factor
Exposure of the neck to radiation is a causative factor in the development of thyroid cancer.
Home environment does not seem to be a strong causative factor for social anxiety disorder.
She cites the profit motive as a causative factor in the decline of the railways.

SMART Vocabulary: related words and phrases

Causing things to happen
activation
actuation
agent
attribute
attribute something to someone
hyperstimulate
hyperstimulation
implement
implementation
in
launch pad
prompt
put someone to somethingidiom
Pygmalion effect
reactivate
realization
realize
render
spark
spell