Iyov's righteousness would likely have secured for him G-d's watchful protection, had it not been for the 'adversary'. The 'adversary' persuades G-d not to grant Iyov the divine protection that the righteous deserve. The result, Iyov is victim to the first two categories of harm and destruction. Iyov's new test involves the third category. Iyov is totally righteous and certainly does not get involved in any precarious life style.
Medical problems are frequently the result of dangerous life styles.
Statistics show that seventy to eighty percent of life threatening diseases and accidents are caused by dangerous habits and activities. The list goes on and on. It is obvious that Iyov would not be involved in any of these types of activities. There is certainly no clear self-induced cause that would have made him vulnerable to the types of disease from which he suffers. Since no natural cause is present he does not need G-d's special intervention to protect him.