total, non-aggressive and aggressive) and PCa death using multivariable-adjusted Cox regression. The number of men, PCa cases and PCa deaths was up to 66,668, 3940 and 473 for plasma glucose and the triglyceride-glucose (TyG) index, and up to 3898, 586 and 102 for plasma insulin, glycated haemoglobin (HbA1c) and leptin. RESULTS: Higher HbA1c was related to a lower risk of non-aggressive PCa but no significant associations were found for insulin resistance markers with the risk of aggressive or total PCa. In PCa cases, higher glucose and TyG index were related to a higher risk of PCa death (hazard ratio [HR] per higher standard deviation, 1.22, 95% CI 1.00-1.49 and 1.24, 95% CI 1.00-1.55), which further increased when restricting the analyses to glucose and TyG index measures taken <10 years before the PCa diagnosis (HR, 1.70, 95% CI 1.09-2.70 and 1.66, 95% CI 1.12-2.51). No associations were observed for other markers in relation to PCa death. CONCLUSIONS: The results of this study showed no associations of insulin resistance markers with the risk of clinically relevant PCa, but higher glucose and TyG index were associated with poorer survival from PCa. The lack of association for other insulin resistance markers may be due to their smaller sample size.

Metabolically (un)healthy obesity and risk of obesity-related cancers: a pooled study.

BACKGROUND: Studies of obesity with or without metabolic aberrations, commonly termed metabolically unhealthy or healthy obesity, in relation to cancer risk are scarce. METHODS: We investigated body mass index (normal weight, overweight, obesity) jointly and in interaction with metabolic health status in relation to obesity-related cancer risk (n = 23 630) among 797 193 European individuals. A metabolic score comprising mid-blood pressure, plasma glucose, and triglycerides was used to define metabolically healthy and unhealthy status. Hazard ratios (HRs) and multiplicative interactions were assessed using Cox regression, and additive interactions were assessed using the relative excess risk for interaction. All statistical tests were 2-sided. RESULTS: Metabolically unhealthy obesity, with a baseline prevalence of 7%, was, compared with metabolically healthy normal weight, associated with an increased relative risk of any obesity-related cancer and of colon, rectal, pancreas, endometrial, liver, gallbladder, and renal cell cancer (P < .05), with the highest risk estimates for endometrial, liver, and renal cell cancer (HR = 2.55-3.00). Metabolically healthy obesity showed a higher relative risk for any obesity-related cancer and colon (in men), endometrial, renal cell, liver, and gallbladder cancer, though the risk relationships were weaker. There were no multiplicative interactions, but there were additive, positive interactions between body mass index and metabolic health status on obesity-related and rectal cancer among men and on endometrial cancer (P < .05). CONCLUSIONS: This study highlights that the type of metabolic obesity phenotype is important when assessing obesity-related cancer risk. In general, metabolic aberrations further increased the obesity-induced cancer risk, suggesting that obesity and metabolic aberrations are useful targets for prevention.

Smoking and Risk of Prostate Cancer and Prostate Cancer Death: A Pooled Study.

BACKGROUND: Prospective and detailed investigations of smoking and prostate cancer (PCa) risk and death are lacking. OBJECTIVE: To investigate prediagnosis smoking habit (status, intensity, duration, and cessation) as a risk factor, on its own and combined with body mass index (BMI), for PCa incidence and death. DESIGN, SETTING, AND PARTICIPANTS: We included 351448 men with smoking information from five Swedish cohorts. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used Cox regression to calculate hazard ratios (HRs) and confidence intervals (CIs) for PCa incidence (n = 24731) and death (n = 4322). RESULTS AND LIMITATIONS: Smoking was associated with a lower risk of any PCa (HR 0.89, 95% CI 0.86-0.92), which was most pronounced for low-risk PCa (HR 0.74, 95% CI 0.69-0.79) and was restricted to PCa cases diagnosed in the prostate-specific antigen (PSA) era. Smoking was associated with a higher risk of PCa death in the full cohort (HR 1.10, 95% CI 1.02-1.18) and in case-only analysis adjusted for clinical characteristics (HR 1.20, 95% CI 1.11-1.31), which was a consistent finding across case groups (p = 0.8 for heterogeneity). Associations by smoking intensity and, to lesser degree, smoking duration and cessation, supported the associations for smoking status. Smoking in combination with obesity (BMI ≥30 kg/m2) further decreased the risk of low-risk PCa incidence (HR 0.40, 95% CI 0.30-0.53 compared to never smokers with BMI <25 kg/m2) and further increased the risk of PCa death (HR 1.49, 95% CI 1.21-1.84). A limitation of the study is that only a subgroup of men had information on smoking habit around the time of their PCa diagnosis. CONCLUSIONS: The lower PCa risk for smokers in the PSA era, particularly for low-risk PCa, can probably be attributed to low uptake of PSA testing by smokers. Poor survival for smokers, particularly obese smokers, requires further study to clarify the underlying causes and the preventive potential of smoking intervention for PCa death. PATIENT SUMMARY: Smokers have a higher risk of dying from prostate cancer, which further increases with obesity.

Protein and amino acid intakes in relation to prostate cancer risk and mortality-A prospective study in the European Prospective Investigation into Cancer and Nutrition.

BACKGROUND: The association between protein intake and prostate cancer risk remains unclear. AIMS: To prospectively investigate the associations of dietary intakes of total protein, protein from different dietary sources, and amino acids with prostate cancer risk and mortality. METHODS: In 131,425 men from the European Prospective Investigation into Cancer and Nutrition, protein and amino acid intakes were estimated using validated dietary questionnaires. Multivariable-adjusted Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: During a mean follow-up of 14.2 years, 6939 men were diagnosed with prostate cancer and 914 died of the disease. Dairy protein was positively associated with overall prostate cancer risk in the three highest fifths compared to the lowest (HRQ3 =1.14 (95% CI 1.05-1.23); HRQ 4=1.09 (1.01-1.18); HRQ5 =1.10 (1.02-1.19)); similar results were observed for yogurt protein (HRQ3 =1.14 (1.05-1.24); HRQ4 =1.09 (1.01-1.18); HRQ5 =1.12 (1.04-1.21)). For egg protein intake and prostate cancer mortality, no association was observed by fifths, but there was suggestive evidence of a positive association in the analysis per standard deviation increment. There was no strong evidence of associations with different tumour subtypes. DISCUSSION: Considering the weak associations and many tests, the results must be interpreted with caution. CONCLUSION: This study does not provide strong evidence for an association of intakes of total protein, protein from different dietary sources or amino acids with prostate cancer risk or mortality. However, our results may suggest some weak positive associations, which need to be confirmed in large-scale, pooled analyses of prospective data.

Interaction between blood pressure and genetic risk score for bladder cancer, and risk of urothelial carcinoma in men.

There is substantial genetic predisposition to bladder cancer (BC). Recently, blood pressure (BP) was positively associated with BC risk in men, but the potential interaction with genetic susceptibility for BC is unknown. We investigated a weighted genetic risk score (wGRS) of 18 BC genetic variants, BP, and their interaction, in relation to incident urothelial cancer (UC, n = 385) risk in 10,576 men. We used Cox regression, the likelihood ratio test, and the relative excess risk for interaction to calculate hazard ratios (HR) of UC, multiplicative interaction and additive interaction respectively. There was evidence of a positive additive interaction between SBP and the wGRS in relation to aggressive (P = 0.02) but not non-aggressive (P = 0.60) UC. The HR of aggressive UC was for SBP ≥ 140 mmHg and the upper 50% of the wGRS combined 1.72 (95% CI 1.03-2.87) compared to the counterpart group. Additionally, the 20-year risk of aggressive UC in 60 year-old men was 0.78% in the low SBP/low wGRS group and 1.33% in the high SBP/high wGRS group. Our findings support a potential additive interaction between the wGRS and SBP on aggressive UC among men. If replicated, the findings on interaction may provide biological and public health insight to prevent aggressive UC.

Association of Blood Pressure with Prostate Cancer Risk by Disease Severity and Prostate Cancer Death: A Pooled Cohort Study.

BACKGROUND: The association of blood pressure (BP) with prostate cancer risk after accounting for asymptomatic prostate-specific antigen (PSA) testing, and with prostate cancer death, is unclear. METHODS: We investigated BP, measured at a mean age of 38 years among 430,472 men from five Swedish cohorts, in association with incident prostate cancer (n = 32,720) and prostate cancer death (n = 6718). HRs were calculated from multivariable Cox regression models. RESULTS: Increasing systolic and diastolic BP levels combined were associated with a slightly lower prostate cancer risk, with a HR of 0.98 (95% CI, 0.97-0.99) per standard deviation (SD) of mid-BP (average of systolic and diastolic BP). The association was restricted to the PSA era (1997 onwards, HR, 0.96; 95% CI, 0.95-0.98), to diagnoses initiated by a PSA test in asymptomatic men (HR, 0.95; 95% CI, 0.93-0.97), and to low-risk prostate cancer (HR, 0.95; 95% CI, 0.92-0.97). There was no clear association with more advanced disease at diagnosis. In cases, a slightly higher risk of prostate cancer death was observed for higher BP levels (HR, 1.05; 95% CI, 1.01-1.08) per SD of mid-BP; however, the association was restricted to distant metastatic disease (Pheterogeneity between case groups = 0.01), and there was no association for BP measured less than 10 years prior to diagnosis. CONCLUSIONS: Prediagnostic BP is unlikely an important risk factor for prostate cancer development and death. Less asymptomatic PSA testing among men with higher BP levels may explain their lower risk of prostate cancer. IMPACT: Elevated BP is unlikely to be an important risk factor for prostate cancer.

Interaction of leisure-time physical activity with body mass index on the risk of obesity-related cancers: A pooled study.

Physical activity (PA) has been associated with a lower risk of some obesity-related cancers, but the combined association and interaction of PA and body weight on obesity-related cancer risk is less clear. We examined the association of leisure-time PA (high/low) and its combination with body mass index (BMI, <25 [low]/≥25 [high] kg/m2 ) on obesity-related cancer risk in 570 021 individuals, aged 43 years on average at baseline, in five Scandinavian cohorts. We used Cox regression to calculate hazard ratios of obesity-related cancers (n = 19 074) and assessed multiplicative and additive interactions between PA and BMI on risk. High leisure-time PA, recorded in 19% of the individuals, was associated with a 7% (95% confidence interval [CI] 4%-10%) lower risk of any obesity-related cancer compared to low PA, with similar associations amongst individuals with a low and a high BMI (6% [1%-11%] and 7% [2%-11%]). High PA was also associated with decreased risks of renal cell (11% [9%-31%]) and colon cancer (9% [2%-16%]). When high PA and low BMI were combined, the relative risk reduction for all obesity-related cancers was 24% (95% CI 20%-28%); endometrial cancer, 47% (35%-57%); renal cell cancer, 39% (27%-51%); colon cancer, 27% (19%-35%); multiple myeloma, 23% (2%-40%) and pancreatic cancer, 21% (4%-35%), compared to low PA-high BMI. There were no additive or multiplicative interactions between PA and BMI on risk. The result of our study suggests a reduced risk of obesity-related cancer by leisure-time PA in both normal weight and overweight individuals, which further decreased for PA and normal weight combined.

The interaction between smoking and bladder cancer genetic variants on urothelial cancer risk by disease aggressiveness.

BACKGROUND: Smoking has shown interactions with bladder cancer (BC) genetic variants, especially N-acetyltransferase-2 (NAT2), a tobacco smoke metabolism gene, on BC risk. The interactions by disease aggressiveness are unknown. METHODS: We investigated the interaction between smoking and 18 single nucleotide polymorphisms (SNPs) for BC, individually and in a genetic risk score (GRS), on urothelial cancer (UC) risk including BC. We analysed data from 25,453 individuals with 520 incident UCs during follow-up, 339 non-aggressive (non-fatal, non-muscle invasive) and 163 aggressive (all other) UCs. Hazard ratios (HRs), absolute risks and additive and multiplicative interactions for two-by-two combinations of never/ever smoking with low/high genetic risk were calculated. RESULTS: Smoking and NAT2 rs1495741 interacted strongly, positively on aggressive UC on both the multiplicative (p = 0.004) and additive (p = 0.0002) scale, which was not observed for non-aggressive UC (pinteractions  ≥ 0.6). This manifested in a higher HR of aggressive UC by ever smoking for the slow acetylation NAT2 genotype (HR, 5.00 [95% confidence interval, 2.67-9.38]) than for intermediate/fast acetylation NAT2 (HR, 1.50 [0.83-2.71]), and in differences in absolute risks by smoking and NAT2 genotype. Smoking also interacted additively and positively with the GRS on any UC (p = 0.01) and non-aggressive UC (p = 0.02), but not on aggressive UC (p = 0.1). Gene-smoking interactions of lesser magnitude than for NAT2 were found for SNPs in APOBEC3A, SLC14A1 and MYNN. CONCLUSIONS: This study suggests that smoking increases UC risk more than expected when combined with certain genetic risks. Individuals with the slow acetylation NAT2 variant might particularly benefit from smoking intervention to prevent lethal UC; however, replication in larger studies is needed.

The relationship between blood pressure and risk of renal cell carcinoma.

BACKGROUND: The relation between blood pressure and kidney cancer risk is well established but complex and different study designs have reported discrepant findings on the relative importance of diastolic blood pressure (DBP) and systolic blood pressure (SBP). In this study, we sought to describe the temporal relation between diastolic and SBP with renal cell carcinoma (RCC) risk in detail. METHODS: Our study involved two prospective cohorts: the European Prospective Investigation into Cancer and Nutrition study and UK Biobank, including >700 000 participants and 1692 incident RCC cases. Risk analyses were conducted using flexible parametric survival models for DBP and SBP both separately as well as with mutuality adjustment and then adjustment for extended risk factors. We also carried out univariable and multivariable Mendelian randomization (MR) analyses (DBP: ninstruments = 251, SBP: ninstruments = 213) to complement the analyses of measured DBP and SBP. RESULTS: In the univariable analysis, we observed clear positive associations with RCC risk for both diastolic and SBP when measured ≥5 years before diagnosis and suggestive evidence for a stronger risk association in the year leading up to diagnosis. In mutually adjusted analysis, the long-term risk association of DBP remained, with a hazard ratio (HR) per standard deviation increment 10 years before diagnosis (HR10y) of 1.20 (95% CI: 1.10-1.30), whereas the association of SBP was attenuated (HR10y: 1.00, 95% CI: 0.91-1.10). In the complementary multivariable MR analysis, we observed an odds ratio for a 1-SD increment (ORsd) of 1.34 (95% CI: 1.08-1.67) for genetically predicted DBP and 0.70 (95% CI: 0.56-0.88) for genetically predicted SBP. CONCLUSION: The results of this observational and MR study are consistent with an important role of DBP in RCC aetiology. The relation between SBP and RCC risk was less clear but does not appear to be independent of DBP.

The Inverse Association of Body Mass Index with Lung Cancer: Exploring Residual Confounding, Metabolic Aberrations and Within-Person Variability in Smoking.

BACKGROUND: The inverse observational association between body mass index (BMI) and lung cancer risk remains unclear. We assessed whether the association is explained by metabolic aberrations, residual confounding, and within-person variability in smoking, and compared against other smoking-related cancers. METHODS: We investigated the association between BMI, and its combination with a metabolic score (MS) of mid-blood pressure, glucose, and triglycerides, with lung cancer and other smoking-related cancers in 778,828 individuals. We used Cox regression, adjusted and corrected for within-person variability in smoking (status/pack-years), calculated from 600,201 measurements in 221,958 participants. RESULTS: Over a median follow-up of 20 years, 20,242 smoking-related cancers (6,735 lung cancers) were recorded. Despite adjustment and correction for substantial within-person variability in smoking, BMI remained inversely associated with lung cancer [HR per standard deviation increase, 0.87 (95% confidence interval 0.85-0.89)]. Individuals with BMI less than 25 kg/m2 and high MS had the highest risk [HR 1.52 (1.44-1.60) vs. BMI ≥25 with low MS]. These associations were weaker and nonsignificant among nonsmokers. Similar associations were observed for head and neck cancers and esophageal squamous cell carcinoma, whereas for other smoking-related cancers, we generally observed positive associations with BMI. CONCLUSIONS: The increased lung cancer risk with low BMI and high MS is unlikely due to residual confounding and within-person variability in smoking. However, similar results for other cancers strongly related to smoking suggest a remaining, unknown, effect of smoking. IMPACT: Extensive smoking-adjustments may not capture all the effects of smoking on the relationship between obesity-related factors and risk of smoking-related cancers.

Fasting serum potassium and long-term mortality in healthy men.

BACKGROUND: Serum potassium levels have been positively associated with cardiovascular mortality, but little is known about the association with cancer mortality and death due to other causes. We examined whether serum levels of potassium were associated with long-term mortality in a healthy cohort. METHODS: Oslo Ischemia Study invited 2341 initially healthy men aged 40-59 years with no use of medication to a comprehensive health survey in 1972. Fasting serum level of potassium (mmol/L) was ascertained at baseline for 1989 men. We have complete follow-up for death throughout 2017. Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) and adjusted for multiple confounders. RESULTS: After a median follow-up of 30 years (interquartile range 21.2-38.7), 1736 deaths were observed, of which 494 were cancer deaths, 688 cardiovascular deaths, and 536 deaths related to other causes. Restricted cubic spline analysis showed that potassium level was linearly and positively associated with long-term cancer mortality; HR per mmol/L 1.8, 95% CI 1.4-2.4. Compared with low levels of potassium (≤ 4.0 mmol/L), men with high levels (≥4.6 mmol/L) showed a significantly 78% higher risk of cancer death. A positive linear association was found for all-cause mortality (HR per mmol/L 1.6, 95% CI 1.4-1.8), and for cardiovascular (HR per mmol/L 1.4, 95% CI 1.1-1.7) and other cause mortality (HR per mmol/L 1.7, 95% CI 1.3-2.2). CONCLUSIONS: These findings suggest that serum potassium level appears to predict long-term mortality in healthy middle-aged men, and it might imply future surveillance strategies for individuals with high serum potassium levels.