Monday, August 13, 2007
Left-handedness and your health
I told my wife today is International Left Handers Day. She comes from a long line of them. She, along with her father, brother, sister and aunt are all proud southpaws.
"If the left hemisphere of the brain controls the right side of the body and the right hemisphere of the brain controls the left side of the body, you know we're the only ones in our right mind," she said.
"That must be lefty humor," I said.
From doors, computers, to scissors, there is no doubt that our world is made for right-handed people. Even anthropologists, have found that right-hand preference spans across all human cultures, including ancient civilizations. Even a test of fetuses (using ultrasound) shows 92 percent sucking their right thumbs, according to the Centre for Addiction and Mental Health at the University of Toronto.
In fact, about 1 in 10 people are left-handed, according to the latest research. Also, left-handedness tends to be more common in men than in women. Being a lefty is also a family affair. A Scientific American Mind article states that two-right handed parents have a 9.5 percent chance of having a left-handed child. A mixed couple, with one lefty and one righty, have about double those chances. Whereas, two left-handed mates have a 26 percent chance of having a southpaw baby.
Just last month, Oxford University researchers discovered a gene that increases the odds of being left-handed. That same gene may carry an increased risk of schizophrenia. It's yet another finding that associates left-handedness with poorer health outcomes.
A Dutch study this year found that left-handed women have a higher risk for cancer, stroke and arterial damage. Some older studies have found associations with a long list of chronic ailments: alcoholism, dyslexia, migraine, asthma, hyperactivity, inflammatory bowel disease and mental disabilities. But even with these higher associated rates, no scientist can offer a definitive cause and effect between left-handedness and illness.
Critics of older studies say that the research is biased. They say it has been influenced by antiquated theories based on left-handedness as a disorder - a product of an excess of fetal testosterone or developmental instability in the uterus. The latest research says there is little to no proof of these factors being true.
There is some good news. Last year, an Australian study found that left-handed people are quicker while playing computer games and sports.
Do you think that left-handedness has an influence on health? Why or why not? Do you think it's easier or harder to be a lefty in today's world?
ABOUT THE BLOGGet a behind-the-scenes look at the latest stories from CNN's chief medical correspondent, Dr. Sanjay Gupta, and the CNN Medical Unit producers. They'll share news and views on health and medical trends -- info that will help you take better care of yourself and the people you love.
PREVIOUS POSTS• "Look, Daddy, there's a snake under my tricycle!"
• Keeping your cool in a heat wave
• An ounce of prevention could save lives
• The future of food
• Addiction claims another innocent life
• Pre-teen body image issues
• Institutionalizing people with disabilities
• Beneath the Carteret Islands
• Disappearing Islands
• The Tour de France and the human body