Статистики за левучарите

Окнаши, левак сум, и ме плашите! Според кое истражување ќе живеам девет години пократко?! Можете да бидете малку поодговорни кога објавувате вакви текстови, собрани од кол и ортома?! Барем извор да наведевте? Еве одма што прогуглав, првата студија што ја најдов (да, и таа вели дека леваците живеат пократко, 25 месеци - а не 108 месеци! - ама причините се зголемен број несреќи и гинење во војна - кај леваците).

STUDY OBJECTIVE--The aim was to examine the relationship between handedness and longevity. DESIGN--This was an archival (retrospective) survey of a cohort of adult men who had played 'first-class cricket'. SETTING--The United Kingdom PARTICIPANTS--The subjects consisted of all of the deceased players included in an encyclopedia of 'first-class cricket' whose bowling hand had been recorded (n = 3165). The study also considered a further 2314 players, born before 1951 but still alive at the time the book was published (1984). MEASUREMENTS AND MAIN RESULTS--Using the bowling hand as an indicator of handedness it was possible to compare the lifespans of 2580 right handed men and 585 left handed men. The average life spans of the two groups differed by 25 months (right = 65.62, left = 63.52), a highly significant difference (p = 0.006). An examination of cause of death (where noted) strongly indicated that the left handed men were more likely to die prematurely in accidents or in warfare. As a consequence, when these unnatural deaths were removed from the sample the longevity difference between the right handers and left handers was considerably reduced. There was no evidence that these results related to any longitudinal change in the proportion of right handers to left handers across the time course of the sample. CONCLUSION--The study found clear evidence that left handedness was associated with a decrease in longevity among a cohort of adult, athletic men. A major factor responsible for this result seemed to be a differential likelihood of accidental death or death during warfare.

Еве, најдов критика на таа студија (стварно постоела), која вели дека леваците живеат девет години помалку од деснаците:

Geographer Sees Small Link Between Longevity And Handedness UB Research Contradicts Earlier Studies That Found "Righties" Live 9 Years Longer Than "Lefties"

BUFFALO, N.Y. -- There is little difference in the longevity of left- and right-handers up until age 65, and right-handers live only about one year longer than left-handers from age 65 on, a University at Buffalo geographer has found.

The findings of Peter Rogerson, professor and chair of geography at UB, differ strikingly from those of earlier studies that estimated that right-handers live up to nine years longer than left-handers.

In a study to be published in a forthcoming issue of Social Biology, Rogerson looked at the handedness, vital status, age at beginning of career, date of birth and date of death for 4,448 baseball players listed in "The Sports Encyclopedia: Baseball." Only those players born before 1920 were included in the study. The study also was limited to players listed as using the same hand for batting and throwing.

Using two statistical tests to compare the survival curves of left- and right-handers, Rogerson determined that the survival rates were similar for both groups between the ages of 25 and 65. However, the survival rates of right-handers between the ages of 65 and 85 were noticeably higher than those for left-handers in that age group. He found that 21 percent of left-handers alive at age 65 would be alive at age 85, while 26 percent of right-handers alive at 65 would be alive at 85.

He calls the difference in longevity "noticeable but small," saying that right-handed 65-year-olds "can expect to live close to one year longer, plus or minus a little more than half a year."

"There's something to it," Rogerson says of the theory that right-handers live longer than left-handers. But the difference in longevity for the two groups "is not as startling" as some studies have suggested.

He says that while these other studies have looked only at persons who had died, his sample included persons who were still living.

"It's important to look at those who are still alive because they give us more information," he says. "Those who have died are just part of the sample.

"For example, a conclusion, based upon data on deceased individuals, that right-handers live longer may in fact be negated if relatively more of the left-handers remain alive.

"Even with no differences in longevity, it might still be expected from an analysis of the deaths in a given period that left-handers would have a lower mean age at death, since some evidence indicates that the incidence of left-handedness has increased over time."

The incidence of left-handedness has increased, Rogerson says, because many natural left-handers no longer are forced, as children, to use their right hands.

Rogerson says his study also differs from others in that he used a much larger sample than most previous studies. The sample size is large enough, he adds, that the results cannot be attributed to chance.

He notes that if there are small differences in the longevity of right-handers and left-handers between the ages of 25 and 65, they are harder to detect in samples of this size because of the small number of deaths in this age range.

He says the difference in longevity among those over 65 might be due to the relationship between handedness and stress at birth. Arguments have been made by some researchers that left-handers experience more prenatal and perinatal stress, which links them to a variety of disorders, including smoking and alcoholism, breast cancer, early-onset Alzheimer's disease and schizophrenia.

Rogerson believes the best argument linking left-handers with decreased longevity is a concept called the Rare Trait Marker Model.

According to the model, there is some "pathological intervention" that interrupts the natural distribution of handedness and causes a percentage of the population to switch its handedness to the side opposite the naturally determined side of preference.

For example, in a population that is 90 percent right-handed and 10 percent left-handed, some individuals -- say 10 percent -- would suffer some stress that would switch their handedness. According to the model, 9 percent of the natural right-handers would become left-handers and 1 percent of the natural left-handers would become right-handers, leaving a population that is 82 percent right-handed and 18 percent left-handed.

In this left-handed population, half would have this preference because of the intervening pathology. The probability of finding a "pathological individual" -- one who would have a decreased survival rate -- in the left-handed group would be 42 times greater than the probability of finding one in the right-handed group.

The UB study was supported by a grant from the National Science Foundation and by a National Science Presidential Young Investigator Award.

Left-handed people 'don't die young' (BBC News)

In times past, left-handed people were thought to be the children of the devil, but a scientific study published this week suggests that sinistrals are not as cursed as was once thought.

Some studies have indicated that left handers are more likely to die prematurely than their right handed counterparts. It was thought that left handers may be more prone to accidents because their sense of spatial awareness is not as acute as right handers.

But new research in the Lancet suggests that left handers are at no greater risk of dying earlier.

Investigators sent a questionnaire inquiring about handedness to people aged between 15 and 70 years. They received 6,097 correctly completed responses.

Nine years later they attempted to trace the respondents. Research revealed that 5,662 were still alive, 387 had died, and 48 could not be traced.

However further analysis revealed that handedness was not related to longevity.

The researchers, led by Dr Simon Ellis, from the Department of Neurology, North Staffordshire, concluded: "Handedness did not make a significant contribution to the outcome of death."

Fala, Okno, sepak, shto ja otvorivte temava (zapravo, sam si ja otvoriv:). Eve ushte ova, da gi utesham sopatnicite levaci:

EDITOR, - In his editorial on left handedness Bryan S Turner presents a narrow view of the evidence regarding handedness and life expectancy.1 He refers to two studies of life expectancy and handedness by Halpern and Coren, both of which are retrospective reports.2, 3 In the first study the age at death and handedness of professional baseball players was noted from the Baseball Encyclopedia,2 and in the second study the age at death and handedness of people who had recently died was noted from responses to a questionnaire returned by next of kin.3

A major problem in questionnaire studies of handedness is response bias as there is often a differential response rate between left handers and right handers. Add to that the fact that left handedness is less common among elderly people and the potential for serious bias in the results becomes clear. The study based on information from next of kin is clearly vulnerable to the problem, particularly as the overall response rate was low (49%).3

The reasons why left handedness is less common among elderly people is controversial, and Halpern and Coren's argument that it is because of differences in life span is by no means universally accepted. Given this uncertainty, retrospective studies such as Halpern and Coren's are not useful as a difference in the age at death may simply reflect longstanding diferences in the proportions of left handers at different ages. Incidentally, the difference of nine years in the mean age at death cited by Turner was from the questionnaire study3 and not, as implied, from the baseball study: in the baseball study the mean difference in age at death was less than a year (right handers 64.64 (SD 15.5); left handers 63.96 (15.4)) and was not significant.2

Not only do these two studies not provide strong evidence for the suggestion that left handers have a reduced life span but there is good evidence against this position. Two large prospective longitudinal studies from the United States have failed to find any differences between left handers and right handers in either mortality or age at death.4, 5 Thus Halpern and Coren's conclusion, repeated by Turner - that left handers have a lower life expectancy than right handers - is not well supported by the facts. Unfortunately, repeating this conclusion without discussing the contrary evidence may not only give rise to unnecessary distress among left handers and their relatives but encourage insurance companies and employers to discriminate unfairly against a sizeable proportion of the population.

левак.....

Ако тоа те теше.