Rachel A. Murphy

Dr. Rachel A. Murphy

School of Population and Public Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 April 2013 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
LMLisa Martin
Lisa Martin
LBLaura Birdsell
Laura Birdsell
NMNeil MacDonald
Neil MacDonald
TRTony Reiman
Tony Reiman
MCM. Thomas Clandinin
M. Thomas Clandinin
Vickie Elaine BaracosVickie Elaine Baracos
Vickie Elaine Baracos
Purpose: Emerging evidence suggests muscle depletion predicts survival of patients with cancer. Patients and Methods: At a cancer center in Alberta, Canada, consecutive patients with cancer (lung or GI; N = 1,473) were assessed at presentation for weight loss history, lumbar skeletal muscle index, and mean muscle attenuation (Hounsfield units) by computed tomography (CT). Univariate and multivariate analyses were conducted. Concordance (c) statistics were used to test predictive accuracy of survival models. Results: Body mass index (BMI) distribution was 17% obese, 35% overweight, 36% normal weight, and 12% underweight. Patients in all BMI categories varied widely in weight loss, muscle index, and muscle attenuation. Thresholds defining associations between these three variables and survival were determined using optimal stratification. High weight loss, low muscle index, and low muscle attenuation were independently prognostic of survival. A survival model containing conventional covariates (cancer diagnosis, stage, age, performance status) gave a c statistic of 0.73 (95% CI, 0.67 to 0.79), whereas a model ignoring conventional variables and including only BMI, weight loss, muscle index, and muscle attenuation gave a c statistic of 0.92 (95% CI, 0.88 to 0.95; P < .001). Patients who possessed all three of these poor prognostic variables survived 8.4 months (95% CI, 6.5 to 10.3), regardless of whether they presented as obese, overweight, normal weight, or underweight, in contrast to patients who had none of these features, who survived 28.4 months (95% CI, 24.2 to 32.6; P < .001). Conclusion: CT images reveal otherwise occult muscle depletion. Patients with cancer who are cachexic by the conventional criterion (involuntary weight loss) and by two additional criteria (muscle depletion and low muscle attenuation) share a poor prognosis, regardless of overall body weight.

21 May 2019 in Circulation
Verified
Journal Article
Open access
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Matti  MarklundMatti Marklund
Matti Marklund
JWJason Wu
Jason Wu
FIFumiaki Imamura
Fumiaki Imamura
LGLiana C. Del Gobbo
Liana C. Del Gobbo
AFAmanda Fretts
Amanda Fretts
O(Outcomes Research Consortium (FORCE)
Outcomes Research Consortium (FORCE)
Background: Global dietary recommendations for and cardiovascular effects of linoleic acid, the major dietary omega-6 fatty acid, and its major metabolite, arachidonic acid, remain controversial. To address this uncertainty and inform international recommendations, we evaluated how in vivo circulating and tissue levels of linoleic acid (LA) and arachidonic acid (AA) relate to incident cardiovascular disease (CVD) across multiple international studies. Methods: We performed harmonized, de novo, individual-level analyses in a global consortium of 30 prospective observational studies from 13 countries. Multivariable-adjusted associations of circulating and adipose tissue LA and AA biomarkers with incident total CVD and subtypes (coronary heart disease, ischemic stroke, cardiovascular mortality) were investigated according to a prespecified analytic plan. Levels of LA and AA, measured as the percentage of total fatty acids, were evaluated linearly according to their interquintile range (ie, the range between the midpoint of the first and fifth quintiles), and categorically by quintiles. Study-specific results were pooled using inverse-variance–weighted meta-analysis. Heterogeneity was explored by age, sex, race, diabetes mellitus, statin use, aspirin use, omega-3 levels, and fatty acid desaturase 1 genotype (when available). Results: In 30 prospective studies with medians of follow-up ranging 2.5 to 31.9 years, 15 198 incident cardiovascular events occurred among 68 659 participants. Higher levels of LA were significantly associated with lower risks of total CVD, cardiovascular mortality, and ischemic stroke, with hazard ratios per interquintile range of 0.93 (95% CI, 0.88–0.99), 0.78 (0.70–0.85), and 0.88 (0.79–0.98), respectively, and nonsignificantly with lower coronary heart disease risk (0.94; 0.88–1.00). Relationships were similar for LA evaluated across quintiles. AA levels were not associated with higher risk of cardiovascular outcomes; in a comparison of extreme quintiles, higher levels were associated with lower risk of total CVD (0.92; 0.86–0.99). No consistent heterogeneity by population subgroups was identified in the observed relationships. Conclusions: In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention.

1 December 2017 in The Lancet Diabetes & Endocrinology
Verified
Journal Article
Open access
JWJason Wu
Jason Wu
Matti  MarklundMatti Marklund
Matti Marklund
FIFumiaki Imamura
Fumiaki Imamura
NTNathan Tintle
Nathan Tintle
AKAndres V Ardisson Korat
Andres V Ardisson Korat
DMDariush Mozaffarian
Dariush Mozaffarian
The metabolic effects of omega-6 polyunsaturated fatty acids (PUFAs) remain contentious, and little evidence is available regarding their potential role in primary prevention of type 2 diabetes. We aimed to assess the associations of linoleic acid and arachidonic acid biomarkers with incident type 2 diabetes. We did a pooled analysis of new, harmonised, individual-level analyses for the biomarkers linoleic acid and its metabolite arachidonic acid and incident type 2 diabetes. We analysed data from 20 prospective cohort studies from ten countries (Iceland, the Netherlands, the USA, Taiwan, the UK, Germany, Finland, Australia, Sweden, and France), with biomarkers sampled between 1970 and 2010. Participants included in the analyses were aged 18 years or older and had data available for linoleic acid and arachidonic acid biomarkers at baseline. We excluded participants with type 2 diabetes at baseline. The main outcome was the association between omega-6 PUFA biomarkers and incident type 2 diabetes. We assessed the relative risk of type 2 diabetes prospectively for each cohort and lipid compartment separately using a prespecified analytic plan for exposures, covariates, effect modifiers, and analysis, and the findings were then pooled using inverse-variance weighted meta-analysis. Participants were 39 740 adults, aged (range of cohort means) 49-76 years with a BMI (range of cohort means) of 23·3-28·4 kg/m2, who did not have type 2 diabetes at baseline. During a follow-up of 366 073 person-years, we identified 4347 cases of incident type 2 diabetes. In multivariable-adjusted pooled analyses, higher proportions of linoleic acid biomarkers as percentages of total fatty acid were associated with a lower risk of type 2 diabetes overall (risk ratio [RR] per interquintile range 0·65, 95% CI 0·60-0·72, p<0·0001; I2=53·9%, pheterogeneity=0·002). The associations between linoleic acid biomarkers and type 2 diabetes were generally similar in different lipid compartments, including phospholipids, plasma, cholesterol esters, and adipose tissue. Levels of arachidonic acid biomarker were not significantly associated with type 2 diabetes risk overall (RR per interquintile range 0·96, 95% CI 0·88-1·05; p=0·38; I2=63·0%, pheterogeneity<0·0001). The associations between linoleic acid and arachidonic acid biomarkers and the risk of type 2 diabetes were not significantly modified by any prespecified potential sources of heterogeneity (ie, age, BMI, sex, race, aspirin use, omega-3 PUFA levels, or variants of the FADS gene; all pheterogeneity≥0·13). Findings suggest that linoleic acid has long-term benefits for the prevention of type 2 diabetes and that arachidonic acid is not harmful. Funders are shown in the appendix.

22 April 2021 in Nature Communications
Verified
Journal Article
Open access
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WWWilliam S William
William S William
NTNathan Tintle
Nathan Tintle
FIFumiaki Imamura
Fumiaki Imamura
FQFrank Qian
Frank Qian
AKAndres V. Ardisson Korat
Andres V. Ardisson Korat
T(The Fatty Acids and Outcomes Research Consortium (FORCE)
The Fatty Acids and Outcomes Research Consortium (FORCE)
The health effects of omega-3 fatty acids have been controversial. Here we report the results of a de novo pooled analysis conducted with data from 17 prospective cohort studies examining the associations between blood omega-3 fatty acid levels and risk for all-cause mortality. Over a median of 16 years of follow-up, 15,720 deaths occurred among 42,466 individuals. We found that, after multivariable adjustment for relevant risk factors, risk for death from all causes was significantly lower (by 15–18%, at least p < 0.003) in the highest vs the lowest quintile for circulating long chain (20–22 carbon) omega-3 fatty acids (eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids). Similar relationships were seen for death from cardiovascular disease, cancer and other causes. No associations were seen with the 18-carbon omega-3, alpha-linolenic acid. These findings suggest that higher circulating levels of marine n-3 PUFA are associated with a lower risk of premature death.

28 February 2011 in Cancer
Verified
Journal Article
Open access
PDF file
Rachel A. MurphyRachel A. Murphy
Rachel A. Murphy
MMMarina Mourtzakis
Marina Mourtzakis
QCQuincy S.C. Chu
Quincy S.C. Chu
Vickie Elaine BaracosVickie Elaine Baracos
Vickie Elaine Baracos
TRTony Reiman
Tony Reiman
VMVera C Mazurak
Vera C Mazurak
BACKGROUND: Involuntary weight loss is a major contributor to mortality and morbidity in patients with advanced cancer. Nutritional intervention with fish oil (FO)‐derived eicosapentaenoic acid (EPA) may prevent deterioration of body composition. This study compared intervention with FO with standard of care (SOC; no intervention) with regard to weight, skeletal muscle, and adipose tissue in newly referred patients with nonsmall cell lung cancer from the time of initiation to completion of first‐line chemotherapy.METHODS: Forty patients completed the study; there were 16 in the FO group (dose of 2.2 g of EPA/day) and 24 patients in the SOC group. Skeletal muscle and adipose tissue were measured using computed tomography images. Blood was collected and weight was recorded at baseline and throughout chemotherapy.RESULTS: Patients in the SOC group experienced an average weight loss of 2.3 ± 0.9 kg whereas patients receiving FO maintained their weight (0.5 ± 1.0 kg) (P = .05). Patients with the greatest increase in plasma EPA concentration after FO supplementation were found to have the greatest gains in muscle (r2 = 0.55; P = .01). Approximately 69% of patients in the FO group gained or maintained muscle mass. Comparatively, only 29% of patients in the SOC group maintained muscle mass, and overall the SOC group lost 1 kg of muscle. No difference in total adipose tissue was observed between the 2 groups.CONCLUSIONS: Nutritional intervention with 2.2 g of FO per day appears to provide a benefit over SOC, resulting in the maintenance of weight and muscle mass during chemotherapy. Cancer 2011. © 2011 American Cancer Society.

22 April 2013 in JAMA Internal Medicine
Verified
Journal Article
Open access
PDF file
QXQian Xiao
Qian Xiao
Rachel A. MurphyRachel A. Murphy
Rachel A. Murphy
DHDenise K. Houston
Denise K. Houston
THTamara B. Harris
Tamara B. Harris
WCWong-Ho Chow
Wong-Ho Chow
YPYikyung Park
Yikyung Park
In Western countries, great emphasis has been put on calcium intake because of its proposed benefit for bone health. Calcium supplementation has become widely used, especially among the elderly population. A recent study1 reported that more than 50% of older men and almost 70% of older women in the United States use supplemental calcium. However, beyond calcium's established role in prevention and treatment of osteoporosis, its health effect on nonskeletal outcomes, including cardiovascular health, remains largely unknown and has become increasingly contentious.2,3