Rachel A Murphy

• PhD
• Professor (Associate) at University of British Columbia

To identify biomarkers of body mass index, body fat, trunk fat, and appendicular lean mass, nontargeted metabolomics was performed in plasma from 319 black men in the Health, Aging and Body Composition study (median age 72 years, median body mass index 26.8 kg/m(2)). Body mass index was calculated from measured height and weight; percent fat, perce...

Purpose: We examined total, light, and moderate-to-vigorous physical activity (MVPA) as predictors of mortality in a nationally representative sample of older adults. Then, we explored the theoretical consequences of replacing sedentary time with the same duration of light activity or MVPA. Methods: Using accelerometer measured activity, the ass...

Polyunsaturated fatty acids (PUFAs) may play a role in fracture, but studies have been largely confined to estimates of dietary intake. We aimed to examine associations between fatty acids measured in late life and fish-oil consumption in early life, midlife, and late life with osteoporotic fracture risk. Osteoporotic fractures were determined from...

This study examined associations of regional fat depots with all-cause mortality over 11 years of follow-up. Data were from 2,187 men and 2,900 women, aged 66-96 years in the AGES-Reykjavik Study. Abdominal visceral fat and subcutaneous fat and thigh intermuscular fat and subcutaneous fat were measured by CT. In men, every standard deviation (SD) i...

Additional information is needed about the role of dietary sodium on health outcomes in older adults. To examine the association between dietary sodium intake and mortality, incident cardiovascular disease (CVD), and incident heart failure (HF) in older adults. We analyzed 10-year follow-up data from 2642 older adults (age range, 71-80 years) parti...

Importance: Mammographic density (MD) and pathogenic variants (PVs) in breast cancer susceptibility genes are major determinants of breast cancer risk, but their association and joint effects on breast cancer risk are unclear. Objective: To investigate the association between the presence or absence of PVs in breast cancer susceptibility genes and...

Despite the well-known benefits of physical activity, older adults do not engage in sufficient amounts; this became worse during the COVID-19 pandemic. This project analyzes the role of social partners for everyday physical activity, specifically, with whom older adults are physically active and whether engaging in physical activity with a close so...

Increasing evidence links the gut microbiome to carcinogenesis. Disruptions in estrogen regulation by the estrobolome—gut microbiota with estrogen‐related functions—may promote breast cancer. However, precise information on estrobolome targets and their underlying mechanisms is limited. This review identifies relevant targets for measuring the estr...

Objective Individuals with colorectal cancer (CRC) have an increased risk of mental disorders, yet mental healthcare utilisation has not been adequately examined. We evaluated mental healthcare utilisation and receipt of minimally adequate treatments for anxiety and/or depression among individuals with and without CRC. Methods and analysis We used...

Studies have identified genetic and epidemiological factors associated with mammographic density (MD) phenotypes. However, MD-associated genetic variants only account for a small proportion of the total estimated heritability. Interrogating interactions between genetic and epidemiological factors could potentially identify additional MD-associated...

Background Breast cancer is the most commonly diagnosed cancer among women in Canada. Screening is effective in reducing breast cancer mortality through early cancer detection. However, data on individual social and medical characteristics contributing to variation in adherence to screening is limited. Methods Using multivariable logistic regressi...

Background: Social isolation is linked to survival and health. However, dietary effects of social activities, and gender differences, over time are unknown. Methods: A prospective study of adults (45+y) reporting daily fruit or vegetable (F/V) intake (at wave 1) from the Canadian Longitudinal Study on Aging (CLSA). Multivariable mixed logistic regr...

Background Breast cancer is multifactorial. Focusing on limited risk factors may miss high-risk individuals. Methods We assessed the performance and overlap of various risk factors in identifying high-risk individuals for invasive breast cancer (BrCa) and ductal carcinoma in situ (DCIS) in 161,849 European-ancestry and 18,549 Asian-ancestry women....

Social interactions play an important role in older adults’ daily well-being. Longer duration of interaction has been associated with higher well-being at the individual level. However, less is known about the extent to which partners differ in their convergence in interaction reports and whether such differences might be associated with daily well...

Physical activity is a means through which stroke survivors can reduce their future stroke risk. Individual intentions (purposeful aims to engage in a behavior) and self-efficacy (beliefs about their capacity to successfully perform the behavior) have been associated with more physical activity. Spouses are underrecognized resources that may facili...

Background The 313-variant polygenic risk score (PRS313) provides a promising tool for clinical breast cancer risk prediction. However, evaluation of the PRS313 across different European populations which could influence risk estimation has not been performed. Methods We explored the distribution of PRS313 across European populations using genotyp...

The COVID-19 pandemic challenged older adults’ health behaviours, making it even more difficult to engage in healthy diets and physical activity than it had been prepandemic. A resource to promote these could be social support. This study uses data from 136 older adults ( M age = 71.39 years, SD = 5.15, range: 63–87) who reported their daily fruit...

Purpose Most breast biopsies are diagnosed as benign breast disease (BBD), with 1.5- to fourfold increased breast cancer (BC) risk. Apart from pathologic diagnoses of atypical hyperplasia, few factors aid in BC risk assessment of these patients. We assessed whether a 313-SNP polygenic risk score (PRS) stratifies risk of BBD patients. Patients and...

Context Social ties are associated with the mortality and morbidity of aging populations; however, the role of social ties in healthy eating practices or gender differences in this link is less understood. Objective The objective of this study was to examine the longitudinal evidence for the impact of changes in social ties on fruit and vegetable...

Background With the burden of colorectal cancer in Canada, there is a need to address the psycho‐oncologic challenges, including mental health. This study aims to explore the lived mental health experiences in patients with CRC across the phases of the CRC care continuum. Methods We employed a patient‐oriented constructivist grounded theory design...

While hundreds of germline genetic variants have been associated with breast cancer risk, the mechanisms underlying the impacts of most of these variants on breast cancer remain uncertain. Metabolomics may offer valuable insights into the mechanisms underlying genetic risks of breast cancer. Among 143 cancer-free female participants, we used linear...

Purpose Mammographic density phenotypes, adjusted for age and body mass index (BMI), are strong predictors of breast cancer risk. BMI is associated with mammographic density measures, but the role of circulating sex hormone concentrations is less clear. We investigated the relationship between BMI, circulating sex hormone concentrations, and mammog...

This study aimed to examine the impact of employment transitions (ETs) on anthropometric changes among middle-aged and older workers (ages 45y+). Using two waves of data from the Canadian Longitudinal Study on Aging, we analyzed the impact of ETs (stayed working, entered retirement, and stopped working) on change in body weight and waist circumfere...

The 313-variant polygenic risk score (PRS313) provides a promising tool for breast cancer risk prediction. However, evaluation of the PRS313 across different European populations which could influence risk estimation has not been performed. Here, we explored the distribution of PRS313 across European populations using genotype data from 94,072 fema...

Background Access to exercise programming that addresses the unique needs of women living with and beyond ovarian cancer is limited. Feasible and accessible supportive care programs to enhance physical function and quality of life are needed. We aimed to assess the feasibility of a 12-week virtually delivered exercise program for women living with...

BACKGROUND The effect of marine omega-3 PUFAs on risk of stroke remains unclear. METHODS We investigated the associations between circulating and tissue omega-3 PUFA levels and incident stroke (total, ischemic, and hemorrhagic) in 29 international prospective cohorts. Each site conducted a de novo individual-level analysis using a prespecified ana...

Objectives Negative and repetitive self-oriented thinking (rumination) is associated with lower well-being and health. The social context of rumination remains underexplored and mostly centers on marital relationships. To embrace the diversity of older adult relationships, this study includes a range of different relationships (e.g., spouses, sibli...

Solitude, defined as physical aloneness or the absence of social interactions, has been associated with both positive and negative outcomes. Older adults spend a significant amount of their waking time by themselves (exacerbated during the pandemic), but they may be better equipped to regulate the negative emotions that are often linked with being...

Rumination involves repetitive, self-oriented, negative thinking and is known to be detrimental to psychological well-being and health. However, little is known about the extent to which rumination is associated with well-being and health in close relationship partners in older age. Additionally, the pandemic was a time that was characterized by hi...

BACKGROUND: It is unknown whether dietary intake of polyunsaturated fatty acids (PUFA) modifies the cardiovascular disease (CVD) risk associated with a family history of CVD. We assessed interactions between biomarkers of low PUFA intake and a family history in relation to long-term CVD risk in a large consortium. METHODS: Blood and tissue PUFA dat...

Introduction: There is conflicting evidence for the association between antihypertensive medications and colorectal cancer risk, possibly reflecting methodological limitations of previously conducted studies. Here, we aimed to clarify associations between commonly prescribed antihypertensive medication classes and colorectal cancer risk in a large,...

Older adults spend significant time by themselves, especially since COVID‐19. Solitude has been associated with positive and negative outcomes. Partners need to balance social connectedness with time for one's own needs. This project examines how individual and partner solitude are associated with daily affect and relationship quality in dyads of o...

A large number of variants identified through clinical genetic testing in disease susceptibility genes are of uncertain significance (VUS). Following the recommendations of the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP), the frequency in case-control datasets (PS4 criterion) can inform the...

Aims Myocardial infarction (MI) is a major cause of death and disability worldwide. Most metabolomics studies investigating metabolites predicting MI are limited by the participant number and/or the demographic diversity. We sought to identify biomarkers of incident MI in the COnsortium of METabolomics Studies. Methods and results We included 7897...

Introduction: Experimental research suggests that affect may influence prospective memory performance, but real-life evidence on affect-prospective memory associations is limited. Moreover, most studies have examined the valence dimension of affect in understanding the influence of affect on cognitive performance in daily life, with insufficient c...

This study investigated everyday associations between one key facet of mindfulness (allocating attention to the present moment) and pain. In Study 1, 89 community-dwelling adults (33-88 years; Mage = 68.6) who had experienced a stroke provided 14 daily end-of-day present-moment awareness and pain ratings. In Study 2, 100 adults (50-85 years; Mage =...

Background Genome-wide studies of gene–environment interactions (G×E) may identify variants associated with disease risk in conjunction with lifestyle/environmental exposures. We conducted a genome-wide G×E analysis of ~ 7.6 million common variants and seven lifestyle/environmental risk factors for breast cancer risk overall and for estrogen recept...

Diabetes medications may modify the risk of certain cancers. We systematically searched MEDLINE, Embase, Web of Science, and Cochrane CENTRAL from 2011 to March 2021 for studies evaluating associations between diabetes medications and the risk of breast, lung, colorectal, prostate, liver, and pancreatic cancers. A total of 92 studies (3 randomized...

Background Polygenic risk score (PRS), calculated based on genome-wide association studies (GWASs), can improve breast cancer (BC) risk assessment. To date, most BC GWASs have been performed in individuals of European (EUR) ancestry, and the generalisation of EUR-based PRS to other populations is a major challenge. In this study, we examined the pe...

Introduction Although colorectal cancer (CRC) screening program is proven to reduce CRC incidence and mortality, understanding patterns and predictors of suboptimal adherence in screening program requires further investigation in Canada. Methods We used self-reported data from five regional cohorts of the Canadian Partnership for Tomorrow’s Health...

Maintaining a healthy body weight helps to reduce the risk of many of the common and most fatal types of cancer. Regular moderate-to-vigorous physical activity and minimal sedentary behavior can help achieve a healthy body weight and reduce cancer risk. Consuming any amount of alcohol increases the risk of cancer. A diet high in whole grains, a var...

Objective To investigate patient and clinical factors that are associated with perceptions of shared decision making between hysterectomy patients and surgeons and to evaluate associations between shared decision making and postoperative health. Methods This study is based on a prospective cohort scheduled for hysterectomy for benign conditions in...

Over one million biopsies are performed annually in the U.S. to evaluate suspicious breast lesions. Most biopsies lead to a diagnosis of benign breast disease (BBD) and these women have a 1.5- to fourfold increase in subsequent breast cancer (BC) risk compared with the general population. A polygenic risk score (PRS) including 313 common variants w...

Introduction: Previous studies have reported inverse associations of circulating and tissue levels of pentadecanoic acid (15:0), heptadecanoic acid (17:0) and trans -palmitoleic acid ( trans 16:1n-7), which have been proposed as potential biomarkers of dairy fat intake, with risk of type-2 diabetes and certain cardiovascular outcomes. Hypothesis: W...

Background Evidence on the association between mental health disorders and cancer risk is inconclusive, despite well-established associations between mental health disorders and lifestyle factors such as smoking. This study examines the relationships between depression, anxiety and cancer risk, and the potential mediating effects of lifestyle facto...

Background Low-frequency variants play an important role in breast cancer (BC) susceptibility. Gene-based methods can increase power by combining multiple variants in the same gene and help identify target genes. Methods We evaluated the potential of gene-based aggregation in the Breast Cancer Association Consortium cohorts including 83,471 cases...

Symptom-system fit theory proposes that problematic behaviors are maintained by the social system (e.g., the couple relationship) in which they occur because they help promote positive relationship functioning in the short-term. Across three daily life studies, we examined whether mixed-gender couples reported more positive relationship functioning...

Purpose Many indications for hysterectomy can negatively affect patients’ quality of life. This study uses patient-reported outcomes to measure changes in self-reported health among hysterectomy patients. Method A prospective cohort of 294 hysterectomy patients completed patient-reported outcomes preoperatively and six months postoperatively in Va...

Objective To compare the long-term physical and mental health outcomes of matched severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) positive and negative patients controlling for seasonal effects. Study Design Retrospective cohort study. Methods This study enrolled patients presenting to emergency departments participating in the Canad...

Poor diet is a major risk factor for many chronic diseases including cancer. Understanding broader contextual factors that influence dietary intake is important for making tangible progress towards improving diet at the population level. This study investigated neighbourhood social and built environment factors and fruit and vegetable intake among...

Research suggests that colorectal cancer (CRC) is associated with mental health disorders, primarily anxiety and depression. To synthesize this evidence, we conducted a systematic review and meta-analysis of studies evaluating the onset of anxiety and depression among patients with CRC. We searched EMBASE and Medline from inception to June 2022. We...

Background Mechanisms through which retirement and later-life job loss lead to subsequent weight change are poorly understood, and include changes to one’s health behaviours (HBs) after employment changes. Our study assessed the potential role of HBs in the impact of employment transitions (ET) on waist circumference (WC), by gender. Methods We us...

An estimated 20 to 50% of post-secondary students experience food insecurity. Students who are food insecure are more likely to have poor health and lower academic performance relative to food secure peers. Food hubs are physical or digital spaces that provide access to food initiatives and wraparound programs such as employment placement or income...

Adequate consumption of nutrients that support infant neurodevelopment is critical among pregnant women and women of childbearing age. Understanding the potential effects of socioeconomic inequalities on nutrient gaps in these life stages is thus important for informing strategies to mitigate negative health consequences. Usual intake (foods and di...

Diabetes medications may modify the risk of certain cancers. We systematically searched MEDLINE, Embase, Web of Science, and Cochrane CENTRAL from 2011 to March 2021 for studies evaluating associations between diabetes medications and the risk of breast, lung, colorectal, prostate, liver, and pancreatic cancers. A total of 92 studies (3 randomized...

Objectives Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using ge...

Background Becoming unemployed is associated with poorer health, including weight gain. Middle- and older-age adults are a growing segment of workforces globally, but they are also more vulnerable to changes to employment status, especially during economic shocks. Expected workforce exits over the next decade may exacerbate both the obesity epidemi...

Hypertension is the main modifiable risk factor for cardiovascular morbidity and mortality but discovering molecular mechanisms for targeted treatment has been challenging. Here we investigate associations of blood metabolite markers with hypertension by integrating data from nine intercontinental cohorts from the COnsortium of METabolomics Studies...

Background Reproductive factors have been shown to be differentially associated with risk of estrogen receptor (ER) positive and ER-negative breast cancer. However, their associations with intrinsic-like subtypes are less clear. Methods Analyses included up to 23,353 cases, and 71,072 controls pooled from 31 population-based case-control or cohort...

Objectives Healthy eating includes a diverse diet as this ensures adequate amounts of various nutrients for different metabolic pathways. Dietary diversity may also improve survival and promote metabolic health. However, the impact of dietary diversity on type 2 diabetes (T2D) in heterogenous populations is unknown. We aimed to examine whether grea...

Objectives To understand potential long-term consequences of the impacts of the COVID-19 pandemic and resulting public health measures on daily life, specifically shifts in health behaviours which contribute to weight gain. Methods Data on unintentional weight gain among adults during the first year of the COVID-19 pandemic was applied to national...

Purpose: Antihypertensive medications may impact colorectal cancer risk. We conducted a systematic review and meta- analysis of associations, with colorectal cancer risk, of five classes of antihypertensive medications: angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), beta-blockers (BBs), calcium channel bl...

The COVID-19 pandemic and resulting public health measures have had significant impacts on daily life, including shifts in health behaviours which contribute to weight gain and may increase subsequent risk of chronic diseases such as cancer. Using OncoSim, a web-based microsimulation tool, we estimated the future burden of cancer in Canada by incor...

Background Human leukocyte antigen (HLA) genes play critical roles in immune surveillance, an important defence against tumors. Imputing HLA genotypes from existing single-nucleotide polymorphism datasets is low-cost and efficient. We investigate the relevance of the major histocompatibility complex region in breast cancer susceptibility, using imp...

Use of menopausal hormone therapy (MHT) is associated with increased risk for breast cancer. However, the relevant mechanisms and its interaction with genetic variants are not fully understood. We conducted a genome-wide interaction analysis between MHT use and genetic variants for breast cancer risk in 27,585 cases and 34,785 controls from 26 obse...

Background Mammographic density (MD) phenotypes, including percent density (PMD), area of dense tissue (DA), and area of non-dense tissue (NDA), are associated with breast cancer risk. Twin studies suggest that MD phenotypes are highly heritable. However, only a small proportion of their variance is explained by identified genetic variants. Method...

Genome-wide association studies (GWAS) have identified more than 200 susceptibility loci for breast cancer, but these variants explain less than a fifth of the disease risk. Although gene–environment interactions have been proposed to account for some of the remaining heritability, few studies have empirically assessed this. We obtained genotype an...

Background: n-3 and n-6 PUFAs have physiologic roles in sleep processes, but little is known regarding circulating n-3 and n-6 PUFA and sleep parameters. Objectives: We sought to assess associations between biomarkers of n-3 and n-6 PUFA intake with self-reported sleep duration and difficulty falling sleeping in the Fatty Acids and Outcome Resea...

Background: Although smoking is the primary risk factor for lung cancer, 15-25% of lung cancers occur in never smokers. Emerging evidence suggests lifestyle factors are associated with lung cancer risk, but few studies among never smokers exist. Methods: A case-control study of never smokers within the Canadian Partnership for Tomorrow's Health...

OBJECTIVE Trans fatty acids (TFAs) have harmful biologic effects that could increase the risk of type 2 diabetes (T2D), but evidence remains uncertain. We aimed to investigate the prospective associations of TFA biomarkers and T2D by conducting an individual participant-level pooled analysis. RESEARCH DESIGN AND METHODS We included data from an in...

Objective To determine associations between serum long-chain (LC) omega-3 fatty acid levels and sleep parameters among adults (N = 1314) in NHANES 2011-2012. Methods Regression analyses accounting for the complex-survey design were used to assess associations between serum LC omega-3 fatty acid levels, sleep duration, difficulty falling sleeping a...

Germline copy number variants (CNVs) are pervasive in the human genome but potential disease associations with rare CNVs have not been comprehensively assessed in large datasets. We analysed rare CNVs in genes and non-coding regions for 86,788 breast cancer cases and 76,122 controls of European ancestry with genome-wide array data. Gene burden test...

Cancer is a leading cause of morbidity and mortality worldwide. Healthy lifestyles can prevent upward of one-third of cancers and are a critical part of reducing the burden of cancer. Some of the most important ways a person can reduce their risk of cancer are by maintaining a healthy weight throughout life; eating a diet rich in whole grains, non-...

Eating a nutritious diet reduces vulnerability to common chronic diseases. Yet, older adults struggle to meet nutritional guidelines; many have found it particularly challenging to access fresh foods such as fruits and vegetables during the pandemic. Thus, it is vital to better understand how older adults may recruit the help of close others to sup...

Purpose Non-European populations are under-represented in genetics studies, hindering clinical implementation of breast cancer polygenic risk scores (PRSs). We aimed to develop PRSs using the largest available studies of Asian ancestry and to assess the transferability of PRS across ethnic subgroups. Methods The development data set comprised 138,...

Background: Obesity is correlated with many biomarkers but the extent to which these correlate with underlying body composition is poorly understood. Objective: Our objectives were: 1) describe/compare distinct contributions of fat/lean mass to BMI-metabolite correlations and 2) identify novel metabolite biomarkers of fat/lean mass. Design: Th...

PurposeBreast cancer incidence among younger women (under age 50) has increased over the past 25 years, yet little is known about the etiology among this age group. The objective of this study was to investigate relationships between modifiable and non-modifiable risk factors and early-onset breast cancer among three prospective Canadian cohorts.Me...

Engaging in regular moderate-to-vigorous intensity physical activity (MVPA) is crucial to reduce future health risk for individuals living with the effects of a stroke and their partners. Although numerous studies point to the importance of social factors in physical activity engagement, little is known about with whom individuals after stroke and...

A combination of genetic and functional approaches has identified three independent breast cancer risk loci at 2q35. A recent fine-scale mapping analysis to refine these associations resulted in 1 (signal 1), 5 (signal 2), and 42 (signal 3) credible causal variants at these loci. We used publicly available in silico DNase I and ChIP-seq data with i...

Metabolomics can detect metabolic shifts resulting from lifestyle behaviors and may provide insight on the relevance of changes to carcinogenesis. We used non-targeted nuclear magnetic resonance to examine associations between metabolic measures and cancer preventive behaviors in 1319 participants (50% male, mean age 54 years) from the BC Generatio...

Background Copy number variants (CNVs) are pervasive in the human genome but potential disease associations with rare CNVs have not been comprehensively assessed in large datasets. We analysed rare CNVs in genes and non-coding regions for 86,788 breast cancer cases and 76,122 controls of European ancestry with genome-wide array data. Results Gene b...

Objective Predominantly plant-based diets can co-benefit human physical health and the planet. Young adults appear to be on the forefront of the shift to plant-based diets. However, little is known about the relationship between plant-based diets and mental health in this population even though mental health disorders contribute substantially to th...

A combination of genetic and functional approaches has identified three independent breast cancer risk loci at 2q35. A recent fine-scale mapping analysis to refine these associations resulted in 1 (signal 1), 5 (signal 2), and 42 (signal 3) credible causal variants at these loci. We used publicly available in silico DNase I and ChIP-seq data with i...

Background Copy number variants (CNVs) are pervasive in the human genome but potential disease associations with rare CNVs have not been comprehensively assessed in large datasets. We analysed rare CNVs in genes and non-coding regions for 86,788 breast cancer cases and 76,122 controls of European ancestry with genome-wide array data. Results Gene...

Background: Use of menopausal hormone therapy (MHT) is associated with increased risk for breast cancer. However, the relevant mechanisms and its interaction with genetic variants are not fully understood. Methods: We conducted a genome-wide interaction analysis between MHT use and genetic variants for breast cancer risk in 27,585 cases and 34,785...

Background: Use of menopausal hormone therapy (MHT) is associated with increased risk for breast cancer. However, the relevant mechanisms and its interaction with genetic variants are not fully understood. Methods: We conducted a genome-wide interaction analysis between MHT use and genetic variants for breast cancer risk in 27,585 cases and 34,785...