Restless legs syndrome (RLS) augmentation associated with dopamine agonist and levodopa usage in a community sample.

OBJECTIVE: Assess the rate of augmentation as it occurs during standard long-term dopaminergic treatment of RLS, potential risk factors or predictors of augmentation, the relationship between treatment duration and augmentation, and the clinical impact of augmentation on subjects' health outcomes. METHODS: Two hundred sixty-six patients with dopamine-treated RLS completed a one-time online survey. All subjects were recruited by their PCP/neurologist and were 18 or older. Augmentation was assessed using NIH guidelines and an augmentation classification system was developed through this research. RESULTS: Overall, 20% of the patients were classified as having definitive or highly suggestive clinical indications of augmentation. Five factors were considered likely to reflect increased risk of developing augmentation, including more frequent RLS symptoms pre-treatment, greater discomfort with RLS symptoms before treatment, and longer treatment duration. RLS augmentation occurred at a rate of about 8% each year for at least the first 8 years of dopamine treatment. Subjects reporting definite or highly suggestive clinical indicators of augmentation had an average IRLS score of 23.6, indicating generally inadequate treatment with generally poor clinical outcomes. Only 25% of the patients reported no indications of augmentation and they were the only group to show on average a low (<15) IRLS score and good clinical outcomes. CONCLUSIONS: As currently used, long term dopaminergic treatment for an average ± SD of 2.7 ± 2.4 years produced significant augmentation problems in at least 20% of the patients and only 25% of the patients were totally free of this problem. It is important for physicians to carefully screen patients for changes in RLS symptoms for as long as they are on dopamine agents, with particular attention paid to those patients who present with the most severe RLS symptoms prior to treatment initiation. Given the marked increase in suffering with augmentation, a method for early detection and intervention would be an important contribution to the effective management and treatment of RLS.

Interleukin-6 (IL6) genotype is associated with fat-free mass in men but not women.

We studied the association of the G-174C promoter polymorphism in the interleukin-6 gene (IL6) with total body fat and fat-free mass (FFM) in 242 men and women (IL6 genotypes: G/G, n = 87; G/C, n = 100; C/C, n = 55) across the adult age span (21-92 years). In men, but not women (significant genotype by sex interactions; p =.023-.048), the C/C group exhibited significantly lower total FFM than the G/G group (54.7 +/- 0.8 kg vs 57.2 +/- 0.7 kg, respectively, p =.020), as well as significantly lower FFM of the lower limbs compared with the G/G group (18.4 +/- 0.3 kg vs 19.8 +/- 0.3 kg, respectively, p =.004). No significant genotype differences were observed in total body fat mass in either men or women. The results indicate that the IL6 G-174C polymorphism is significantly associated with FFM in men but not women.

C174T polymorphism in the CNTF receptor gene is associated with fat-free mass in men and women.

We performed gene screening of the ciliary neurotrophic factor receptor (CNTFR) gene and genotyped three newly identified polymorphisms: C-1703T in the 5' promoter region, T1069A in intron 5, and C174T in exon 9. We studied the association of these CNTFR variants with muscle strength, mass, and body composition in 465 men and women (20-90 yr) from the Baltimore Longitudinal Study of Aging. Only the C174T variant was significantly associated with muscle-related phenotypes. In the entire cohort, when corrected for age, sex, race, physical activity, and height, homozygotes for the common C allele at C174T (CC) exhibited lower total body mass and body mass index than carriers of the rare T allele, which appeared to be due to significant differences in total nonosseous fat-free mass (FFM) (48.0 +/- 0.4 vs. 50.0 +/- 0.7 kg; P = 0.011) and lower limb FFM (16.5 +/- 0.1 vs. 17.2 +/- 0.2 kg; P = 0.002). The CC group also exhibited significantly lower quadriceps concentric and eccentric isokinetic strength values at both 30 and 180 degrees /s than the T allele carriers (all P < 0.04), but these differences were no longer significant after adjustment for lower limb FFM. There were no significant sex-by-genotype interactions. The results indicate that the C174T polymorphism in exon 9 of CNTFR is significantly associated with FFM in men and women, with concomitant differences in muscular strength.