The association between reproductive factors and frailty risk: a population-based analysis from the UK biobank

Previous studies have demonstrated that reproductive factors are associated with future frailty or frailty-related health issues in women. In view of the limited evidence, investigating the association between different reproductive factors and frailty in older women requires further exploration. The purpose of this study is to explore whether reproductive factors contribute to an increased risk of frailty in older women.

This study included 238,555 female participants from the UK Biobank. Reproductive factors and several frailty-related indicators were obtained through self-reported data. A binomial logistic regression analysis was used to assess the association between reproductive factors and frailty in older women, while adjusting for age, race, smoking and drinking status, body mass index (BMI), Townsend deprivation index, education, occupation, income level, history of oral contraceptive use, and history of hormone replacement therapy (HRT) use. Finally, stratified analysis and sensitivity analysis were performed to verify the robustness of our results.

Compared with the menarche age of 12-13 years old, the risk of frailty was higher in those < 12 years old (OR: 1.118, 95%CI: 1.086-1.151). The age at menopause and reproductive lifespan is associated with frailty in a J-shaped dose-response manner. Women with the first live birth(AFB) younger than 21 years have an increased risk compared to those AFB aged 24-26 years (OR: 1.057, 95%CI: 1.011-1.106). Higher parity is associated with a reduced risk of frailty in older women (OR: 0.851, 95%CI: 0.807-0.898). In addition, no significant difference was observed between the risk of stillbirth and the risk of frailty.

According to our research results, age at menarche, age at menopause, AFB, reproductive lifespan, number of miscarriages and parity are associated with frailty in old women.