This is the 8748th most frequent Korean word.
간질환을
"Liver disease."
Here, '간질환을' (liver disease) is the object of the verb '예방하기' (to prevent).
간질환을 예방하기 위해 규칙적인 운동이 중요하다.
Regular exercise is important to prevent liver disease.
In this sentence, '간질환을' (liver disease) acts as the object of the verb '앓고 있어' (to suffer from).
그는 간질환을 앓고 있어 건강 관리를 철저히 해야 한다.
He has liver disease and needs to manage his health thoroughly.
Here, '간질환을' (liver disease) serves as the object for '올바르게 치료하려면' (to properly treat).