I just did a little research about Sue Lyon, who played Lolita in the 1962 Kubrick film. The most detailed, and also most sleazy, account is on E! online: http://www.eonline.com/Features/Specials/Lyon/
[See update, below.] The E! story is yet another small act in the series of exploitations that began before the movie and exploded after it. Lyon was the youngest of five children in a poor family (her father died when she was a baby), and she was sent out to model as a pre-teen in order to bring in some cash. She won the role of Lolita when she was 13 or 14--the actual age of Lolita--but was, I gather, fifteen when the film was shot. So she was only a tiny bit older than the character, but was cast because she looked more adult than others her age. She had large breasts, unlike Nabokov's Lolita. So much effort went into confounding the audience's prurient/moral expectations about filming this story. How do you film it without doing damage?
Lyon went on to have a fairly terrible life. Divorced several times, she married a man in prison for murder at one point; before that she had married an African-American man and fled with him to Spain due to the uproar. She is now married to someone else and doesn't grant interviews. She's been diagnosed as bipolar but apparently found treatment later in life.
Incarnating Lolita appears to have done her no good. She received much of the lurid attention that the fictional Lolita did, and it should be remembered that the tendency then and even now was to portray Lolita as the seductress of a relatively helpless "middle aged man." E! Online says as much. The entwined artistic and commercial imperatives to film Lolita, combined with Lyon's poverty, the lure of celebrity, and finally the ageless pleasure of condemning girls for arousing sexual desire in others: the same cultural constellation trapped Lyons and Nabokov's Lolita, another fatherless child.
UPDATE 10-1-12: Sorry, folks, looks like E! has taken the story down. If anyone has other links they'd like to share, please do so in the comments.