Association of body mass index and body fat distribution with risk of lung cancer in older women

Exploring the Impact of the Obesity Paradox on Lung Cancer and Other Malignancies

Simple Summary

Studies have shown that obesity is associated with many adverse health effects, including worse cancer outcomes. Many studies paradoxically suggest a survival benefit for obesity in treatment outcomes of cancers such as non-small-cell lung cancer. This relationship is not seen in animal models. We hypothesize that this relationship is secondary to suboptimal quantification of adiposity, enhanced immunotherapy response, and variables such as sex, medications, and smoking status. There are many ways to measure and classify adiposity, but the ability to distinguish abdominal obesity is likely key in predicting accurate prognosis. There are many ways obesity impacts cancer treatment course from diagnosis to survivorship. In this paper, we aim to analyze the factors contributing to the obesity paradox and its effect on lung cancer. This can aid the treatment and prognosis of lung cancer and may support further research into obesity-specific impacts on this malignancy.

Abstract

There is a paradoxical relationship between obesity, as measured by BMI, and many types of cancer, including non-small-cell lung cancer. Obese non-small-cell lung cancer patients have been shown to fare better than their non-obese counterparts. To analyze the multifaceted effects of obesity on oncologic outcomes, we reviewed the literature on the obesity paradox, methods to measure adiposity, the obesity-related derangements in immunology and metabolism, and the oncologic impact of confounding variables such as gender, smoking, and concomitant medications such as statins and metformin. We analyzed how these aspects may contribute to the obesity paradox and cancer outcomes with a focus on lung cancer. We concluded that the use of BMI to measure adiposity is limited and should be replaced by a method that can differentiate abdominal obesity. We also concluded that the concomitant metabolic and immunologic derangements caused by obesity contribute to the obesity paradox. Medications, gender, and smoking are additional variables that impact oncologic outcomes, and further research needs to be performed to solidify the mechanisms.

Carbonated beverage consumption is associated with lower C-peptide in adolescents

Background Too much consumption of carbonated beverages increases the risk of diabetes. Insulin deficiency and the body's decreased sensitivity to insulin cause diabetes. C-peptide can assess a person's own insulin secretion. The decrease of C-peptide is closely related to the occurrence of diabetes and its chronic complications. The present study assessed the effect of carbonated beverages on C-peptide in adolescents and analyzed the correlation between C-peptide and the drinking index (DI). Methods The subjects investigated including 463 adolescents were divided into a carbonated beverages group, a non-carbonated beverages group and a control group. The general demographic characteristics, beverage consumption status, physical activity and family history of hypertension and diabetes were interviewed with a questionnaire designed by us. All the subjects maintained their original lifestyle and received the oral glucose tolerance test. Various biochemical indicators and C-peptides were detected in these three groups. The data were analyzed by statistical analysis, and multivariate logistic regression analysis was used to examine the risk factors related to C-peptide. Results Blood glucose, blood lipid, liver function and renal function had no statistically significant difference among the three groups. C-peptide levels were lower in the carbonated beverages group and the non-carbonated beverages group than in the control group. Compared to the non-carbonated beverages group, there was a significant decrease in C-peptide levels in the carbonated beverages group. Logistic analysis demonstrated that DI was negatively correlated with C-peptide levels when the physical activity was adjusted. The odds ratio (OR) (OR = 2.540, 95% confidence interval [CI] 1.121-5.752) value difference was statistically significant at a stratification level of DI ≥ 6. Conclusions The C-peptide of adolescents was affected by the long-term consumption of beverages, and the effect of carbonated beverages was even more obvious. DI ≥ 6 bottle-years was a risk factor for diabetes, and we can constitute prevention and control measures accordingly so as to reduce the incidence of diabetes.

Height and lung cancer risk: A meta-analysis of observational studies

BACKGROUND

The association between height and lung cancer risk has been investigated by epidemiological studies but the results are inconsistent. This meta-analysis was to evaluate whether the height is associated with lung cancer.

METHODS

We identified relevant articles by searching the MEDLINE and EMBASE databases, and reviewed the reference lists of selected papers. A random effect model was used to calculate summary odds ratios (OR) and relative risk (RR) with 95% confidence intervals (95% CI). Publication bias was estimated using Egger's regression asymmetry test.

RESULTS

We included a total 16 studies (15 prospective studies and one case-control study) on adult height and lung cancer risk in the meta-analysis. Overall, per 10-cm height increases were associated with increased risk of lung cancer (RR 1.06; 95% CI 1.03-1.09, I2 = 43.6%).

CONCLUSIONS

In this meta-analysis, high adult height is related to increased lung cancer risk. Well-designed, large prospective studies are required to obtain a better indication of the relationship.

Abdominal Obesity and Lung Cancer Risk: Systematic Review and Meta-Analysis of Prospective Studies

Several meta-analyses of observational studies have been performed to examine the association between general obesity, as measured by body mass index (BMI), and lung cancer. These meta-analyses suggest an inverse relation between high BMI and this cancer. In contrast to general obesity, abdominal obesity appears to play a role in the development of lung cancer. However, the association between abdominal obesity (as measured by waist circumference (WC) (BMI adjusted) and waist to hip ratio (WHR)) and lung cancer is not fully understood due to sparse available evidence regarding this association. PubMed and Web of Science databases were searched for studies assessing the association between abdominal obesity and lung cancer up to October 2016. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. Six prospective cohort studies with 5827 lung cancer cases among 831,535 participants were included in our meta-analysis. Each 10 cm increase in WC and 0.1 unit increase in WHR were associated with 10% (RR 1.10; 95% CI 1.04, 1.17; I² = 27.7%, p-heterogeneity = 0.198) and 5% (RR 1.05; 95% CI 1.00, 1.11; I² = 25.2%, p-heterogeneity = 0.211) greater risks of lung cancer, respectively. According to smoking status, greater WHR was only positively associated with lung cancer among former smokers (RR 1.11; 95% CI 1.00, 1.23). In contrast, greater WC was associated with increased lung cancer risk among never smokers (RR 1.11; 95% CI 1.00, 1.23), former smokers (RR 1.12; 95% CI 1.03, 1.22) and current smokers (RR 1.16; 95% CI 1.08, 1.25). The summary RRs for highest versus lowest categories of WC and WHR were 1.32 (95% CI 1.13, 1.54; I² = 18.2%, p-heterogeneity = 0.281) and 1.10 (95% CI 1.00, 1.23; I² = 24.2%, p-heterogeneity = 0.211), respectively. In summary, abdominal obesity may play an important role in the development of lung cancer.

Association between Adult Height and Risk of Colorectal, Lung, and Prostate Cancer: Results from Meta-analyses of Prospective Studies and Mendelian Randomization Analyses

BACKGROUND

Observational studies examining associations between adult height and risk of colorectal, prostate, and lung cancers have generated mixed results. We conducted meta-analyses using data from prospective cohort studies and further carried out Mendelian randomization analyses, using height-associated genetic variants identified in a genome-wide association study (GWAS), to evaluate the association of adult height with these cancers.

METHODS AND FINDINGS

A systematic review of prospective studies was conducted using the PubMed, Embase, and Web of Science databases. Using meta-analyses, results obtained from 62 studies were summarized for the association of a 10-cm increase in height with cancer risk. Mendelian randomization analyses were conducted using summary statistics obtained for 423 genetic variants identified from a recent GWAS of adult height and from a cancer genetics consortium study of multiple cancers that included 47,800 cases and 81,353 controls. For a 10-cm increase in height, the summary relative risks derived from the meta-analyses of prospective studies were 1.12 (95% CI 1.10, 1.15), 1.07 (95% CI 1.05, 1.10), and 1.06 (95% CI 1.02, 1.11) for colorectal, prostate, and lung cancers, respectively. Mendelian randomization analyses showed increased risks of colorectal (odds ratio [OR] = 1.58, 95% CI 1.14, 2.18) and lung cancer (OR = 1.10, 95% CI 1.00, 1.22) associated with each 10-cm increase in genetically predicted height. No association was observed for prostate cancer (OR = 1.03, 95% CI 0.92, 1.15). Our meta-analysis was limited to published studies. The sample size for the Mendelian randomization analysis of colorectal cancer was relatively small, thus affecting the precision of the point estimate.

CONCLUSIONS

Our study provides evidence for a potential causal association of adult height with the risk of colorectal and lung cancers and suggests that certain genetic factors and biological pathways affecting adult height may also affect the risk of these cancers.

Cancer risk of petrochemical workers exposed to airborne PAHs in industrial Lanzhou City, China

This paper reports the connections between red blood cells abnormality risk of petrochemical workers and their exposure to airborne polycyclic aromatic hydrocarbons (PAHs). Urinary 1-hydroxypyrene (1-OHP), as the biomarker of PAHs exposure, was adopted to assess the exposure risk of the petrochemical workers to PAHs in Xigu, the west suburb of Lanzhou where petrochemical industries are located. Fifty-three workers, sub-grouped to 36 petrochemical workers and 17 office workers, participated in this investigation. Logistic regression model and spearman correlation analysis were performed to estimate the associations between PAHs exposure levels and red blood cells abnormality risk of petrochemical workers. Strong associations between some red cell indices (MCH, MCHC, RDW) and 1-OHP concentration were found. Results also show that the red blood cells abnormality risk increased with increasing PAHs exposure level. Compared with office workers, risk level of red blood cells abnormality in petrochemical workers was higher by 41.7 % (OR, 1.417; 95 % CI: 0.368-5.456) than that in office workers. This result was verified by the tissue-to-human blood partition coefficient for pyrene and 1-OHP. The quantitative assessments of the potential health risk through inhalation exposure to PAHs were conducted using the Incremental Lifetime Cancer Risk (ILCR) model. It was found the ILCR from inhalation exposure to PAHs for the petrochemical workers ranged from 10(-5) to 10(-4) with 95 % probability, indicating that petrochemical plant workers were under a high potential cancer risk level.

Association of body mass index with chromosome damage levels and lung cancer risk among males

Epidemiological studies have shown an etiological link between body mass index (BMI) and cancer risk, but evidence supporting these observations is limited. This study aimed to investigate potential associations of BMI with chromosome damage levels and lung cancer risk. First, we recruited 1333 male workers from a coke-oven plant to examine their chromosome damage levels; and then, a cohort study of 12 052 males was used to investigate the association of BMI with lung cancer incidence. We further carried out a meta-analysis for BMI and male lung cancer risk based on cohort studies. We found that men workers with excess body weight (BMI ≥ 25 kg/m²) had lower levels of MN frequencies than men with normal-weight (BMI: 18.5–24.9). Our cohort study indicated that, the relative risk (RR) for men with BMI ≥ 25 to develop lung cancer was 35% lower than RR for normal-weight men. Further meta-analysis showed that, compared to normal-weight men, men with BMI ≥ 25 had decreased risk of lung cancer among both the East-Asians and others populations. These results indicate that men with excess body weight had significant decreased chromosome damage levels and lower risk of lung cancer than those with normal-weight. However, further biological researches were needed to validate these associations.

Hormones of adipose tissue and their biologic role in lung cancer

INTRODUCTION

Adipose tissue secretes numerous bioactive peptides, collectively termed "adipocytokines" or "adipokines". Adipokines act in a paracrine, autocrine, or endocrine manner and regulate several physiological and pathological processes. Increasing evidence indicates that adipokines are implicated also in several malignancies, including lung cancer as well.

AIM

The aim of this study is to summarize data concerning adipokines in lung cancer pathogenesis, prognosis and survival; the role of adipokines in lung cancer cachexia is also examined.

MATERIALS AND METHODS

A systematic literature search was performed in the electronic database of Medline. Several studies and review articles met the inclusion criteria.

RESULTS

Leptin and adiponectin are the best studied adipokines. The majority of the relevant studies has investigated the potential correlations mainly between leptin, adiponectin, and sometimes also resistin, and nutritional status, systemic inflammation of lung cancer or lung cancer cachexia and have also assessed their prognostic significance. Few other studies have studied genetic variations in leptin, leptin receptor and adiponectin genes and their association with lung cancer susceptibility and prognosis. The ongoing list of adipokines associated with lung cancer also includes resistin, chemerin, and visfatin.

CONCLUSIONS

Increasing evidence points to the involvement of certain adipocytokines in lung cancer development, progression and prognosis. No conclusive evidence exists so far with regards to the role of adipocytokines in lung cancer cachexia. Future, longitudinal studies are warranted in order to clarify the role of adipocytokines in lung cancer and also uncover adipocytokines as novel therapeutic targets.

Obesity in relation to lung cancer incidence in African American women

PURPOSE

Although a number of studies have found an inverse association between body mass index (BMI) and risk of lung cancer, there is little information on this relation in African Americans, who experience a higher incidence of lung cancer.

METHODS

We assessed the relation of BMI to incidence of lung cancer in the Black Women's Health Study, an ongoing prospective follow-up of 59,000 women in the USA. Cox proportional hazard models were used to estimate hazard ratios for various levels of BMI relative to BMI 18.5-24.9 kg/m2 ("normal weight") with adjustment for age, education, pack-years of smoking, and other covariates. Two other anthropometric measures, waist circumference (WC) and waist/hip ratio (WHR), were also assessed. A total of 323 primary lung cancer cases were identified from 1995 to 2011.

RESULTS

The hazard ratio (HR) for BMI ≥ 30 relative to BMI 18.5-24.9 was 0.69 (95% CI 0.51-0.92). As expected, cigarette smoking was strongly associated with increased risk of lung cancer. In analyses stratified by smoking status, the HR for BMI ≥ 30 relative to BMI 18.5-24.9 was 0.62 (0.38-1.00) among current smokers, 0.90 (0.56-1.42) among former smokers, and 0.83 (0.41-1.70) among never smokers (p for interaction = 0.28). Control for pack-years of smoking or age started smoking had little effect on the hazard ratios. WC and WHR were not materially associated with lung cancer risk.

CONCLUSION

Our results indicate that high BMI is associated with a lower risk of lung cancer in African American women, particularly among current smokers.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Body mass index and lung cancer risk: results from the ICARE study, a large, population-based case-control study

BACKGROUND

The association between body mass index (BMI) and lung cancer is still disputed because of possible residual confounding by smoking and preclinical weight loss in case-control studies. We examined this association using data from the multicenter ICARE study in France, a large, population-based case-control study.

METHODS

A total of 2,625 incident lung cancer cases and 3,381 controls were included. Weight was collected at interview, 2 years before the interview, and at age 30. Lifetime smoking exposure was calculated using the comprehensive smoking index (CSI). Adjusted odds ratios (aORs) and 95 % confidence intervals were estimated by unconditional logistic regression and controlled for age, area, education, CSI, occupational exposure, previous chronic bronchitis, and parental history of lung cancer. We also examined the role of weight change. Analyses were stratified by smoking status and sex.

RESULTS

When compared with that of men with normal BMI 2 years before the interview, lung cancer aORs (95 % CI) among men with BMIs of <18.5, 25-29.9, 30-32.4, and ≥32.5 kg/m(2) were 2.7 (95 % CI 1.2-6.2), 0.9 (95 % CI 0.7-1.1), 0.8 (95 % CI 0.6-1.1), and 0.8 (95 % CI 0.6-1.0), respectively (p(trend) = 0.02). Results were more pronounced among current smokers and were similar in men and women. Weight gain over time was associated with a significant decreased risk of lung cancer.

CONCLUSIONS

We found an inverse dose-dependent association between lung cancer risk and BMI 2 years prior to interview in current smokers. IMPACT STATEMENT: BMI might be an individual factor impacting the risk of lung cancer related to smoking's carcinogen-induced DNA damage.

Effects of supplemental vitamin D and calcium on biomarkers of inflammation in colorectal adenoma patients: a randomized, controlled clinical trial

Vitamin D and calcium affect several pathways involved in inflammation, tumor growth, and immune surveillance relevant to carcinogenesis. Also, epidemiologic evidence indicates that calcium and vitamin D may reduce risk for developing colorectal adenomas and cancer. To investigate the effects of calcium and vitamin D on biomarkers of inflammation in colorectal adenoma patients, we conducted a pilot, randomized, double-blind, placebo-controlled, 2 × 2 factorial clinical trial (n = 92) of 2 g/d calcium and/or 800 IU/d vitamin D(3) supplementation versus placebo over 6 months. Plasma concentrations of proinflammatory markers [C-reactive protein (CRP), TNF-α, interleukin (IL)-6, IL-1β, and IL-8] and an anti-inflammatory marker (IL-10) were measured using ELISAs. After 6 months of treatment, in the vitamin D(3) supplementation group, CRP decreased 32% overall (P = 0.11), 37% in men (P = 0.05), and 41% among non-nonsteroidal anti-inflammatory drug (NSAID) users (P = 0.05) relative to placebo. In the vitamin D(3) supplementation group, TNF-α decreased 13%, IL-6 32%, IL-1β 50%, and IL-8 15%; in the calcium supplementation group, IL-6 decreased 37%, IL-8 11%, and IL-1β 27%. Although these changes were not statistically significant, a combined inflammatory markers z-score decreased 77% (P = 0.003) in the vitamin D(3) treatment group overall, 83% (P = 0.01) among men, and 48% among non-NSAID users (P = 0.01). There was no evidence of synergy between vitamin D(3) and calcium or effects on IL-10. These preliminary results are consistent with a pattern of reduction in tumor-promoting inflammation biomarkers with vitamin D(3) or calcium supplementation alone and support further investigation of vitamin D(3) as a chemopreventive agent against inflammation and colorectal neoplasms.

Lifestyle as risk factor for cancer: Evidence from human studies

It is increasingly appreciated that the chances of developing cancer are significantly affected by the choice of our lifestyle. There are several uncontrollable risk factors which account for the majority of cancers, but we can modify our lifestyle to reduce enhanced threat of cancer. Healthy lifestyle behaviors for cancer risk reduction include a healthy diet, weight management, regular exercise, reduction in alcohol consumption and smoking cessation. In this article, we present evidences on the association between certain lifestyle characteristics and their contribution for developing breast, prostate, lung and colon cancers, using information derived from human studies.

Height and site-specific cancer risk: A cohort study of a korean adult population

To evaluate the association between height and risk of cancer in an East Asian, middle-income population, the authors followed up a cohort of 788,789 Koreans (449,214 men and 339,575 women) aged 40-64 years for cancer incidence between 1994 and 2003. Cox proportional hazards regression analysis was used to evaluate the association. Each 5-cm increment in height was associated with 5% and 7% higher risk of all-sites cancer in men and women, respectively, after adjustment for age, body mass index, and behavioral and socioeconomic factors. When the associations were evaluated for site-specific cancers, a positive association was observed for cancer of the colon and thyroid in both men and women. Among gender-specific cancers, prostate cancer was positively associated with height in men. In women, there was a positive association between height and cancers of the breast and ovary, which did not change even after additional adjustment for reproductive factors. Although more clarification is needed for some site-specific cancers, the same positive association of height with cancer in a middle-income Korean population as found in high-income Western populations supports the influence of early life environment on cancer development in adulthood.

Body mass index and waist circumference in relation to lung cancer risk in the Women's Health Initiative

Investigators in several epidemiologic studies have observed an inverse association between body mass index (BMI) and lung cancer risk, while others have not. The authors used data from the Women's Health Initiative to study the association of anthropometric factors with lung cancer risk. Over 8 years of follow-up (1998-2006), 1,365 incident lung cancer cases were ascertained among 161,809 women. Cox proportional hazards models were used to estimate hazard ratios adjusted for covariates. Baseline BMI was inversely associated with lung cancer in current smokers (highest quintile vs. lowest: hazard ratio (HR) = 0.62, 95% confidence interval (CI): 0.42, 0.92). When BMI and waist circumference were mutually adjusted, BMI was inversely associated with lung cancer risk in both current smokers and former smokers (HR = 0.40 (95% CI: 0.22, 0.72) and HR = 0.61 (95% CI: 0.40, 0.94), respectively), and waist circumference was positively associated with risk (HR = 1.56 (95% CI: 0.91, 2.69) and HR = 1.50 (95% CI: 0.98, 2.31), respectively). In never smokers, height showed a borderline positive association with lung cancer. These findings suggest that in smokers, BMI is inversely associated with lung cancer risk and that waist circumference is positively associated with risk.

Body Mass Index and Lung Cancer Risk in Women

BACKGROUND

Studies have suggested that leanness in adulthood may be a risk factor for lung cancer; however, there is justifiable concern that the observed association may be due to residual confounding by smoking, preclinical weight loss, competing causes of death, or some combination of these.

METHODS

To examine this association we used data from the Canadian National Breast Screening Study, which included 89,835 women ages 40-59 years at recruitment between 1980 and 1985. During a mean of 16 years of follow-up, we observed 750 incident lung cancer cases. We used Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals for the association between body mass index (BMI) and lung cancer.

RESULTS

After adjustment for pack-years of smoking and other covariates, there was some evidence for inverse associations in current smokers (hazard ratio for highest BMI quintile relative to the lowest = 0.63; 95% confidence interval = 0.48-0.83) and in former smokers (0.69; 0.39-1.23), whereas in never-smokers, BMI was positively associated with lung cancer (2.19; 1.00-4.80). The results for current and former smokers were not altered by exclusion of cases diagnosed within the first 5 years of follow-up; however, in never-smokers the strength of the association was reduced.

CONCLUSIONS

The present study contributes to the aggregate evidence suggesting that there may be an inverse association between BMI and lung cancer among smokers. However, the contrasting pattern of associations between BMI and lung cancer seen in ever-smokers and never-smokers in this study requires explanation.

Never smokers and lung cancer risk: a case-control study of epidemiological factors

We performed an analysis of potential epidemiological risk factors for lung cancer using data from 280 cases and 242 hospital-based controls, all lifetime never smokers (those who had smoked <100 cigarettes in their lifetimes) and frequency matched on age, gender and ethnicity. The data on demographic characteristics, medical history of respiratory diseases (asthma, emphysema, pneumonia and hay fever), weight and height, family history, female characteristics and environmental tobacco smoke (ETS) and dust exposure were derived from personal interviews. We performed a logistic regression analysis of these variables adjusting for age, gender, ethnicity, income and years of education. Exposure to ETS (OR = 2.08, 95% CI [1.25-3.43]) and dusts (OR = 2.43, 95% CI [1.53-3.88]) were associated with significantly increased risk. In the analysis for joint effects, exposure to both ETS and dusts conferred a higher risk (OR = 3.25, 95% CI [1.58-6.70]) than exposure to either alone. Family history of any cancer with onset before age 50 in at least 1 first degree relative was a significant risk predictor (OR = 1.70, 95% CI [1.10-2.64]). Individuals with a self-reported physician-diagnosed history of hay fever, but not asthma, had a decreased lung cancer risk (OR = 0.57, 95% CI [0.35-0.92]). In the multivariate analysis, exposure to ETS and dusts, and family history of cancer with onset before age 50 were significant risk factors, while a history of hay fever (occurring without asthma) was significantly protective.

Adult height in relation to mortality from 14 cancer sites in men in London (UK): evidence from the original Whitehall study

BACKGROUND

Adult height has been related to organ-specific malignancies in relatively few studies. Findings are discrepant for some sites and several studies are subject to a series of methodological limitations.

MATERIALS AND METHODS

We examined the association of adult height with death attributed to 14 cancer sites using data from the original Whitehall cohort. This is a prospective study of 18,403 middle-aged, non-industrial, London-based, male government employees who were examined in the late 1960s and then followed up for mortality for a maximum of 35 years.

RESULTS

There were 11,099 deaths during follow-up, 3101 (28%) of which were ascribed to cancer. Cox proportional hazards regression models revealed modest effects for height in relation to site-specific cancers. Following adjustment for covariates that included employment grade (an indicator of socioeconomic position), body mass index and smoking habit, increased height was associated with elevated mortality rates for cancer of combined sites [hazards ratio per 5 cm increase in height (95% confidence interval); P for trend across height categories: 1.05 (1.03, 1.08); P < 0.001], lung [1.13 (1.06, 1.20); P < 0.001], prostate [1.07 (0.99, 1.15); P = 0.08], kidney [1.20 (0.99, 1.46); P = 0.08], skin [1.35 (1.06, 1.70); P = 0.02] and leukaemia [1.11 (0.96, 1.28); P = 0.02].

CONCLUSIONS

Amongst other explanations, the weak positive height-cancer gradients apparent herein may be ascribed to early life exposures that correlate with adult height, such as high caloric intake.

Body Mass Index and Lung Cancer

STUDY OBJECTIVES

An inverse relationship between body mass index (BMI) and the risk of lung cancer, suggesting that leanness is a risk factor for lung cancer, has been reported in previous studies. In order to evaluate the risk of lung cancer associated with lower levels of BMI in preclinical patients, we conducted a case-control study based on the results of community mass screening.

DESIGN

The relationship between BMI (at the time of diagnosis, and at 1 to 5 years prior to diagnosis) and lung cancer was investigated in a case-control study of 363 lung cancer cases and 1,089 control subjects conducted between April 1993 and March 2003. Control subjects were selected from mass-screening subjects with no abnormalities on chest radiography and routine laboratory tests.

RESULTS

In men, an inverse association between BMI and lung cancer was observed after adjustment for age and smoking (BMI < 20.8; range of the referent group, > or = 22.9 to < 25.0; odds ratio, 1.9; p = 0.0025; 95% confidence interval, 1.3 to 2.9). In women, however, no association was found between BMI and lung cancer (BMI < 20.8, p = 0.3868; and BMI </= 25.0, p = 0.4603, respectively). In addition, a negative association between BMI at 4 to 5 years prior to diagnosis and lung cancer was not observed in either gender (men, p = 0.2937 to 0.5783; women, p = 0.2042 to 0.9326).

CONCLUSIONS

Our present study indicated the possibility that the previously reported association between leanness and the risk of lung cancer in women was not correct, and this apparent association might be influenced by other factors such as smoking and smoking-related respiratory diseases. A larger-scale cohort study combined with mass-screening project will confirm our results.

Effects of excess weight on cancer incidences depending on cancer sites and histologic findings among men: Korea National Health Insurance Corporation Study

PURPOSE

The effects of excess weight on the development of cancers are controversial, and little is known for populations outside the United States and Europe. We conducted this study to assess the effects of excess weight with a large cohort of Koreans.

METHODS

We assessed the relationship between body mass index (BMI) and various cancers in a 10-year follow-up cohort of 781,283 Korean men who were free of prior cancer at baseline. Weight and height were measured, and questionnaires related to health behaviors and medical history were completed. Data on newly developed cancers were obtained from two organizations in Korea. A proportional hazards model was used to examine the relationship between BMI and cancer.

RESULTS

Adenocarcinoma in the colon and rectosigmoid, hepatocellular carcinoma, cholangiocarcinoma, adenocarcinoma in the prostate, renal cell carcinoma, papillary carcinoma in the thyroid, small-cell carcinoma in the lung, non-Hodgkin's lymphoma, and melanoma had positive dose-dependent relationships with BMI (all P < .05). Although no linear trend was found (P = .267), obese men who never smoked with a BMI of >or= 30 kg/m(2) had an increased risk of developing gastric adenocarcinoma (relative risk = 1.73). Other cancers, such as leukemia, multiple myeloma, and gallbladder and pancreatic cancer, did not show significant associations.

CONCLUSION

These findings show that, even in Koreans, obesity clearly increases the risk of many types of cancers and the strength of the associations varies with the organ and histologic type. Because these obesity-related cancers are reported to be rapidly increasing in Korea and many other Asian countries, controlling obesity epidemics could be an effective tool for preventing these cancers in these areas.

Childhood body mass index and later cancer risk: A 50-year follow-up of the Boyd Orr study

Associations between childhood BMI and adult cancer risk were investigated in a historical cohort study based on the Carnegie ("Boyd Orr") Survey of Diet and Health in Pre-War Britain (1937-9). In 14 centres in England and Scotland, children had their height and weight measured. We included 2,347 individuals aged between 2 and 14 years 9 months at the time of measurement, who were traced through the National Health Service Central Register. Relative cancer risk (registration or death) was estimated in relation to age- and sex-specific BMI SD scores. We studied associations with (i) all cancers, (ii) cancer groups stratified according to their relationship to smoking and (iii) certain site-specific cancers. In the 50 years of follow-up, 188 men and 192 women developed cancer. There was a 9% increase (95% CI -3 to 22%) in risk of cancer in adulthood per SD increase in BMI measured in childhood. There was no evidence of confounding by childhood or adulthood socioeconomic position, other anthropometric variables, childhood energy intake or birth order. There was a 30% increase (95% CI 10-54%) in risk of smoking-related cancers per SD increase in childhood BMI. There was no relationship between BMI and cancers not related to smoking. Associations for all cancers and non-smoking-related cancers tended to be stronger in children who were measured at an older (>8 years) rather than a younger (< or =8 years) age. We conclude that childhood BMI is related to increased risk of cancer in later life, particularly smoking-related cancers.

Bladder cancer prevention. Part I: what do I tell my patients about lifestyle changes and dietary supplements?

PURPOSE OF REVIEW

Comprehensive reviews of lifestyle changes and dietary supplements that may prevent bladder cancer are needed in order to facilitate discussions between clinicians and patients.

RECENT FINDINGS

Novel data exist that numerous lifestyle/diet and dietary supplements may lower the risk of this disease. For example, reducing arsenic exposure, incorporating dietary changes, and vitamin E supplements continue to accumulate research that supports their use with some patients at a higher risk for this disease. Regardless, smoking cessation seems to have the largest impact on reducing risk and incorporating these other changes after smoking cessation may reduce an individual's risk to an even greater extent.

SUMMARY

However, a large percentage of cases of individuals diagnosed with this cancer apparently have no known etiology. Diets lower in calories or possibly specific sub-types of fat, and higher in fruits and especially vegetables, seem to provide some protection. Other dietary/supplement options may affect risk, but these benefits could be seriously attenuated by smoking. Dietary selenium, but currently not selenium supplements, may also affect risk, especially in non-smokers. Dietary vitamin E, and vitamin E supplements, may provide some protection. Non-selective (e.g. non-steroidal anti-inflammatory drugs) and selective cyclooxygenase-2 inhibitors are generating interest because bladder tumors seem to contain higher concentrations of this enzyme. Drinking-water quality, especially arsenic concentrations, may seriously affect risk. Providing recommendations for patients with regard to some of these lifestyle modifications is currently recommended because the majority of these alterations are also recommended currently for cardiovascular or general oncology disease reduction.

Height, Leg Length, and Cancer: The Caerphilly Study

The incidence of several cancers increases with height. Some studies report that leg length, a marker of prepubertal growth, is the component of height underlying these associations, but few prospective studies have investigated this issue. We examined height-cancer associations in a 21-yr follow-up of a cohort based on 2,512 men aged 45-59 living in the town of Caerphilly, South Wales, U.K., between 1979 and 1983. The men underwent a detailed examination, and 2,393 (95.3%) had measures of height and sitting height (from which leg length and trunk length were derived) recorded and were cancer-free at baseline. Cox proportional hazards models were used to investigate associations of height, leg length, and trunk length with overall and site-specific cancer incidence; 328 men developed cancer over the follow-up period. Associations with height were weak and did not reach conventional levels of statistical significance. In models controlling for age, socioeconomic position, smoking, and body mass index, cancer incidence was weakly positively associated with increases in height; hazard ratio (HR, 95% confidence interval) per standard deviation (6 cm) increase in height was 1.09 (0.97, 1.21; P = 0.14). Associations were somewhat stronger in relation to leg length (HR 1.09; (0.97-1.22) than trunk length (HR 1.05; 0.94-1.18). Height-cancer associations were strongest for lung cancer (HR 1.21; 0.96-1.51). This analysis provides limited support for the suggestion that leg length is the component of height underlying height-cancer associations

Lung cancer risk reduction after smoking cessation: observations from a prospective cohort of women

PURPOSE

We conducted this study because the duration of excess lung cancer risk among former smokers has been inconsistently reported, doubt has been raised regarding the population impact of smoking cessation, and differential risk reduction by histologic cell type after smoking cessation needs to be confirmed.

METHODS

The Iowa Women's Health Study is a prospective cohort study of 41,836 Iowa women aged 55 to 69 years. In 1986, mailed questionnaires were used to collect detailed smoking history. Age-adjusted lung cancer incidence through 1999 was analyzed according to years of smoking abstinence. Relative risks were estimated using Cox regression analysis.

RESULTS

There were 37,078 women in the analytic cohort. Compared with the never smokers, former smokers had an elevated lung cancer risk (relative risk, 6.6; 95% confidence interval, 5.0 to 8.7) up to 30 years after smoking cessation for all former smokers. However, a beneficial effect of smoking cessation was observed among recent and distant former smokers. The risk of adenocarcinoma remained elevated up to 30 years for both former heavier and former lighter smokers.

CONCLUSION

The risk for lung cancer is increased for both current and former smokers compared with never smokers and declines for former smokers with increasing duration of abstinence. The decline in excess lung cancer risk among former smokers is prolonged compared with other studies, especially for adenocarcinoma and for heavy smokers, suggesting that more emphasis should be placed on smoking prevention and lung cancer chemoprevention.

Leanness and lung cancer risk: fact or artifact?

BACKGROUND

More than a dozen studies have examined the association between leanness and increased lung cancer risk. None of the prospective studies has been large enough to allow exclusion of smokers or persons with preexisting disease, two factors that cause both leanness and poor survival and thus may cause a spurious association between low body mass index and fatal lung cancer.

METHODS

Using Cox proportional hazards models, we examined this issue in a cohort of 941,105 U.S. adults enrolled in an American Cancer Society prospective study in 1982. During 14 years of follow-up, 14,066 people died of lung cancer.

RESULTS

In analyses restricted to lifelong nonsmokers who did not report preexisting disease, leanness was not substantially associated with lung cancer mortality in men (rate ratio = 0.9; 95% confidence interval = 0.3-3.1) or in women (rate ratio = 1.2; 95% confidence interval = 0.7-2.1). However, leanness was associated with increased lung cancer risk in analyses that attempted to control for, rather than exclude, smokers and persons with preexisting disease.

CONCLUSIONS

These data suggest that the association between leanness and lung cancer mortality is not causal but rather is an artifact of the effects of smoking and preexisting disease.

Potential lifestyle and dietary supplement options for the prevention and postdiagnosis of bladder cancer

Apart from smoking, certain occupational exposures, and schistosomiasis, little is known about other potential lifestyle risk factors for bladder cancer. Other investigations thus far have also been important because of the large number of individuals who are diagnosed with this cancer that apparently have no known risk factors. Preventing the recurrence of bladder cancer has generated some interest because several preliminary trials have found that a combination dietary supplement of vitamins and minerals or a probiotic agent (Lactobacillus casei) may impact this outcome favorably. Advising patients on some of these lifestyle modifications is currently recommended because the majority of them are also currently recommended for cardiovascular disease reduction.

A case-control study of lung cancer among Czech women

Few data are available to explain the continuing increase in lung cancer mortality among Czech women. The study was designed to examine the role of active smoking and other known or suspected factors. Data collected by personal interviews during the 15 months of a hospital-based case control study are reported. A total of 140 microscopically confirmed cases and 280 frequency-matched controls were analysed using multiple logistic regression. Cigarette smoking was the most important factor associated with excess risk for lung cancer among women. Significantly increased risk was found both among current smokers (OR=11.20, 95% CI 5.9-21.2), and ex-smokers (OR=10.02, 95% CI 5.5-18.4). Positive dose-response gradients (P<0.001) were observed between lung cancer risk and the daily number of cigarettes, duration of smoking, number of pack-years, inhaling, and grade of nicotine dependence assessed by the Fagerström test (Heatherton TF, Kozlowski LT, Frecker RC, Fagerström KO. Br J Addict 1991;86:1119-1470; Pomerleau OF. In: Bolliger CT, Fagerström KO, editors. The Tobacco Epidemic. Basle: Karger, 1997: 122-131). Exposure to environmental smoke was associated with elevated lung cancer risk (OR=3.58, for lifetime non-smokers exposed both in childhood and in adult age). Physical exercise and body mass index were inversely associated with lung cancer risk. For the category of physical exercise of more than 5 h per week, the odds ratio was 0.38, compared to subjects admitting no physical exercise. For body mass index, the odds ratio for the highest (compared to the lowest) quartile was 0.50. Chronic cough and phlegm (at least 3 months per year) were associated with excess risk (OR=6.07) only if their duration was less than 2 years before diagnosis of lung cancer, and, therefore, they were suspected of being more likely early symptoms of preclinical lung cancer rather than its cause. Our results support the statement that cigarette smoking is by far the most important cause of the on-going epidemic of lung cancer among Czech women, and are consistent with the concept of a balance between risk and protective factors whose eventual maintenance or alteration determine the development of disease (as suggested by Rylander R, Axelsson G, Andersson L, Liljequist T, Bergman B. Lung Cancer 1996;14(Suppl 1): S75-S83). Concerted control of smoking appears to be an urgent priority in lung cancer prevention among women, including specific approaches targeted on the female population.

A prospective study of insulin-like growth factor-I, IGF-binding proteins-1, -2 and -3 and lung cancer risk in women

Insulin-like growth factor-I (IGF-I) has mitogenic and anti-apoptotic properties and has been implicated in the development of breast, colorectum, prostate and lung cancer. IGF binding proteins (IGFBPs) are not only carrier proteins for IGFs but also hold a central position in IGF ligand-receptor interactions through influences on the bioavailability and distribution of IGFs in the extracellular environment. A case-control study nested within the New York University Women's Health Study Cohort included 93 women diagnosed with lung cancer at least 6 months after recruitment into the study. Two controls (n = 186) were matched to each case on age, date of blood sampling, menopausal status, day of menstrual cycle and questionnaire data of smoking status at the time of blood donation. Serum IGF-I, IGFBP-1, -2 and -3, insulin and cotinine were measured. Mean serum levels of IGF-I, IGFBP-1, -2 and -3 were not significantly different between the case and control groups. Univariate logistic regression analyses showed no association of lung cancer risk with serum levels of IGF-I or any of the IGFBPs. These results remained virtually the same in multivariate analyses, including adjustment for cotinine, time since last meal, BMI, IGF-I or IGFBP-3, respectively. Exclusion of cases diagnosed within 3 years of recruitment in the cohort, or restriction of the analyses to adenocarcinomas only, did not alter these results. Our study does not offer evidence in support of an association between prediagnostic serum levels of IGF-I or IGFBP-1, -2 and -3 and lung cancer risk in women.