Obesity and the risk of intracerebral hemorrhage: the multicenter study on cerebral hemorrhage in Italy.

BACKGROUND AND PURPOSE: The effect of obesity on the risk of intracerebral hemorrhage (ICH) may depend on the pathophysiology of vessel damage. To further address this issue, we investigated and quantified the correlations between obesity and obesity-related conditions in the causal pathways leading to ICH. METHODS: A total of 777 ICH cases ≥ 55 years of age (287 lobar ICH and 490 deep ICH) were consecutively enrolled as part of the Multicenter Study on Cerebral Hemorrhage in Italy and compared with 2083 control subjects by a multivariate path analysis model. Separate analyses were conducted for deep and lobar ICH. RESULTS: Obesity was not independently associated with an increased risk of lobar ICH (odds ratio [OR], 0.76; 95% confidence interval [CI], 0.58-1.01) or deep ICH (OR, 1.18; 95% CI, 0.95-1.45) when compared with control subjects. The path analysis confirmed the nonsignificant total effect of obesity on the risk of lobar ICH (OR, 0.77; 95% CI, 0.58-1.02) but demonstrated a significant indirect effect on the risk of deep ICH (OR, 1.28; 95% CI, 1.03-1.57), mostly determined by hypertension (OR, 1.07; 95% CI, 1.04-1.11) and diabetes mellitus (OR, 1.04; 95% CI, 1.01-1.07). Obesity was also associated with an increased risk of deep ICH when compared with lobar ICH (OR, 1.62; 95% CI, 1.14-2.31). CONCLUSIONS: Obesity increases the risk of deep ICH, mostly through an indirect effect on hypertension and other intermediate obesity-related comorbidities, but has no major influence on the risk of lobar ICH. This supports the hypothesis of different, vessel-specific, biological mechanisms underlying the relationship between obesity and cerebral hemorrhage.

Habituation of sympathetic sudomotor and vasomotor skin responses: neural and non-neural components in healthy subjects.

OBJECTIVE: Sympathetic skin response (SSR) and skin vasomotor response (SVR) habituation was thought to be induced by neural mechanisms. Here, we investigate the hypothesis that non-neural mechanisms could also be involved. METHODS: We recorded sympathetic skin nerve activity (SSNA) from median nerve by microneurography and the corresponding SSR and SVR in 16 healthy subjects. Superficial electrical stimulation of the opposite median nerve was used to induce arousal responses. RESULTS: Throughout stimulation, SSNA, SSR and SVR amplitude showed a significant reduction. During the first ten stimuli, SSNA showed a marked decrease highly correlated to SSR and SVR changes. During the subsequent 20 stimuli SSNA did not change whereas SSR and SVR significantly decreased. SVR was significantly influenced by skin temperature changes. CONCLUSIONS: Both neural and non-neural mechanisms are involved in SSR and SVR habituation. The neural mechanisms were predominant during the first part of stimulation whereas non-neural mechanisms prevailed during the last part of stimulation. SIGNIFICANCE: During repeated arousal stimuli SSR and SVR amplitude changes did not reflect the strength of the corresponding sympathetic nerve traffic and must be interpreted with caution.

Parallel changes in resting muscle sympathetic nerve activity and blood pressure in a hypertensive OSAS patient demonstrate treatment efficacy.

Studies comparing the efficacy of continuous positive airway pressure (CPAP) versus surgery in correcting cardiovascular abnormalities in OSAS are lacking. We describe an OSAS patient with hypertension who responded favorably to CPAP treatment, whereas subsequent uvulopalatopharyngoplasty (UPPP) was less successful. While CPAP markedly lowered daytime muscle sympathetic nerve activity (MSNA) and blood pressure (BP), findings after UPPP were comparable to pre-treatment baseline. Thus, parallel changes in MSNA and BP demonstrated treatment efficacy.