Early childhood as a sensitive period for the effect of growth on childhood bone mass: Evidence from Generation XXI birth cohort

Investigating femoral growth disruption in subadults from the 10th-13th century St. Étienne cemetery of Toulouse, France

OBJECTIVES

The skeleton embodies an individual's environment and lived experiences. Studying childhood growth disruption can, therefore, aid in understanding the experiences of children in the past. This study evaluates growth disruption in a medieval Toulousian subadult sample to explore factors that may have influenced childhood growth and mortality at this site and to assess the utility of Harris line (HL) interpretations in bioarchaeology.

MATERIALS AND METHODS

Femoral growth disruption was assessed in n = 71 subadults (0.125-12.42 years) from the 10th-13th century St. Étienne cemetery of Toulouse, France, using femoral length, total area, cortical area, and relative cortical area. Femoral radiographs were assessed for HLs. To determine the prevalence of growth disruption, z-scores were calculated using data from the Denver growth study.

RESULTS

The majority of subadults in this sample suffered from femoral growth disruption. Young children (1.0-3.99 years) were the most affected, with >65% experiencing reduced appositional growth and linear growth stunting at time-of-death. Additionally, while many individuals presented with observable HLs, linear and appositional growth did not significantly differ between individuals with and without HLs.

DISCUSSION

Maternal malnutrition and inadequate complementary feeding practices likely contributed to the high prevalence of growth disruption among the youngest individuals in the study. The older children and adolescents buried at St. Étienne experienced an amelioration in growth deficits, indicating an improvement in nutrition and/or disease load. The results of this study suggest that more consideration is required when interpreting the presence/absence of HLs, and that studies assessing HLs may benefit from using a more individualistic approach.

Childhood and adolescent nutrition outcomes among girls exposed to gender-based violence: A rapid evidence assessment of quantitative research

BACKGROUND

An emerging evidence base has explored the nutritional consequences of gender-based violence (GBV) perpetrated against girls during childhood/adolescence. We conducted a rapid evidence assessment of quantitative studies describing associations between GBV and girls' nutrition.

METHODS

We adapted systematic review methods and included empirical, peer-reviewed studies, published after 2000 (until November, 2022), that were written in Spanish or English and reported quantitative associations between girls' exposure to GBV and nutrition outcomes. A variety of GBV forms were considered: childhood sexual abuse (CSA), child marriage, preferential feeding of boys, sexual IPV and dating violence. Nutrition outcomes included anemia, underweight, overweight, stunting, micronutrient deficiencies, meal frequency, and dietary diversity.

RESULTS

In total, 18 studies were included, 13 of which were conducted in high-income countries. Most sources utilized longitudinal or cross-sectional data to quantify associations between CSA, sexual assault, and intimate partner/dating violence and elevated BMI/overweight/obesity/adiposity. Findings suggest that CSA perpetrated by parents/caregivers is associated with elevated BMI/overweight/obesity/adiposity via cortisol reactivity and depression; this relationship may be compounded by additional intimate partner/dating violence in adolescence. The effects of sexual violence on BMI are likely to emerge during a sensitive period of development between late adolescence and young adulthood. Emerging evidence was found regarding the relationship between child marriage (and the related exposure: age at first pregnancy) and undernutrition. The association between sexual abuse and reduced height and leg length was inconclusive.

CONCLUSION

Given that only 18 studies were included, the relationship between girls' direct exposure to GBV and malnutrition has received little empirical attention, especially with respect to studies conducted in LMIC and fragile settings. Most studies focused on CSA and overweight/obesity, where significant associations were found. Future research should test the moderation and mediation effects of intermediary variables (depression, PTSD, cortisol reactivity, impulsivity, emotional eating) and consider sensitive periods of development. Research should also explore the nutritional consequences of child marriage.

Association between dehydroepiandrosterone sulphate levels at 7 years old and bone mineral density at 10 years old: a prospective cohort study

We aimed to explore the effect of dehydroepiandrosterone sulphate (DHEAS) at age 7 on areal bone mineral density (aBMD) at age 10 and to distinguish the direct and indirect effects (explained by sexual maturity and by aBMD at age 7), for each sex, after adjustment for body mass index (BMI) z-score. In a subsample of 274 children (139 girls, 135 boys) from Generation XXI cohort, aBMD was assessed with dual-energy X-ray absorptiometry (DXA) scan at ages 7 and 10. The increase in aBMD at age 10 for each 10 µg/dL increase in DHEAS levels at age 7 was estimated using path analysis. Both the direct and the indirect effects were calculated. In girls, higher DHEAS levels at age 7 were associated with higher aBMD at age 10. No direct effect was observed. The indirect effect via higher aBMD at age 7 explained 61% of the total effect, and the indirect effect via higher Tanner stage explained 21%. After adjustment for BMI, the total effect remained statistically significant, explained in 33% by the indirect effect of DHEAS on Tanner stage and Tanner stage on aBMD. In boys, no effect of DHEAS on aBMD was observed.

CONCLUSION

An indirect effect of DHEAS at age 7 on aBMD at age 10 was found in girls, but not in boys, as higher DHEAS levels were associated with more advanced sexual maturation at age 10, and more advanced sexual maturation to higher aBMD. No direct effect of DHEAS on aBMD was observed.

WHAT IS KNOWN

• Conditions associated with elevated DHEAS, adrenarche's biomarker, are accompanied by advanced bone maturity. • Whether adrenal androgens influence bone mineralization in childhood remains puzzling, and longitudinal data is scarce.

WHAT IS NEW

• In girls, but not in boys, higher DHEAS at age 7 was associated with higher aBMD at age 10. • This was partially explained by the indirect effect of DHEAS at age 7 on sexual maturity at age 10, as DHEAS at age 7 was positively associated with sexual maturity at age 10, which was further associated with aBMD.

Challenges of translating epidemiologic research: An application to rheumatic and musculoskeletal disorders

Translation of research into public health policy is featured in common definitions of epidemiology, as an end result of scientific discovery on disease occurrence and causes. This dual nature of epidemiology, which brings together discovery and its use, seems to imply two main dimensions by which to judge epidemiologic research: technical or field-specific quality and societal value. This paper uses our research on the epidemiology of rheumatic and musculoskeletal disorders as a starting point to discuss the interface between these dimensions, exploring a number of conceptual, practical and ethical challenges that epidemiologists increasingly need to address when aiming for research translation. Those include not only the appraisal of the technical quality of research, which is familiar to researchers, but also the judgement on the usefulness and actual use of knowledge, as well as the assessment of the legitimacy of research based on translation potential. Several challenges lie ahead, but interdisciplinary conceptual and technical developments have the potential to guide future epidemiologic research of consequence. Approaches that recognize complexity and formalize the involvement of stakeholders in the research process within transparent frameworks open promising avenues for an effective translation of epidemiologic research projected into the future.

Evidence for a sensitive period of plasticity in brown adipose tissue during early childhood among indigenous Siberians

OBJECTIVES

Evolutionary theorists have debated the adaptive significance of developmental plasticity in organisms with long lifespans such as humans. This debate in part stems from uncertainty regarding the timing of sensitive periods. Does sensitivity to environmental signals fluctuate across development or does it steadily decline? We investigated developmental plasticity in brown adipose tissue (BAT) among indigenous Siberians in order to explore the timing of phenotypic sensitivity to cold stress.

METHODS

BAT thermogenesis was quantified using infrared thermal imaging in 78 adults (25 men; 33 women). Cold exposure during gestation, infancy, early childhood, middle childhood, and adolescence was quantified using: (1) the average ambient temperature across each period; (2) the number of times daily temperature dropped below -40°F during each period. We also assessed past cold exposure with a retrospective survey of participation in outdoor activities.

RESULTS

Adult BAT thermogenesis was significantly associated with the average temperature (p = 0.021), the number of times it was below -40°F (p = 0.026), and participation in winter outdoor activities (p = 0.037) during early childhood.

CONCLUSIONS

Our results suggest that early childhood represents an important stage for developmental plasticity, and that culture may play a critical role in shaping the timing of environmental signals. The findings highlight a new pathway through which the local consequences of global climate change may influence human biology, and they suggest that ambient temperature may represent an understudied component of the developmental origins of health and disease.