Nice summary but I would point out that Huntington’s is hereditary and the association with caffeine is of an earlier age of onset, not increased risk.
Simonin C, Duru C, Salleron J, et al. Association between caffeine intake and age at onset in Huntington's disease. Neurobiol Dis. 2013; 58: 179- 182.
Simonin C, Duru C, Salleron J, et al. Association between caffeine intake and age at onset in Huntington's disease. Neurobiol Dis. 2013; 58: 179- 182.