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Objective: To explore the diagnostic contribution of the 18F-FDG-PET/CT in a population of patients with classical fever of unknown origin (FUO), to pinpoint its place in the diagnostic decision tree in a real-life setting, and to identify the factors associated with a diagnostic 18F-FDG-PET/CT. Method: All adult patients (aged ≥ 18 years) with a diagnosis of classical FUO who underwent an 18F-FDG-PET/CT in the University Hospital of Montpellier (France) between April 2012 and December 2017 were included. True positive 18F-FDG-PET/CT, which evidenced a specific disease causing FUO, were considered to be contributive. Results: Forty-four patients with FUO have been included (20 males, 24 females; mean age 57.5 ± 17.1 years). Diagnoses were obtained in 31 patients (70.5%), of whom 17 (38.6%) had non-infectious inflammatory diseases, 9 had infections (20.5%), and 3 had malignancies (6.8%). 18F-FDG-PET/CT was helpful for making a final diagnosis (true positive) in 43.6% of all patients. Sensitivity and specificity levels were 85% and 37%, respectively. A total of 135 investigations were performed before 18F-FDG-PET/CT, mostly CT scans (93.2%) and echocardiography (59.1%), and 108 after 18F-FDG-PET/CT, mostly biopsies (including the biopsy of a temporal artery) (25%) and MRIs (34%). In multivariate analysis, the hemoglobin level was significantly associated with a helpful 18F-FDG-PET/CT (p = 0.019, OR 0.41; 95% CI (0.20–0.87)), while the CRP level was not associated with a contributive 18F-FDG-PET/CT. Conclusion: 18F-FDG-PET/CT may be proposed as a routine initial non-invasive procedure in the diagnostic workup of FUO, especially in anemic patients who could be more likely to benefit from 18F-FDG-PET/CT.

Lean body mass (LBM) is a determinant of areal bone mineral density (aBMD) through its mechanical actions and quite possibly through its endocrine functions. The threefold aims of this study are: to determine the effects of obesity (OB) on aBMD and myokines; to examine the potential link between myokines and bone parameters; and to determine whether the effects of LBM on aBMD are mediated by myokines. aBMD and myokine levels were evaluated in relation to the body mass index (BMI) in 179 women. Compared with normal-weight controls (CON; n = 40), women with OB (n = 139) presented higher aBMD, myostatin and follistatin levels and lower irisin levels. Except for irisin levels, all differences between the OB and CON groups were accentuated with increasing BMI. For the whole population (n = 179), weight, BMI, fat mass (FM) and LBM were positively correlated with aBMD at all bone sites, while log irisin were negatively correlated. The proportion of the LBM effect on aBMD was partially mediated (from 14.8% to 29.8%), by log irisin, but not by follistatin or myosin. This study showed that myokine levels were greatly influenced by obesity. However, irisin excepted, myokines do not seem to mediate the effect of LBM on bone tissue.

Obesity is characterized by an alteration in body composition (BC); however, it is not known whether this alteration is modified by aging or sex. The aims of this study were to analyze BC in individuals with obesity based on age and sex and to determine the prevalence of sarcopenia. Seven hundred and fifty-five obese individuals were subdivided into four age groups. The hole (WB) and segmental BC were determined using dual-energy X-ray absorptiometry (DXA). In men, the WB lean tissue mass (LTM) and fat mass (FM) adjusted by weight and height were relatively constant with age. In women, the WBLTM was higher and WBFM was lower in the >65 group compared to the 18–34 group. A decrease in the LTM and FM at lower limbs and an increase in the trunk were observed, particularly in women, inducing a lower appendicular lean mass index (ALMI; appendicular LTM/height2) in the >65 group compared to the 18–34 group in both sexes. This study demonstrated that even though the WBLTM and FM are relatively constant with age, individuals with obesity present a localized redistribution of these two components. This body composition change leads to a decrease of the ALMI with age, one of the criteria included in the sarcopenia definition.