We found a significantly increased risk of receiving > 1 prescription for insulin/insulin analogues 0 to 9 years of age among children with chromosomal anomalies (RR 2.37, 95% CI 1.91–2.96), and specifically in children with Down syndrome (RR 3.44, 95% CI 2.70–4.37), Down syndrome with CHD (RR 3.86, 95% CI 2.88–5.16) and Down syndrome without CHD (RR 2.78, 95% CI 1.82–4.27) compared to reference children (Table 2 and Fig. 3). This evidence concerns the gene INS and Down syndrome.