How long does a person need to be obese to affect his or her pubertal development?

Earlier obesity in girls seems to be associated with an early onset of puberty , though the association is not as clear in boys . The effect of different hormones like leptin is supposed to play a role. .Some studies have shown that obesity before five years of age, is more likely to be associated with earlier puberty including menarche, perhaps due to the effect of insulin related factors.