Political instability and child anemia in Peru: a national interrupted time-series analysis, 2006-2024

Peru underwent marked political instability after the 2016 electoral cycle. Whether that period coincided with a change in the national trajectory of child anemia among children aged 6-35 months has not been evaluated using a long national time series.

We conducted a secondary analysis of the Demographic and Family Health Survey (ENDES), 2006-2024 (123,600 children aged 6-35 months with valid hemoglobin). We estimated weighted annual prevalences of anemia (hemoglobin <11.0 g/dL) and mean hemoglobin. The primary analysis used segmented interrupted time-series regression with a flexible pre-trend (knot in 2011), Prais-Winsten AR(1) correction, and a prespecified cut-point in 2017. Sensitivity analyses included alternative cut-points (2016, 2018, 2020), exclusion of 2020-2021, an interrupted time-series model with mean hemoglobin as a continuous outcome, and composition-adjusted predicted prevalence.

Anemia decreased from 56.4% (2006) to 41.4% (2011), plateaued (~43%) between 2012 and 2016, fell to 36.5% in 2021, and rebounded to 43.1% in 2023. The slope in 2006-2010 was -3.48 percentage points per year; in 2011-2016 it was near zero (-0.09 pp./year). In 2017 we observed a favorable level change relative to the counterfactual (-4.4 pp), followed by a positive and statistically significant change in slope (β₃ = 3.83; 95% CI 1.80-5.87; p = 0.001), consistent with loss of momentum and a subsequent rebound. The interrupted time-series model of mean hemoglobin showed directionally consistent results (slope change -0.137 g/dL/year; p = 0.014).

The post-2016 period coincided with an initial decline relative to the counterfactual, followed by an adverse slope and a recent rebound. This pattern is compatible with programmatic fragility in a context of political and institutional instability, but should not be interpreted as proof of a direct causal effect of political instability itself. Anemia-control policies require mechanisms that protect operational continuity from political turnover and other concurrent health-system shocks.