Cancer, for all of the modern emphasis on genes, is largely determined by life, not inheritance, according to a huge study of tens of thousands of twins.

The report in the New England Journal of Medicine underscores the conclusion that many cancers can be avoided by lifestyle choices such as good diet, exercising and eschewing tobacco.

In a commentary accompanying the journal's report, Dr Robert Hoover, director of the epidemiology and biostatistics program at the National Cancer Institute in the United States, wrote that though there are genes that cause high rates of cancer in some families, such fatalism, for the most part, is not warranted.

"I think there is this kind of fatalistic approach to genes that the general public seems to have now - that if your mum, dad, sister or brother had something, that you're doomed to have it too," says Dr Hoover.

Overall, genetic factors seemed to account for between 21 per cent and 42 per cent of risk, depending on the type of cancer, with an average of about 30 per cent.

The rest of the cancer risk was chalked up to "environmental" factors such as experiences in the womb, upbringing and smoking, drinking and eating habits.

The study was conducted by scientists from Sweden, Denmark and Finland. It drew on extensive twin registries in the three nations that permitted the authors to study 44,788 pairs of twins born between 1870 and 1958. Cancer registries revealed that 10,803 of these people developed cancer.

The scientists compared cancers in identical twins to non-identical, or fraternal, twins.

The authors were able to reach firm or reasonably firm conclusions about the most common cancers - breast, colorectal, prostate, stomach and lung.

"Though the genome project has a lot of promises for ... treatment of cancer ... it won't explain all cancers," said the study's lead author, Swedish Professor Paul Lichtenstein. "It will not be a miracle and solve all problems."

Among the cancers reliably examined, prostate cancer had the highest rate of heritability - 42 per cent. This is in stark contrast to other cancers, where a host of studies have pointed fingers at environmental influences.

Smoking, for instance, is linked not only to lung cancer, but to cancers of the stomach and mouth. Infection with human papilloma virus increases risk for cervical cancer. A woman's lifetime exposure to estrogen, as well as exercise, seems to influence her risk for breast cancer. Physical activity, amount of red meat, fruits and vegetables and other aspects of diet have been implicated in colorectal cancer, and others.

Sense of Humor Twin Study Results Genetic or Environmental? With humor, its environment, silly.
By Dru Sefton NEWHOUSE NEWS SERVICE April 25th

The study suggests sense of humor is the upshot of upbringing. Sure, you can inherit your mom's bone structure. But can you inherit her funnybone? Five researchers in Britain set out to determine just that, whether nature or nurture played a bigger role in development of a sense of humor. The shared environment, rather than genetic factors, explains the familial aggregation of humour appreciation ...

The shared environment, rather than genetic factors, explains the familial aggregation of humour appreciation as assessed by the specific off the wall cognitive type of cartoons used in this study. In other words it s the environment, silly.

One of the researchers, Tim Spector, wasn't surprised. "I have a brother, and we share a very similar sense of humor," Spector said from his office in the genetic epidemiology unit at St. Thomas Hospital in London. Attribute that to our upbringing and listening to my father's jokes.

Spector and his colleagues used 127 pairs of twins, aged 20 to 75, and The Far Side cartoons to conduct their experiment. Some twins (71 pairs) were genetically identical; the rest were fraternal, or nonidentical.

The scientists separated the pairs and gave each one five cartoons. Then each twin rated the cartoons from zero ( waste of paper) to 10 (one of the funniest cartoons they had ever seen).

Spector said he had specific reasons for selecting cartoonist Gary Larson s quirky drawings for the test."I'm a fan of Larson and I like his cartoons, but I know a number of people who don t find them funny." So they seemed well suited for such a study.

One of Spector's personal favorites rated a high response with many of the twins In the one-panel drawing, a group of people look at a composer slumped over a piano. His head is on the keyboard and his skeletal arm hangs at his side. "Shhh, a woman says. The Maestro is decomposing."

Spector admitted, "We had a few twins who didn t understand the cartoons."

When results were tabulated, the researchers deduced that twin pairs showed considerable similarity in their responses to the cartoons. However, identical twins those who share the exact same genes were no more likely to have a similar sense of humor than fraternal twins. This suggests that upbringing is important, the researchers concluded.

Janene Wolsey Baadsgaard, author of 10 books, could have told you as much. "I guess you could say my family did its own study," aid Baadsgaard, whose works include the recent Grin and Share It Raising a Family With a Sense of Humor.

LEARNING TO ENJOY LIFE

Baadsgaard explained that when she was growing up, many of her relatives suffered from depression and anxiety."I come from a family that didn t seem to enjoy life very much," she said.

So when she married, she wanted to help her children look at life with humor. "So you want to have kids?" "Will our life change?" we asked friends about having children. Their eyes got big as saucers. They gazed back at us as if they were watching an owl swim under water.

I learned a lot from my husband. "He seemed so much happier than the family I came from," Baadsgaard said. "I saw how he approached life, I observed his habits, and learned how to live with humor."

Baadsgaard now has 10 children, ranging in age from 3 months to 24 years old. Her first grandchild was born at the same time she was in the hospital giving birth to her youngest.

The Baadsgaard children learn through laughter. If Mom and Dad want to teach the kids not to be rowdy during mealtime, then Mom and Dad will excitedly heave forkfuls of food at each other, run around the table, stop and say, "See how silly that looks?"

The old adage about not wasting toothpaste by squeezing from the middle of the tube turns into a messy demonstration with Mom squirting toothpaste all over the bathroom, then asking, Now, is that a good idea?

I think a mother and father can make a huge difference in a child s sense of humor, Baadsgaard said. It s a sense of playfulness, a sense of gratitude, a feeling of "I' m here in the world to lift people, not to be lifted." Her philosophy on raising children with a sense of humor is simple "If you know you re going to laugh about something 10 years later, why not laugh about it now?"

A good example was the major disaster her family just experienced at home near Spanish Fork, Utah. One of the children accidentally left the upstairs bathroom water running. The resulting flood seeped down into a storage room and destroyed quite a bit of food. The adults responded with laughter. We've just trained ourselves to laugh, Baadsgaard said. It's the only real control you have. But a little humor goes a long way. Nadine Block, executive director of the educational nonprofit Center for Effective Discipline, cautioned parents not to get too giggly.  

ABLE TO TELL A JOKE?

"A sense of humor more than anything else is dependent on a frame of mind". DON L.F. NILSEN, executive secretary of The International Society for Humor Studies. In some quarters, humor is an actual academic field of study, and multidisciplinary at that. The International Society for Humor Studies, for instance, encompasses psychology, linguistics, literature, biology, education, philosophy and sociology. Society members also are journalists, nurses, counselors and managers.

Don L.F. Nilsen, its executive secretary, said that, "In general, research has shown that nearly everyone can possess and sharpen a sense of humor nless a person is too paranoid or too literal."

"A paranoid person has a siege mentality," Nilsen said, "often thinking something humorous is out to get him. A literal person isn't able to see beneath the literal meaning of a joke."

And, he adds, "You can have an appreciation for humor without being able to tell a joke." "Many humor researchers have a great sense of humor analysis, but we re really bad at telling jokes at our conferences," said Nilsen, a linguistics professor in the English department at Arizona State University in Tempe.

Sense of humor more than anything else is dependent on a frame of mind, Nilsen said. That s why performers have someone else warm up an audience, put them in a humorous state of mind.Then, when the performer comes out, Nilsen said, "just about anything they re going to say will seem funny."

Source: Johns Hopkins Medical Institutions (http//hopkins.med.jhu.edu) Date   Posted 4/26/2000

OCD Twin Study Results Study Shows Obsessive-Compulsive Disorder Runs In Families

OCD affects as high as 3 percent of the world's population. Although it touches all ages, the period of greatest risk is from childhood to middle age. Twin studies have shown identical twins have a higher incidence of OCD almost 90 percent than fraternal twins, where the odds of both having the disorder is close to 50 percent.