Effects of dietary interventions on DNA methylation in adult humans: systematic review and meta-analysis

Protective Effects of Micronutrient Supplements, Phytochemicals and Phytochemical-Rich Beverages and Foods Against DNA Damage in Humans: A Systematic Review of Randomized Controlled Trials and Prospective Studies

Accumulation of deoxyribonucleic acid (DNA) damage diminishes cellular health, increases risk of developmental and degenerative diseases, and accelerates aging. Optimizing nutrient intake can minimize accrual of DNA damage. The objectives of this review are to: 1) assemble and systematically analyze high-level evidence for the effect of supplementation with micronutrients and phytochemicals on baseline levels of DNA damage in humans, and 2) use this knowledge to identify which of these essential micronutrients or nonessential phytochemicals promote DNA integrity in vivo in humans. We conducted systematic literature searches of the PubMed database to identify interventional, prospective, cross-sectional, or in vitro studies that explored the association between nutrients and established biomarkers of DNA damage associated with developmental and degenerative disease risk. Biomarkers included lymphocyte chromosome aberrations, lymphocyte and buccal cell micronuclei, DNA methylation, lymphocyte/leukocyte DNA strand breaks, DNA oxidation, telomere length, telomerase activity, and mitochondrial DNA mutations. Only randomized, controlled interventions and uncontrolled longitudinal intervention studies conducted in humans were selected for evaluation and data extraction. These studies were ranked for the quality of their study design. In all, 96 of the 124 articles identified reported studies that achieved a quality assessment score ≥ 5 (from a maximum score of 7) and were included in the final review. Based on these studies, nutrients associated with protective effects included vitamin A and its precursor β-carotene, vitamins C, E, B1, B12, folate, minerals selenium and zinc, and phytochemicals such as curcumin (with piperine), lycopene, and proanthocyanidins. These findings highlight the importance of nutrients involved in (i) DNA metabolism and repair (folate, vitamin B12, and zinc) and (ii) prevention of oxidative stress and inflammation (vitamins A, C, E, lycopene, curcumin, proanthocyanidins, selenium, and zinc). Supplementation with certain micronutrients and their combinations may reduce DNA damage and promote cellular health by improving the maintenance of genome integrity.

Translation of nutrigenomic research for personalised and precision nutrition for cancer prevention and for cancer survivors

Personalised and precision nutrition uses information on individual characteristics and responses to nutrients, foods and dietary patterns to develop targeted nutritional advice that is more effective in improving the diet and health of each individual. Moving away from the conventional 'one size fits all', such targeted intervention approaches may pave the way to better population health, including lower burden of non-communicable diseases. To date, most personalised and precision nutrition approaches have been focussed on tackling obesity and cardiometabolic diseases with limited efforts directed to cancer prevention and for cancer survivors. Advances in understanding the biological basis of cancer and of the role played by diet in cancer prevention and in survival after cancer diagnosis, mean that it is timely to test and to apply such personalised and precision nutrition approaches in the cancer area. This endeavour can take advantage of the enhanced understanding of interactions between dietary factors, individual genotype and the gut microbiome that impact on risk of, and survival after, cancer diagnosis. Translation of these basic research into public health action should include real-time acquisition of nutrigenomic and related data and use of AI-based data integration methods in systems approaches that can be scaled up using mobile devices.

Adipose cell-free DNA in diabetes

Cancer-associated necrosis is a well-known source of cell-free DNA (cfDNA). However, the origins of cfDNA are not strictly limited to cancer. Additionally, dietary exposure induces apoptosis-induced proliferation in adipocytes, leading to the release of cfDNA. The genetic information derived from cfDNA as a result of apoptosis-induced proliferation contains specific methylation patterns in adipose tissue that can be used as a marker to detect the risk of developing Type 2 diabetes Mellitus (T2DM) in the future. cfDNA is superior to peripheral blood leukocytes (PBL) and whole blood samples for reflecting tissue pathology due to the frequent use of PBL and whole blood samples that do not match tissue pathology. The difficulty of demonstrating that cfDNA is derived from adipose tissue. We propose several promising techniques by analyzing cfDNA derived from adipose tissue to detect T2DM risk. First, adipose-specific genes such as ADIPOQ and Leptin were utilized. Second, MCTA-Seq, EpiSCORE, deconvolution, multiplexing, and automated machine learning (AutoML) were used to determine the proportion of total methylation in related genes.

A perspective on diet, epigenetics and complex diseases: where is the field headed next?

Dietary factors can regulate epigenetic processes during life, modulating the intracellular pools of metabolites necessary for epigenetic reactions and regulating the activity of epigenetic enzymes. Their effects are strong during the prenatal life, when epigenetic patterns are written, allowing organogenesis. However, interactions between diet and the epigenome continue throughout life and likely contribute to the onset and progression of various complex diseases. Here, we review the contribution of dietary factors to the epigenetic changes observed in complex diseases and suggest future steps to better address this issue, focusing on neurobehavioral, neuropsychiatric and neurodegenerative disorders, cardiovascular diseases, obesity and Type 2 diabetes, cancer and inflammatory skin diseases.

DNA Methylation Aberrant in Atherosclerosis

Atherosclerosis (AS) is a pathological process involving lipid oxidation, immune system activation, and endothelial dysfunction. The activated immune system could lead to inflammation and oxidative stress. Risk factors like aging and hyperhomocysteinemia also promote the progression of AS. Epigenetic modifications, including DNA methylation, histone modification, and non-coding RNA, are involved in the modulation of genes between the environment and AS formation. DNA methylation is one of the most important epigenetic mechanisms in the pathogenesis of AS. However, the relationship between the progression of AS and DNA methylation is not completely understood. This review will discuss the abnormal changes of DNA methylation in AS, including genome-wide hypermethylation dominating in AS with an increase of age, hypermethylation links with methyl supply and generating hyperhomocysteinemia, and the influence of oxidative stress with the demethylation process by interfering with the hydroxyl-methylation of TET proteins. The review will also summarize the current status of epigenetic treatment, which may provide new direction and potential therapeutic targets for AS.

DNA methylation-based biomarkers of aging were slowed down in a two-year diet and physical activity intervention trial: the DAMA study

Several biomarkers of healthy aging have been proposed in recent years, including the epigenetic clocks, based on DNA methylation (DNAm) measures, which are getting increasingly accurate in predicting the individual biological age. The recently developed "next-generation clock" DNAmGrimAge outperforms "first-generation clocks" in predicting longevity and the onset of many age-related pathological conditions and diseases. Additionally, the total number of stochastic epigenetic mutations (SEMs), also known as the epigenetic mutation load (EML), has been proposed as a complementary DNAm-based biomarker of healthy aging. A fundamental biological property of epigenetic, and in particular DNAm modifications, is the potential reversibility of the effect, raising questions about the possible slowdown of epigenetic aging by modifying one's lifestyle. Here, we investigated whether improved dietary habits and increased physical activity have favorable effects on aging biomarkers in healthy postmenopausal women. The study sample consists of 219 women from the "Diet, Physical Activity, and Mammography" (DAMA) study: a 24-month randomized factorial intervention trial with DNAm measured twice, at baseline and the end of the trial. Women who participated in the dietary intervention had a significant slowing of the DNAmGrimAge clock, whereas increasing physical activity led to a significant reduction of SEMs in crucial cancer-related pathways. Our study provides strong evidence of a causal association between lifestyle modification and slowing down of DNAm aging biomarkers. This randomized trial elucidates the causal relationship between lifestyle and healthy aging-related epigenetic mechanisms.

The regulation mechanisms and the Lamarckian inheritance property of DNA methylation in animals

DNA methylation is a stable and heritable epigenetic mechanism, of which the main functions are stabilizing the transcription of genes and promoting genetic conservation. In animals, the direct molecular inducers of DNA methylation mainly include histone covalent modification and non-coding RNA, whereas the fundamental regulators of DNA methylation are genetic and environmental factors. As is well known, competition is present everywhere in life systems, and will finally strike a balance that is optimal for the animal's survival and reproduction. The same goes for the regulation of DNA methylation. Genetic and environmental factors, respectively, are responsible for the programmed and plasticity changes of DNA methylation, and keen competition exists between genetically influenced procedural remodeling and environmentally influenced plastic alteration. In this process, genetic and environmental factors collaboratively decide the methylation patterns of corresponding loci. DNA methylation alterations induced by environmental factors can be transgenerationally inherited, and exhibit the characteristic of Lamarckian inheritance. Further research on regulatory mechanisms and the environmental plasticity of DNA methylation will provide strong support for understanding the biological function and evolutionary effects of DNA methylation.

Nutrigenomics: lessons learned and future perspectives

The omics technologies of metabolomics, transcriptomics, proteomics, and metagenomics are playing an increasingly important role in nutrition science. With the emergence of the concept of precision nutrition and the need to understand individual responses to dietary interventions, it is an opportune time to examine the impact of these tools to date in human nutrition studies. Advances in our mechanistic understanding of dietary interventions were realized through incorporation of metabolomics, proteomics, and, more recently, metagenomics. A common observation across the studies was the low intra-individual variability of the omics measurements and the high inter-individual variation. Harnessing this data for use in the development of precision nutrition will be important. Metabolomics in particular has played a key role in the development of biomarkers of food intake in an effort to enhance the accuracy of dietary assessments. Further work is needed to realize the full potential of such biomarkers and to demonstrate integration with current strategies, with the goal of overcoming the well-established limitations of self-reported approaches. Although many of the nutrigenomic studies performed to date were labelled as proof-of-concept or pilot studies, there is ample evidence to support the use of these technologies in nutrition science. Incorporating omic technologies from the start of study designs will ensure that studies are sufficiently powered for such data. Furthermore, multi-disciplinary collaborations are likely to become even more important to aid analyses and interpretation of the data.

Sperm DNA Methylation at Metabolism-Related Genes in Vegan Subjects

Objective

To investigate if epigenome of sperm cells could be dynamically affected by nutrition.

Design and Methods

We assessed 40 healthy volunteers with different dietary habits and collected their demographic characteristics, as well as clinical and anthropometric parameters. We compared methylation profiles in sperm quantified by bisulfite pyrosequencing, at promoter-associated CpG sites of genes involved in metabolism including fat mass and obesity-associated (FTO) and melanocortin-4 receptor (MC4R) from six vegans and 34 omnivores. In addition, the FTO rs9939609 (T>A) was genotyped.

Results

Higher DNA methylation levels were detected in the sperm of vegan at FTO gene CpG1 (p=0.02), CpG2 (p=0.001), CpG3 (p=0.004), and CpG4 (p=0.003) sites and at MC4R-CpG2 site [p=0.016] as compared to sperm of omnivores. This association was not related to FTO genotype.

Conclusions

Although limited by the small number of investigated cases, our data provide insight into the role of diet on sperm DNA methylation in genes involved in metabolism.

Exertional sodium loss does not increase immediate salt appetite or dietary sodium intake in athletes

We tested whether salt preference increases immediately after exertion-induced Na⁺ loss in sweat, and whether this may generalise to an increase in habitual dietary Na⁺ intake. For the first aim, trained athletes (n = 20) exercised in 2 ambient temperatures and sweat Na⁺ loss related to immediate salt preference assessed by taste, intake and psychophysical tests. For the second aim, we compared dietary and urinary Na⁺, and salt preference, seasoning and hedonics in the athletes and sedentary men (n = 20). No relationship was found between sodium loss during exercise and immediate preference for salt or psychophysical responses, and no differences in comparison to sedentary men. However, athlete diet had fewer foods (29.4 ± 1.5 vs 37.8 ± 1.9, p < 0.001), less seasoning (19 vs 32. p = 0.011) and more athletes reported dietary limitations (31 vs 11, p < 0.05), although nutrient content did not differ. Together these might suggest athlete adherence to a healthy diet at the expense of variety and flavour and a dissociation between dietary reports and intake. Athletes, more than controls, liked foods rich in energy and K⁺ suggesting compensatory-driven hedonics, although overall their intake did not differ. The findings are consistent with the absence of a salt appetite responding to Na⁺ loss in humans, and specifically that trained athletes do not increase their preference for salt in immediate response to exertion-induced Na⁺ loss and are not at risk for increased dietary Na⁺ compared to sedentary men.

DNA Methylation Profiles of Vegans and Non-Vegetarians in the Adventist Health Study-2 Cohort

We sought to determine if DNA methylation patterns differed between vegans and non-vegetarians in the Adventist Health Study-2 cohort. Genome-wide DNA methylation derived from buffy coat was profiled in 62 vegans and 142 non-vegetarians. Using linear regression, methylation of CpG sites and genes was categorized or summarized according to various genic/intergenic regions and CpG island-related regions, as well as the promoter. Methylation of genes was measured as the average methylation of available CpG's annotated to the nominated region of the respective gene. A permutation method defining the null distribution adapted from Storey et al. was used to adjust for false discovery. Differences in methylation of several CpG sites and genes were detected at a false discovery rate < 0.05 in region-specific and overall analyses. A vegan diet was associated predominantly with hypomethylation of genes, most notably methyltransferase-like 1 (METTL1). Although a limited number of differentially methylated features were detected in the current study, the false discovery method revealed that a much larger proportion of differentially methylated genes and sites exist, and could be detected with a larger sample size. Our findings suggest modest differences in DNA methylation in vegans and non-vegetarians, with a much greater number of detectable significant differences expected with a larger sample.

Epigenetic factors in atherosclerosis: DNA methylation, folic acid metabolism, and intestinal microbiota

Atherosclerosis is a complex disease, influenced by both genetic and non-genetic factors. The most important epigenetic mechanism in the pathogenesis of atherosclerosis is DNA methylation, which involves modification of the gene without changes in the gene sequence. Nutrients involved in one-carbon metabolism interact to regulate DNA methylation, especially folic acid and B vitamins. Deficiencies in folic acid and other nutrients, such as vitamins B6 and B12, can increase homocysteine levels, induce endothelial dysfunction, and accelerate atherosclerotic pathological processes. Supplemented nutrients can improve DNA methylation status, reduce levels of inflammatory factors, and delay the process of atherosclerosis. In this review, the influence of intestinal flora on folate metabolism and epigenetics is also considered.

The Effects of Dietary Interventions on DNA Methylation: Implications for Obesity Management

Previous evidence from in vivo and observational research suggested how dietary factors might affect DNA methylation signatures involved in obesity risk. However, findings from experimental studies are still scarce and, if present, not so clear. The current review summarizes studies investigating the effect of dietary interventions on DNA methylation in the general population and especially in people at risk for or with obesity. Overall, these studies suggest how dietary interventions may induce DNA methylation changes, which in turn are likely related to the risk of obesity and to different response to weight loss programs. These findings might explain the high interindividual variation in weight loss after a dietary intervention, with some people losing a lot of weight while others much less so. However, the interactions between genetic, epigenetic, environmental and lifestyle factors make the whole framework even more complex and further studies are needed to support the hypothesis of personalized interventions against obesity.

Epigenome-wide DNA methylation and risk of breast cancer: a systematic review

BACKGROUND

DNA methylation is a potential biomarker for early detection of breast cancer. However, robust evidence of a prospective relationship between DNA methylation patterns and breast cancer risk is still lacking. The objective of this study is to provide a systematic analysis of the findings of epigenome-wide DNA methylation studies on breast cancer risk, in light of their methodological strengths and weaknesses.

METHODS

We searched major databases (MEDLINE, EMBASE, Web of Science, CENTRAL) from inception up to 30th June 2019, for observational or intervention studies investigating the association between epigenome-wide DNA methylation (using the HM450k or EPIC BeadChip), measured in any type of human sample, and breast cancer risk. A pre-established protocol was drawn up following the Cochrane Reviews rigorous methodology. Study selection, data abstraction, and risk of bias assessment were performed by at least two investigators. A qualitative synthesis and systematic comparison of the strengths and weaknesses of studies was performed.

RESULTS

Overall, 20 studies using the HM450k BeadChip were included, 17 of which had measured blood-derived DNA methylation. There was a consistent trend toward an association of global blood-derived DNA hypomethylation and higher epigenetic age with higher risk of breast cancer. The strength of associations was modest for global hypomethylation and relatively weak for most of epigenetic age algorithms. Differences in length of follow-up periods may have influenced the ability to detect associations, as studies reporting follow-up periods shorter than 10 years were more likely to observe an association with global DNA methylation. Probe-wise differential methylation analyses identified between one and 806 differentially methylated CpGs positions in 10 studies. None of the identified differentially methylated sites overlapped between studies. Three studies used breast tissue DNA and suffered major methodological issues that precludes any conclusion. Overall risk of bias was critical mainly because of incomplete control of confounding. Important issues relative to data preprocessing could have limited the consistency of results.

CONCLUSIONS

Global DNA methylation may be a short-term predictor of breast cancer risk. Further studies with rigorous methodology are needed to determine spatial distribution of DNA hypomethylation and identify differentially methylated sites associated with risk of breast cancer.

PROSPERO REGISTRATION NUMBER

CRD42020147244.

Physical activity, obesity and sedentary behavior in cancer etiology: epidemiologic evidence and biologic mechanisms

An estimated 30–40% of cancers can be prevented through changes in modifiable lifestyle and environmental risk factors known to be associated with cancer incidence. Despite this knowledge, there remains limited awareness that these associations exist. The purpose of this review article was to summarize the epidemiologic evidence concerning the contribution of physical activity, sedentary behavior, and obesity to cancer etiology and to provide an overview of the biologic mechanisms that may be operative between these factors and cancer incidence. Strong and consistent evidence exists that higher levels of physical activity reduce the risk of six different cancer sites (bladder, breast, colon, endometrial, esophageal adenocarcinoma, gastric cardia), whereas moderate evidence inversely associates physical activity with lung, ovarian, pancreatic and renal cancer, and limited evidence inversely correlates physical activity with prostate cancer. Sedentary behavior, independent of physical activity, has been shown to increase the risk of colon, endometrial, and lung cancers. Obesity is an established risk factor for 13 different cancer sites (endometrial, postmenopausal breast, colorectal, esophageal, renal/kidneys, meningioma, pancreatic, gastric cardia, liver, multiple myeloma, ovarian, gallbladder, and thyroid). The main biologic mechanisms whereby physical activity, sedentary behavior, and obesity are related to cancer incidence include an effect on endogenous sex steroids and metabolic hormones, insulin sensitivity, and chronic inflammation. Several emerging pathways related to oxidative stress, DNA methylation, telomere length, immune function, and gut microbiome are presented. Key recommendations for future research in both the epidemiology and biology of the associations between physical activity, sedentary behavior, obesity, and cancer risk are also provided.

DNA methylation pattern changes following a short-term hypocaloric diet in women with obesity

BACKGROUND/OBJECTIVES

We aimed to investigate the effects of short-term hypocaloric diet-induced weight loss on DNA methylation profile in leukocytes from women with severe obesity.

METHODS

Eleven women with morbid obesity (age: 36.9 ± 10.3 years; BMI: 58.5 ± 10.5 kg/m²) were assessed before and after 6 weeks of a hypocaloric dietary intervention. The participants were compared with women of average weight and the same age (age: 36.9 ± 11.8 years; BMI: 22.5 ± 1.6 kg/m²). Genome-wide DNA methylation analysis was performed in DNA extracted from peripheral blood leukocytes using the Infinium Human Methylation 450 BeadChip assay. Changes (Δβ) in the methylation level of each CpGs were calculated. A threshold with a minimum value of 10%, p < 0.001, for the significant CpG sites based on Δβ and a false discovery rate of <0.05 was set.

RESULTS

Dietary intervention changed the methylation levels at 16,064 CpG sites. These CpGs sites were related to cancer, cell cycle-related, MAPK, Rap1, and Ras signaling pathways. However, regardless of hypocaloric intervention, a group of 878 CpGs (related to 649 genes) remained significantly altered in obese women when compared with normal-weight women. Pathway enrichment analysis identified genes related to the cadherin and Wnt pathway, angiogenesis signaling, and p53 pathways by glucose deprivation.

CONCLUSION

A short-term hypocaloric intervention in patients with severe obesity partially restored the obesity-related DNA methylation pattern. Thus, the full change of obesity-related DNA methylation patterns could be proportional to the weight-loss rate in these patients after dietary interventions.

DNA methylation ambiguity in the Fibrillin-1 (FBN1) CpG island shore possibly involved in Marfan syndrome

Fibrillin-1 (FBN1) is responsible for haploinsufficient and autosomal dominant Marfan syndrome. Even in the same Marfan pedigree, penetrance and expressivity in heterozygous individuals can differ and result in variable disease onset and severity. Thus, other factors in addition to mutations in FBN1 are likely to contribute to the disease. In this study, we examined the regulation of FBN1 in porcine Marfan syndrome model, focusing on DNA methylation patterns distinguishable as wild-type (WT) and FBN1 null (KO) alleles in heterozygous cells. Most importantly, the ratio of the transcriptionally active hypomethylated WT allele was altered during cellular passage and highly correlated with FBN1 mRNA level compared with that in the KO allele. Transcribed FBN1 RNA from the KO allele was abolished after splicing coupled with translational initiation, suggesting that the functional FBN1 mRNA levels were affected by DNA methylation of the WT allele.

Influence of nutrients involved in one-carbon metabolism on DNA methylation in adults—a systematic review and meta-analysis

Context

Aberrant DNA methylation is linked to various diseases. The supply of methyl groups for methylation reactions is mediated by S-adenosylmethionine, which depends on the availability of folate and related B vitamins.

Objectives

To investigate the influence of key nutrients involved in 1-carbon metabolism on DNA methylation in adults.

Data sources

Systematic literature searches were conducted in the Cochrane Library, Medline, Embase, Cumulative Index to Nursing and Allied Health Literature Plus, Scopus, and Web of Science databases. Studies that met the inclusion criteria and were published in English were included.

Data extraction

The first author, study design, sample size, population characteristics, type and duration of intervention, tissue type or cells analyzed, molecular techniques, and DNA methylation outcomes.

Data synthesis

A meta-analysis of randomized, controlled trials (RCTs) was conducted to investigate the effect of 1-carbon metabolism nutrients on global DNA methylation. Functional analysis and visualization were performed using BioVenn software.

Results

From a total of 2620 papers screened by title, 53 studies met the inclusion criteria. Qualitative analysis indicated significant associations between 1-carbon metabolism nutrients and DNA methylation. In meta-analysis of RCTs stratified by method of laboratory analysis, supplementation with folic acid alone or in combination with vitamin B12 significantly increased global DNA methylation in studies using liquid chromatography–mass spectrometry, which had markedly lower heterogeneity (n = 3; Z = 3.31; P = 0.0009; I2 = 0%) in comparison to other methods. Functional analysis highlighted a subset of 12 differentially methylated regions that were significantly related to folate and vitamin B12 biomarkers.

Conclusion

This study supports significant associations between 1-carbon metabolism nutrients and DNA methylation. However, standardization of DNA methylation techniques is recommended to reduce heterogeneity and facilitate comparison across studies.

Systematic Review registration

PROSPERO registration number: CRD42018091898.

Effects of bariatric surgery on DNA methylation in adults: a systematic review and meta-analysis

BACKGROUND

DNA methylation is an epigenetic mechanism through which environmental factors, including obesity, influence health. Obesity is a major modifiable risk factor for many common diseases, including cardiovascular diseases and cancer. Obesity-induced metabolic stress and inflammation are key mechanisms that affect disease risk and that may result from changes in methylation of metabolic and inflammatory genes.

OBJECTIVES

This review aims to report the effects of weight loss induced by bariatric surgery (BS) on DNA methylation in adults with obesity focusing on changes in metabolic and inflammatory genes.

METHODS

A systematic review was performed using MEDLINE, EMBASE, and Scopus, to identify studies in adult humans that reported DNA methylation after BS.

RESULTS

Of 15,996 screened titles, 15 intervention studies were identified, all of which reported significantly lower body mass index postsurgery. DNA methylation was assessed in 5 different tissues (blood = 7 studies, adipose tissues = 4, skeletal muscle = 2, liver, and spermatozoa). Twelve studies reported significant changes in DNA methylation after BS. Meta-analysis showed that BS increased methylation of PDK4 loci in skeletal muscle and blood in 2 studies, while the effects of BS on IL6 methylation levels in blood were inconsistent. BS had no overall effect on LINE1 or PPARGC1 methylation.

CONCLUSION

The current evidence supports the reversibility of DNA methylation at specific loci in response to BS-induced weight loss. These changes are consistent with improved metabolic and inflammatory profiles of patients after BS. However, the evidence regarding the effects of BS on DNA methylation in humans is limited and inconsistent, which makes it difficult to combine and compare data across studies.

Association between greater leg length and increased incidence of colorectal cancer: the atherosclerosis risk in communities (ARIC) study

PURPOSE

Previous studies have reported that taller people have an increased risk of colorectal cancer (CRC). We examined the association of two height components-leg length and sitting height-with CRC risk in 14,532 individuals aged 45-64 years in the Atherosclerosis Risk in Communities study.

METHODS

Anthropometrics were measured at baseline (1987-1989). Incident CRC cases (n = 382) were ascertained from 1987 to 2012. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios for CRC and colon cancer across quintiles of sex-specific leg length and sitting height.

RESULTS

The highest (versus the lowest) quintile of leg length was associated with a 36% greater CRC risk (p-trend = 0.04), and 51% greater colon cancer risk (p-trend = 0.01). For the top four quintiles combined, risk was increased by 34% for CRC and by 45% for colon cancer versus the lowest quintile. Total height and sitting height were not significantly associated with CRC or colon cancer risk. A small number of cases (n = 57) limited our ability to conduct subgroup analyses for rectal cancer.

CONCLUSIONS

A positive association of leg length with CRC and colon cancer risk suggests that biological mechanisms leading to greater leg length during puberty may explain the association between taller height and CRC.