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Socioeconomic Disparities in the Association of Age at First Live Birth with Incident Stroke Among Chinese Parous Women: A Prospective Cohort Study
27 Pages Posted: 6 Nov 2023
More...Abstract
Background: Stroke has become a significant health issue in China. Women’s age at first live birth (AFLB) may be associated with subsequent stroke, and the association might differ across socioeconomic status (SES).
Methods: Using data from the China Kadoorie Biobank, 290,932 Chinese parous women were recruited in the baseline survey between 2004 and 2008 and followed up until 2015. Latent class analysis was employed to identify urban-rural SES classes. Cox proportional hazard regression was performed to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for AFLB’s association with incident stroke. Population attributable fraction (PAF) was calculated to demonstrate the population-level impact of later AFLB on stroke.
Findings: Around 8·9% of parous women developed stroke after AFLB. Compared with women with AFLB <22 years, those with older AFLB had a higher risk of total stroke, with fully adjusted HRs (95% CI) of 1·71 (1·65-1·77) for 22-24 years and 3·37 (3·24-3·51) for ≥25 years. The associations of AFLB with ischemic stroke were stronger among rural-low-SES participants. The highest PAFs (95% CI) of ischemic stroke (60·1% [46·2-70·3%]) were found for urban-high-SES individuals.
Interpretation: Older AFLB was associated with higher risks of incident stroke and its subtypes among Chinese parous women, with stronger associations between AFLB and ischemic stroke among rural-low-SES participants.
Funding: Supported by the British Heart Foundation, Cancer Research UK, Chinese Ministry of Science and Technology, Chinese National Natural Science Foundation, the Kadoorie Charitable Foundation in Hong Kong, Medical Research Council UK and the Wellcome Trust.
Declaration of Interest: The authors declare that they have no conflicts of interest.
Ethical Approval: The CKB study obtained ethical approval from the Oxford University Tropical Research Ethics Committee (Approval No. 025-04) and the Chinese Center for Disease Control and Prevention Ethical Review Committee (Approval No. 005/ 2004). All participants provided written informed consent.
Keywords: age at first live birth, stroke, parous women, socioeconomic status, rural-urban
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