Maternal investment, maturational rate of the offspring and mechanical competence of the adult female skeleton.

Alison A Macintosh,Jonathan C K Wells,Jay T Stock

doi:10.1093/emph/eoy015

Abstract

ABSTRACTLay summaryGirls with a slower life history trajectory build a larger body with larger and mechanically stronger bones. Thus, variation in the emergence of slower versus faster life history trajectories during development can have consequences for bone mechanical competence, and hence fracture risk in adulthood. Background and objectivesVariation in life history trajectory, specifically relative investment in growth versus reproduction, has been associated with chronic disease risk among women, but whether this scenario extends to skeletal health and fracture risk is unknown. This study investigates the association of life history traits (proxies for maternal investment and maturational rate) with female bone outcomes in adulthood.MethodologyBody size variables, regional muscle and fat areas, and cross-sectional bone size and strength outcomes were obtained from 107 pre-menopausal women encompassing a wide range of physical activity levels. Developmental parameters (birth weight, age at menarche) were obtained from questionnaires.ResultsHigh birth weight was significantly associated with a proportionately larger body and larger, mechanically stronger bones, independently of physical activity level. It was also positively but non-significantly associated with age at menarche. Later menarche was significantly associated with larger and mechanically stronger bones and substantially less absolute and relative regional subcutaneous fat. Age at menarche exhibited stronger relationships with adult adiposity than did physical activity.Conclusions and implicationsBoth larger birth weight and later menarche contribute to a slower life history trajectory, which is associated with greater body size, leanness and bone mechanical competence in early adulthood. In contrast, earlier sexual maturity prioritized energy allocation in adiposity over body size and skeletal strength. Thus, the level of maternal investment and the woman’s own life history trajectory shape investment in skeletal properties, with implications for fracture risk later in life.

Highlights

There is compelling evidence that patterns of nutrition and growth in early life predict diverse components of health in later life
168 | Macintosh et al Conclusions and implications: Both larger birth weight and later menarche contribute to a slower life history trajectory, which is associated with greater body size, leanness and bone mechanical competence in early adulthood
In a related review article, we argue that the pace of life history of mothers is associated with their body size, composition and metabolic profile, their non-communicable disease (NCD) risk, and their capacity to invest in the generation [9]

Summary

Introduction

There is compelling evidence that patterns of nutrition and growth in early life predict diverse components of health in later life. Birth weight is inversely associated with the risk of chronic non-communicable disease (NCD) in adulthood [1], while on the other, rapid weight gain in post-natal life increases risk of the same diseases [2] These findings have given rise to the ‘developmental origins of adult health and disease hypothesis’ [3]. Both short stature and elevated weight and adiposity are associated with greater NCD risk [4,5,6,7], highlighting how developmental trajectory shapes adult health in the long term These data can be reinterpreted using a life-history perspective [8, 9]. As extrinsic mortality risk declines, the returns on investment in maintenance increase: extending the duration of the reproductive career allows more offspring to be produced, increasing fitness

Methods

Results

Discussion

Conclusion