I wonder if the scientist in question doesn't know of the possibility of confounders, didn't mention them to the reporter, or the reporter just didn't think that was exciting enough to include in the article. It seems just possible that there is something about 1% fat milk drinkers that is different from 2% fat milk drinkers, which causes them to drink 1% fat milk and which also causes them to have longer telomeres. Unfortunately, there is no link to the study, so we can't see what was controlled for. But if I were a betting man I'd bet that most of the difference is caused by other causes than the difference in milk drinking.
What's worse is when the article touts all of the variables that have been controlled for as if the issue has been completely ameliorated.
I think this is correct. The non-milk-drinkers had telomere lengths between those of the reduced-fat and the full-fat groups, which leads me to conclude that among milk-drinkers, those who go for the reduced-fat milk tend to live a healthier overall lifestyle. Those who go for the full-fat milk tend to live a less healthy lifestyle. The non-milk-drinker category is a mixed bag, since the preferred-fat-percent variable is lost.
Right, there is a huge difference between correlation and causation.