Polygynous Family Structure and Child Undernutrition in Nigeria

Abstract

Interest is growing in the research literature in exploring how child nutrition is affected by sociocultural practices, such as polygyny. However, evaluation of the effect of polygyny on child nutrition is hindered by the complexity of the relationship. This paper investigates the effect of polygyny on anthropometric outcomes while recognising that unobservable household characteristics may simultaneously influence both the decision to form a polygynous union and the ability of the household to adequately nourish children. We apply an instrumental variable approach based on the occurrence of same-sex siblings in a woman’s first two births to generate exogenous variation in polygyny. Using data from the 2008 and 2013 Nigeria Demographic and Health Surveys, we find a detrimental effect of polygyny on child undernutrition. Our results show that the effect of polygyny is substantially reduced when we control for household characteristics, suggesting that part of the link between polygyny and child undernutrition is mediated through these channels. Nevertheless, the estimated coefficients of polygyny remain sizeable and strongly statistically significant even after controlling for these characteristics. Polygynous families may have different behavioural childcare practices, and/or the reduced bargaining power of women associated with polygynous families could be associated with higher rates of child undernutrition.

Acknowledgements

We received constructive comments from two anonymous reviewers and editor, which significantly improved the paper. The authors are also grateful to James Fenske for valuable comments on previous versions of this manuscript. The usual disclaimer applies. This paper has been prepared as an output of the Nigeria Strategy Support Program, which has been managed by the International Food Policy Research Institute (IFPRI) and has been financially made possible by the generous support of the American people through the United States Agency for International Development (USAID) in connection with the Feed the Future Nigeria Agricultural Policy Project. The research presented here was also funded by and conducted as part of the CGIAR Research Program on Policies, Institutions, and Markets (PIM), which is led by IFPRI.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary materials

Supplementary Materials are available for this article which can be accessed via the online version of this journal available at https://doi.org/10.1080/00220388.2021.1898591

Notes

1. The widespread prevalence of polygynous families could explain, in part, why child stunting rates remained stagnant over the past one and half decades in sub-Saharan African countries, where the under-five stunting rate merely reduced from 38 per cent in 2000 to 32 per cent in 2016 (World Health Organization [WHO], 2017).

2. Polygyny, the practice of one man being married to multiple wives at the same time, is a common family structure in many parts of sub-Saharan Africa.

3. In contrast, other highly populated countries have witnessed considerable declines in child undernutrition (Headey, 2013). For example, Bangladesh reduced its stunting prevalence from 51 per cent in 2004 to 36 per cent in 2014.

4. More recently, Anjorin et al. (2020), using a multilevel analysis of cross-sectional surveys for a group of 32 countries in Sub-Saharan Africa, found that polygyny at the contextual level has been a major factor of undernutrition in these countries although the results vary substantially among countries in the group.

5. It is notable that Becker (1974) and Grossbard (1978) were the first to examine to the economic effects of polygyny, with further contributions by Bergstrom (1994). More recently Gould, Moav, and Simhon (2008) and Lagerloef (2005) paid particular attention to the importance of heterogeneity for polygyny and the quality-quantity trade-off for children. Tertilt (2005), by using a quantitative model of the overall impact of polygyny on development in Sub-Saharan Africa, showed that enforcing monogamy lowers fertility, shrinks the spouse age gap, and reverses the direction of marriage payments.

6. Lower resource levels are associated with lower expenditures on food and nutrition-relevant nonfood expenditures, such as health, sanitation, electricity, water, and housing quality. which can deteriorate the nutrition status of children (Omariba & Boyle, 2007).

7. Less educated parents may also achieve less diverse income due to limited labour market participation. A more diverse set of income sources could help to improve the nutritional status of children.

8. Household welfare is measured using a wealth index constructed using a principal components analysis that combines ownership of durable goods, such as radios, bicycles, and cars, and housing characteristics (Rutstein & Johnson, 2004).

9. Rosenzweig and Wolpin (2000) argue that same-sex siblings may involve reduced childbearing expenditures for parents, probably because they can share clothing and footwear.

10. In our robustness exercises we use same sex × wealth interaction as alternative instruments and main results remain similar (see Table A4).

Additional information

Funding

This work was supported by the UDAID and PIM.