Evidence browser

E2 ModerateCohortPEM unclearObservational

Pain is associated with reduced quality of life and functional status in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Strand, Elin Bolle, Mengshoel, Anne Marit, Sandvik, Leiv et al.·Scandinavian journal of pain·2019

This study compared 87 ME/CFS patients with 94 healthy people to understand how pain affects quality of life. Researchers found that ME/CFS patients experience significantly more pain, anxiety, and depression, and have lower quality of life than healthy controls. Within the ME/CFS group, pain was strongly linked to reduced physical functioning and overall quality of life, suggesting that managing pain could help improve how well patients function daily.

Pain and Sensitization

Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in Chronic Fatigue Syndrome: An Observational Study in Patients and Healthy Subjects.

Polli, Andrea, Van Oosterwijck, Jessica, Nijs, Jo et al.·Clinical therapeutics·2019

This study looked at whether oxidative stress (cellular damage from normal metabolism) is related to pain in ME/CFS patients, and how it connects to the vagus nerve, which helps control the body's relaxation response. Researchers had ME/CFS patients and healthy people do a mild exercise test and measured their pain, oxidative stress levels, and nerve activity before and after. They found that oxidative stress was linked to pain in ME/CFS patients, but unlike healthy people, ME/CFS patients didn't show improvements in pain or oxidative stress after exercise.

Pain and SensitizationAutonomic Nervous System

E2 ModerateBehavioralPEM unclearCross-Sectional

Myalgic encephalomyelitis/chronic fatigue syndrome patients' reports of symptom changes following cognitive behavioural therapy, graded exercise therapy and pacing treatments: Analysis of a primary survey compared with secondary surveys.

Geraghty, Keith, Hann, Mark, Kurtev, Stoyan·Journal of health psychology·2019

This study asked ME/CFS patients about their experiences with three different treatment approaches: cognitive behavioural therapy (CBT), graded exercise therapy (GET), and pacing. The researchers found that pacing—where patients carefully manage their activity levels without pushing beyond their limits—was reported as most helpful and caused the fewest problems. In contrast, GET led to significant symptom worsening in over half of patients, while CBT helped only a small percentage of people.

Endometriosis as a Comorbid Condition in Chronic Fatigue Syndrome (CFS): Secondary Analysis of Data From a CFS Case-Control Study.

Boneva, Roumiana S, Lin, Jin-Mann S, Wieser, Friedrich et al.·Frontiers in pediatrics·2019

This study looked at 36 women with ME/CFS to see how many also had endometriosis (a painful condition where tissue grows outside the uterus) and whether it affected their health differently. More than one-third of the women with ME/CFS had endometriosis, and those women reported more ME/CFS symptoms, pelvic pain, and earlier menopause than women with ME/CFS alone. However, endometriosis did not seem to worsen their overall fatigue or functioning.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Multidimensional Comparison of Cancer-Related Fatigue and Chronic Fatigue Syndrome: The Role of Psychophysiological Markers.

Park, Hye Youn, Jeon, Hong Jun, Bang, Young Rong et al.·Psychiatry investigation·2019

This study compared fatigue in people with cancer (CRF) and people with ME/CFS to see if these conditions are similar or different. Researchers measured fatigue levels, mood, stress, sleep quality, and specific biological markers like inflammation and brain activity. While both groups reported similar amounts of fatigue, they showed different underlying biological patterns, suggesting the two conditions may have different causes.

BiomarkersImmune System

Does fatigue and distress in a clinical cohort of adolescents with chronic fatigue syndrome correlate with fatigue and distress in their parents?

Loades, Maria E, Rimes, Katharine A, Ali, Sheila et al.·Child: care, health and development·2019

This study asked whether parents of teenagers with ME/CFS experience similar levels of tiredness and emotional distress as their children. Researchers surveyed 115 adolescents with ME/CFS, along with their mothers and fathers, about fatigue, mood, anxiety, and how well the family was functioning. The main finding was that parents' own tiredness and distress were not directly linked to how severe their child's illness was, but family stress and poor coping skills were connected to teenagers feeling more depressed.

E2 ModerateBehavioralPEM unclearLongitudinal

Unemployment and work disability in individuals with chronic fatigue syndrome/myalgic encephalomyelitis: a community-based cross-sectional study from Spain.

Castro-Marrero, Jesús, Faro, Mónica, Zaragozá, María Cleofé et al.·BMC public health·2019

This Spanish study looked at 1,086 people with ME/CFS to understand why some are unable to work. Researchers found that more than half (58.6%) were unemployed due to illness. Several factors made work disability more likely, including severe fatigue and pain, autonomic problems (like dizziness or heart issues), neurological symptoms, depression, sleep problems, and having pain start at an older age.

Sleep

Psychological and demographic factors associated with fatigue and social adjustment in young people with severe chronic fatigue syndrome/myalgic encephalomyelitis: a preliminary mixed-methods study.

Ali, Sheila, Adamczyk, Lucy, Burgess, Mary et al.·Journal of behavioral medicine·2019

This study followed 51 young people (aged 12-25) with severe ME/CFS over about 5 months to understand what affects their fatigue and ability to attend school or work. Researchers found that young people who were more afraid of activity and worried about making their symptoms worse tended to have higher fatigue levels and struggled more with social life. Interestingly, girls were less likely to attend school or work, but this wasn't connected to having worse fatigue or social problems.

E2 ModerateCohortPEM requiredCross-Sectional

Evidence for similarity in symptoms and mechanism: The extra-pulmonary symptoms of severe asthma and the polysymptomatic presentation of fibromyalgia.

Hyland, Michael E, Lanario, Joseph W, Wei, Yinghui et al.·Immunity, inflammation and disease·2019

This study found that people with severe asthma report many symptoms beyond breathing problems—such as fatigue, pain, and digestive issues—that are very similar to symptoms seen in fibromyalgia and chronic fatigue syndrome. The researchers compared symptom patterns between asthma patients and people with various functional disorders, finding that asthma and fibromyalgia symptoms were 75% similar in type and pattern. This suggests these conditions may share common underlying mechanisms related to how the body's systems interact.

Differentiating Post-Polio Syndrome from Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.

Klebek, Lauren, Sunnquist, Madison, Jason, Leonard A·Fatigue : biomedicine, health & behavior·2019

This study compared three similar long-term illnesses that cause fatigue and muscle problems: Post-polio syndrome (PPS), ME, and CFS. Researchers used questionnaires and computer analysis to identify which symptoms best distinguish these conditions from each other. They found that people with ME/CFS tend to have more severe overall functional impairment than those with PPS, and that three specific areas—brain fog, post-exertional malaise (getting worse after activity), and hormone-related symptoms—are most helpful in telling these illnesses apart.

Evidence of Clinical Pathology Abnormalities in People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) from an Analytic Cross-Sectional Study.

Nacul, Luis, de Barros, Barbara, Kingdon, Caroline C et al.·Diagnostics (Basel, Switzerland)·2019

Researchers tested blood samples from 272 people with ME/CFS and 136 healthy people to look for measurable differences that might help diagnose the condition. They found that people with severe ME/CFS had notably lower levels of an enzyme called creatine kinase (CK) in their blood compared to healthy people and those with milder ME/CFS. This is the first study to report this pattern, suggesting that CK levels might be useful for identifying who has the most severe form of the disease.

Biomarkers

E2 ModerateCohortPEM requiredCross-Sectional

Cytokine profiles in patients with Q fever fatigue syndrome.

Raijmakers, Ruud P H, Koeken, Valerie A C M, Jansen, Anne F M et al.·The Journal of infection·2019

This study looked at inflammatory markers in people who developed prolonged fatigue after Q fever infection. Researchers compared blood samples from patients with Q fever fatigue syndrome, chronic fatigue syndrome patients, people who had Q fever but recovered, and healthy controls. They found that Q fever fatigue syndrome patients had higher levels of specific inflammation proteins, suggesting chronic inflammation may be driving their ongoing fatigue.

Immune System

Deconstructing post-exertional malaise: An exploratory factor analysis.

McManimen, Stephanie L, Sunnquist, Madison L, Jason, Leonard A·Journal of health psychology·2019

This study looked at post-exertional malaise (PEM)—the worsening of symptoms that happens after physical activity in ME/CFS—to understand whether it is one unified experience or two different types. The researchers found that PEM actually consists of two separate experiences: a whole-body fatigue and a muscle-specific fatigue. This suggests that PEM is more complex than previously thought and may need to be understood as having distinct components.

E2 ModerateCohortPEM unclearObservational

Unexplained exertional intolerance associated with impaired systemic oxygen extraction.

Melamed, Kathryn H, Santos, Mário, Oliveira, Rudolf K F et al.·European journal of applied physiology·2019

This study examined 313 patients with unexplained exercise intolerance using specialized heart and lung testing. Researchers found that about 12.5% of these patients have trouble exercising because their muscles cannot extract and use oxygen properly from the bloodstream, rather than having heart or lung problems. In these patients, the blood remained less acidic during exercise and had higher oxygen levels than expected, suggesting the muscles simply weren't using the available oxygen efficiently.

E2 ModerateBehavioralPEM not requiredCase-Control

Cognitive and behavioural responses to symptoms in adolescents with chronic fatigue syndrome: A case-control study nested within a cohort.

Loades, Maria Elizabeth, Rimes, Katharine, Lievesley, Kate et al.·Clinical child psychology and psychiatry·2019

This study looked at how adolescents with ME/CFS think about and respond to their symptoms, compared to teenagers with asthma. Researchers found that young people with ME/CFS tend to have unhelpful thought patterns—like believing symptoms cause permanent damage—and unhelpful behaviors like pushing through activity or avoiding it completely. These unhelpful patterns were linked to more fatigue and disability over a 3-month follow-up period.

Cognitive Impairment

E2 ModerateCohortPEM unclearObservational

MtDNA population variation in Myalgic encephalomyelitis/Chronic fatigue syndrome in two populations: a study of mildly deleterious variants.

Venter, Marianne, Tomas, Cara, Pienaar, Ilse S et al.·Scientific reports·2019

This study looked at mitochondrial DNA (the genetic material in the energy-producing parts of our cells) in people with ME/CFS to see if differences in this DNA might help explain the condition. Researchers compared DNA samples from ME/CFS patients in the UK and South Africa to look for variations. Interestingly, they found that ME/CFS patients were less likely to have certain common genetic variations that most people carry, but they did not find any confirmed disease-causing mutations.

Energy Metabolism

E2 ModerateBehavioralPEM not requiredCase-Control

Perfectionism and beliefs about emotions in adolescents with chronic fatigue syndrome and their parents: a preliminary investigation in a case control study nested within a cohort.

Loades, Maria E, Rimes, Katharine A, Lievesley, Kate et al.·Psychology & health·2019

This study looked at whether perfectionism and unhelpful ways of thinking about emotions might be connected to ME/CFS in teenagers and their parents. Researchers compared 121 adolescents with ME/CFS to teenagers with asthma and healthy teenagers, measuring their perfectionism and attitudes toward emotions. Interestingly, teenagers with ME/CFS did not show significantly more perfectionism than the other groups, but the study did find that when mothers had unhelpful beliefs about emotions, their teenagers were more likely to have similar beliefs.

E2 ModerateCohortPEM not requiredLongitudinal

Increased risk of chronic fatigue syndrome in patients with inflammatory bowel disease: a population-based retrospective cohort study.

Tsai, Shin-Yi, Chen, Hsuan-Ju, Lio, Chon-Fu et al.·Journal of translational medicine·2019

This study found that people with inflammatory bowel disease (IBD) are more than twice as likely to develop ME/CFS compared to people without IBD. The researchers looked at medical records from Taiwan and followed patients over time to see who developed ME/CFS. The increased risk was especially high in men and older adults with IBD who didn't have other chronic conditions.

Immune System