NPR much better than WebMD in explaining observational study on fish oil/macular degeneration

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One story – an NPR blog story – ran only 428 words.

Another – on WebMD – ran 661 words.

Usually you’d think the longer story did a better job evaluating the evidence.

But in these examples of two stories on the same study, the shorter NPR blog story did a far better job of reminding readers of the limitations of drawing conclusions from observational studies. It stated:

“But (the researcher) couldn’t resist adding a professorial caveat: “But in order to strengthen a possible causal relationship, we need randomized trial data.”

Good point. Christen’s study, published online in the Archives of Opthalmology, sorted through a lot of data: 39,876 women participating in the Women’s Health Study. But it’s not a randomized trial, and it relies on the women to report what they ate. So it doesn’t prove that it’s the oily fish that’s reducing their risk of macular degeneration.

Other studies are trying to nail down that link. A randomized trial looking at whether taking Omega-3 supplements prevents advanced macular degeneration is currently underway, funded by the National Eye Institute. An earlier trial found that taking zinc and antioxidants reduced the risk of advanced age-related macular degeneration by about 25 percent.

And Christen’s group is starting a randomized trial on whether taking Omega-3 supplements affects rates of cardiovascular disease and cancer.

Bottom line: Christen says he eats “lots of tuna.” Stay tuned for those randomized trials.

But WebMD only cautioned:

“More research is needed to confirm these findings.”

Wow. What were all the additional words used on? Much of it was on quotes like this:

• if omega-3 fatty acids could prevent AMD from occurring it would be “amazing.”

• ‘This will be a great breakthrough, if it is true.”

• “The article makes a very important contribution by providing clear evidence that omega-3 fatty acid intake can help prevent macular degeneration.”

That last quote is especially problematic. We can debate how clear this evidence is. And NPR’s blog did a much better job of explaining that – and more efficiently as well.

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A Health Blog

March 18, 2011 at 4:25 am

And how about this for drawing conclusions:
“Results for fish intake showed that consumption of one or more servings of fish per week, when compared to less than one per month, was associated with a 42 percent lower risk of age related macular degeneration. This lower risk appeared to be due primarily to consumption of canned tuna fish and dark-meat fish.”