Abstract
OBJECTIVE: This study aimed to investigate the association of pregnancy history with biological age (BA) and BA acceleration, and to explore joint effect with lifestyle factors. METHODS: This cross-sectional study used data from the UK Biobank, a population-based cohort recruited across UK between 2006 and 2010, with followed up until the end of 2022. Female participants with available data on chronological age, pregnancy history, lifestyle factors, and clinical biochemistry biomarkers were included. BA and aging acceleration were estimated using Klemera-Doubal Method (KDM BA) and PhenoAge algorithms. The KDM BA, PhenoAge, KDM BA acceleration, and PhenoAge acceleration were calculated. Multivariable general linear regression models were used to assess the associations of pregnancy history alone and combined with lifestyle with BA and BA acceleration. RESULTS: Among 137,218 participants [mean (SD) age, 55.73 (8.01) years], 115 675 (84.3%) reported a history of pregnancy. Compared to those who had never been pregnant, women with a history of pregnancy had a decrease in BA [β = -0.312 (95% CI, -0.432 to -0.191) for KDM BA; β = -0.242 (95% CI, -0.302 to -0.183) for PhenoAge], and BA acceleration [β = -0.021 (95% CI, -0.034 to -0.009) for KDM BA acceleration; β = -0.088 (95% CI, -0.102 to -0.075) for PhenoAge acceleration]. Women with unhealthier lifestyle behaviors had higher BA and BA acceleration, regardless of pregnancy history (P for interaction > 0.05). CONCLUSIONS: In this large population-based study, pregnancy was associated with lower BA and BA acceleration, while an unhealthier lifestyle was associated with higher BA and BA acceleration. These findings suggest that both reproductive and lifestyle factors may play a role in developing anti-aging interventions and guiding healthy aging policies.