Page 23 - IJPS-11-1

International Journal of
Population Studies A review on early-life determinants of frailty

homeostasis due to dysregulations across multiple categories based on their constituent components: physical,
physiological systems. The susceptibility to hospitalization, cognitive, social, and biopsychosocial frailty. The present
disability, and mortality, as well as difficulties in study focused on physical frailty because it has received
recovering from stressors in frail older adults, has been the most attention in research and has significant health
well documented (Ensrud et al., 2008; Ma et al., 2020; implications. Physical frailty is often considered the entry
Vermeiren et al., 2016; Wu et al., 2019; Xu et al., 2020). point for frailty assessment in clinical settings due to its
Frailty is conceptualized as a distinct clinical entity from relative ease of measurement and strong predictive value
disability; however, research in this area has been slow for for identifying individuals at risk of poor health outcomes.
multiple reasons, such as an incomplete understanding
of the natural history and etiology of frailty. A significant 2. Methods
advancement in the field came in 2001, introducing two
commonly used assessment tools: the frailty phenotype 2.1. Search strategy
and the frailty index (Fried et al., 2001; Mitnitski et al., This review was conducted in adherence with the
2001). Following that, there has been an increase in Preferred Reporting Items for Systematic Reviews and
empirical research on frailty, concentrating on developing Meta-Analyses guidelines (Page et al., 2021). We searched
new instruments, quantifying the burden of frailty, PubMed, one of the largest and most comprehensive
establishing its relationship with negative health results, databases for biomedical literature, for original research
and pinpointing associated risk factors. papers published from since its inception until June 1, 2023,
Factors during early life are theorized to have a long- focusing on studies investigating the link between early-
term impact on subsequent health through individual life risk factors (measured before the age of 18 years) and
and combined effects of biological, behavioral, and physical frailty in later life. The search utilized keywords
psychosocial mechanisms. There is a consensus that and their variations, including early life, newborn, baby,
physical, behavioral, psychosocial, and environmental risk infancy, childhood, adolescence, and frailty. We also
factors in early life are related to the development of frailty reviewed the bibliographies of relevant original research
in old age. Over the past two decades, we have witnessed articles and reviews that satisfied our inclusion criteria.
a proliferation of literature on early-life risk factors for
frailty in developed and developing countries and areas. 2.2. Inclusion and exclusion criteria
There have been limited efforts to thoroughly understand Two researchers, H.L. and M.W., independently reviewed
the impact of early-life risk factors on the development the titles and abstracts to assess the suitability of the
of frailty in later life (Barrera et al., 2023). The present studies. They, the full texts of articles that met the initial

study is among the first to systematically review and screening criteria were examined. Any disagreements
summarize these factors and the mechanisms driving in the article selection process were resolved through
their association with frailty in old age. We summarized discussions between the two investigators. Consultation
empirical studies examining how early-life risk factors from a third investigator (C.W.) was acquired if necessary.
contributed to the development of frailty. We classified We initially screened the titles and abstracts to identify
these risk factors into four dimensions: biological factors, potentially eligible papers and then thoroughly examined
socioeconomic circumstances, healthy lifestyles, and their full text. Subsequently, we reviewed the full text of all
environmental exposures (Figure 1). This study enhances 355 records and selected 40 based on their relevance to our
our understanding of early-life risk factors for frailty and research topic – the link between early-life risk factors and
provides crucial insights for developing targeted frailty physical frailty in later life.
prevention strategies to mitigate these early-life risk
factors. 3. Key findings
Researchers have sought to capture the complexity 3.1. Biological factors
of frailty by proposing various assessment instruments
grounded in distinct theoretical frameworks (Buta et al., Multiple studies have identified the role of body size in
2016; Cigolle et al., 2009; Guo et al., 2022; Wu, 2023). early life, such as birth weight, body length, and body mass
These frameworks serve as the basis for understanding index (BMI), in the development of frailty. In addition,
and quantifying the frailty construct and guide the childhood intelligence has been linked to frailty. Most
development of measurement tools that can be applied evidence was produced in studies focusing on populations
across diverse settings and for different purposes. In in developed regions; more attention should be paid to
general, frailty assessment tools can be classified into four developing countries and areas.

Volume 11 Issue 1 (2025) 17 https://doi.org/10.36922/ijps.1982