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.