Prevalence of fibromyalgia 10 years after infection with Giardia lamblia: a controlled prospective cohort study

Abstract:

Objectives: To investigate whether acute infection with Giardia lamblia is associated with fibromyalgia 10 years after infection and whether fibromyalgia is associated with irritable bowel syndrome (IBS) and chronic fatigue (CF) in this setting.

Methods: A cohort study was established after an outbreak of G. lamblia in Bergen, Norway, 2004. Laboratory-confirmed cases and a matched control group were followed for 10 years. The main outcome was fibromyalgia 10 years after giardiasis, defined by the 2016 revisions of the fibromyalgia diagnostic criteria using the Fibromyalgia Survey Questionnaire (FSQ).

Results: The prevalence of fibromyalgia was 8.6% (49/572) among Giardia exposed compared to 3.1% (21/673) in controls (p<0.001). Unadjusted odds for having fibromyalgia was higher for Giardia exposed compared to controls (odds ratio (OR): 2.91, 95% confidence interval (CI): 1.72, 4.91), but adjusted for IBS and CF it was not (OR: 1.05, 95% CI: 0.57, 1.95). Among participants without CF the odds for fibromyalgia was 6.27 times higher for participants with IBS than those without (95% CI: 3.31, 11.91) regardless of exposure. Among participants without IBS the odds for fibromyalgia was 4.80 times higher for those with CF than those without (95% CI: 2.75, 8.37).

Conclusions: We found a higher prevalence of fibromyalgia among Giardia exposed compared to controls 10 years after the acute infection. Fibromyalgia was strongly associated with IBS and CF, and the difference between the exposed and controls can be attributed to the high prevalence of IBS and CF among the Giardia exposed. Notably, this study was not designed to establish causality between Giardia exposure and the outcomes.

Source: Hunskar GS, Rortveit G, Litleskare S, Eide GE, Hanevik K, Langeland N, Wensaas KA. Prevalence of fibromyalgia 10 years after infection with Giardia lamblia: a controlled prospective cohort study. Scand J Pain. 2021 Oct 21;22(2):348-355. doi: 10.1515/sjpain-2021-0122. PMID: 34679267. https://www.degruyter.com/document/doi/10.1515/sjpain-2021-0122/html (Full text)

Infections in temporal proximity to HPV vaccination and adverse effects following vaccination in Denmark: A nationwide register-based cohort study and case-crossover analysis

Abstract:

Background: Public trust in the human papilloma virus (HPV) vaccination programme has been challenged by reports of potential severe adverse effects. The reported adverse symptoms were heterogeneous and overlapping with those characterised as chronic fatigue syndrome (CFS) and have been described as CFS-like symptoms. Evidence suggests that CFS is often precipitated by an infection. The aim of the study was to examine if an infection in temporal proximity to HPV vaccination is a risk factor for suspected adverse effects following HPV vaccination.

Methods and findings: The study was a nationwide register-based cohort study and case-crossover analysis. The study population consisted of all HPV vaccinated females living in Denmark, born between 1974 and 2006, and vaccinated between January 1, 2006 and December 31, 2017. The exposure was any infection in the period ± 1 month around time of first HPV vaccination and was defined as (1) hospital-treated infection; (2) redemption of anti-infective medication; or (3) having a rapid streptococcal test done at the general practitioner. The outcome was referral to a specialised hospital setting (5 national HPV centres opened June 1, 2015) due to suspected adverse effects following HPV vaccination.

Multivariable logistic regression was used to estimate the association between infection and later HPV centre referral. The participants were 600,400 HPV-vaccinated females aged 11 to 44 years. Of these, 48,361 (9.7%) females had a hospital-treated infection, redeemed anti-infective medication, or had a rapid streptococcal test ± 1 month around time of first HPV vaccination. A total of 1,755 (0.3%) females were referred to an HPV centre. Having a hospital-treated infection in temporal proximity to vaccination was associated with significantly elevated risk of later referral to an HPV centre (odds ratio (OR) 2.75, 95% confidence interval (CI) 1.72 to 4.40; P < 0.001). Increased risk was also observed among females who redeemed anti-infective medication (OR 1.56, 95% CI 1.33 to 1.83; P < 0.001) or had a rapid streptococcal test (OR 1.45, 95% CI 1.10 to 1.93; P = 0.010).

Results from a case-crossover analysis, which was performed to adjust for potential unmeasured confounding, supported the findings. A key limitation of the study is that the HPV centres did not open until June 1, 2015, which may have led to an underestimation of the risk of suspected adverse effects, but stratified analyses by year of vaccination yielded similar results.

Conclusions: Treated infection in temporal proximity to HPV vaccination is associated with increased risk for later referral with suspected adverse vaccine effects. Thus, the infection could potentially be a trigger of the CFS-like symptoms in a subset of the referred females. To our knowledge, the study is the first to investigate the role of infection in the development of suspected adverse effects after HPV vaccination and replication of these findings are needed in other studies.

Source: Krogsgaard LW, Petersen I, Plana-Ripoll O, Bech BH, Lützen TH, Thomsen RW, Rytter D. Infections in temporal proximity to HPV vaccination and adverse effects following vaccination in Denmark: A nationwide register-based cohort study and case-crossover analysis. PLoS Med. 2021 Sep 8;18(9):e1003768. doi: 10.1371/journal.pmed.1003768. Epub ahead of print. PMID: 34495975. https://pubmed.ncbi.nlm.nih.gov/34495975/

Are cytokines associated with neuropsychiatric syndromes in humans?

Abstract:

Traditional aetiological models in neuropsychiatry have placed little emphasis on the abnormal behavioural responses (decreased psychomotor activity, anorexia, weight loss, decreased social exploration and sexual behaviour, impaired cognitive function and increased somnolence) that are common to both psychiatric syndromes, notably depression, and the illness behaviour of sick animals.

In recent years, the possible role of cytokines, as mediators of not only the immunological and metabolic responses to infection and inflammation but also a co-ordinated behavioural response, has been described. Further, a range of possible mechanisms for these effects has been postulated, notably involving corticotropin releasing factor (CRF) and prostaglandins of the E series (PgE) with the central nervous system (CNS).

Here we outline a series of human clinical conditions where neuropsychiatric syndromes co-occur with a host response to infection or inflammation. These may be characterized by cytokine production (e.g. acute, recurrent and chronic viral illness, systemic autoimmune diseases and chronic fatigue syndrome).

Other clinical situations characterized by exposure to or in vivo production of cytokines (e.g. treatment of chronic infections and malignancies, progression and/or recurrence of malignancies) are also discussed.

We postulate that the stereotyped behavioural repertoire observed is mediated by cytokine-dependent mechanisms within the CNS. Systematic studies of the behavioural responses of such patient groups are suggested, noting specifically correlations between the time course and severity of immune and neuroendocrine and behavioural responses and dose-response effects.

 

Source: Hickie I, Lloyd A. Are cytokines associated with neuropsychiatric syndromes in humans? Int J Immunopharmacol. 1995 Aug;17(8):677-83. http://www.ncbi.nlm.nih.gov/pubmed/8847162