Objective To investigate the association between BMI and the incidence of ischaemic stroke in essential hypertensive (EH) patients.

Methods A total of 2158 EH patients were divided into EH without ischaemic stroke group and EH with ischaemic stroke group. Four BMI quartiles were defined based on BMI level (The first quartile: BMI ≤22.68 kg/m², n=540; The second quartile: BMI 22.69–24.82 kg/m², n=538; The third quartile: BMI 24.83–26.84 kg/m², n=541; The fourth quartile: BMI ≥26.85 kg/m², n=539). The incidence of ischaemic stroke in four BMI levels was evaluated by multivariable logistic regression analyses.

Results (1) The average BMI in EH with ischaemic stroke group is lower than that in EH without ischaemic stroke group (24.36±3.21 vs 25.15±3.31kg/m², p<0.001). (2) Form the first quartile to fourth quartile of BMI, the incidence of ischaemic stroke were decreasing (37.6%, 34.8%, 30.9%, 23.0%, p<0.001). With 6.2% (95% CI 3.3% to 9.0%) decreased risk of incidence ischaemic stroke per 1 kg/m² increase of BMI. (3) Compared with the lowest BMI group, the adjusted OR (aOR) for ischaemic stroke in the highest BMI group was significantly lower (aOR: 0.800, 95% CI: 0.730 to 0.875, p<0.001). (4) In male group, comparing with the lowest BMI group, the aOR for ischaemic stroke in the highest BMI group was significantly lower (aOR: 0.811, 95% CI: 0.717 to 0.918, p=0.001); Similar trend was found in female group (aOR: 0.776, 95% CI: 0.678 to 0.889, p<0.001).

Conclusion Lower BMI was associated with increased incidence of ischaemic stroke in EH patients.