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Background: Despite accumulating evidence of an association between air pollution and renal disease, studies on the association between long-term exposure to air pollution and renal function are still contradictory. This study aimed to investigate this association in a large population with relatively low exposure and with improved estimation of renal function as well as renal injury biomarkers., Methods: We performed a cross-sectional analysis in the middle-aged general population participating in the Swedish CardioPulmonary bioImaging Study (SCAPIS; n = 30 154). Individual 10-year exposure to total and locally emitted fine particulate matter (PM 2.5 ), inhalable particulate matter (PM 10 ), and nitrogen oxides (NO x ) were modelled using high-resolution dispersion models. Linear regression models were used to estimate associations between exposures and estimated glomerular filtration rate (eGFR, combined creatinine and cystatin C) and serum levels of renal injury biomarkers (KIM-1, MCP-1, IL-6, IL-18, MMP-2, MMP-7, MMP-9, FGF-23, and uric acid), with consideration of potential confounders., Results: Median long-term PM 2.5 exposure was 6.2 µg/m 3 . Almost all participants had a normal renal function and median eGFR was 99.2 mL/min/1.73 m 2 . PM 2.5 exposure was associated with 1.3% (95% CI 0.6, 2.0) higher eGFR per 2.03 µg/m 3 (interquartile range, IQR). PM 2.5 exposure was also associated with elevated serum matrix metalloproteinase 2 (MMP-2) concentration, with 7.2% (95% CI 1.9, 12.8) higher MMP-2 per 2.03 µg/m 3 . There was a tendency towards an association between PM 10 and higher levels of uric acid, but no associations were found with the other biomarkers. Associations with other air pollutants were null or inconsistent., Conclusion: In this large general population sample at low exposure levels, we found a surprising association between PM 2.5 exposure and a higher renal filtration. It seems unlikely that particle function would improve renal function. However, increased filtration is an early sign of renal injury and may be related to the relatively healthy population at comparatively low exposure levels. Furthermore, PM 2.5 exposure was associated with higher serum concentrations of MMP-2, an early indicator of renal and cardiovascular pathology., (© 2024. The Author(s).)

Background: Aims were to examine gender differences in patients with gout with regard to a) self-reported gout severity, b) illness perceptions (IP), c) impact on daily activities and Quality of Life (QoL), d) advice from healthcare professionals, e) having changed dietary- or alcohol habits., Methods: Adult patients with gout identified in primary and secondary care in Sweden between 2015 and 2017 (n = 1589) were sent a questionnaire about demographics, gout disease severity, IP (using the Brief Illness Perception Questionnaire, (B-IPQ)) and disease management. T-tests, Chi square tests, ANalysis Of VAriance (ANOVA) and linear regression models were used for gender comparisons., Results: Eight hundred sixty-eight patients responded to the questionnaire. Women, n = 177 (20%), experienced more severe gout symptoms (p = 0.011), albeit similar frequencies of flares compared to men. Women experienced modest but significantly worse IP with regard to consequences, identity, concerns and emotional response (p < 0.05) as well as daily activities such as sleeping (p < 0.001) and walking (p = 0.042) and QoL (p = 0.004). Despite this and a higher frequency of obesity in women (38 vs 21%, P < 0.001) and alcohol consumption in men (p < 0.001), obese women had received significantly less advice regarding weight reduction (47 vs 65%, p = 0.041) compared to obese men. On the other hand, women reported having acted on dietary advice to a larger degree., Conclusions: Despite only modestly worse gout severity and perception, women appear to have been given less information regarding self-management than men. These gender differences should be given attention and addressed in clinical care., (© 2023. The Author(s).)

Background: Increased level of urate is the strongest risk factor for gout development but since only a minority of hyperuricemics are affected by gout, other pathogenic factors must be considered. Low birth weight is associated with future morbidities causing hyperuricemia, such as diabetes and renal disease. The purpose of this study was to investigate if, and to what extent, maternal and perinatal factors, including birth weight, are associated with future risk of being diagnosed with gout., Methods: A population-based retrospective nested case-control registry study based on regional and national health care registers in Sweden. All incident cases of gout born in 1973 and onward who had received ≥1 diagnosis of gout from 2000 through 2019 in the region of western Sweden were included. Up to 5 non-gout controls were matched to each case by age, sex, and county at the year of first gout diagnosis. A range of maternal, gestational, and perinatal factors were analyzed for their potential association to future gout development. This included the health of the mother, gestational length, birth weight, number of siblings, and congenital malformations., Results: Maternal diabetes, any congenital malformation, and being small for gestational age were factors that significantly increased the risk for future gout development, odds ratio (95% CI) 3.1 (1.3 to 7.4) (p=0.01), 1.33 (1.04 to 1.7) (p=0.02), and 1.75 (1.3 to 2.3) (p<.0001), respectively., Conclusions: In this study, maternal diabetes and being small for gestational age increased the risk for future gout development in young adults. As of today, these conditions are becoming more prevalent and may contribute to the ongoing gout epidemic. These results require both confirmation and further delineation of underlying mechanisms., (© 2022. The Author(s).)

Background: Gout is predicted by a number of comorbidities and lifestyle factors. We aimed to identify discrete phenotype clusters of these factors in a Swedish population-based health survey. In these clusters, we calculated and compared the incidence and relative risk of gout., Methods: Cluster analyses were performed to group variables with close proximity and to obtain homogenous clusters of individuals (n = 22,057) in the Malmö Preventive Project (MPP) cohort. Variables clustered included obesity, kidney dysfunction, diabetes mellitus (DM), hypertension, cardiovascular disease (CVD), dyslipidemia, pulmonary dysfunction (PD), smoking, and the use of diuretics. Incidence rates and hazard ratios (HRs) for gout, adjusted for age and sex, were computed for each cluster., Results: Five clusters (C1-C5) were identified. Cluster C1 (n = 16,063) was characterized by few comorbidities. All participants in C2 (n = 750) had kidney dysfunction (100%), and none had CVD. In C3 (n = 528), 100% had CVD and most participants were smokers (74%). C4 (n = 3673) had the greatest fractions of obesity (34%) and dyslipidemia (74%). In C5 (n = 1043), proportions with DM (51%), hypertension (54%), and diuretics (52%) were highest. C1 was by far the most common in the population (73%), followed by C4 (17%). These two pathways included 86% of incident gout cases. The four smaller clusters (C2-C5) had higher incidence rates and a 2- to 3-fold increased risk for incident gout., Conclusions: Five distinct clusters based on gout-related comorbidities and lifestyle factors were identified. Most incident gout cases occurred in the cluster of few comorbidities, and the four comorbidity pathways had overall a modest influence on the incidence of gout.

Background: Fertility preservation is particularly challenging in young women diagnosed with hematopoietic cancers, as transplantation of cryopreserved ovarian cortex in these women carries the risk for re-introducing cancer cells. Therefore, the construction of a bioengineered ovary that can accommodate isolated small follicles was proposed as an alternative to minimize the risk of malignancy transmission. Various options for viable bioengineered scaffolds have been reported in the literature. Previously, we reported three protocols for producing mouse ovarian scaffolds with the decellularization technique. The present study examined these scaffolds further, specifically with regards to their extracellular composition, biocompatibility and ability to support recellularization with mesenchymal stem cells., Material and Methods: Three decellularization protocols based on 0.5% sodium dodecyl sulfate (Protocol 1; P1), or 2% sodium deoxycholate (P2), or a combination of the two detergents (P3) were applied to produce three types of scaffolds. The levels of collagen, elastin and sulfated glycosaminoglycans (sGAGs) were quantified in the remaining extracellular matrix. Detailed immunofluorescence and scanning electron microscopy imaging were conducted to assess the morphology and recellularization efficiency of the constructs after 14 days in vitro utilizing red fluorescent protein-labelled mesenchymal stem cells., Results: All protocols efficiently removed the DNA while the elastin content was not significantly reduced during the procedures. The SDS-protocol (P1) reduced the sGAG and the collagen content more than the SDC-protocol (P2). All scaffolds were biocompatible and recellularization was successful, particularly in several P2-derived scaffolds. The cells were extensively distributed throughout the constructs, with a denser distribution observed towards the ovarian cortex. The cell density was not significantly different (400 to 550 cells/mm 2 ) between scaffold types. However, there was a tendency towards a higher cell density in the SDC-derived constructs. Scanning electron microscope images showed fibrous scaffolds with a dense repopulated surface structure., Conclusions: While there were differences in the key structural macromolecules between protocols, all scaffolds were biocompatible and showed effective recellularization. The results indicate that our SDC-protocol might be better than our SDS-protocol. However, additional studies are necessary to determine their suitability for attachment of small follicles and folliculogenesis.

Background: Hyperuricemia is closely associated with cardiovascular disease (CVD). However, it has not been definitively established whether this association is independent of traditional cardiovascular risk factors (CVRFs) and whether it is gender-dependent. The aim of this study was to investigate in a population-based cohort (age range, 50-64 years) stratified by sex the association between the serum urate (SU) concentration and subclinical atherosclerosis, as reflected in the coronary artery calcification (CAC) score, common carotid intima-media thickness (CIMT), and carotid plaque score., Methods: The study involved participants in the Swedish CArdioPulmonary bioImage Study (SCAPIS) Pilot cohort (N = 1040; 48.8% males). This pilot cohort is part of the large population-based SCAPIS with 30,000 participants in the age range of 50-64 years, aimed at improving risk prediction for CVD. Subjects with a self-reported previous history of CVD (N = 68) or gout (N = 3) were excluded. The CAC score was assessed with the Agatston method using computed tomography. CIMT and carotid plaques were quantified by ultrasound. The associations between the SU quartiles and different levels of CAC, CIMT, and carotid plaques were assessed by multivariable logistic regression., Results: Age, BMI, education level, smoking, physical activity, hs-CRP, hypertension, and dyslipidemia showed no differences between males and females, while CAC (score > 0) and diabetes were both twice as common in men than in women (58% vs 26% and 8% vs 4%, respectively). Higher SU quartiles were in both sexes associated with BMI, hs-CRP, and the prevalence of hypertension, and in women, they were also associated with the prevalence of dyslipidemia. The three upper quartiles of SU (>308μmol/L) were linked to higher CAC scores in men, when adjusting for CVRFs, but not in women. CIMT and carotid plaques showed no correlation to SU in either sex., Conclusions: Higher levels of SU are associated with the presence of CAC in men but not in women, whereas SU is not associated with CIMT or carotid plaques in either men or women. This implies that the biological effects of SU differ in men and women or that SU has varying effects on different vascular beds or during the different stages of the atherosclerotic process.

Background: In order to preserve fertility in young women with disseminated cancer, e.g. leukemia, an approach that has been suggested is to retransplant isolated small follicles within an ovarian matrix free from malignant cells and with no risk for contamination. The present study evaluates the first step to create a bioengineered ovarian construct that can act as growth-supporting tissue for isolated small follicles that are dependent on a stroma for normal follicular maturation. The present study used the intact mouse ovary to develop a mouse ovarian scaffold through various protocols of decellularization., Material and Methods: Potential Immunogenic DNA and intracellular components were removed from whole mouse ovaries by agitation in a 0.5% sodium dodecyl sulfate solution (Protocol 1; P1), or in a 2% sodium deoxycholate solution (P2) or by a combination of the two (P3). The remaining decelluralized ovarian extracellular matrix structure was then assessed based on the DNA- and protein content, and was further evaluated histologically by haematoxylin and eosin-, Verhoeff's van gieson- (for elastin), Masson's trichrome- (for collagens) and Alcian blue (for glycosaminoglycans) staining. We also evaluated the decellularization efficiency using the mild detergent Triton-X100 (1%)., Results: Sodium dodecyl sulfate efficiently removed DNA and intracellular components from the ovarian tissue but also significantly reduced the integrity of the remaining ovarian extracellular matrix. Sodium deoxycholate, a considerably milder detergent compared to sodium dodecyl sulfate, preserved the ovarian extracellular matrix better, evident by a more distinct staining for glycosaminoglycan, collagen and elastic fibres. Triton-X100 was found ineffective as a decellularization reagent for mouse ovaries in our settings., Conclusions: The sodium dodecyl sulfate generated ovarian scaffolds contained minute amounts of DNA that may be an advantage to evade a detrimental immune response following engraftment. The sodium deoxycholate generated ovarian scaffolds had higher donor DNA content, yet, retained the extracellular composition better and may therefore have improved recellularization and other downstream bioengineering applications. These two novel types of mouse ovarian scaffolds serve as promising scaffold-candidates for future ovarian bioengineering experiments.

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Background: The aim of this study is to examine the occurrence of comorbidities at the time of first diagnosis of gout compared with matched population controls, overall and by sex, as well as to examine the crude and age-standardized prevalence of these comorbidities in men and women with gout at first diagnosis., Methods: A population-based study used data from Swedish national and regional registers, including 14,113 gout patients aged ≥ 20 years, with a first recorded diagnosis of gout between 1 January 2006 and 31 December 2012, and 65,782 population controls, matched by age, sex and county. Prevalence ratios (95% confidence intervals) comparing gout cases and controls were calculated, overall and by sex. Crude and age-standardized prevalence (95% confidence interval) of all comorbidities in gout patients were calculated, to show differences between sexes, taking also the higher age at diagnosis in women into account., Results: All examined comorbidities were 1.2-2.5-fold more common in gout patients at diagnosis than in population controls in both sexes. Women with gout were on average 6 years older than men at first gout diagnosis and most comorbidities, including obesity and diuretic use, were or tended to be more frequent in women than in men. When standardizing for age, women had a higher prevalence of thromboembolism (6.6% vs 5.2%) and chronic obstructive pulmonary disease (3.1% vs 2.4%). Men, on the other hand, had a higher prevalence of coronary heart disease (9.4% vs 6.4%), atrial fibrillation (9.0% vs 6.0%), congestive heart failure (7.7% vs 6.6%) and stroke (4.1% vs 3.3%)., Conclusions: The occurrence of most comorbidities was significantly increased at first diagnosis of gout in both sexes. Women were older at diagnosis and had higher occurrence of most comorbidities, including obesity and diuretic use, factors that increase serum urate, and this needs to be taken into account when starting and optimizing urate lowering therapy. These sex differences were attenuated when standardizing for age and the occurrence of cardiovascular diseases was actually higher in men.

Background: To investigate the risk of first-time acute coronary syndrome (ACS), stroke and venous thromboembolism (VTE) in patients with ankylosing spondylitis (AS), psoriatic arthritis (PsA) and undifferentiated spondyloarthritis (uSpA), compared to each other and to the general population (GP)., Methods: This is a prospective nationwide cohort study. Cohorts with AS (n = 6448), PsA (n = 16,063) and uSpA (n = 5190) patients and a GP (n = 266,435) cohort, were identified 2001-2009 in the Swedish National Patient and Population registers. The follow-up began 1 January 2006, or 6 months after the first registered spondyloarthritis (SpA) diagnosis thereafter, and ended at ACS/stroke/VTE event, death, emigration or 31 December 2012. Crude and age- and sex-standardized incidence rates (SIRs) and hazard ratios (HRs) were calculated for incident ACS, stroke or VTE, respectively., Results: Standardized to the GP cohort, SIRs for ACS were 4.3, 5.4 and 4.7 events per 1000 person-years at risk in the AS, PsA and uSpA cohort, respectively, compared to 3.2 in the GP cohort. SIRs for stroke were 5.4, 5.9 and 5.7 events per 1000 person-years at risk in the AS, PsA and uSpA cohort compared to 4.7 in the GP cohort. Corresponding SIRs for VTE were 3.6, 3.2 and 3.5 events per 1000 person-years at risk compared to 2.2 in the GP cohort. Age-and sex-adjusted HRs (95% CI) for ACS events were significantly increased in AS (1.54 (1.31-1.82)), PsA (1.76 (1.59-1.95)) and uSpA (1.36 (1.05-1.76)) compared to GP. Age-adjusted HRs for ACS was significantly decreased in female AS patients (0.59 (0.37-0.97)) compared to female PsA patients. Age-and sex-adjusted HRs for stroke events were significantly increased in AS (1.25 (1.06-1.48)) and PsA (1.34 (1.22-1.48)), and nonsignificantly increased in uSpA (1.16 (0.91-1.47)) compared to GP. For VTE the age-and sex-adjusted HRs for AS, PsA and uSpA were equally and significantly increased with about 50% compared to GP., Conclusions: Patients with AS, PsA and uSpA are at increased risk for ACS and stroke events, which emphasizes the importance of identification of and intervention against cardiovascular risk factors in SpA patients. Increased alertness for VTE is warranted in patients with SpA.

Background: Gout is the most common inflammatory arthritic disease and is caused by crystal deposition secondary to persistent hyperuricemia. Etiological treatment with urate-lowering therapy (ULT) has been available since the 1950s but previous studies have demonstrated suboptimal degree of treatment. In recent years we have seen recommendations for ULT earlier in the course of the disease, but there are few contemporary reports reflecting the current situation. Therefore we set out to investigate proportion receiving and persisting with ULT after gout diagnosis and predictors thereof., Method: A population-based cohort study using regional and national population-based registers. Cohort of patients (n = 7709) from western Sweden with incident gout aged 18 years and above from 2011 to 2013. An incident case of gout was defined as having been given a diagnosis of gout (ICD-10 M10, M14.0-14.1) not preceded by a gout diagnosis or a dispensation of ULT during the previous 5 years. Main outcome measures were cumulative incidence and predictors for start of, and persistence with, ULT in gout., Results: Within the first year after first gout diagnosis, 32% received ULT. Male sex, presence of diabetes or cardiovascular comorbidity, reduced kidney function but not diagnosed "end-stage kidney failure" increased the likelihood of receiving ULT. Of those starting ULT a majority (75%) did not persist with ULT treatment within the first 2 years. Age <50 years, lack of comorbidities, and "normal kidney function" or "end-stage kidney failure" were associated with non-persistence with ULT., Conclusions: Only a minority of patients received ULT and a majority of these did not persist with treatment over the next 2 years. However, the older patients with renal impairment and comorbidities, possibly suffering from a more severe gout disease, were more likely to receive and persist with treatment. There is thus still room for considerable improvement with regards to management of ULT in gout.

Background: Symptoms and prognosis of patients with rheumatoid arthritis (RA) have improved with more intensive therapy, including the biological disease-modifying anti-rheumatic drugs (bDMARDs). Real life data concerning how comorbidities are distributed among patients treated or not treated with bDMARDs are scarce. Our objective was to investigate differences in comorbidity and health care consumption in RA patients, with and without bDMARDs., Methods: This cross-sectional study was performed in the Southwestern part of Sweden. Patients, aged ≥ 18 years and diagnosed with RA in secondary health care during 2009-2010, were identified in the regional health care database. Aggregated data of comorbidity and health care consumption were retrieved between 2006 and 2010. RA patients treated with bDMARDs on 31st December 2010 were identified in the Swedish Rheumatology Quality Register (SRQ), which includes the biologics register Anti-Rheumatic Therapy in Sweden (ARTIS). Descriptive, comparative, univariate and multiple logistic regression analyses were used to identify factors associated with bDMARDs., Results: Seven thousand seven hundred and twelve (7712) RA patients were identified (age 64.8 ± 14.9 years, women 74.3%), of whom 1137 (14.7%) were treated with bDMARDs. Overall, the most common comorbidities were infections (69.2%), hypertension (41.1%), chronic respiratory disease (15.3%), ischemic heart disease (14.0%) and malignancy (13.7%). Patients without bDMARDs were older and had more comorbidity. In the multiple logistic regression analysis, older age, cerebrovascular and chronic respiratory disease, heart failure, depression and malignancy were all associated with no present bDMARDs. Infections were associated with bDMARDs. Patients treated with bDMARDs consumed more secondary outpatient care but less visits in primary health care compared to patients without bDMARDs., Conclusions: Patients treated with bDMARDs versus no bDMARDs were younger and had significantly lower period prevalence for most common comorbidities, with the exception of infections. Differences in comorbidities between RA patients with or without bDMARDs should be taken into consideration when evaluating effectiveness and safety of bDMARDs in ordinary care.

Background: The role of environmental exposures in the pathogenesis of ankylosing spondylitis (AS) remains unclear. In particular, two types of exposures have been suspected to play a role: mechanical stress and infections. The objective of this case-control study was to determine if childhood infections are associated with later development of AS., Methods: The cases with AS were identified through the Swedish national outpatient specialised-care register, based on having been given at least one AS diagnosis in the register between 2001 and 2010. Five controls per case were identified in the Swedish population register, matched at the time-point of the index case's first spondyloarthritis diagnosis on sex, birth year, and county. All cases/controls matched prior to the age of 17 years were excluded, as well as all cases/controls given a diagnosis of reactive arthritis or juvenile arthritis at any time point, or any other diagnosis of a rheumatic disease, psoriasis, iridocyclitis, or inflammatory bowel disease before the time-point of matching. All events of hospitalisation with an infection before the age of 17 years were retrieved from the register, and categorised according to the focus of the infection. Odds ratios (ORs) and confidence intervals (CIs) were determined through conditional logistic regression analyses., Results: Of the 2453 cases with AS and 10,257 controls, 17.4 % of the cases and 16.3 % of the controls had been hospitalised with an infection before the age of 17 years (OR 1.08, 95 % CI 0.96-1.22). Appendicitis (1.5 % cases; 2.5 % controls; OR 0.59, 95 % CI 0.41-0.83), respiratory tract infections (cases 11.2 %; controls 9.2 %; OR 1.24, 95 % CI 1.07-1.44) and, in particular, tonsillitis (cases 3.7 %; controls 2.8 %; OR 1.31, 95 % CI 1.03-1.67) were associated with AS. There were no associations between AS and any other type of infection, and the point estimates were similar in several sensitivity analyses., Conclusions: Childhood appendicitis was associated with a decreased risk, whereas respiratory tract infections were associated with an increased risk for later development of AS. These findings support a possible relationship between childhood infections and later development of AS, although the study is limited to infections resulting in inpatient care.

Background: The aim of the present study was to describe prevalence and trends in the incidence of gout and patterns of urate-lowering treatment (ULT) in the Western Swedish Health Care Region (WSHCR) from 2002 to 2012., Methods: We used regional and national healthcare registers to estimate the prevalence and incidence of gout in 2012, and trends in incidence for each calendar year from 2005 to 2012. We also investigated the pattern of ULT for gout using the Swedish Prescribed Drug Register., Results: In 2012, in the population aged 20 years and above, the prevalence of gout was 1.8 % (95 % confidence interval (CI) 1.77 to 1.82) and the incidence was 190 cases (95 % CI 180 to 200) per 100,000 person-years. Applying more strict definitions for a gout case rendered a prevalence of 1.36 % (95 % CI 1.34 to 1.38) and 0.5 (95 % CI 0.49 to 0.51) per 100,000 person-years, respectively. The incidence of gout increased steadily and significantly from 2005 to 2012, with an almost 50 % increase in the total population. There was no significant difference in the prevalence of gout in rural compared to urban areas. ULT was dispensed to only 42 % of patients with gout in 2012 who had ever been diagnosed with gout during the preceding 10-year period., Conclusions: Gout is the most common arthritic disease in WSHCR, Sweden, and has increased substantially over the last decade, with only a minority of prevalent cases in 2012 receiving ULT.

Background: The diagnostic golden standard for gout is to detect monosodium urate (MSU) crystals in synovial fluid. While some gout classification criteria include this variable, most gout diagnoses are based on clinical features. This discrepancy between clinical practice and classification criteria can hinder gout epidemiological studies. Here, the objective was to validate gout diagnoses (International Classification of Diseases (ICD)-10 gout codes) in primary and secondary care relative to five classification criteria (Rome, New York, ARA, Mexico, and Netherlands). The frequency with which MSU crystal identification was used to establish gout diagnosis was also determined., Methods: In total, 394 patients with ≥1 ICD-10 gout diagnosis between 2009 and 2013 were identified from the medical records of two primary care centers (n = 262) and one secondary care center (n = 132) in Gothenburg, Sweden. Medical records were assessed for all classification criteria., Results: Primary care patients met criteria cutoffs more frequently when ≥2 gout diagnoses were made. Even then, few primary care patients met the Rome and New York cutoffs (19 % and 8 %, respectively). The ARA, Mexico, and Netherlands cutoffs were met more frequently by primary care patients with ≥2 gout diagnoses (54 %, 81 %, and 80 %, respectively). Mexico and Netherlands cutoffs were met more frequently by the rheumatology department patients (80 % and 71 %, respectively), even when patients with only 1 gout diagnosis were included. Analysis of MSU crystals served to establish gout diagnoses in only 27 % of rheumatology department and 2 % of primary care cases., Conclusions: If a patient was deemed to have gout at ≥2 primary care center or ≥1 rheumatology-center visits according to an ICD-10 gout code, the positive predictive value of this variable in relation with the Mexico and Netherlands classification criteria was ≥80 % for both primary care and rheumatology care settings in Sweden. MSU crystal identification was rarely used to establish gout diagnosis.

Introduction: Fibromyalgia (FM) is characterized by chronic pain. Impaired growth hormone responses and reduced serum insulin-like growth factor 1 (IGF-1) are common in FM. The aim was to examine changes in serum IGF-1, cerebrospinal fluid (CSF), neuropeptides, and cytokines during aerobic exercise in FM patients., Methods: In total, 49 patients (median age, 52 years) with FM were included in the study. They were randomized to either the moderate- to high-intensity Nordic Walking (NW) program (n = 26) or the supervised low-intensity walking (LIW) program (n = 23). Patients participated in blood tests before and after 15 weeks of aerobic exercise. Changes in serum levels of free IGF-1, pain rating on a 0- to 100-mm scale, pain threshold, and 6-minute walk test (6MWT) were examined. CSF, neuropeptides, matrix metalloproteinase 3 (MMP-3), and inflammatory cytokines were determined. Nonparametric tests were used for group comparisons and correlation analyses., Results: Serum free IGF-1 levels did not change during 15 weeks of exercise between the two groups, although the 6MWT significantly improved in the NW group (p = 0.033) when compared with LIW. Pain did not significantly change in any of the groups, but tended to decrease (p = 0.052) over time in the total group. A tendency toward a correlation was noted between baseline IGF-1 and a decrease of pain in response to exercise (r = 0.278; p = 0.059). When adjusted for age, this tendency disappeared. The change in serum free IGF-1 correlated positively with an alteration in CSF substance P (SP) levels (rs = 0.495; p = 0.072), neuropeptide Y (NPY) (rs = 0.802; p = 0.001), and pain threshold (rs = 0.276; p = 0.058). Differing CSF SP levels correlated positively to a change in pain threshold (rs = 0.600; p = 0.023), whereas the shift in CSF MMP-3 inversely correlated with an altered pain threshold (rs = -0.569; p = 0.034)., Conclusions: The baseline level of serum free IGF-1 did not change during high or low intensity of aerobic exercise. Changes in IGF-1 correlated positively with a variation in CSF SP, NPY, and pain threshold. These data indicate a beneficial role of IGF-1 during exercise in FM.