Role of blood pressure on stroke-related mortality: a 45-year follow-up study in China

BACKGROUND: Hypertension is associated with stroke-related mortality. However, the long-term association of blood pressure (BP) and the risk of stroke-related mortality and the influence path of BP on stroke-related death remain unknown. The current study aimed to estimate the long-term causal associations between BP and stroke-related mortality and the potential mediating and moderated mediating model of the associations. METHODS: This is a 45-year follow-up cohort study and a total of 1696 subjects were enrolled in 1976 and 1081 participants died by the latest follow-up in 2020. COX proportional hazard model was used to explore the associations of stroke-related death with baseline systolic blood pressure (SBP)/diastolic blood pressure (DBP) categories and BP changes from 1976 to 1994. The mediating and moderated mediating effects were performed to detect the possible influencing path from BP to stroke-related deaths. E value was calculated in the sensitivity analysis. RESULTS: Among 1696 participants, the average age was 44.38 ± 6.10 years, and 1124 were men (66.3%). After a 45-year follow-up, a total of 201 (11.9%) stroke-related deaths occurred. After the adjustment, the COX proportional hazard model showed that among the participants with SBP ≥ 160 mmHg or DBP ≥ 100 mmHg in 1976, the risk of stroke-related death increased by 217.5% (hazard ratio [HR] = 3.175, 95% confidence interval [CI]: 2.297–4.388), and the adjusted HRs were higher in male participants. Among the participants with hypertension in 1976 and 1994, the risk of stroke-related death increased by 110.4% (HR = 2.104, 95% CI: 1.632–2.713), and the adjusted HRs of the BP changes were higher in male participants. Body mass index (BMI) significantly mediated the association of SBP and stroke-related deaths and this mediating effect was moderated by gender. CONCLUSIONS: In a 45-year follow-up, high BP and persistent hypertension are associated with stroke-related death, and these associations were even more pronounced in male participants. The paths of association are mediated by BMI and moderated by gender.