This is the 10265th most frequent Russian word.
болезней
The word "болезней" is the genitive plural form of "болезнь," meaning "diseases" or "illnesses."
Here, 'болезней' is used in its genitive plural form to indicate the type (diseases) that the medications help prevent.
Лекарства помогают предотвращать развитие болезней.
Medications help prevent the development of diseases.
The word 'болезней' is in the genitive to describe the risks associated with diseases.
Опасность болезней увеличивается без профилактики.
The risk of diseases increases without prevention.
'Болезней' is in the genitive plural to show possession or relation to the study.