C'mon, man. The use of the 'attributable fraction' (AF) in legal cases about toxin exposure is well established, if not uniformly legally applied. Careful epidemiology routinely produces the `excess relative risk' of an exposed population to a specific exposure. From this the AF can be computed as ERR/(1+ERR). For example, for uranium miners in the early days of the nuclear program the AF for lung cancer (via radon in mines) was 60% or more. Large scale epidemiology for U.S. cabin crews is already past the planning phases. Naturally not much can be said about one individual's case (except via intrusive genetic testing for predisposing factors), but the AF permits at least a rational way of proceeding.

Is that used in France too? It’s not clear to me what part of the article you’re reacting to