The effect of the local environment on child nutritional outcomes: how does seasonality relate to wasting amongst children under 5 in south-west coastal Bangladesh?

The impact of short-term environmental changes on child nutritional status is not constant within populations. In many countries, the seasons are closely linked with many factors that are known to affect nutritional outcomes, such as food consumption, crop harvests, employment opportunities and illness. With extreme seasonal variation becoming more common, understanding how seasonality is related to child nutritional outcomes is vital. This study will explore spatial and temporal variation and determinants for acute malnutrition in a coastal river delta in south-west Bangladesh over the period of a year. Using a rural longitudinal survey, conducted in 2014–15 with 3 survey waves, wasting amongst children under 5 was studied. Spatial variation was analysed through ‘socio-ecological systems’, which capture interactions between ecosystems, livelihoods and populations. Wasting prevalence varied from 18.2% in the monsoon season to 8.7% post-major rice harvest (Aman). Seasons did not relate to wasting consistently over socio-ecological systems, with some systems showing greater variability over time, highlighting distinct seasonal dynamics in nutritional status. Wealthier socio-ecological systems had lower wasting generally, as expected, with greater livelihood diversification opportunities and strategies to smooth consumption. Nutrition interventions must consider seasonal peaks in acute malnutrition, as well as the environmental context when implementing programmes to maximise effectiveness. With increasing variability in seasonal changes, inequalities in the impact of season must be accounted for in health promotion activities. Furthermore, timing and season of survey implementation is an important factor to be accounted for in nutrition research, especially when comparing between two cross-sectional surveys