Abstract 4581: Systematic Review of the Effects of Excess Body Weight and Obesity on the Incidence of Ischemic and Hemorrhagic Stroke
Background. Obesity has been shown to be associated with increased risk of stroke in most but not all epidemiological studies, but the extent of the association with the various types of stroke is uncertain. We attempted to determine whether a graded association occurs between excess body weight and the incidence of stroke and its subtypes by performing a meta-analysis of the cohort studies available.
Methods. We searched MEDLINE, EMBASE, the Cochrane Library, and bibliographies of retrieved articles. Studies were included if their follow-up observation was at least 5 years and if they reported the number of individuals exposed and the corresponding number of events in each weight category. We used a random effect model and a funnel plot and Egger’s test with trim-and-fill procedure, when necessary.
Findings. Overall 26 studies (617,970 individuals and 15,784 stroke events) met the inclusion criteria and between 7 and 19 of them were available for direct comparisons depending on the stroke subtype and the body weight categories analysed. Overall, there were graded and highly significant associations for both total and ischemic stroke rates and the overweight/obesity state. Compared with normal weight individuals (BMI<25), the pooled RR (95% C.I.) for total stroke were 1.15 (1.01–1.30) among overweight (BMI 25–29.9) and 1.48 (1.23–1.79) among obese individuals (BMI≥30). Subgroup analysis indicated RR= 1.33 (1.15–1.55) in overweight and RR=1.88 (1.54 –2.29) in obese individuals for ischemic strokes and respectively RR= 1.02 (0.90 –1.17) and 1.30 (1.12–1.49) for hemorrhagic stroke. Separate analyses of studies carried respectively in male or female individuals provided similar results.
Conclusions. We conclude that the overweight and the obese conditions were associated with progressively increasing risk of ischemic stroke, whereas a higher probability of hemorrhagic stroke was apparent only for obese individuals.