Long-term and intergenerational benefits of early childhood health interventions

Poor health, high rates of fertility, and under-nutrition are common and related obstacles faced by low-income individuals in many regions of the world today. These obstacles have been exacerbated by the COVID-19 pandemic, conflict, and climate change. Existing research shows the combination of these obstacles limit individuals in achieving their full potential human capital (Prendergast and Humphrey, 2014; Grantham-McGregor et al., 2007). Moreover, mounting correlational evidence highlights that disadvantage in human capital experienced in one generation may persist to the next.  It is widely believed that positive investments during sensitive periods of development, such as pregnancy and early childhood, can have lasting effects on human capital formation, leading to better economic opportunities over the life course and across generations. While global investment in maternal and child health has increased substantially in recent decades, our understanding of the long-term and intergenerational impacts of these investments, including their potential to reduce persistent parent-child human capital inequalities, remains limited.

To address these issues, we leverage unique data that connects three generations, along with a robust causal identification approach to provide long-term and intergenerational evidence regarding the enduring effects of widely implemented public health interventions on human capital and labour and migration outcomes in the Matlab area of Bangladesh.  To identify the effects, we take advantage of the quasi-randomly placed Maternal and Child Health and Family Planning (MCH-FP) Programme introduced in the 1970s. MCH-FP revolutionised the field by using a home-based delivery model, integrating family planning with mother- and-child health services, such as vaccination against common diseases. Bangladesh has been a leader among low- and middle-income countries in decreasing fertility rates and improving human capital. Moreover, malnutrition rates in Bangladesh are comparable to lower-income countries today, though Matlab’s mortality and fertility rates today are low and closer to rates in middle-income countries.

We investigate the impact of the MCH-FP programme on two generations. Long-term effects are evaluated through the first generation, which comprises individuals born between 1982 and 1988 when both family planning and intensive early child health interventions were accessible in the treatment area. Their longer-term adult human capital, labour and migration outcomes are assessed when they are approximately 24 to 30 years old. Intergenerational effects are measured by the second-generation cohort, which includes the first-born children of females in the first-generation cohort. Their human capital outcomes are measured at 0 to 14 years old.

The MCH-FP Programme

The MCH-FP programme was initiated in 1977 by icddr,b (formerly known as International Center for Diarrhoeal Disease Research, Bangladesh) in the Matlab district of Bangladesh. MCH-FP was distributed in approximately half the study villages, leaving a comparison area to ensure rigorous evaluation. Interventions started with family planning and maternal health interventions (tetanus toxoid vaccinations, and iron and folic acid tablets) and in 1982 intensive child health interventions were introduced, including vaccinations against diseases like measles, tetanus, pertussis, polio, and tuberculosis, and vitamin A supplementation. These interventions were crucial in improving the early childhood health environments, leading to better nutrition, health, and cognitive development. A key feature of the programme was that interventions were free and administered in the beneficiary’s home during monthly visits made by local female health workers. The comparison area had access to standard government health and family planning services which included access to modern family planning in the clinics (rather than in the home). Childhood vaccines were not available in the comparison area, or most of Bangladesh, until the late 1980s.

Data collection and evaluation design

Outcomes are drawn from the Matlab Health and Socio-Economic Survey 2 (MHSS2) collected between 2012 and 2015. MHSS2 is a panel follow up of individuals in the 1996 MHSS1 survey primary sample and their descendants. This survey is linked at the individual level with MHSS1, a pre-programme census of the study area, Matlab demographic surveillance data on vital events (births, marriages, deaths, in- and out-migrations) collected between 1974 and 2014, and data on potentially confounding programmes such as access to microcredit, primary schools, health facilities, flood mitigation, and arsenic exposure.  Extensive in-person tracking throughout Bangladesh and phone interviews led to unusually low attrition for a 35-year follow-up survey—less than 10%—in an area with notably high rates of migration. Around 60% of sampled men had migrated out of the study area, 25% to international locations.

Long-term effects: Human capital, labour and migration

1.    Human capital effects persist into adulthood

Human capital gains documented in adolescence (Barham 2012, Joshi and Schultz 2013) persist into adulthood for the first generation in terms of height and grades attained but not for cognition. Both males and females are about one centimeter taller and short stature is reduced by almost 50%. In addition, males experienced significant improvements in education gaining almost one more year of education and scoring 0.2 SD higher on a math test. There are no programme effects on education for first generation females which is consistent with the availability of a successful nationwide girl’s secondary school scholarship programme operating in both the treatment and comparison areas at the time (Shamsuddin, 2015).

2.    Reduction in human capital inequality

To understand the distributional effects of the programme on first-generation human capital, we decompose the treatment effect by terciles of an individual’s pre-programme health endowment. We use mother’s height as a proxy for the first generations’ health endowment since it is not affected by the programme and height reflects the early childhood health environment. Results show programme effects for the first generation are largest among those born to the shortest mothers, where potential gains from health improvements were the largest. This result indicates that MCH-FP contributed to breaking the parent-child human capital correlation and reduced human capital inequality for the first generation.

3.    Improved labour market outcomes and shifting migration patterns

The first generation also experienced important improvements in labour market outcomes and  reduction in migration for work to urban areas of Bangladesh of almost 25%. Relative to the comparison area, treatment area men had higher quality jobs reflected by a 30% increase in both work in professional or semi-professional occupations and the use of academic skills on the job. In addition, treated individuals had higher engagement in entrepreneurial activities and had more business loans, consistent with starting new businesses. There was no programme effect on annual earnings and the reduction in migration was to urban areas of Bangladesh not international destinations. These results suggest that rural-urban migration can be reduced without a loss of earnings if job quality in the local area  improves, which in this setting was driven in part by individual entrepreneurship. The lack of an effect on earnings may also be temporary as these men are early in their careers. If working in a professional or entrepreneurial job earlier in one’s career changes the earnings trajectory, programme’s effect on lifetime earnings could be larger. It will be important to examine the trajectory for these young men in the future when earnings are generally higher and the accumulation of capital from migration more complete.

These findings are important and differ from other studies that find increased earnings resulting from early childhood interventions. These results highlight that it is critical to understand the role work migration plays in the long-term programme effects because migration is a key determinant of earnings in some contexts. In addition, job quality is an important component of labour market outcomes that is often not included in analyses. The reduction in migrations and the increase in job quality and entrepreneurial activity are informative to policy makers given the present policy debates on both rural-urban migration and international migration.

4.    Gender dynamics in economic participation

Programme effects for women are more limited since only 30% of women work for pay. However, first generation treatment area women are more likely than comparison area women to be entrepreneurial and engage in paid agricultural work raising small animals on their own land, but the increase is not large enough to affect annual income.

Intergenerational effects: A legacy of improved human capital outcomes

1. Improvements in human capital among second generation females

Intergenerational effects reveal second generation females experienced increased height, with programme effects larger than the first generation (1.6 cm), and a reduction in stunting of 50%. Cognitive effects of 0.26 SD also resurfaced among the 7- to 14-year-olds. There were no impacts on males.

2.  Intergenerational pathways need further research

Behavioural and biological mechanisms link human capital between the generations but are not well understood. We can rule out that effects are driven by child mortality or fertility selection and find no effects on typical early childhood health investments or maternal empowerment that could explain the pattern of second-generation results by sex. Gender effects are also not a result of second-generation females initially having worse human capital than males, leaving more room for improvement. There are numerous potential mechanisms, many not collected in datasets, and further research is needed to understand the key mechanisms and sex-specific dimensions of the intergenerational transmission of human capital.

Conclusions

Together our research (Barham et al. 2023a, 2023b) demonstrates that investments in the early health environment can generate substantial and enduring effects on human capital and labour market outcomes, but that these effects may be more nuanced than policymakers might predict. In Matlab, short-term human capital gains persisted over the life course and were associated with higher quality employment but not with higher wages, due in part to the decision by many respondents to opt for higher quality local employment over migrating to major cities like Dhaka. While wages did not improve over the time horizon of the study, the interventions nevertheless yielded enduring effects in terms of the intergenerational transmission of advantages in height and cognition. Policymakers who fail to consider these intergenerational and distributional effects when allocating resources for children may inadvertently underinvest, missing an opportunity to mitigate human capital disparities and potentially reshape economic and migration outcomes of both current and future generations.

References

Barham, T (2012), “Enhancing Cognitive Functioning: Medium-Term Effects of a Health and Family Planning Program in Matlab.” American Economic Journal: Applied Economics, 4(1): 245–273.

Barham, T, B Champion, G Kagy and J Hamadani (2023a), “Improving the Early Childhood Environment: Direct and Distributional Effects on Human Capital for Multiple Generations.” Working Paper. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4669860

Barham, T, R Kuhn, and P Turner (2023b), “No Place Like Home: Long-Run Impacts of Early Child Health and Family Planning on Labor and Migration Outcomes.” Journal of Human Resources DOI: https://doi.org/10.3368/jhr.0322-12209R2.

Grantham-McGregor, S, Y B Cheung, S Cueto, P Glewwe, L Richter, B Strupp, International Child Development Steering Group, et al. (2007), “Developmental Potential in the First 5 Years For Children in Developing Countries.” The Lancet, 369(9555): 60–70.

Joshi, S, and T P Schultz (2013), “Family Planning and Women’s and Children’s Health: Long- term Consequences of an Outreach Program in Matlab, Bangladesh.” Demography, 50(1): 149–180.

Prendergast, A J, and J H Humphrey (2014), “The Stunting Syndrome in Developing Countries.” Paediatrics and International Child Health, 34(4): 250–265.

Shamsuddin, M (2015), “Labour Market Effects of a Female Stipend Programme in Bangladesh.” Oxford Development Studies, 43(4): 425–447.