Related:
http://tatoeba.org/spa/sentences/show/3350935
From infography
http://www.besthealthdegrees.co...s-of-dying.jpg

15+ year
3x
higger
mortatity
who'd never obese

all need to be changed.

Perhaps something like:
"People who were obese at 15 years of age or over (?) have a three times higher risk of mortality than those who'd never been obese."

I changed Its ok?

I changed Its ok?

In my opinion the English sentence is now good.

Now I understand what you mean by "ambigous".
Judging from the link you provide I'd think that the intended meaning is "for at least 15 years" (at any age) and not "at the age of 15 or over".

Thank to both.
Gracias a los dos.

"for at least 15 years" o "at the age of 15 or over" What is the difference please?

Here is the study they quote from:
http://www.eurekalert.org/pub_r...-tlw032011.php

Maybe Patrick can tell us if the current English sentence is a correct paraphrase.

Thanks for the article. When I said earlier the sentence was "good" I based that on grammar, syntax etc and not on how accurately it reflected the article, which I hadn't read at that stage.

Having read the article, the English sentence is not correct. The study refers to how long someone has lived with obesity as a risk factor for mortality NOT at what age they became obese.

To reflect the report the sentence would need to be something like:

"People who have been obese for 15 years or more have a three times higher risk of mortality than those who have never been obese."

>"for at least 15 years" o "at the age of 15 or over" What is the difference please?

"for at least 15 years" refers to a duration of 15 years with no reference to age, it could be from birth to 15 years of age, or any other 15 year period in someone's life.
"at the age of 15 or over" refers to the age of 15 or more, ie it does not refer to someone who is under 15 years of age but to someone who is aged 15 or older.