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INTRODUCTION: The aim of this study was to assess the performance of VibraTip, a device used to test a person's vibration perception during routine checks for peripheral neuropathy, against two thresholds of the Neuropathy Disability Score (NDS) for diagnosing distal symmetrical polyneuropathy (DSPN) in patients with type 2 diabetes mellitus (T2DM). METHODS: One hundred consecutive subjects with T2DM were enrolled in the study, of whom 54 were men. The mean age was 62.3 years, and the mean T2DM duration was 12.6 years. VibraTip was used at one foot site (on the pulp of the hallux; protocol A) and at three foot sites (pulp of the hallux and first and third metatarsal head; protocol B). NDS thresholds of ≥ 3 and ≥ 6 were used to establish the diagnosis of DSPN. RESULTS: Against the NDS ≥ 3 threshold, VibraTip showed a very high sensitivity (91.3%) and negative predictive value (NPV) (92%) and a high specificity (85.2%) with protocol A, and a very high sensitivity (95.6%) and NPV (96.1%) and a very high specificity (90.7%) with protocol B. Against the NDS ≥ 6 threshold, VibraTip showed a very high sensitivity (100%) and NPV (100%) and a very high specificity (95.2%) with protocol A, and very high sensitivity (100%) and NPV (100%) and very high specificity (96.8%) with protocol B. CONCLUSIONS: The diagnostic performance of VibraTip is very high in patients with T2DM, rendering it a very useful device as a screening tool, particularly for the exclusion of DSPN. VibraTip performs very well at both NDS thresholds, but particularly well at the NDS ≥ 6 threshold. There appears to be no need to examine sites other than the hallux site with Vibratip.
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BACKGROUND: The serotonergic system may be implicated in susceptibility to nicotine dependence as nicotine increases 5-hydroxytryptamine (5-HT) release in brain and symptoms of nicotine withdrawal may be modulated by diminished serotonergic neurotransmission. We examined the association of polymorphisms of genes involved in release and receptor function of 5-HT with cigarette smoking initiation in subjects of Caucasian origin. METHODS: 5-HTTLPR polymorphism of the 5-HT transporter gene and -759C/T (rs3813929) and -697G/C (rs518147) polymorphisms of the 5-HT(2C) receptor gene were analyzed in 172 smoking initiators and 254 non-initiators, using PCR-RFLP method. Smoking behavior was assessed with a questionnaire about tobacco use. RESULTS: We found no differences in the frequency of the 5-HTTLPR genotypes between smoking initiators and non-initiators. However, the frequency of 5-HT(2C) -759T allele was significantly higher in non-initiators than smoking initiators (29.5% vs 16.3%, p=0.002) and the same was true for 5-HT(2C) -697C allele carriers (48.8% vs 34.9%, p=0.004). Sex-dependent analysis revealed that these increased frequencies of -759T and -697C allele carriers were present only in males. No association was observed between any quantitative measures of smoking and these three polymorphisms. CONCLUSIONS: 5-HTTLPR polymorphism was not associated with smoking initiation in either male or female subjects. However, significant association was found between 5-HT(2C) receptor gene polymorphisms and smoking initiation in male Caucasian subjects.
