Digit ratio (2D:4D) – a proxy for prenatal sex steroids – shows sex, nationality and ethnic differences and is linked to pubertal onset. It is unclear whether right-left 2D:4D (Dr-l) also correlates with prenatal sex steroids, as evidence of these differences has been less conclusive. The present study examined the effects of sex, nation, ethnicity, age and self-reported pubertal development (i.e. the rate of physical development and age at menarche [females] or first shave [males]) on Dr-l in a large online study (the BBC internet study). Digit lengths were self-measured in 201,865 adults (110,955 males) and the sample of nations included 41 countries. Participants reported the self-perceived rate of physical pubertal development on a five-point scale (from very slow to very fast) and provided information on the age at menarche or first shave. Adult (>17 years) males had lower Dr-l than females with weak effect size across 41 nations (males-females; d = −.065, p < .0001). There were sex and ethnicity effects on Dr-l across seven ethnic groups with males < females and lower Dr-l in Whites and Middle/Near Eastern participants compared to Asian, Black and Chinese respondents. Considering age effects, the authors focused on participants >12 years; there were stable sex differences and a weak positive effect of age on Dr-l. Dr-l showed a positive relationship with the rate of physical development and a negative relationship with age at menarche or first shave. Relationships were present in males and females with stronger effects in the latter. It is concluded that Dr-l shows a weak sex difference (males < females) independent of nation, ethnicity and age, and suggest that Dr-l is a proxy for prenatal sex steroids.

Despite the increasing interest in the determinants of adolescent undernutrition in low- and middle-income countries, a comprehensive multi-level overview at the country level is missing. Using the nationally representative 2014 Nepal Adolescent Nutrition Survey, this study aimed to provide a comprehensive overview of the sociocultural and economic determinants of stunting and thinness of adolescent boys and girls in Nepal. Multivariate logistic regression models were used to estimate the associations between multiple individual, household and community determinants and stunting and thinness among 3773 adolescents aged 10–19 years (1888 boys and 1885 girls). The prevalence rates of stunting and thinness indicated suboptimal nutritional status and an inadequate growth environment in Nepali adolescents. The results highlighted an association of paternal occupation and education, household income, number of earning household members, geographical place of residence, caste/ethnicity and nutritional knowledge with stunting, with higher odds for males and older adolescents. Paternal occupation, education, household income, geographical region, caste/ethnicity and nutrition knowledge were associated with thinness, with higher odds for males and younger adolescents. The findings underscore the importance of involving adolescents, their parents and their communities in interventions. Such interventions should not only be aimed at improving adolescent nutrition but also at optimizing adolescents’ growth environment for better health and development. Future research should focus on context-specific causal pathways and mechanisms through which sociocultural and economic determinants influence nutritional outcomes within broader societal, cultural and political settings. A longitudinal approach, including a range of dietary and nutrition indicators would allow understanding how and when the relative importance of these factors change during adolescence.

David Barker established growth as a seminal link between early development and later health attainment and disease risk. This was nothing less than a paradigm shift in health and medicine, turning the focus of disease causality away from contemporary environmental influences to earliest growth as a time when functional anatomy and physiology sets in place critical structures and function for a lifetime.

Barker’s prodigious work investigated time- and place-specific interactions between maternal condition and exogenous environmental influences, focusing on how growth unfolds across development to function as a mechanistic link to ensuing health. Subsequent applications do not always attend to the specificity and sensitivity issues included in his original work, and commonly overlook the long-standing methods and knowledge base of auxology. Methodological areas in need of refinement include enhanced precision in how growth is represented and assessed. For example, multiple variables have been used as a referent for ‘growth,’ which is problematic because different body dimensions grow by different biological clocks with unique functional physiologies. In addition, categorical clinical variables obscure the spectrum of variability in growth experienced at the individual level. Finally, size alone is a limited measure as it does not capture how individuals change across age, or actually grow.

The ground-breaking notion that prenatal influences are important for future health gave rise to robust interest in studying the fetus. Identifying the many pathways by which size is realized permits targeted interventions addressing meaningful mechanistic links between growth and disease risk to promote health across the lifespan.