Quality of Life (QoL) is roughly defined as "The subjective perception of a human being about his/her well-being across 4 domains: Physical, Emotional, Social and Vocational domains".
To capture this subjective perception, health professionals use scales such as PedSQL to transform the perception into and objective measure.
A single SD drop from the normal values for a particular population puts an individual at risk wile 2 SD drops is considered as a significant compromise in QoL.
Thus a risk would be any factor that causes a deviation from normal thresholds.
To minimize the risks you need to capture the deteriorated domain, identify the reason of that deterioration and apply tactics that improve the affected domain or balance the total QoL via maximizing other domains.
For example; a child with leukaemia during induction would be subjected to the risk factor "intense chemotherapy" which causes a significant compromise of physical and possibly emotional domains.
The other 2 domains; Social and vocational - schooling for the child - should be maximised to balance the total QoL until the intense chemotherapy is done and physical domain regain its integrity. Emotional domain could be improved in most cases through proper communication with the child and his family.