Improving nutrition in early childhood leads to substantial increases in wage rates for men, suggesting that investments in early childhood nutrition can be long-term drivers of economic growth. These are the conclusions of authors of an Article in this week's edition of The Lancet.
Between 1969 and 1977, the Institute of Nutrition of Central America and Panama (INCAP), undertook a study of the effect of improved protein intakes on physical and mental development of children from four villages of mixed Spanish-Amerindian ethnic origin in Guatemala.
Dr Reynaldo Martorell, Rollins School of Public Health, Emory University, Atlanta, GA, USA, and colleagues obtained economic data from 1424 of these Guatemalans from the period 2002-2004. The subjects represented 60% of the original children. In the original study, two villages were randomly assigned a nutritious supplement (atole) for all children and two villages a less nutritious one (fresco). The researchers estimated annual income, hours worked, and average hourly wages from all economic activities. They then used modelling to assess the relation between economic variables and exposure to atole or fresco at specific ages between birth and seven years.
They found that exposure to atole before, but not after, age 3 years was associated with higher hourly wages, but only for men. For exposure to atole from 0-2 years, the increase was $0.67 per hour, equivalent to a 46% increase in average wages. There was also a tendency (although non-statistically significant) for hours worked to be reduced and for annual incomes to be greater for those exposed to atole from 0-2 years.
The authors hypothesise the reason for no increased income effects in women could be differences between the sexes in labour force participation and in work activities, with the vast majority of women being involved in low-productivity work such as agricultural processing.
They conclude: "Future research should investigate the pathways of nutritional supplementation on wage rates through physical strength, perhaps as mediated by height or lean body mass, and cognitive ability. Preliminary explanations suggest that the primary pathway is through cognitive skills, not physical strength.
"Our findings underscore the importance of further investigations in other settings of the long-term effects of improving early childhood nutrition on income."
In an accompanying Comment, Dr Scott Grosse, and Dr Kakoli Roy, Centers for Disease Control and Prevention, Atlanta, GA, USA, say: "The size of the effect on earnings in men was as surprising as the absence of a similar association for women. We look forward to future analyses from Martorell and colleagues' study that quantify each of the causal pathways from early nutrition to earnings, which would provide more conclusive evidence to build support for sustainable large-scale nutritional programmes."
Dr Reynaldo Martorell, Rollins School of Public Health, Emory University, Atlanta, GA, USA T) +1 404-727-9888 E) rmart77@sph.emory.edu
Dr Scott Grosse, Centers for Disease Control and Prevention, Atlanta, GA, USA T) +1 404-639-3286 E) sgrosse@cdc.gov
PDF OF ARTICLE: http://multimedia.thelancet.com/pdf/press/nintervention.pdf
Journal
The Lancet