The biorhythm of human skeletal growth

Abstract

Evidence of a periodic biorhythm is retained in tooth enamel in the form of Retzius lines. The periodicity of Retzius lines (RP) correlates with body mass and the scheduling of life history events when compared between some mammalian species. The correlation has led to the development of the inter-specific Havers-Halberg oscillation (HHO) hypothesis, which holds great potential for studying aspects of a fossil species biology from teeth. Yet, our understanding of if, or how, the HHO relates to human skeletal growth is limited. The goal here is to explore associations between the biorhythm and two hard tissues that form at different times during human ontogeny, within the context of the HHO. First, we investigate the relationship of RP to permanent molar enamel thickness and the underlying daily rate that ameloblasts secrete enamel during childhood. Following this, we develop preliminary research conducted on small samples of adult human bone by testing associations between RP, adult femoral length (as a proxy for attained adult stature) and cortical osteocyte lacunae density (as a proxy for the rate of osteocyte proliferation). Results reveal RP is positively correlated with enamel thickness, negatively correlated with femoral length, but weakly associated with the rate of enamel secretion and osteocyte proliferation. These new data imply that a slower biorhythm predicts thicker enamel for children but shorter stature for adults. Our results develop the intra-specific HHO hypothesis suggesting that there is a common underlying systemic biorhythm that has a role in the final products of human enamel and bone growth.

Histology of dental long‐period biorhythms in Canis familiaris

“…Indeed, Mahoney et al. () have reported correlations between femur length and RP in a modern human population sample, and Hogg and colleagues (Hogg et al. ; Hogg & Bromage, ) have found correlations between human body size and RP between populations; however, regression slopes among them seem to vary (e.g.…”

“…Modern humans have arguably more variation in body mass than most other mammal species, domestic dogs being one exception (Bromage et al 2016b). Indeed, Mahoney et al (2017) have reported correlations between femur length and RP in a modern human population sample, and Hogg and colleagues (Hogg et al 2014;Hogg & Bromage, 2018) have found correlations between human body size and RP between populations; however, regression slopes among them seem to vary (e.g. a positive regression slope for Indians, but a negative one for English and Peruvians), so much more work is needed in this area.…”

Microscopic markers of an infradian biorhythm in human juvenile ribs

“…Retzius periodicity was linked to the rate of primary bone deposition in the humeri of seven age-matched children [16]. Femoral osteocyte lacunae density was inconsistently related to RP in a sample of adult humans [15]. Thus, there is currently some evidence that suggests a relationship between RP and stature in adult humans, and between RP and primary bone growth in a small sample of infants.…”

“…The role of the infradian biorhythm for human growth and development is poorly understood. Studies of small samples of adult humans indicate that RP is negatively correlated with final attained adult stature [14,15]. This makes sense as the biorhythm is accelerated to achieve greater height within a developmental period that is constrained for humans, relative to inter-specific comparisons of RP [11].…”

Individual chronobiological regularity in track-and-field sprint

“…There is also a theory of three biorhythms that begin to act at the time of human birth [22,23]. According to various studies [22,24,25] this theory is unproven. Other data [23,26] indicate that there are interrelationships of competitive performance with the values of the three biorhythms.…”