Wednesday, October 26, 2011

Are Girls Worse at Math and Does That Translate to Lower Salaries Later in Life?

One of the best parts about living in Chicago is access to the country's top universities.  Yesterday, I had the opportunity to hear a lecture by one of the area's top economists on the topic of math performance in girls and boys and future salary potential.  As the mother of three daughters, I'm more than interested in this topic.  As a scientist in a male-dominated career, I feel like somewhat of an expert already.  But here's what I learned:

  • There are no differences in math performance among girls and boys in elementary school.  The evidence showing that boys may be slightly better than girls at math is noted at age 15.
  • Boys are really only better at spatial ability (whereas girls are better at verbal).  Interestingly, this is related to testosterone levels.  Boys (and girls) with more testosterone are better at spatial ability than those with less testosterone. 
  • There is really no connection between spatial ability and math scores, EXCEPT in geometry.  Tests, such as the SAT and ACT, that skew heavy on geometry result in higher scores for boys than girls.  But when it comes to algebra and calculus, which have nothing to do with spatial ability, there are no measurable differences between girls and boys. 
  • When it comes to career salaries, there is a gender gap.  Men make more money than women.  Much of this is explained by the following:
    • Women are less likely to take jobs with long hours or a competitive pay structure.
    • Women are more likely to select jobs that are family-friendly versus those with higher pay.
    • Women are more likely to step out of the work force for family reasons, which results in lower pay at a given point in time.  For example, if you compare a 40 yr old man and woman who are both lawyers, the woman may make less money on paper, but she may have taken 5 years off to raise a kid or care for a sick relative and that is not always accounted for in surveys.
    • In interviews, men tend to over-represent their experience resulting in better opportunities or higher pay, whereas women tend to under-represent their skills. 
At this point in the lecture, a hairy spider walked across my table and I stood up like a crazy person and waved my arms around like an idiot until someone removed it (not even squished it, but gently took it away to live out its days in a planter or toilet).  That is neither here nor there, but was a subtle reminder that you can take the scientist out of the lab, but you can't take the girl out of the scientist. 

The most interesting finding for me was that even after you factor out all of the reasons above, men still make more money than women at a given job.  There is an underlying perception or expectation that men will outperform women.  I'm sure if you compare 2011 to 1961, things are much better today and we are likely moving in the right direction for the future.  But hearing these research results reminds me that women just need to work harder than men in a given career to achieve the same level of success.  This is especially true in male-dominated careers like science and engineering.....and spider catching.

Thursday, October 13, 2011

Should You Stop Taking Your Supplements or Not?

I'm a few days late in commenting on two studies that were published this week suggesting that vitamin and mineral supplements are harmful.  One study tracked 38,000 women starting when they were 55-69 years.  The researchers asked them to fill out questionnaires periodically on their supplement usage (and a bunch of other things) and then they just waited for them to die (morbid, but true).  Results showed that after 20 years, those women taking a vitamin and mineral supplement had a 2.4% higher risk of death than those who didn't take a supplement.  Iron seemed to be the nutrient most associated with a higher risk of dying earlier.

A different study looked at 35,000 men who either took a selenium supplement (200 ug/d), a vitamin E supplement (400 IU/day), both supplements, or none.  After tracking these guys for 7 to 12 years, those taking either supplement (or both) had a higher risk of developing prostate cancer (17% higher risk for those taking the vitamin E).  
The fun in being late to report on these studies is that I can respond to many of the comments that are being posted on various news sites and other blogs.  Some range from rather insightful to loony.  And I apologize to anyone who's words I'm using below...but I just couldn't let these go without commentary:

"I would like to know who funded the study. Could it have been a pharmaceutical company?"

Dr. T: Both studies were funded by the National Cancer Institute.  Why on earth would a pharma company pay the millions of dollars needed for these large studies?   

"Big pharma profits down, no new drugs in the pipeline, running out of people to over medicate, time to attack vitamins! The bottom line.This study is a classic example of scientific reductionism being used to fulfil a particular need. In this case, it’s supplement bashing, a well-known preoccupation of Big Pharma."  

Dr. T: Ah of course, this is why.  Pharma companies want people to get sick so they somehow convinced the National Cancer Institute to give  millions of dollars to university professors who then were in on it too and designed a study to make people die more quickly from taking supplements...."a well-known preoccupation of Big Pharma".   I hope this person declines any drugs their physician prescribes to them for a life-threatening disease (all developed and proven effective from a pharma company) since they feel so strongly about "scientific reductionism".  And if someone could kindly explain what that term even means, I would greatly appreciate it. 

"Vitamins should not be taken to INCREASE LIFE SPAN. Vitamins should be taken to enhance life."

Dr. T: This is true, no one ever said vitamins were going to extend your life.  But if they do cut your life short, are they really enhancing your life?  

"Maybe they died in car accidents going to buy more vitamins"

Dr. T:  This is actually the smartest comment in the bunch.  The study looking at women and supplement use did not evaluate whether vitamins CAUSED early death, but rather they were looking for whether there was an association.  It is possible that women who were already sick happened to be taking more vitamins.  Or that these women who take vitamins have other behaviors that increase their risk of death.  That said, the prostate study coming out in the same week, plus earlier studies showing similar results, all suggest that people need to think twice before taking a supplement (see below for more info on that).  

"This is utter BS. Bad science is plaguing the world. Especially that which pertains to the use of vitamins. Countless studies of vitamin megadoses show phenomenally positive effects on human health. Of course, these are predominantly unheard studies as the pharmaceutical industry will stop at nothing to keep people on their meds instead of letting them take preventative measures with vitamins, natural assets that give our bodies the strength to fight disease."

Dr. T: It is possible this is the same person with the same conspiracy theory above.  First off, these two studies are some of the highest quality research out there since they have tens of thousands of people.  There are NO studies with tens of thousands of subjects looking at megadosing of vitamins.  In fact, most of those studies have 10 to 50 people and results seem to always work best in people that are already deficient.  For example, mega-dosing of iron helps children grow and learn in less developed countries (because they are low in iron).  And finally, these studies are being published in top tier journals that are run independently by university professors...not pharma companies.  And what exactly is a "natural asset"?

So back to the title...should you stop taking your supplements?  Maybe.  Some things to consider:

1. Do you drink fancy drinks containing vitamins, eat energy bars with vitamins, have a bowl of fortified breakfast cereal every day?  If so, you really don't need a supplement.  

2. You really don't need more than ~100% of the daily value in a supplement.  If you are taking more than that, you may want to re-consider what you are taking.  

3. You may only need to supplement selected vitamins and minerals.  For example, a vitamin D supplement is really only needed for those living in northern locations or those who are never outside without sunscreen.  Women who are menstruating and do not consume red meat probably need to take iron but men do not.  Those who do not eat any fruits and vegetables (gasp!) should take a vitamin C supplement but if you are smart enough to eat those foods, you probably don't.  

4. Is a "whole-food supplement" better than a regular supplement?  At this point, we don't know.  There are no big studies looking at food-based sources of vitamins and minerals and health.  It may be that it doesn't matter where the vitamins come from.  Or they may be better, but not clear yet.  I would still stick to the 3 principles above until we have more information. 

And I promised a friend I would look at natural remedies for cold and flu so hope to get to that topic next! 

Wednesday, October 5, 2011

Another Possible Reason Why Girls May be Hitting Puberty Earlier

There's no doubt that young girls these days are maturing a lot faster than when we were little.  On average, puberty is starting as young as 9 years in Caucasions and 8 years in African-Americans (and that's an average, so for some individuals, it starts much sooner).  Just look at the bra section in seems to get bigger each year.

A number of theories exist as to why this is happening, most notably the increase in childhood obesity.  Young girls who are obese have a much higher risk of developing early versus non-obese peers.  Fat cells produce estrogen, which may kick off the puberty process early.  Young boys who are obese may have delayed puberty for the same reason...however the estrogen blocks testosterone from initiating puberty.  Either way, those of you with children would probably agree that they are happiest when they are 'average'.  Early puberty or late puberty does not make for a happy child and therefore by default, a happy parent.

Other theories for why puberty is starting earlier include things like pesticides, hormones in milk, and other contaminants in our environment.  And it may not just be whether the children themselves are exposed to these contaminants, but both parents as well.  

A new study this month is suggesting another possible cause for early puberty: low levels of vitamin D.  The research showed that girls in northern latitudes (where there is much less sun and therefore less vitamin D being made in the skin) are more likely to have their first period earlier than those in southern latitudes.  This is a very important finding because girls who have their first period before age 12 have a much higher risk of breast cancer later in life.  

This study doesn't prove that taking a vitamin D supplement will delay a girl's first period, but it does provide more rationale for why its important for girls to drink milk (which has vitamin D) and/or take a multi-vitamin containing vitamin D.  These results also suggest that children in northern climates may benefit from having vitamin D levels tested at the pediatrician's office to rule out a deficiency.  

And most importantly (for me anyway), this is a darn good reason for a winter vacation in a nice climate!