Does child labour affect final height?

Although the negative effects of child labour on health are well known, the impact of child labour on final height is still controversial.

To assess the effect of child labour on the final height of young adults.

The study included 2063 adults aged 23-25 years from a cohort study of all live births (6827) in Ribeirão Preto, Brazil (1978-79). Height was measured in centimetres. Information on work, physical activity and smoking was obtained retrospectively and the other variables were obtained at cohort baseline. Work was classified according to age at first job: <14 (child labour), 14-16 and >or=17 years. Analyses were performed separately for males and females. Multiple linear regression analysis followed bivariate and stratified analysis.

The average height for males and females were respectively 176.0 cm [95% confidence interval (CI) 175.6-176.4] and 162.7 cm (95% CI 162.3-163.0). Labour before the age of 14 years was performed by 20% of males and 12% of females. In the bivariate analysis, child labour was statistically associated with final height for both males (P < 0.01) and females (P < 0.01). However, the association was not maintained after adjusting for confounders.

We were not able to demonstrate significant height differences between those previously employed or not employed as a child, other than differences explained by other social and biological factors.