Men may be the root cause of why women go into menopause, according to a new study that the authors say debunks the prevailing theory on the evolution of the condition. The Canadian researchers suggest that men’s preference for younger women left older women with less chance of reproducing, and that meant mutations affecting fertility later in life could accumulate. Natural selection protects fertility when reproduction chances are highest. These findings go against the conventional thought that menopause prevented older women from reproducing.
Researchers from McMaster University used computer simulations to track the effects of male preference for younger females and concluded that, over generations, gene mutations that resulted in a sharp decrease in fertility hormones could have led to older women reaching a point where they could no longer reproduce.
If men did not discriminate between younger and older women, then perhaps menopause would not have occurred, the researchers wrote.
BOTTOM LINE: Men’s preference for younger women may be the root cause of why women go into menopause.
CAUTIONS: The theory is based on mathematical models and is one of many hypotheses.
WHERE TO FIND IT: PLOS Computational Biology, June 13
Tobacco ads tied to risk of teen smoking
Every 10 tobacco ads a teenager sees may increase his or her risk of smoking for the first time by up to 40 percent, a German study found.
The researchers surveyed over 1,300 10- to 15-year-olds in 21 public schools in Germany about how often they saw tobacco ads. Two and a half years later, the students were surveyed again, and this time they were also asked how many cigarettes they smoked and how often they smoked.
Nearly 40 percent of the students said they tried smoking within the study period, and 30 percent said they were daily smokers. The more tobacco ads a teen saw, the higher the likelihood that he or she smoked.
When the smokers were asked what influenced them to begin, they answered that the strongest influence was their peers, followed by exposure to tobacco ads. Nearly 13 percent of all of the students surveyed said they had seen tobacco ads more than 10 times. Those who reported seeing between 11 and 55 tobacco ads were twice as likely to become a regular smoker.
BOTTOM LINE: Every 10 tobacco ads a teen sees may increase his or her risk of starting to smoke by up to 40 percent.
CAUTIONS: The study relied on teens’ self-reports of how much advertising they watched and how much they smoked, which may not have been accurate. The researchers did not take into account other factors, such as household smoking habits.
WHERE TO FIND IT: British Medical Journal, June 12