The distribution of the transient global amnesia in the province of Ferrara, Italy, a clue to the pathogenesis?

The pathophysiology of transient global amnesia (TGA) is still uncertain. In the province of Ferrara (Fe-province), Italy, given the health organization and the alarming clinical features, the cases of TGA in the resident population virtually correspond to the resident outpatients diagnosed as TGA cases in the ER of the University Hospital of Ferrara. Thanks to this, a retrospective survey identified 35 (14 men, 21 women) first-ever TGA cases in the resident population in 2018 (346,975 inhabitants) giving a crude incidence rate of 10.10/100,000 (95% CI 7.00-14.00), 8.40/100,000 (95% CI 4.60-14.10) for men, and 11.60/100,000 (95% CI 7.20-17.80) for women, a non-significant gender difference. The incident cases of TGA were evenly distributed according to both season and month. The monthly cases of TGA followed the Poisson distribution (goodness-of-fit test: λ = 2.9, χ = 2.557, 5 degrees of freedom, p > 0.70). The incidence of TGA in the Fe-province was higher in the highest level of urbanization (21.40/100,000 95% CI 13.10-33.00) than in the lowest one (4.20/100,000 95% CI 1.92-8.00). The incident cases of TGA increased with the level of urbanization (χ trend test = 19.940, p < 0.001) and the population density (inhabitants/km) level (χ trend test = 46.684, p < 0.001). Since urbanization is likely involved in stress-related disorders, these findings achieved in a well-defined homogeneous population seem to support the hypothesis of the involvement of stress, maybe in vulnerable individuals, in TGA.