PTH patients had increased unadjusted risk of SI [(RR, 1.45; 95% CI, 1.39–1.51) p < 0.0001], SA [(RR, 1.66; 95% CI, 1.50–1.83) p < 0.0001], and combined SI or SA [(RR, 1.46; 95% CI 1.40–1.53) p < 0.0001], compared to veterans with TBI and without headache. The gene discussed is PTH; the disease is Headache.