After correction for multiple testing (P < 0.002), there was a positive association between IGF-I concentration and carpal tunnel syndrome (HR per 5 nmol/l higher concentration = 1.12, 95% CI, 1.08–1.16), and inverse associations with varicose veins (0.90, 0.85–0.95), cataracts (0.97, 0.95–0.99), diabetes (0.92, 0.90–0.95), and iron deficiency anaemia (0.90, 0.86–0.93). The gene discussed is IGF1; the disease is carpal tunnel syndrome.