Psychometric properties of the Persian version of the Tinnitus Handicap Inventory (THI-P)

Introduction: Tinnitus can have a significant effect on an individual’s quality of life, and is very difficult quantify. One of the most popular questionnaires used in this area is the Tinnitus Handicap Inventory (THI). The aim of this study was to determine the reliability and validity of a Persian translation of the Tinnitus Handicap Inventory (THI-P).   Materials and Methods: This prospective clinical study was performed in the Otolaryngology Department of Guilan University of Medical Sciences, Iran. A total of 102 patients aged 23–80 years with tinnitus completed the (THI-P). The patients were instructed to complete the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI). Audiometry was performed. Eight-five patients were asked to complete the THI-P for a second time 7–10 days after the initial interview. We assessed test–retest reliability and internal reliability of the THI-P. Validity was assessed by analyzing the THI-P of patients according to their age, tinnitus duration and psychological distress (BDI and STAI). A factor analysis was computed to verify if three subscales (functional, emotional, and catastrophic) represented three distinct variables.   Results: Test–retest correlation coefficient scores were highly significant. The THI-P and its subscales showed good internal consistency reliability (α = 0.80 to 0.96). High-to-moderate correlations were observed between THI-P and psychological distress and tinnitus symptom ratings. A confirmatory factor analysis failed to validate the three subscales of THI, and high inter-correlations found between the subscales question whether they represent three distinct factors. Conclusion:  The results suggest that the THI-P is a reliable and valid tool which can be used in a clinical setting to quantify the impact of tinnitus on the quality of life of Iranian patients

The evolutionary genetics of lactase persistence in seven ethnic groups across the Iranian plateau

Abstract Background The ability to digest dietary lactose is associated with lactase persistence (LP) in the intestinal lumen in human. The genetic basis of LP has been investigated in many populations in the world. Iran has a long history of pastoralism and the daily consumption of dairy products; thus, we aim to assess how LP has evolved in the Iranian population. We recruited 400 adult individuals from seven Iranian ethnic groups, from whom we investigated their lactose tolerance and screened the genetic variants in their lactase gene locus. Results The LP frequency distribution ranged from 0 to 29.9% in the seven Iranian ethnic groups with an average value of 9.8%. The variants, − 13910*T and − 22018*A, were significantly associated with LP phenotype in Iranians. We found no evidence of hard selective sweep for − 13910*T and − 22018*A in Persians, the largest ethnic group of Iran. The extremely low frequency of − 13915*G in the Iranian population challenged the view that LP distribution in Iran resulted from the demic diffusion, especially mediated by the spread of Islam, from the Arabian Peninsula. Conclusions Our results indicate the distribution of LP in seven ethnic groups across the Iranian plateau. Soft selective sweep rather than hard selective sweep played a substantial role in the evolution of LP in Iranian populations

Correction to: The evolutionary genetics of lactase persistence in seven ethnic groups across the Iranian plateau

Abstract In the original publication of this article [1], the colors of the Fig. 1 are wrong, and are revised in the updated figure below

The association of serum clusterin levels and Clusterin rs11136000 polymorphisms with Alzheimer disease in a Turkish cohort

Objectives: Several large-scale genome association studies have shown that variants in the "Clusterin"' (CLU) gene are important risk factors for Alzheimer's disease (AD). It has also been shown that plasma CLU levels were elevated in patients with AD and associated with disease severity and progression. In this study, we aimed to investigate whether the CLU rs11136000 polymorphism was associated with AD in our cohort of Turkish patients. We also evaluated the association of serum CLU levels and rs11136000 genotypes between patients and controls. Materials and Methods: Genotyping was performed in 327 patients who were diagnosed as having AD (mean age: 67.2 +/- 10.8 years) and 344 controls (mean age: 57.7 +/- 13.1 years). The rs11136000 genotypes were determined using quantitative real-time polymerase chain reaction with hydrolysis probes. Serum CLU levels were assessed in 25 patients with AD and 10 controls using enzyme-linked immunosorbent assay. Results: Our results showed no significant difference in genotype and allele frequencies of CLU rs11136000 polymorphisms between patients with AD and controls. Serum CLU levels in patients with AD did not differ from those of the controls. Furthermore, serum CLU levels showed no major difference between carriers of CC and TT + CT genotypes in the controls and patients with AD. Conclusion: Our results suggest that the CLU rs11136000 polymorphism is not associated with AD in our Turkish patients, and rs11136000 genotypes may not have an effect on serum CLU levels