• Growth
• Inequalties
• Childhood height
• Ethnicity

Height is the joint product of genetic and environmental influences, and is an important marker of nutritional status and health in early life. While height steadily increased throughout the 20th century as living standards improved, socio-economic inequalities in height persisted in many populations (whereby individuals from more socio-economically deprived backgrounds were, on average, shorter). It has been postulated that 20% of the variation in height observed within contemporary populations is explained by environmental exposures, such as maternal smoking in pregnancy, overcrowding, childhood illness and diet.1 These environmental influences are thought to contribute to socio-economic inequalities in height. Research from a contemporary cohort (the Avon Longitudinal Study of Parents and their Children) indicated that height inequalities in middle childhood had already been established at birth and that prenatal, genetic or epigenetic factors were the most important drivers.2

In high-income countries, there is evidence to suggest that socio-economic gradients in height have been diminishing. One study comparing the 1958 British birth cohort (a predominantly white population) and their offspring showed that childhood height increased by 1 cm between the two generations and that the degree of socio-economic inequality narrowed due to a greater height gain among offspring from more disadvantaged backgrounds.3 Comparisons of childhood height between the more recent UK cohorts (the 1970 British Birth Cohort Study and the Millennium Cohort Study) also found weakening inequalities in height.4

Hancock et al5 demonstrate …