Rethinking water, sanitation, and hygiene for human growth and development

ABSTRACT

Life history theory emphasises plasticity in developmental and biological programming where conditions in early life, lead to long-term consequences for health and wellbeing. Studies linking water, sanitation, and hygiene, nutrition, and child growth and development have emphasised the optimisation of linear growth as a key metric for the evaluation of intervention efficacy. Life history characteristics pertaining to human growth and phenotypic plasticity, suggest that different developmental outcomes in early childhood may be responsive to different stimuli at different ages. Energy utilisation by the human brain, from birth through childhood, accounts for a disproportionate percentage of the resting metabolic rate. Undernutrition in early life, and its relative resultant energy deficiency, may trigger adaptive physiological mechanisms prioritising brain growth at the expense of body growth. Emphasis placed on linear growth may have impeded the significance of WASH due to excluding aspects of child development beyond height/weight. We propose that incorporating evolutionary public health and life history theory perspectives, allows for the identification of age-appropriate biological outcomes and WASH indicators, while anticipating the timing and life-course suitability of the interventions being operationalised. Finally, integrating reflections regarding context allows for the development of transformative WASH interventions.

KEYWORDS:

• WASH
• life history theory
• evolutionary public health
• early childhood development
• humanitarian settings

Acknowledgements

We acknowledge the support of the DSI-NRF Centre of Excellence in Human Development, the SAMRC/Wits Developmental Pathways for Health Research Unit. Opinions expressed and conclusions arrived at are those of the authors.

Disclosure statement

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

Additional information

Funding

We acknowledge the support of the Isaac Newton Trust/Wellcome Trust ISSF/University of Cambridge Joint Research Grants Scheme.