A number of factors were associated with inadequate glycaemic control (overall p < 0.001), including education below secondary level (OR: 1.47, 95% CI: 0.98–1.97), rural residence (OR: 1.80, 95% CI: 1.33–2.28), obesity (OR: 1.17, 95% CI: 1.11–1.22), use of oral glucose-lowering drugs and/or insulin (OR: 4.06, 95% CI: 2.58–5.54 and OR: 2.44, 95% CI: 1.70–3.19, respectively), non-adherence to diet (OR: 2.13, 95% CI: 1.33–2.93) and treatment (OR: 2.08, 95% CI: 1.61–2.54), and physical inactivity (OR: 2.15, 95% CI: 1.35–2.95). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.