Yale Food Addiction Scale 2.0 (YFAS 2.0) and modified YFAS 2.0 (mYFAS 2.0): Rasch analysis and differential item functioning.

BACKGROUND: Food addiction (FA) is a prevalent concern that may manifest as poorly controlled food consumption and promote overweight/obesity. Thus, having a well-established instrument for assessment may facilitate better prevention and treatment. The current study investigated the psychometric properties of two common measures of FA (i.e., the Yale Food Addiction Scale [YFAS] 2.0 and its modified version, mYFAS 2.0) using a robust statistical analysis (Rasch model). METHODS: In this cross-sectional study, the scales were sent to 974 students studying in higher education (60% females) in Taiwan through online media including email and social networks. Rasch modeling was used to assess dimensionality, difficulty level, and item misfit and hierarchy. Differential item functioning (DIF) was performed to examine consistency of the items across gender and weight status. RESULTS: Rasch analysis indicated 3 items of the 35 items belonging to the YFAS 2.0 (8.6%) and none belonging to the mYFAS 2.0 were misfit. Unidimensionality and construct validity of both scales were supported by appropriate goodness-of-fit for diagnostic criteria. The person separation was 3.14 (reliability = 0.91) for the YFAS 2.0 and 2.17 (reliability = 0.82) for mYFAS 2.0, indicating the scales could distinguish participants into more than 3 strata. Only one substantial DIF was found for diagnostic criteria of "Failure to fulfill major role obligation" in the YFAS 2.0 across gender. CONCLUSION: According to Rasch modeling, both the YFAS 2.0 and mYFAS 2.0 have acceptable construct validity in Chinese-speaking youth. Scoring methods using either diagnostic criteria or symptom counts for both the YFAS 2.0 and mYFAS 2.0 are supported by the present Rasch findings.

Food addiction is related to eating disorders and may overlap with a variety of disorders, including binge-eating disorder, night-eating syndrome, bulimia nervosa or other conditions. Therefore, it is important for healthcare providers to assess food addiction and one commonly used method is using the Yale Food Addiction Scale (YFAS) developed by Gearhardt and her colleagues. The YFAS has been updated and revised into two versions: the YFAS 2.0 and modified YFAS 2.0 (i.e., mYFAS 2.0). Psychometric testing studies have reported the feasibility and adequate properties for both the YFAS 2.0 and mYFAS 2.0. However, prior studies' findings were based on classical test theory (CTT) findings. The present study thus used a modern test theory (i.e., Rasch models) to examine if both the YFAS 2.0 and mYFAS 2.0 have similarly satisfactory psychometric properties shown in the CTT findings. The present findings using Rasch models support the use of both the YFAS 2.0 and mYFAS 2.0 to assess food addiction among youth. Therefore, healthcare providers may use either the YFAS 2.0 or mYFAS 2.0 to assess levels of food addiction.

Evolutionary histories of coxsackievirus B5 and swine vesicular disease virus reconstructed by phylodynamic and sequence variation analyses.

Coxsackievirus (CV)-B5 is a common human enterovirus reported worldwide; swine vesicular disease virus (SVDV) is a porcine variant of CV-B5. To clarify the transmission dynamics and molecular basis of host switching between CV-B5 and SVDV, we analysed and compared the VP1 and partial 3Dpol gene regions of these two viruses. Spatiotemporal dynamics of viral transmission were estimated using a Bayesian statistical inference framework. The detected selection events were used to analyse the key molecules associated with host switching. Analyses of VP1 sequences revealed six CV-B5 genotypes (A1-A4 and B1-B2) and three SVDV genotypes (I-III). Analyses of partial 3Dpol revealed five clusters (A-E). The genotypes evolved sequentially over different periods, albeit with some overlap. The major hub of CV-B5 transmission was in China whereas the major hubs of SVDV transmission were in Italy. Network analysis based on deduced amino acid sequences showed a diverse extension of the VP1 structural protein, whereas most sequences were clustered into two haplotypes in the partial 3Dpol region. Residue 178 of VP1 showed four epistatic interactions with residues known to play essential roles in viral host tropism, cell entry, and viral decoating.

Phylodynamic Characterization of an Ocular-Tropism Coxsackievirus A24 Variant.

Recent phylodynamic studies have focused on using tree topology patterns to elucidate interactions among the epidemiological, evolutionary, and demographic characteristics of infectious agents. However, because studies of viral phylodynamics tend to focus on epidemic outbreaks, tree topology signatures of tissue-tropism pathogens might not be clearly identified. Therefore, this study used a novel Bayesian evolutionary approach to analyze the A24 variant of coxsackievirus (CV-A24v), an ocular-tropism agent of acute hemorrhagic conjunctivitis. Analyses of the 915-nucleotide VP1 and 690-nt 3Dpol regions of 21 strains isolated in Taiwan and worldwide during 1985-2010 revealed a clear chronological trend in both the VP1 and 3Dpol phylogenetic trees: the emergence of a single dominant cluster in each outbreak. The VP1 sequences included three genotypes: GI (prototype), GIII (isolated 1985-1999), and GIV (isolated after 2000); no VP1 sequences from GII strains have been deposited in GenBank. Another five genotypes identified in the 3Dpol region had support values >0.9. Geographic and demographic transitions among CV-A24v clusters were clearly identified by Bayes algorithm. The transmission route was mapped from India to China and then to Taiwan, and each prevalent viral population declined before new clusters emerged. Notably, the VP1 and 3Dpol genes had high nucleotide sequence similarities (94.1% and 95.2%, respectively). The lack of co-circulating lineages and narrow tissue tropism affected the CV-A24v gene pool.