生存因子（Living Factors）

共用题干
第一篇

Ulcers

Even though ulcers appear to run in families,lifestyle plays more of a role than genetic
（基因的）factors in causing the illness, according to a report in the April 13th issue of
Journal of Internal Medicine. In particular,smoking and stress in men and the regular use
of pain-releasing medicines in women were linked with an increased risk of developing an
ulcer（溃疡）.
Overall,61% of ulcer risk appears to be due to environmental factors,such as
smoking,and the remaining 39% is due to genes,according to Dr. lsmo Raiha of the
University of Turkey and colleagues at the University of Helsinki,Finland.Some
researchers had suggested that families may spread Helicobacteria pyloni（幽门螺旋菌）,
the bacteria（细菌）that can cause ulcers. However, the new study suggests this is
unlikely,according to the report.
Raiha and colleagues studied data from more than 13,000 pairs of twins to examine
the roles of genetic and environmental factors in the origin of ulcer. Both twins were more
likely to develop an ulcer if the pain were genetically the same as compared with a pair of
fraternal（由两受精卵发育而成的）twins , suggesting that there must be some genetic
susceptibility（敏感性）to ulcer development.
However,the risk was no greater in twins living together compared with twins living
apart,suggesting that shared exposure to H.pyloni was not to blame." Environmental
effects were not due to factons shared by family members,and they were related to smoking
and stress in men and the use of pain-releasing medicines in women,"the authors write in
their report.

61% of ulcer risk seems to be caused by
A:unknown factors.
B:economic factors.
C:environmental factors.
D:genetic factors.