Page 24 - IJPS-11-1

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

Figure 1. Early-life biological, social, lifestyle, and environmental factors for frailty in old age

3.1.1. Birth weight and birth length body sizes at birth are at an increased risk of developing
Infants with birth weights deviating from the standard frailty. At the same time, only males are more likely to be
range present a heightened risk of experiencing an array of frail due to accelerated BMI gain during childhood.
adverse health outcomes, both in the immediate and long- In addition to BMI at birth, Haapanen et al. (2022)
term future (Haapanen et al., 2018; Maharani et al., 2023). found an association between higher maternal BMI and
Haapanen et al. (2018) found that lower birth weight and increased offspring frailty level, as assessed by the frailty
shorter birth length were associated with a higher risk index, in midlife and a slower increase in frailty level into
of frailty, as measured by the physical frailty phenotype old age. These findings shed new light on the critical life
approach, among 1078 older adults from the Helsinki Birth stages for preventing frailty and highlight the importance
Cohort Study. Frail individuals had a mean birth weight of improving health for women of reproductive age to
of 3.25 kg, significantly lower than the non-frail ones reduce health disparities.
(3.45 kg). The average birth length was significantly shorter
among the frail than the non-frail individuals (49.5 vs. Different plausible mechanisms, such as environmental
50.5 cm). Pre-frail individuals also had a lower mean factors, genetics, epigenetics, and early-life programming,
birth weight and length than non-frail individuals. A 1-kg might influence the association between childhood
increase in birth weight was associated with a 60% lower growth and frailty in later life. The period of early infancy
risk of frailty. More recently, Maharani et al. (2023) found is crucial for muscle development. An adverse prenatal
that either low (<2.5 kg) or high birth weight (>4.0 kg) was environment may compromise muscle tissue development
associated with a higher level of frailty than normal birth at the expense of the development of vital organs (e.g., the
weight among over half a million middle-aged and older brain) (Hales & Barker, 2013). As a result, infants born
adults from UK Biobank. These findings underscored the with smaller body size might have reduced muscle tissue,
impact of birth weight on frailty development in old age. which could manifest as decreased muscle strength, a key
frailty criterion (Ylihärsilä et al., 2007).
3.1.2. BMI
3.1.3. Intelligence
Haapanen et al. (2018) revealed an inverse relationship
between BMI at birth and frailty in old age using data from Using data from the Lothian Birth Cohort 1936 conducted
1078 older adults in the Helsinki Birth Cohort Study. A one- in Scotland, Gale et al. (2016) examined whether and
unit increase in birth BMI was associated with a 98% lower how intelligence in childhood was related to frailty
risk of frailty at 71 years. In a comparison paper, Haapanen in old age among 876 community-dwelling adults at

et al. (2019) investigated whether body size growth later an average of 70 years. All participants were tested for
in infancy and childhood was related to frailty in old age general intelligence at the age of 11 years as part of the
and found sex-specific results. Greater BMI gain between 2 Scottish Mental Survey. A standard deviation decrease in
and 11 years was associated with frailty among boys, while intelligence was associated with a 57% risk of frailty in
no similar associations were found among girls. Taken sex-adjusted analyses; however, the association attenuated
together, these findings suggest that persons with smaller and was no longer significant after adjusting for potential

Volume 11 Issue 1 (2025) 18 https://doi.org/10.36922/ijps.1982