Lower Intelligence of Men Born Year After 1969 Flu Pandemic

This is a fascinating study of a particular environmental effect on fetal development. The complete abstract appears below.

Ann Neurol. 2009 Mar 18;66(3):284-289. Register data suggest lower intelligence in men born the year after flu pandemic.. Eriksen W, Sundet JM, Tambs K. (Division of Mental Health, Norwegian Institute of Public Health, Oslo, Norway)

OBJECTIVE: To test the hypothesis that prenatal exposure to the Hong Kong flu, an influenza pandemic that haunted Europe during winter 1969 to 1970, was associated with reduced intelligence in adulthood.

METHODS: Data from the Medical Birth Register of Norway were linked with register data from the National Conscript Service. The sample comprised all registered boys born alive in single birth after 37 to 43 weeks' gestation during 1967 to 1973 (n = 205,634). Intelligence test scores, recorded at military conscription, were available for 182,913 individuals.

RESULTS: The mean intelligence score increased from one birth year to another, except for a downturn in 1970. The birth year 1970 was inversely associated with intelligence score (-0.03 standard deviation [SD]; p < 0.001) after adjustments for birth characteristics, parental characteristics, and the trend of increasing scores over the 7 birth years. Analyses with the sample stratified by birth month showed that the inverse association between the birth year 1970 and intelligence score was significant only among men born in July (-0.04 SD; p = 0.049), August (-0.05 SD; p = 0.013), September (-0.09 SD; p < 0.001), and October (-0.06 SD; p = 0.008). Thus, the intelligence scores of the men born 6 to 9 months after the epidemic were lower than the mean values for the men born in the same months a few years before or after.

INTERPRETATION: Early prenatal exposure to the Hong Kong flu may have interfered with fetal cerebral development and caused reduced intelligence in adulthood. Ann Neurol 2009;66:284-289.

 

 

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Comments

[Norge]

The moon May be made of gamel cheese also. Just what organization gave the so called "intelligence test?" Who wrote the tests and for what group of peoples and for what agenda?

May is the very important "speculative" word used and therein lies the works credibility. Perhaps during those years of so called lower levels there was more chlorine in the drinking water than so called normal that affected the stimulus response of partisipants in regulated tests.

Just speculation.

[Dan Agin - Huffpost Blogger]

Thanks for your comment. Maybe the rational thing to do is read the original paper and deal with its contents. You may find answers to your questions. In fact, there is hard evidence that viral infections can cause fetal damage. One well-known culprit is cytomegalovirus. And why not? A viral pathogen, after all, does infect cells, and the embryo and fetus are collections of cells. If a particular flu virus makes you sick, you can assume it may be dangerous for a fetus. So the observed correlation is not surprising. As for IQ tests, what they measure is a problem separate from establishing the existence of an effect of infection. If the fetal developing nervous system is infected by a pathogen, an effect on later functioning of that nervous system would not be a surprise. The report is an alarm bell, and I think such alarm bells should be taken seriously and a search made for more evidence. That's the gist of medical science. Anyway, thanks again.

[Norge]

Yes it is another possibility though again it involves definitions and assumptions. It does of course seem logical that the fetus will be affected in one way or other by invading alien organisms or the radication of certain bacterias from the body in our rush to be more healthy and more intelligent.

Asma for example seems to have become to be such an explosive problem at certain times of the year because we humans have cleansed our bodies these last 50 years of every conceived evil bacteria. Perhaps some of these flu viruses and becoming sick by them also help us in the reinforcing of our own immune systems against more advanced mutated viruses of the future.

I am a bacteria and virus friendly person and know life on earth would not exist without those organisms.
I do appreciate how all powerful that micro world is over our perceived powers.

Incidently I have just this last week recovered from the common flu virus and actually feel stronger and more invigerated.

Have a nice day-:)

[royniles]

Why do you keep deleting my comments that this study is less than conclusive?

[Dan Agin - Huffpost Blogger]

The authors do NOT say the study is conclusive, they say Hong Kong flu MAY have interfered with fetal cerebral development, which is the most reasonable conclusion given all the other data about the effects of viral infections of fetal development. If the smoke alarm goes off in your house, it's prudent to find out why. These correlation studies are all we have, since we cannot do controlled experiments with pregnant women.

[Dan Agin - Huffpost Blogger]

correction: "effects of viral infections ON fetal development"

[anfractuous]

As I've always suspected!

[ndem]

and pregnant women exposed to swine flu? is this why all the fuss about pregnant women?

[philistine]

Wow.

That would seem to support an inclusive public health plan, rather than one that excludes furriners 'n sech. Public Health shouldn't be an oxymoron.